Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 1 | /* pngfix.c |
| 2 | * |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 3 | * Copyright (c) 2014-2015 John Cunningham Bowler |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 4 | * |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 5 | * Last changed in libpng 1.6.20 [December 3, 2015] |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 6 | * |
| 7 | * This code is released under the libpng license. |
| 8 | * For conditions of distribution and use, see the disclaimer |
| 9 | * and license in png.h |
| 10 | * |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 11 | * Tool to check and fix the zlib inflate 'too far back' problem. |
| 12 | * See the usage message for more information. |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 13 | */ |
| 14 | #include <stdlib.h> |
| 15 | #include <stdio.h> |
| 16 | #include <string.h> |
| 17 | #include <ctype.h> |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 18 | #include <limits.h> |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 19 | #include <errno.h> |
| 20 | #include <assert.h> |
| 21 | |
| 22 | #define implies(x,y) assert(!(x) || (y)) |
| 23 | |
| 24 | #ifdef __GNUC__ |
| 25 | /* This is used to fix the error: |
| 26 | * |
| 27 | * pngfix.c: |
| 28 | * In function 'zlib_advance': |
| 29 | * pngfix.c:181:13: error: assuming signed overflow does not |
| 30 | * occur when simplifying conditional to constant [-Werror=strict-overflow] |
| 31 | */ |
| 32 | # define FIX_GCC volatile |
| 33 | #else |
| 34 | # define FIX_GCC |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 35 | #endif |
| 36 | |
| 37 | #define PROGRAM_NAME "pngfix" |
| 38 | |
| 39 | /* Define the following to use this program against your installed libpng, |
| 40 | * rather than the one being built here: |
| 41 | */ |
| 42 | #ifdef PNG_FREESTANDING_TESTS |
| 43 | # include <png.h> |
| 44 | #else |
| 45 | # include "../../png.h" |
| 46 | #endif |
| 47 | |
| 48 | #if PNG_LIBPNG_VER < 10603 /* 1.6.3 */ |
| 49 | # error "pngfix will not work with libpng prior to 1.6.3" |
| 50 | #endif |
| 51 | |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 52 | #ifdef PNG_SETJMP_SUPPORTED |
| 53 | #include <setjmp.h> |
| 54 | |
| 55 | #if defined(PNG_READ_SUPPORTED) && defined(PNG_EASY_ACCESS_SUPPORTED) &&\ |
| 56 | (defined(PNG_READ_DEINTERLACE_SUPPORTED) ||\ |
| 57 | defined(PNG_READ_INTERLACING_SUPPORTED)) |
| 58 | |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 59 | /* zlib.h defines the structure z_stream, an instance of which is included |
| 60 | * in this structure and is required for decompressing the LZ compressed |
| 61 | * data in PNG files. |
| 62 | */ |
| 63 | #ifndef ZLIB_CONST |
| 64 | /* We must ensure that zlib uses 'const' in declarations. */ |
| 65 | # define ZLIB_CONST |
| 66 | #endif |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 67 | #include <zlib.h> |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 68 | #ifdef const |
| 69 | /* zlib.h sometimes #defines const to nothing, undo this. */ |
| 70 | # undef const |
| 71 | #endif |
| 72 | |
| 73 | /* zlib.h has mediocre z_const use before 1.2.6, this stuff is for compatibility |
| 74 | * with older builds. |
| 75 | */ |
| 76 | #if ZLIB_VERNUM < 0x1260 |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 77 | # define PNGZ_MSG_CAST(s) constcast(char*,s) |
| 78 | # define PNGZ_INPUT_CAST(b) constcast(png_bytep,b) |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 79 | #else |
| 80 | # define PNGZ_MSG_CAST(s) (s) |
| 81 | # define PNGZ_INPUT_CAST(b) (b) |
| 82 | #endif |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 83 | |
| 84 | #ifndef PNG_MAXIMUM_INFLATE_WINDOW |
| 85 | # error "pngfix not supported in this libpng version" |
| 86 | #endif |
| 87 | |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 88 | #if ZLIB_VERNUM >= 0x1240 |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 89 | |
| 90 | /* Copied from pngpriv.h */ |
| 91 | #ifdef __cplusplus |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 92 | # define voidcast(type, value) static_cast<type>(value) |
| 93 | # define constcast(type, value) const_cast<type>(value) |
| 94 | # define aligncast(type, value) \ |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 95 | static_cast<type>(static_cast<void*>(value)) |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 96 | # define aligncastconst(type, value) \ |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 97 | static_cast<type>(static_cast<const void*>(value)) |
| 98 | #else |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 99 | # define voidcast(type, value) (value) |
| 100 | # define constcast(type, value) ((type)(value)) |
| 101 | # define aligncast(type, value) ((void*)(value)) |
| 102 | # define aligncastconst(type, value) ((const void*)(value)) |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 103 | #endif /* __cplusplus */ |
| 104 | |
| 105 | #if PNG_LIBPNG_VER < 10700 |
| 106 | /* Chunk tags (copied from pngpriv.h) */ |
| 107 | #define PNG_32b(b,s) ((png_uint_32)(b) << (s)) |
| 108 | #define PNG_U32(b1,b2,b3,b4) \ |
| 109 | (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0)) |
| 110 | |
| 111 | /* Constants for known chunk types. */ |
| 112 | #define png_IDAT PNG_U32( 73, 68, 65, 84) |
| 113 | #define png_IEND PNG_U32( 73, 69, 78, 68) |
| 114 | #define png_IHDR PNG_U32( 73, 72, 68, 82) |
| 115 | #define png_PLTE PNG_U32( 80, 76, 84, 69) |
| 116 | #define png_bKGD PNG_U32( 98, 75, 71, 68) |
| 117 | #define png_cHRM PNG_U32( 99, 72, 82, 77) |
| 118 | #define png_fRAc PNG_U32(102, 82, 65, 99) /* registered, not defined */ |
| 119 | #define png_gAMA PNG_U32(103, 65, 77, 65) |
| 120 | #define png_gIFg PNG_U32(103, 73, 70, 103) |
| 121 | #define png_gIFt PNG_U32(103, 73, 70, 116) /* deprecated */ |
| 122 | #define png_gIFx PNG_U32(103, 73, 70, 120) |
| 123 | #define png_hIST PNG_U32(104, 73, 83, 84) |
| 124 | #define png_iCCP PNG_U32(105, 67, 67, 80) |
| 125 | #define png_iTXt PNG_U32(105, 84, 88, 116) |
| 126 | #define png_oFFs PNG_U32(111, 70, 70, 115) |
| 127 | #define png_pCAL PNG_U32(112, 67, 65, 76) |
| 128 | #define png_pHYs PNG_U32(112, 72, 89, 115) |
| 129 | #define png_sBIT PNG_U32(115, 66, 73, 84) |
| 130 | #define png_sCAL PNG_U32(115, 67, 65, 76) |
| 131 | #define png_sPLT PNG_U32(115, 80, 76, 84) |
| 132 | #define png_sRGB PNG_U32(115, 82, 71, 66) |
| 133 | #define png_sTER PNG_U32(115, 84, 69, 82) |
| 134 | #define png_tEXt PNG_U32(116, 69, 88, 116) |
| 135 | #define png_tIME PNG_U32(116, 73, 77, 69) |
| 136 | #define png_tRNS PNG_U32(116, 82, 78, 83) |
| 137 | #define png_zTXt PNG_U32(122, 84, 88, 116) |
| 138 | #endif |
| 139 | |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 140 | /* The 8-byte signature as a pair of 32-bit quantities */ |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 141 | #define sig1 PNG_U32(137, 80, 78, 71) |
| 142 | #define sig2 PNG_U32( 13, 10, 26, 10) |
| 143 | |
| 144 | /* Is the chunk critical? */ |
| 145 | #define CRITICAL(chunk) (((chunk) & PNG_U32(32,0,0,0)) == 0) |
| 146 | |
| 147 | /* Is it safe to copy? */ |
| 148 | #define SAFE_TO_COPY(chunk) (((chunk) & PNG_U32(0,0,0,32)) != 0) |
| 149 | |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 150 | /* Fix ups for builds with limited read support */ |
| 151 | #ifndef PNG_ERROR_TEXT_SUPPORTED |
| 152 | # define png_error(a,b) png_err(a) |
| 153 | #endif |
| 154 | |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 155 | /********************************* UTILITIES **********************************/ |
| 156 | /* UNREACHED is a value to cause an assert to fail. Because of the way the |
| 157 | * assert macro is written the string "UNREACHED" is produced in the error |
| 158 | * message. |
| 159 | */ |
| 160 | #define UNREACHED 0 |
| 161 | |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 162 | /* 80-bit number handling - a PNG image can be up to (2^31-1)x(2^31-1) 8-byte |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 163 | * (16-bit RGBA) pixels in size; that's less than 2^65 bytes or 2^68 bits, so |
| 164 | * arithmetic of 80-bit numbers is sufficient. This representation uses an |
| 165 | * arbitrary length array of png_uint_16 digits (0..65535). The representation |
| 166 | * is little endian. |
| 167 | * |
| 168 | * The arithmetic functions take zero to two uarb values together with the |
| 169 | * number of digits in those values and write the result to the given uarb |
| 170 | * (always the first argument) returning the number of digits in the result. |
| 171 | * If the result is negative the return value is also negative (this would |
| 172 | * normally be an error). |
| 173 | */ |
| 174 | typedef png_uint_16 udigit; /* A 'unum' is an array of these */ |
| 175 | typedef png_uint_16p uarb; |
| 176 | typedef png_const_uint_16p uarbc; |
| 177 | |
| 178 | #define UDIGITS(unum) ((sizeof unum)/(sizeof (udigit)) |
| 179 | /* IMPORTANT: only apply this to an array, applied to a pointer the result |
| 180 | * will typically be '2', which is not useful. |
| 181 | */ |
| 182 | |
| 183 | static int |
| 184 | uarb_set(uarb result, png_alloc_size_t val) |
| 185 | /* Set (initialize) 'result' to 'val'. The size required for 'result' must |
| 186 | * be determined by the caller from a knowledge of the maximum for 'val'. |
| 187 | */ |
| 188 | { |
| 189 | int ndigits = 0; |
| 190 | |
| 191 | while (val > 0) |
| 192 | { |
| 193 | result[ndigits++] = (png_uint_16)(val & 0xffff); |
| 194 | val >>= 16; |
| 195 | } |
| 196 | |
| 197 | return ndigits; |
| 198 | } |
| 199 | |
| 200 | static int |
| 201 | uarb_copy(uarb to, uarb from, int idigits) |
| 202 | /* Copy a uarb, may reduce the digit count */ |
| 203 | { |
| 204 | int d, odigits; |
| 205 | |
| 206 | for (d=odigits=0; d<idigits; ++d) |
| 207 | if ((to[d] = from[d]) != 0) |
| 208 | odigits = d+1; |
| 209 | |
| 210 | return odigits; |
| 211 | } |
| 212 | |
| 213 | static int |
| 214 | uarb_inc(uarb num, int in_digits, png_int_32 add) |
| 215 | /* This is a signed 32-bit add, except that to avoid overflow the value added |
| 216 | * or subtracted must be no more than 2^31-65536. A negative result |
| 217 | * indicates a negative number (which is an error below). The size of |
| 218 | * 'num' should be max(in_digits+1,2) for arbitrary 'add' but can be just |
| 219 | * in_digits+1 if add is known to be in the range -65535..65535. |
| 220 | */ |
| 221 | { |
| 222 | FIX_GCC int out_digits = 0; |
| 223 | |
| 224 | while (out_digits < in_digits) |
| 225 | { |
| 226 | add += num[out_digits]; |
| 227 | num[out_digits++] = (png_uint_16)(add & 0xffff); |
| 228 | add >>= 16; |
| 229 | } |
| 230 | |
| 231 | while (add != 0 && add != (-1)) |
| 232 | { |
| 233 | num[out_digits++] = (png_uint_16)(add & 0xffff); |
| 234 | add >>= 16; |
| 235 | } |
| 236 | |
| 237 | if (add == 0) |
| 238 | { |
| 239 | while (out_digits > 0 && num[out_digits-1] == 0) |
| 240 | --out_digits; |
| 241 | return out_digits; /* may be 0 */ |
| 242 | } |
| 243 | |
| 244 | else /* negative result */ |
| 245 | { |
| 246 | while (out_digits > 1 && num[out_digits-1] == 0xffff) |
| 247 | --out_digits; |
| 248 | |
| 249 | return -out_digits; |
| 250 | } |
| 251 | } |
| 252 | |
| 253 | static int |
| 254 | uarb_add32(uarb num, int in_digits, png_uint_32 add) |
| 255 | /* As above but this works with any 32-bit value and only does 'add' */ |
| 256 | { |
| 257 | if (in_digits > 0) |
| 258 | { |
| 259 | in_digits = uarb_inc(num, in_digits, add & 0xffff); |
| 260 | return uarb_inc(num+1, in_digits-1, add >> 16)+1; |
| 261 | } |
| 262 | |
| 263 | return uarb_set(num, add); |
| 264 | } |
| 265 | |
| 266 | static int |
| 267 | uarb_mult_digit(uarb acc, int a_digits, uarb num, FIX_GCC int n_digits, |
| 268 | png_uint_16 val) |
| 269 | /* Primitive one-digit multiply - 'val' must be 0..65535. Note that this |
| 270 | * primitive is a multiply and accumulate - the result of *num * val is added |
| 271 | * to *acc. |
| 272 | * |
| 273 | * This is a one-digit multiply, so the product may be up to one digit longer |
| 274 | * than 'num', however the add to 'acc' means that the caller must ensure |
| 275 | * that 'acc' is at least one digit longer than this *and* at least one digit |
| 276 | * longer than the current length of 'acc'. (Or the caller must otherwise |
| 277 | * ensure 'adigits' is adequate from knowledge of the values.) |
| 278 | */ |
| 279 | { |
| 280 | /* The digits in *acc, *num and val are in the range 0..65535, so the |
| 281 | * result below is at most (65535*65535)+2*65635 = 65535*(65535+2), which is |
| 282 | * exactly 0xffffffff. |
| 283 | */ |
| 284 | if (val > 0 && n_digits > 0) /* Else the product is 0 */ |
| 285 | { |
| 286 | png_uint_32 carry = 0; |
| 287 | int out_digits = 0; |
| 288 | |
| 289 | while (out_digits < n_digits || carry > 0) |
| 290 | { |
| 291 | if (out_digits < a_digits) |
| 292 | carry += acc[out_digits]; |
| 293 | |
| 294 | if (out_digits < n_digits) |
| 295 | carry += (png_uint_32)num[out_digits] * val; |
| 296 | |
| 297 | acc[out_digits++] = (png_uint_16)(carry & 0xffff); |
| 298 | carry >>= 16; |
| 299 | } |
| 300 | |
| 301 | /* So carry is 0 and all the input digits have been consumed. This means |
| 302 | * that it is possible to skip any remaining digits in acc. |
| 303 | */ |
| 304 | if (out_digits > a_digits) |
| 305 | return out_digits; |
| 306 | } |
| 307 | |
| 308 | return a_digits; |
| 309 | } |
| 310 | |
| 311 | static int |
| 312 | uarb_mult32(uarb acc, int a_digits, uarb num, int n_digits, png_uint_32 val) |
| 313 | /* calculate acc += num * val, 'val' may be any 32-bit value, 'acc' and 'num' |
| 314 | * may be any value, returns the number of digits in 'acc'. |
| 315 | */ |
| 316 | { |
| 317 | if (n_digits > 0 && val > 0) |
| 318 | { |
| 319 | a_digits = uarb_mult_digit(acc, a_digits, num, n_digits, |
| 320 | (png_uint_16)(val & 0xffff)); |
| 321 | |
| 322 | /* Because n_digits and val are >0 the following must be true: */ |
| 323 | assert(a_digits > 0); |
| 324 | |
| 325 | val >>= 16; |
| 326 | if (val > 0) |
| 327 | a_digits = uarb_mult_digit(acc+1, a_digits-1, num, n_digits, |
| 328 | (png_uint_16)val) + 1; |
| 329 | } |
| 330 | |
| 331 | return a_digits; |
| 332 | } |
| 333 | |
| 334 | static int |
| 335 | uarb_shift(uarb inout, int ndigits, unsigned int right_shift) |
| 336 | /* Shift inout right by right_shift bits, right_shift must be in the range |
| 337 | * 1..15 |
| 338 | */ |
| 339 | { |
| 340 | FIX_GCC int i = ndigits; |
| 341 | png_uint_16 carry = 0; |
| 342 | |
| 343 | assert(right_shift >= 1 && right_shift <= 15); |
| 344 | |
| 345 | while (--i >= 0) |
| 346 | { |
| 347 | png_uint_16 temp = (png_uint_16)(carry | (inout[i] >> right_shift)); |
| 348 | |
| 349 | /* Bottom bits to top bits of carry */ |
| 350 | carry = (png_uint_16)((inout[i] << (16-right_shift)) & 0xffff); |
| 351 | |
| 352 | inout[i] = temp; |
| 353 | |
| 354 | /* The shift may reduce ndigits */ |
| 355 | if (i == ndigits-1 && temp == 0) |
| 356 | ndigits = i; |
| 357 | } |
| 358 | |
| 359 | return ndigits; |
| 360 | } |
| 361 | |
| 362 | static int |
| 363 | uarb_cmp(uarb a, int adigits, uarb b, int bdigits) |
| 364 | /* Return -1/0/+1 according as a<b/a==b/a>b */ |
| 365 | { |
| 366 | if (adigits < bdigits) |
| 367 | return -1; |
| 368 | |
| 369 | if (adigits > bdigits) |
| 370 | return 1; |
| 371 | |
| 372 | while (adigits-- > 0) |
| 373 | if (a[adigits] < b[adigits]) |
| 374 | return -1; |
| 375 | |
| 376 | else if (a[adigits] > b[adigits]) |
| 377 | return 1; |
| 378 | |
| 379 | return 0; |
| 380 | } |
| 381 | |
| 382 | #if 0 /*UNUSED*/ |
| 383 | static int |
| 384 | uarb_eq32(uarb num, int digits, png_uint_32 val) |
| 385 | /* Return true if the uarb is equal to 'val' */ |
| 386 | { |
| 387 | switch (digits) |
| 388 | { |
| 389 | case 0: return val == 0; |
| 390 | case 1: return val == num[0]; |
| 391 | case 2: return (val & 0xffff) == num[0] && (val >> 16) == num[1]; |
| 392 | default: return 0; |
| 393 | } |
| 394 | } |
| 395 | #endif |
| 396 | |
| 397 | static void |
| 398 | uarb_printx(uarb num, int digits, FILE *out) |
| 399 | /* Print 'num' as a hexadecimal number (easier than decimal!) */ |
| 400 | { |
| 401 | while (digits > 0) |
| 402 | if (num[--digits] > 0) |
| 403 | { |
| 404 | fprintf(out, "0x%x", num[digits]); |
| 405 | |
| 406 | while (digits > 0) |
| 407 | fprintf(out, "%.4x", num[--digits]); |
| 408 | } |
| 409 | |
| 410 | else if (digits == 0) /* the number is 0 */ |
| 411 | fputs("0x0", out); |
| 412 | } |
| 413 | |
| 414 | static void |
| 415 | uarb_print(uarb num, int digits, FILE *out) |
| 416 | /* Prints 'num' as a decimal if it will fit in an unsigned long, else as a |
| 417 | * hexadecimal number. Notice that the results vary for images over 4GByte |
| 418 | * in a system dependent way, and the hexadecimal form doesn't work very well |
| 419 | * in awk script input. |
| 420 | * |
| 421 | * |
| 422 | * TODO: write uarb_div10 |
| 423 | */ |
| 424 | { |
| 425 | if (digits * sizeof (udigit) > sizeof (unsigned long)) |
| 426 | uarb_printx(num, digits, out); |
| 427 | |
| 428 | else |
| 429 | { |
| 430 | unsigned long n = 0; |
| 431 | |
| 432 | while (digits > 0) |
| 433 | n = (n << 16) + num[--digits]; |
| 434 | |
| 435 | fprintf(out, "%lu", n); |
| 436 | } |
| 437 | } |
| 438 | |
| 439 | /* Generate random bytes. This uses a boring repeatable algorithm and it |
| 440 | * is implemented here so that it gives the same set of numbers on every |
| 441 | * architecture. It's a linear congruential generator (Knuth or Sedgewick |
| 442 | * "Algorithms") but it comes from the 'feedback taps' table in Horowitz and |
| 443 | * Hill, "The Art of Electronics" (Pseudo-Random Bit Sequences and Noise |
| 444 | * Generation.) |
| 445 | * |
| 446 | * (Copied from contrib/libtests/pngvalid.c) |
| 447 | */ |
| 448 | static void |
| 449 | make_random_bytes(png_uint_32* seed, void* pv, size_t size) |
| 450 | { |
| 451 | png_uint_32 u0 = seed[0], u1 = seed[1]; |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 452 | png_bytep bytes = voidcast(png_bytep, pv); |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 453 | |
| 454 | /* There are thirty-three bits; the next bit in the sequence is bit-33 XOR |
| 455 | * bit-20. The top 1 bit is in u1, the bottom 32 are in u0. |
| 456 | */ |
| 457 | size_t i; |
| 458 | for (i=0; i<size; ++i) |
| 459 | { |
| 460 | /* First generate 8 new bits then shift them in at the end. */ |
| 461 | png_uint_32 u = ((u0 >> (20-8)) ^ ((u1 << 7) | (u0 >> (32-7)))) & 0xff; |
| 462 | u1 <<= 8; |
| 463 | u1 |= u0 >> 24; |
| 464 | u0 <<= 8; |
| 465 | u0 |= u; |
| 466 | *bytes++ = (png_byte)u; |
| 467 | } |
| 468 | |
| 469 | seed[0] = u0; |
| 470 | seed[1] = u1; |
| 471 | } |
| 472 | |
| 473 | /* Clear an object to a random value. */ |
| 474 | static void |
| 475 | clear(void *pv, size_t size) |
| 476 | { |
| 477 | static png_uint_32 clear_seed[2] = { 0x12345678, 0x9abcdef0 }; |
| 478 | make_random_bytes(clear_seed, pv, size); |
| 479 | } |
| 480 | |
| 481 | #define CLEAR(object) clear(&(object), sizeof (object)) |
| 482 | |
| 483 | /* Copied from unreleased 1.7 code. |
| 484 | * |
| 485 | * CRC checking uses a local pre-built implementation of the Ethernet CRC32. |
| 486 | * This is to avoid a function call to the zlib DLL and to optimize the |
| 487 | * byte-by-byte case. |
| 488 | */ |
| 489 | static png_uint_32 crc_table[256] = |
| 490 | { |
| 491 | 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, |
| 492 | 0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, |
| 493 | 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, |
| 494 | 0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, |
| 495 | 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856, |
| 496 | 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, |
| 497 | 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, |
| 498 | 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, |
| 499 | 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, |
| 500 | 0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a, |
| 501 | 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, |
| 502 | 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, |
| 503 | 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, |
| 504 | 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, |
| 505 | 0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e, |
| 506 | 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01, |
| 507 | 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, |
| 508 | 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950, |
| 509 | 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, |
| 510 | 0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, |
| 511 | 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, |
| 512 | 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, |
| 513 | 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010, |
| 514 | 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f, |
| 515 | 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, |
| 516 | 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, |
| 517 | 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, |
| 518 | 0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, |
| 519 | 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344, |
| 520 | 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, |
| 521 | 0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, |
| 522 | 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, |
| 523 | 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, |
| 524 | 0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c, |
| 525 | 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, |
| 526 | 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, |
| 527 | 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, |
| 528 | 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, |
| 529 | 0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c, |
| 530 | 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713, |
| 531 | 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, |
| 532 | 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242, |
| 533 | 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, |
| 534 | 0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, |
| 535 | 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278, |
| 536 | 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, |
| 537 | 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66, |
| 538 | 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9, |
| 539 | 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, |
| 540 | 0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, |
| 541 | 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, |
| 542 | 0x2d02ef8d |
| 543 | }; |
| 544 | |
| 545 | /* The CRC calculated here *IS* conditioned, the corresponding value used by |
| 546 | * zlib and the result value is obtained by XORing with CRC_INIT, which is also |
| 547 | * the first value that must be passed in (for the first byte) to crc_one_byte. |
| 548 | */ |
| 549 | #define CRC_INIT 0xffffffff |
| 550 | |
| 551 | static png_uint_32 |
| 552 | crc_one_byte(png_uint_32 crc, int b) |
| 553 | { |
| 554 | return crc_table[(crc ^ b) & 0xff] ^ (crc >> 8); |
| 555 | } |
| 556 | |
| 557 | static png_uint_32 |
| 558 | crc_init_4(png_uint_32 value) |
| 559 | { |
| 560 | /* This is an alternative to the algorithm used in zlib, which requires four |
| 561 | * separate tables to parallelize the four byte operations, it only works for |
| 562 | * a CRC of the first four bytes of the stream, but this is what happens in |
| 563 | * the parser below where length+chunk-name is read and chunk-name used to |
| 564 | * initialize the CRC. Notice that the calculation here avoids repeated |
| 565 | * conditioning (xor with 0xffffffff) by storing the conditioned value. |
| 566 | */ |
| 567 | png_uint_32 crc = crc_table[(~value >> 24)] ^ 0xffffff; |
| 568 | |
| 569 | crc = crc_table[(crc ^ (value >> 16)) & 0xff] ^ (crc >> 8); |
| 570 | crc = crc_table[(crc ^ (value >> 8)) & 0xff] ^ (crc >> 8); |
| 571 | return crc_table[(crc ^ value) & 0xff] ^ (crc >> 8); |
| 572 | } |
| 573 | |
| 574 | static int |
| 575 | chunk_type_valid(png_uint_32 c) |
| 576 | /* Bit whacking approach to chunk name validation that is intended to avoid |
| 577 | * branches. The cost is that it uses a lot of 32-bit constants, which might |
| 578 | * be bad on some architectures. |
| 579 | */ |
| 580 | { |
| 581 | png_uint_32 t; |
| 582 | |
| 583 | /* Remove bit 5 from all but the reserved byte; this means every |
| 584 | * 8-bit unit must be in the range 65-90 to be valid. So bit 5 |
| 585 | * must be zero, bit 6 must be set and bit 7 zero. |
| 586 | */ |
| 587 | c &= ~PNG_U32(32,32,0,32); |
| 588 | t = (c & ~0x1f1f1f1f) ^ 0x40404040; |
| 589 | |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 590 | /* Subtract 65 for each 8-bit quantity, this must not overflow |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 591 | * and each byte must then be in the range 0-25. |
| 592 | */ |
| 593 | c -= PNG_U32(65,65,65,65); |
| 594 | t |=c ; |
| 595 | |
| 596 | /* Subtract 26, handling the overflow which should set the top |
| 597 | * three bits of each byte. |
| 598 | */ |
| 599 | c -= PNG_U32(25,25,25,26); |
| 600 | t |= ~c; |
| 601 | |
| 602 | return (t & 0xe0e0e0e0) == 0; |
| 603 | } |
| 604 | |
| 605 | /**************************** CONTROL INFORMATION *****************************/ |
| 606 | |
| 607 | /* Information about a sequence of IDAT chunks, the chunks have been re-synced |
| 608 | * using sync_stream below and the new lengths are recorded here. Because the |
| 609 | * number of chunks is unlimited this is handled using a linked list of these |
| 610 | * structures. |
| 611 | */ |
| 612 | struct IDAT_list |
| 613 | { |
| 614 | struct IDAT_list *next; /* Linked list */ |
| 615 | unsigned int length; /* Actual length of the array below */ |
| 616 | unsigned int count; /* Number of entries that are valid */ |
| 617 | # define IDAT_INIT_LENGTH 16 |
| 618 | png_uint_32 lengths[IDAT_INIT_LENGTH]; |
| 619 | }; |
| 620 | |
| 621 | static void |
| 622 | IDAT_list_init(struct IDAT_list *list) |
| 623 | { |
| 624 | CLEAR(*list); |
| 625 | |
| 626 | list->next = NULL; |
| 627 | list->length = IDAT_INIT_LENGTH; |
| 628 | } |
| 629 | |
| 630 | static size_t |
| 631 | IDAT_list_size(struct IDAT_list *list, unsigned int length) |
| 632 | /* Return the size in bytes of an IDAT_list of the given length. */ |
| 633 | { |
| 634 | if (list != NULL) |
| 635 | length = list->length; |
| 636 | |
| 637 | return sizeof *list - sizeof list->lengths + |
| 638 | length * sizeof list->lengths[0]; |
| 639 | } |
| 640 | |
| 641 | static void |
| 642 | IDAT_list_end(struct IDAT_list *IDAT_list) |
| 643 | { |
| 644 | struct IDAT_list *list = IDAT_list->next; |
| 645 | |
| 646 | CLEAR(*IDAT_list); |
| 647 | |
| 648 | while (list != NULL) |
| 649 | { |
| 650 | struct IDAT_list *next = list->next; |
| 651 | |
| 652 | clear(list, IDAT_list_size(list, 0)); |
| 653 | free(list); |
| 654 | list = next; |
| 655 | } |
| 656 | } |
| 657 | |
| 658 | static struct IDAT_list * |
| 659 | IDAT_list_extend(struct IDAT_list *tail) |
| 660 | { |
| 661 | /* Use the previous cached value if available. */ |
| 662 | struct IDAT_list *next = tail->next; |
| 663 | |
| 664 | if (next == NULL) |
| 665 | { |
| 666 | /* Insert a new, malloc'ed, block of IDAT information buffers, this |
| 667 | * one twice as large as the previous one: |
| 668 | */ |
| 669 | unsigned int length = 2 * tail->length; |
| 670 | |
| 671 | if (length < tail->length) /* arithmetic overflow */ |
| 672 | length = tail->length; |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 673 | |
| 674 | next = voidcast(IDAT_list*, malloc(IDAT_list_size(NULL, length))); |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 675 | CLEAR(*next); |
| 676 | |
| 677 | /* The caller must handle this: */ |
| 678 | if (next == NULL) |
| 679 | return NULL; |
| 680 | |
| 681 | next->next = NULL; |
| 682 | next->length = length; |
| 683 | tail->next = next; |
| 684 | } |
| 685 | |
| 686 | return next; |
| 687 | } |
| 688 | |
| 689 | /* GLOBAL CONTROL STRUCTURE */ |
| 690 | struct global |
| 691 | { |
| 692 | /* PUBLIC GLOBAL VARIABLES: OWNER INITIALIZE */ |
| 693 | unsigned int errors :1; /* print file errors to stderr */ |
| 694 | unsigned int warnings :1; /* print libpng warnings to stderr */ |
| 695 | unsigned int optimize_zlib :1; /* Run optimization search */ |
| 696 | unsigned int quiet :2; /* don't output summaries */ |
| 697 | unsigned int verbose :3; /* various internal tracking */ |
| 698 | unsigned int skip :3; /* Non-critical chunks to skip */ |
| 699 | # define SKIP_NONE 0 |
| 700 | # define SKIP_BAD_CRC 1 /* Chunks with a bad CRC */ |
| 701 | # define SKIP_UNSAFE 2 /* Chunks not safe to copy */ |
| 702 | # define SKIP_UNUSED 3 /* Chunks not used by libpng */ |
| 703 | # define SKIP_TRANSFORM 4 /* Chunks only used in transforms */ |
| 704 | # define SKIP_COLOR 5 /* Everything but tRNS, sBIT, gAMA and sRGB */ |
| 705 | # define SKIP_ALL 6 /* Everything but tRNS and sBIT */ |
| 706 | |
| 707 | png_uint_32 idat_max; /* 0 to perform no re-chunking */ |
| 708 | |
| 709 | int status_code; /* Accumulated status code */ |
| 710 | # define TOO_FAR_BACK 0x01 /* found a too-far-back error */ |
| 711 | # define CRC_ERROR 0x02 /* fixed an invalid CRC */ |
| 712 | # define STREAM_ERROR 0x04 /* damaged PNG stream (may be fixable) */ |
| 713 | # define TRUNCATED 0x08 /* truncated but still readable */ |
| 714 | # define FILE_ERROR 0x10 /* could not read the file */ |
| 715 | # define WRITE_ERROR 0x20 /* write error (this terminates the read) */ |
| 716 | # define INTERNAL_ERROR 0x40 /* internal limits/errors encountered */ |
| 717 | |
| 718 | /* PUBLIC GLOBAL VARIABLES: USED INTERNALLY BY IDAT READ CODE */ |
| 719 | struct IDAT_list idat_cache; /* Cache of file IDAT information buffers */ |
| 720 | /* The structure is shared across all uses of this global control |
| 721 | * structure to avoid reallocation between IDAT streams. |
| 722 | */ |
| 723 | }; |
| 724 | |
| 725 | static int |
| 726 | global_end(struct global *global) |
| 727 | { |
| 728 | |
| 729 | int rc; |
| 730 | |
| 731 | IDAT_list_end(&global->idat_cache); |
| 732 | rc = global->status_code; |
| 733 | CLEAR(*global); |
| 734 | return rc; |
| 735 | } |
| 736 | |
| 737 | static void |
| 738 | global_init(struct global *global) |
| 739 | /* Call this once (and only once) to initialize the control */ |
| 740 | { |
| 741 | CLEAR(*global); |
| 742 | |
| 743 | /* Globals */ |
| 744 | global->errors = 0; |
| 745 | global->warnings = 0; |
| 746 | global->quiet = 0; |
| 747 | global->verbose = 0; |
| 748 | global->idat_max = 0; /* no re-chunking of IDAT */ |
| 749 | global->optimize_zlib = 0; |
| 750 | global->skip = SKIP_NONE; |
| 751 | global->status_code = 0; |
| 752 | |
| 753 | IDAT_list_init(&global->idat_cache); |
| 754 | } |
| 755 | |
| 756 | static int |
| 757 | skip_chunk_type(const struct global *global, png_uint_32 type) |
| 758 | /* Return true if this chunk is to be skipped according to the --strip |
| 759 | * option. This code needs to recognize all known ancillary chunks in order |
| 760 | * to handle the --strip=unsafe option. |
| 761 | */ |
| 762 | { |
| 763 | /* Never strip critical chunks: */ |
| 764 | if (CRITICAL(type)) |
| 765 | return 0; |
| 766 | |
| 767 | switch (type) |
| 768 | { |
| 769 | /* Chunks that are treated as, effectively, critical because they affect |
| 770 | * correct interpretation of the pixel values: |
| 771 | */ |
| 772 | case png_tRNS: case png_sBIT: |
| 773 | return 0; |
| 774 | |
| 775 | /* Chunks that specify gamma encoding which should therefore only be |
| 776 | * removed the the user insists: |
| 777 | */ |
| 778 | case png_gAMA: case png_sRGB: |
| 779 | if (global->skip >= SKIP_ALL) |
| 780 | return 1; |
| 781 | return 0; |
| 782 | |
| 783 | /* Chunks that affect color interpretation - not used by libpng and rarely |
| 784 | * used by applications, but technically still required for correct |
| 785 | * interpretation of the image data: |
| 786 | */ |
| 787 | case png_cHRM: case png_iCCP: |
| 788 | if (global->skip >= SKIP_COLOR) |
| 789 | return 1; |
| 790 | return 0; |
| 791 | |
| 792 | /* Other chunks that are used by libpng in image transformations (as |
| 793 | * opposed to known chunks that have get/set APIs but are not otherwise |
| 794 | * used.) |
| 795 | */ |
| 796 | case png_bKGD: |
| 797 | if (global->skip >= SKIP_TRANSFORM) |
| 798 | return 1; |
| 799 | return 0; |
| 800 | |
| 801 | /* All other chunks that libpng knows about and affect neither image |
| 802 | * interpretation nor libpng transforms - chunks that are effectively |
| 803 | * unused by libpng even though libpng might recognize and store them. |
| 804 | */ |
| 805 | case png_fRAc: case png_gIFg: case png_gIFt: case png_gIFx: case png_hIST: |
| 806 | case png_iTXt: case png_oFFs: case png_pCAL: case png_pHYs: case png_sCAL: |
| 807 | case png_sPLT: case png_sTER: case png_tEXt: case png_tIME: case png_zTXt: |
| 808 | if (global->skip >= SKIP_UNUSED) |
| 809 | return 1; |
| 810 | return 0; |
| 811 | |
| 812 | /* Chunks that libpng does not know about (notice that this depends on the |
| 813 | * list above including all known chunks!) The decision here depends on |
| 814 | * whether the safe-to-copy bit is set in the chunk type. |
| 815 | */ |
| 816 | default: |
| 817 | if (SAFE_TO_COPY(type)) |
| 818 | { |
| 819 | if (global->skip >= SKIP_UNUSED) /* as above */ |
| 820 | return 1; |
| 821 | } |
| 822 | |
| 823 | else if (global->skip >= SKIP_UNSAFE) |
| 824 | return 1; |
| 825 | |
| 826 | return 0; |
| 827 | } |
| 828 | } |
| 829 | |
| 830 | /* PER-FILE CONTROL STRUCTURE */ |
| 831 | struct chunk; |
| 832 | struct IDAT; |
| 833 | struct file |
| 834 | { |
| 835 | /* ANCESTORS */ |
| 836 | struct global *global; |
| 837 | |
| 838 | /* PUBLIC PER-FILE VARIABLES: CALLER INITIALIZE */ |
| 839 | const char * file_name; |
| 840 | const char * out_name; /* Name of output file (if required) */ |
| 841 | |
| 842 | /* PUBLIC PER-FILE VARIABLES: SET BY PNG READ CODE */ |
| 843 | /* File specific result codes */ |
| 844 | int status_code; /* Set to a bit mask of the following: */ |
| 845 | int read_errno; /* Records a read error errno */ |
| 846 | int write_errno; /* Records a write error errno */ |
| 847 | |
| 848 | /* IHDR information */ |
| 849 | png_uint_32 width; |
| 850 | png_uint_32 height; |
| 851 | png_byte bit_depth; |
| 852 | png_byte color_type; |
| 853 | png_byte compression_method; |
| 854 | png_byte filter_method; |
| 855 | png_byte interlace_method; |
| 856 | |
| 857 | udigit image_bytes[5]; |
| 858 | int image_digits; |
| 859 | |
| 860 | /* PROTECTED PER-FILE VARIABLES: USED BY THE READ CODE */ |
| 861 | FILE * file; /* Original PNG file */ |
| 862 | FILE * out; /* If a new one is being written */ |
| 863 | jmp_buf jmpbuf; /* Set while reading a PNG */ |
| 864 | |
| 865 | /* PROTECTED CHUNK SPECIFIC VARIABLES: USED BY CHUNK CODE */ |
| 866 | /* The following variables are used during reading to record the length, type |
| 867 | * and data position of the *next* chunk or, right at the start, the |
| 868 | * signature (in length,type). |
| 869 | * |
| 870 | * When a chunk control structure is instantiated these values are copied |
| 871 | * into the structure and can then be overritten with the data for the next |
| 872 | * chunk. |
| 873 | */ |
| 874 | fpos_t data_pos; /* Position of first byte of chunk data */ |
| 875 | png_uint_32 length; /* First word (length or signature start) */ |
| 876 | png_uint_32 type; /* Second word (type or signature end) */ |
| 877 | png_uint_32 crc; /* Running chunk CRC (used by read_chunk) */ |
| 878 | |
| 879 | /* These counts are maintained by the read and write routines below and are |
| 880 | * reset by the chunk handling code. They record the total number of bytes |
| 881 | * read or written for the chunk, including the header (length,type) bytes. |
| 882 | */ |
| 883 | png_uint_32 read_count; /* Count of bytes read (in the chunk) */ |
| 884 | png_uint_32 write_count; /* Count of bytes written (in the chunk) */ |
| 885 | int state; /* As defined here: */ |
| 886 | # define STATE_SIGNATURE 0 /* The signature is being written */ |
| 887 | # define STATE_CHUNKS 1 /* Non-IDAT chunks are being written */ |
| 888 | # define STATE_IDAT 2 /* An IDAT stream is being written */ |
| 889 | |
| 890 | /* Two pointers used to enable clean-up in the event of fatal errors and to |
| 891 | * hold state about the parser process (only one of each at present.) |
| 892 | */ |
| 893 | struct chunk * chunk; |
| 894 | struct IDAT * idat; |
| 895 | |
| 896 | /* Interface to allocate a new chunk or IDAT control structure. The result |
| 897 | * is returned by setting one or other of the above variables. Note that the |
| 898 | * relevant initializer is called by the allocator function. The alloc_ptr |
| 899 | * is used only by the implementation of the allocate function. |
| 900 | */ |
| 901 | void * alloc_ptr; |
| 902 | void (*alloc)(struct file*,int idat); |
| 903 | /* idat: allocate IDAT not chunk */ |
| 904 | }; |
| 905 | |
| 906 | /* Valid longjmp (stop) codes are: */ |
| 907 | #define LIBPNG_WARNING_CODE 1 /* generic png_error */ |
| 908 | #define LIBPNG_ERROR_CODE 2 /* generic png_error */ |
| 909 | #define ZLIB_ERROR_CODE 3 /* generic zlib error */ |
| 910 | #define INVALID_ERROR_CODE 4 /* detected an invalid PNG */ |
| 911 | #define READ_ERROR_CODE 5 /* read failed */ |
| 912 | #define WRITE_ERROR_CODE 6 /* error in write */ |
| 913 | #define UNEXPECTED_ERROR_CODE 7 /* unexpected (internal?) error */ |
| 914 | |
| 915 | static void |
| 916 | emit_string(const char *str, FILE *out) |
| 917 | /* Print a string with spaces replaced by '_' and non-printing characters by |
| 918 | * an octal escape. |
| 919 | */ |
| 920 | { |
| 921 | for (; *str; ++str) |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 922 | if (isgraph(UCHAR_MAX & *str)) |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 923 | putc(*str, out); |
| 924 | |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 925 | else if (isspace(UCHAR_MAX & *str)) |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 926 | putc('_', out); |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 927 | |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 928 | else |
| 929 | fprintf(out, "\\%.3o", *str); |
| 930 | } |
| 931 | |
| 932 | static const char * |
| 933 | strcode(int code) |
| 934 | { |
| 935 | switch (code) |
| 936 | { |
| 937 | case LIBPNG_WARNING_CODE: return "warning"; |
| 938 | case LIBPNG_ERROR_CODE: return "libpng"; |
| 939 | case ZLIB_ERROR_CODE: return "zlib"; |
| 940 | case INVALID_ERROR_CODE: return "invalid"; |
| 941 | case READ_ERROR_CODE: return "read"; |
| 942 | case WRITE_ERROR_CODE: return "write"; |
| 943 | case UNEXPECTED_ERROR_CODE: return "unexpected"; |
| 944 | default: return "INVALID"; |
| 945 | } |
| 946 | } |
| 947 | |
| 948 | static void |
| 949 | emit_error(struct file *file, int code, const char *what) |
| 950 | /* Generic error message routine, takes a 'stop' code but can be used |
| 951 | * elsewhere. Always outputs a message. |
| 952 | */ |
| 953 | { |
| 954 | const char *reason; |
| 955 | int err = 0; |
| 956 | |
| 957 | switch (code) |
| 958 | { |
| 959 | case LIBPNG_WARNING_CODE: reason = "libpng warning:"; break; |
| 960 | case LIBPNG_ERROR_CODE: reason = "libpng error:"; break; |
| 961 | case ZLIB_ERROR_CODE: reason = "zlib error:"; break; |
| 962 | case INVALID_ERROR_CODE: reason = "invalid"; break; |
| 963 | case READ_ERROR_CODE: reason = "read failure:"; |
| 964 | err = file->read_errno; |
| 965 | break; |
| 966 | case WRITE_ERROR_CODE: reason = "write error"; |
| 967 | err = file->write_errno; |
| 968 | break; |
| 969 | case UNEXPECTED_ERROR_CODE: reason = "unexpected error:"; |
| 970 | err = file->read_errno; |
| 971 | if (err == 0) |
| 972 | err = file->write_errno; |
| 973 | break; |
| 974 | default: reason = "INVALID (internal error):"; break; |
| 975 | } |
| 976 | |
| 977 | if (err != 0) |
| 978 | fprintf(stderr, "%s: %s %s [%s]\n", file->file_name, reason, what, |
| 979 | strerror(err)); |
| 980 | |
| 981 | else |
| 982 | fprintf(stderr, "%s: %s %s\n", file->file_name, reason, what); |
| 983 | } |
| 984 | |
| 985 | static void chunk_end(struct chunk **); |
| 986 | static void IDAT_end(struct IDAT **); |
| 987 | |
| 988 | static int |
| 989 | file_end(struct file *file) |
| 990 | { |
| 991 | int rc; |
| 992 | |
| 993 | /* If either of the chunk pointers are set end them here, the IDAT structure |
| 994 | * must be deallocated first as it may deallocate the chunk structure. |
| 995 | */ |
| 996 | if (file->idat != NULL) |
| 997 | IDAT_end(&file->idat); |
| 998 | |
| 999 | if (file->chunk != NULL) |
| 1000 | chunk_end(&file->chunk); |
| 1001 | |
| 1002 | rc = file->status_code; |
| 1003 | |
| 1004 | if (file->file != NULL) |
| 1005 | (void)fclose(file->file); |
| 1006 | |
| 1007 | if (file->out != NULL) |
| 1008 | { |
| 1009 | /* NOTE: this is bitwise |, all the following functions must execute and |
| 1010 | * must succeed. |
| 1011 | */ |
| 1012 | if (ferror(file->out) | fflush(file->out) | fclose(file->out)) |
| 1013 | { |
| 1014 | perror(file->out_name); |
| 1015 | emit_error(file, READ_ERROR_CODE, "output write error"); |
| 1016 | rc |= WRITE_ERROR; |
| 1017 | } |
| 1018 | } |
| 1019 | |
| 1020 | /* Accumulate the result codes */ |
| 1021 | file->global->status_code |= rc; |
| 1022 | |
| 1023 | CLEAR(*file); |
| 1024 | |
| 1025 | return rc; /* status code: non-zero on read or write error */ |
| 1026 | } |
| 1027 | |
| 1028 | static int |
| 1029 | file_init(struct file *file, struct global *global, const char *file_name, |
| 1030 | const char *out_name, void *alloc_ptr, void (*alloc)(struct file*,int)) |
| 1031 | /* Initialize a file control structure. This will open the given files as |
| 1032 | * well. The status code returned is 0 on success, non zero (using the flags |
| 1033 | * above) on a file open error. |
| 1034 | */ |
| 1035 | { |
| 1036 | CLEAR(*file); |
| 1037 | file->global = global; |
| 1038 | |
| 1039 | file->file_name = file_name; |
| 1040 | file->out_name = out_name; |
| 1041 | file->status_code = 0; |
| 1042 | file->read_errno = 0; |
| 1043 | file->write_errno = 0; |
| 1044 | |
| 1045 | file->file = NULL; |
| 1046 | file->out = NULL; |
| 1047 | /* jmpbuf is garbage: must be set by read_png */ |
| 1048 | |
| 1049 | file->read_count = 0; |
| 1050 | file->state = STATE_SIGNATURE; |
| 1051 | |
| 1052 | file->chunk = NULL; |
| 1053 | file->idat = NULL; |
| 1054 | |
| 1055 | file->alloc_ptr = alloc_ptr; |
| 1056 | file->alloc = alloc; |
| 1057 | |
| 1058 | /* Open the files: */ |
| 1059 | assert(file_name != NULL); |
| 1060 | file->file = fopen(file_name, "rb"); |
| 1061 | |
| 1062 | if (file->file == NULL) |
| 1063 | { |
| 1064 | file->read_errno = errno; |
| 1065 | file->status_code |= FILE_ERROR; |
| 1066 | /* Always output: please give a readable file! */ |
| 1067 | perror(file_name); |
| 1068 | return FILE_ERROR; |
| 1069 | } |
| 1070 | |
| 1071 | if (out_name != NULL) |
| 1072 | { |
| 1073 | file->out = fopen(out_name, "wb"); |
| 1074 | |
| 1075 | if (file->out == NULL) |
| 1076 | { |
| 1077 | file->write_errno = errno; |
| 1078 | file->status_code |= WRITE_ERROR; |
| 1079 | perror(out_name); |
| 1080 | return WRITE_ERROR; |
| 1081 | } |
| 1082 | } |
| 1083 | |
| 1084 | return 0; |
| 1085 | } |
| 1086 | |
| 1087 | static void |
| 1088 | log_error(struct file *file, int code, const char *what) |
| 1089 | /* Like emit_error but checks the global 'errors' flag */ |
| 1090 | { |
| 1091 | if (file->global->errors) |
| 1092 | emit_error(file, code, what); |
| 1093 | } |
| 1094 | |
| 1095 | static char |
| 1096 | type_char(png_uint_32 v) |
| 1097 | { |
| 1098 | /* In fact because chunk::chunk_type is validated prior to any call to this |
| 1099 | * function it will always return a-zA-Z, but the extra codes are just there |
| 1100 | * to help in finding internal (programming) errors. Note that the code only |
| 1101 | * ever considers the low 7 bits of the value (so it is not necessary for the |
| 1102 | * type_name function to mask of the byte.) |
| 1103 | */ |
| 1104 | if (v & 32) |
| 1105 | return "!abcdefghijklmnopqrstuvwxyz56789"[(v-96)&31]; |
| 1106 | |
| 1107 | else |
| 1108 | return "@ABCDEFGHIJKLMNOPQRSTUVWXYZ01234"[(v-64)&31]; |
| 1109 | } |
| 1110 | |
| 1111 | static void |
| 1112 | type_name(png_uint_32 type, FILE *out) |
| 1113 | { |
| 1114 | putc(type_char(type >> 24), out); |
| 1115 | putc(type_char(type >> 16), out); |
| 1116 | putc(type_char(type >> 8), out); |
| 1117 | putc(type_char(type ), out); |
| 1118 | } |
| 1119 | |
| 1120 | static void |
| 1121 | type_sep(FILE *out) |
| 1122 | { |
| 1123 | putc(':', out); |
| 1124 | putc(' ', out); |
| 1125 | } |
| 1126 | |
| 1127 | static png_uint_32 current_type(struct file *file, int code); |
| 1128 | |
| 1129 | PNG_NORETURN static void |
| 1130 | stop(struct file *file, int code, const char *what) |
| 1131 | /* Return control when a PNG file cannot be read. This outputs an 'ERR' |
| 1132 | * summary line too. |
| 1133 | */ |
| 1134 | { |
| 1135 | log_error(file, code, what); |
| 1136 | |
| 1137 | /* The chunk being read is typically identified by file->chunk or, if this is |
| 1138 | * NULL, by file->type. This may be wrong if libpng reads ahead, but this |
| 1139 | * only happens with IDAT where libpng reads the header then jumps around |
| 1140 | * finding errors in the previous chunks. We know that is happening because |
| 1141 | * we are at the start of the IDAT (i.e. no IDAT data has yet been written.) |
| 1142 | * |
| 1143 | * SUMMARY FORMAT (stop): |
| 1144 | * |
| 1145 | * IDAT ERR status code read-errno write-errno message file |
| 1146 | * |
| 1147 | * 'uncompressed' will be 0 if there was a problem in the IHDR. The errno |
| 1148 | * values are emit_string(strerror(errno)). |
| 1149 | */ |
| 1150 | if (file->global->quiet < 2) /* need two quiets to stop this. */ |
| 1151 | { |
| 1152 | png_uint_32 type; |
| 1153 | |
| 1154 | if (file->chunk != NULL) |
| 1155 | type = current_type(file, code); /* Gropes in struct chunk and IDAT */ |
| 1156 | |
| 1157 | else |
| 1158 | type = file->type; |
| 1159 | |
| 1160 | if (type) |
| 1161 | type_name(type, stdout); |
| 1162 | |
| 1163 | else /* magic: an IDAT header, produces bogons for too many IDATs */ |
| 1164 | fputs("HEAD", stdout); /* not a registered chunk! */ |
| 1165 | |
| 1166 | printf(" ERR %.2x %s ", file->status_code, strcode(code)); |
| 1167 | /* This only works one strerror at a time, because of the way strerror is |
| 1168 | * implemented. |
| 1169 | */ |
| 1170 | emit_string(strerror(file->read_errno), stdout); |
| 1171 | putc(' ', stdout); |
| 1172 | emit_string(strerror(file->write_errno), stdout); |
| 1173 | putc(' ', stdout); |
| 1174 | emit_string(what, stdout); |
| 1175 | putc(' ', stdout); |
| 1176 | fputs(file->file_name, stdout); |
| 1177 | putc('\n', stdout); |
| 1178 | } |
| 1179 | |
| 1180 | file->status_code |= FILE_ERROR; |
| 1181 | longjmp(file->jmpbuf, code); |
| 1182 | } |
| 1183 | |
| 1184 | PNG_NORETURN static void |
| 1185 | stop_invalid(struct file *file, const char *what) |
| 1186 | { |
| 1187 | stop(file, INVALID_ERROR_CODE, what); |
| 1188 | } |
| 1189 | |
| 1190 | static void |
| 1191 | type_message(struct file *file, png_uint_32 type, const char *what) |
| 1192 | /* Error message for a chunk; the chunk name comes from 'type' */ |
| 1193 | { |
| 1194 | if (file->global->errors) |
| 1195 | { |
| 1196 | fputs(file->file_name, stderr); |
| 1197 | type_sep(stderr); |
| 1198 | type_name(type, stderr); |
| 1199 | type_sep(stderr); |
| 1200 | fputs(what, stderr); |
| 1201 | putc('\n', stderr); |
| 1202 | } |
| 1203 | } |
| 1204 | |
| 1205 | /* Input file positioning - we jump around in the input file while reading |
| 1206 | * stuff, these wrappers deal with the error handling. |
| 1207 | */ |
| 1208 | static void |
| 1209 | file_getpos(struct file *file, fpos_t *pos) |
| 1210 | { |
| 1211 | if (fgetpos(file->file, pos)) |
| 1212 | { |
| 1213 | /* This is unexpected, so perror it */ |
| 1214 | perror(file->file_name); |
| 1215 | stop(file, READ_ERROR_CODE, "fgetpos"); |
| 1216 | } |
| 1217 | } |
| 1218 | |
| 1219 | static void |
| 1220 | file_setpos(struct file *file, const fpos_t *pos) |
| 1221 | { |
| 1222 | if (fsetpos(file->file, pos)) |
| 1223 | { |
| 1224 | perror(file->file_name); |
| 1225 | stop(file, READ_ERROR_CODE, "fsetpos"); |
| 1226 | } |
| 1227 | } |
| 1228 | |
| 1229 | static void |
| 1230 | getpos(struct file *file) |
| 1231 | /* Get the current position and store it in 'data_pos'. The corresponding |
| 1232 | * setpos() function is chunk specific because it uses the copy of the |
| 1233 | * position for the specific chunk. |
| 1234 | */ |
| 1235 | { |
| 1236 | file_getpos(file, &file->data_pos); |
| 1237 | } |
| 1238 | |
| 1239 | |
| 1240 | /* Read utility - read a single byte, returns a value in the range 0..255 or EOF |
| 1241 | * on a read error. In the latter case status_code and read_errno are updated |
| 1242 | * appropriately. |
| 1243 | */ |
| 1244 | static int |
| 1245 | read_byte(struct file *file) |
| 1246 | { |
| 1247 | int ch = getc(file->file); |
| 1248 | |
| 1249 | if (ch >= 0 && ch <= 255) |
| 1250 | { |
| 1251 | ++(file->read_count); |
| 1252 | return ch; |
| 1253 | } |
| 1254 | |
| 1255 | else if (ch != EOF) |
| 1256 | { |
| 1257 | file->status_code |= INTERNAL_ERROR; |
| 1258 | file->read_errno = ERANGE; /* out of range character */ |
| 1259 | |
| 1260 | /* This is very unexpected; an error message is always output: */ |
| 1261 | emit_error(file, UNEXPECTED_ERROR_CODE, "file read"); |
| 1262 | } |
| 1263 | |
| 1264 | # ifdef EINTR |
| 1265 | else if (errno == EINTR) /* Interrupted, try again */ |
| 1266 | { |
| 1267 | errno = 0; |
| 1268 | return read_byte(file); |
| 1269 | } |
| 1270 | # endif |
| 1271 | |
| 1272 | else |
| 1273 | { |
| 1274 | /* An error, it doesn't really matter what the error is but it gets |
| 1275 | * recorded anyway. |
| 1276 | */ |
| 1277 | if (ferror(file->file)) |
| 1278 | file->read_errno = errno; |
| 1279 | |
| 1280 | else if (feof(file->file)) |
| 1281 | file->read_errno = 0; /* I.e. a regular EOF, no error */ |
| 1282 | |
| 1283 | else /* unexpected */ |
| 1284 | file->read_errno = EDOM; |
| 1285 | } |
| 1286 | |
| 1287 | /* 'TRUNCATED' is used for all cases of failure to read a byte, because of |
| 1288 | * the way libpng works a byte read is never attempted unless the byte is |
| 1289 | * expected to be there, so EOF should not occur. |
| 1290 | */ |
| 1291 | file->status_code |= TRUNCATED; |
| 1292 | return EOF; |
| 1293 | } |
| 1294 | |
| 1295 | static png_byte |
| 1296 | reread_byte(struct file *file) |
| 1297 | /* Read a byte when an error is not expected to happen because the byte has |
| 1298 | * been read before without error. |
| 1299 | */ |
| 1300 | { |
| 1301 | int ch = getc(file->file); |
| 1302 | |
| 1303 | if (errno != 0) |
| 1304 | file->read_errno = errno; |
| 1305 | |
| 1306 | if (ch < 0 || ch > 255) |
| 1307 | stop(file, UNEXPECTED_ERROR_CODE, "reread"); |
| 1308 | |
| 1309 | return (png_byte)ch; |
| 1310 | } |
| 1311 | |
| 1312 | static png_uint_32 |
| 1313 | reread_4(struct file *file) |
| 1314 | /* The same but for a four byte quantity */ |
| 1315 | { |
| 1316 | png_uint_32 result = 0; |
| 1317 | int i = 0; |
| 1318 | |
| 1319 | while (++i <= 4) |
| 1320 | result = (result << 8) + reread_byte(file); |
| 1321 | |
| 1322 | return result; |
| 1323 | } |
| 1324 | |
| 1325 | static void |
| 1326 | skip_12(struct file *file) |
| 1327 | /* Skip exactly 12 bytes in the input stream - used to skip a CRC and chunk |
| 1328 | * header that has been read before. |
| 1329 | */ |
| 1330 | { |
| 1331 | /* Since the chunks were read before this shouldn't fail: */ |
| 1332 | if (fseek(file->file, 12, SEEK_CUR) != 0) |
| 1333 | { |
| 1334 | if (errno != 0) |
| 1335 | file->read_errno = errno; |
| 1336 | |
| 1337 | stop(file, UNEXPECTED_ERROR_CODE, "reskip"); |
| 1338 | } |
| 1339 | } |
| 1340 | |
| 1341 | static void |
| 1342 | write_byte(struct file *file, int b) |
| 1343 | /* Write one byte to the output - this causes a fatal error if the write |
| 1344 | * fails and the read of this PNG file immediately terminates. Just |
| 1345 | * increments the write count if there is no output file. |
| 1346 | */ |
| 1347 | { |
| 1348 | if (file->out != NULL) |
| 1349 | { |
| 1350 | if (putc(b, file->out) != b) |
| 1351 | { |
| 1352 | file->write_errno = errno; |
| 1353 | file->status_code |= WRITE_ERROR; |
| 1354 | stop(file, WRITE_ERROR_CODE, "write byte"); |
| 1355 | } |
| 1356 | } |
| 1357 | |
| 1358 | ++(file->write_count); |
| 1359 | } |
| 1360 | |
| 1361 | /* Derivatives of the read/write functions. */ |
| 1362 | static unsigned int |
| 1363 | read_4(struct file *file, png_uint_32 *pu) |
| 1364 | /* Read four bytes, returns the number of bytes read successfully and, if all |
| 1365 | * four bytes are read, assigns the result to *pu. |
| 1366 | */ |
| 1367 | { |
| 1368 | unsigned int i = 0; |
| 1369 | png_uint_32 val = 0; |
| 1370 | |
| 1371 | do |
| 1372 | { |
| 1373 | int ch = read_byte(file); |
| 1374 | |
| 1375 | if (ch == EOF) |
| 1376 | return i; |
| 1377 | |
| 1378 | val = (val << 8) + ch; |
| 1379 | } while (++i < 4); |
| 1380 | |
| 1381 | *pu = val; |
| 1382 | return i; |
| 1383 | } |
| 1384 | |
| 1385 | /* CRC handling - read but calculate the CRC while doing so. */ |
| 1386 | static int |
| 1387 | crc_read_many(struct file *file, png_uint_32 length) |
| 1388 | /* Reads 'length' bytes and updates the CRC, returns true on success, false |
| 1389 | * if the input is truncated. |
| 1390 | */ |
| 1391 | { |
| 1392 | if (length > 0) |
| 1393 | { |
| 1394 | png_uint_32 crc = file->crc; |
| 1395 | |
| 1396 | do |
| 1397 | { |
| 1398 | int ch = read_byte(file); |
| 1399 | |
| 1400 | if (ch == EOF) |
| 1401 | return 0; /* Truncated */ |
| 1402 | |
| 1403 | crc = crc_one_byte(crc, ch); |
| 1404 | } |
| 1405 | while (--length > 0); |
| 1406 | |
| 1407 | file->crc = crc; |
| 1408 | } |
| 1409 | |
| 1410 | return 1; /* OK */ |
| 1411 | } |
| 1412 | |
| 1413 | static int |
| 1414 | calc_image_size(struct file *file) |
| 1415 | /* Fill in the image_bytes field given the IHDR information, calls stop on |
| 1416 | * error. |
| 1417 | */ |
| 1418 | { |
| 1419 | png_uint_16 pd = file->bit_depth; |
| 1420 | |
| 1421 | switch (file->color_type) |
| 1422 | { |
| 1423 | default: |
| 1424 | stop_invalid(file, "IHDR: colour type"); |
| 1425 | |
| 1426 | invalid_bit_depth: |
| 1427 | stop_invalid(file, "IHDR: bit depth"); |
| 1428 | |
| 1429 | case 0: /* g */ |
| 1430 | if (pd != 1 && pd != 2 && pd != 4 && pd != 8 && pd != 16) |
| 1431 | goto invalid_bit_depth; |
| 1432 | break; |
| 1433 | |
| 1434 | case 3: |
| 1435 | if (pd != 1 && pd != 2 && pd != 4 && pd != 8) |
| 1436 | goto invalid_bit_depth; |
| 1437 | break; |
| 1438 | |
| 1439 | case 2: /* rgb */ |
| 1440 | if (pd != 8 && pd != 16) |
| 1441 | goto invalid_bit_depth; |
| 1442 | |
| 1443 | pd = (png_uint_16)(pd * 3); |
| 1444 | break; |
| 1445 | |
| 1446 | case 4: /* ga */ |
| 1447 | if (pd != 8 && pd != 16) |
| 1448 | goto invalid_bit_depth; |
| 1449 | |
| 1450 | pd = (png_uint_16)(pd * 2); |
| 1451 | break; |
| 1452 | |
| 1453 | case 6: /* rgba */ |
| 1454 | if (pd != 8 && pd != 16) |
| 1455 | goto invalid_bit_depth; |
| 1456 | |
| 1457 | pd = (png_uint_16)(pd * 4); |
| 1458 | break; |
| 1459 | } |
| 1460 | |
| 1461 | if (file->width < 1 || file->width > 0x7fffffff) |
| 1462 | stop_invalid(file, "IHDR: width"); |
| 1463 | |
| 1464 | else if (file->height < 1 || file->height > 0x7fffffff) |
| 1465 | stop_invalid(file, "IHDR: height"); |
| 1466 | |
| 1467 | else if (file->compression_method != 0) |
| 1468 | stop_invalid(file, "IHDR: compression method"); |
| 1469 | |
| 1470 | else if (file->filter_method != 0) |
| 1471 | stop_invalid(file, "IHDR: filter method"); |
| 1472 | |
| 1473 | else switch (file->interlace_method) |
| 1474 | { |
| 1475 | case PNG_INTERLACE_ADAM7: |
| 1476 | /* Interlacing makes the image larger because of the replication of |
| 1477 | * both the filter byte and the padding to a byte boundary. |
| 1478 | */ |
| 1479 | { |
| 1480 | int pass; |
| 1481 | int image_digits = 0; |
| 1482 | udigit row_width[2], row_bytes[3]; |
| 1483 | |
| 1484 | for (pass=0; pass<=6; ++pass) |
| 1485 | { |
| 1486 | png_uint_32 pw = PNG_PASS_COLS(file->width, pass); |
| 1487 | |
| 1488 | if (pw > 0) |
| 1489 | { |
| 1490 | int digits; |
| 1491 | |
| 1492 | /* calculate 1+((pw*pd+7)>>3) in row_bytes */ |
| 1493 | digits = uarb_mult_digit(row_bytes, uarb_set(row_bytes, 7), |
| 1494 | row_width, uarb_set(row_width, pw), pd); |
| 1495 | digits = uarb_shift(row_bytes, digits, 3); |
| 1496 | digits = uarb_inc(row_bytes, digits, 1); |
| 1497 | |
| 1498 | /* Add row_bytes * pass-height to the file image_bytes field |
| 1499 | */ |
| 1500 | image_digits = uarb_mult32(file->image_bytes, image_digits, |
| 1501 | row_bytes, digits, |
| 1502 | PNG_PASS_ROWS(file->height, pass)); |
| 1503 | } |
| 1504 | } |
| 1505 | |
| 1506 | file->image_digits = image_digits; |
| 1507 | } |
| 1508 | break; |
| 1509 | |
| 1510 | case PNG_INTERLACE_NONE: |
| 1511 | { |
| 1512 | int digits; |
| 1513 | udigit row_width[2], row_bytes[3]; |
| 1514 | |
| 1515 | /* As above, but use image_width in place of the pass width: */ |
| 1516 | digits = uarb_mult_digit(row_bytes, uarb_set(row_bytes, 7), |
| 1517 | row_width, uarb_set(row_width, file->width), pd); |
| 1518 | digits = uarb_shift(row_bytes, digits, 3); |
| 1519 | digits = uarb_inc(row_bytes, digits, 1); |
| 1520 | |
| 1521 | /* Set row_bytes * image-height to the file image_bytes field */ |
| 1522 | file->image_digits = uarb_mult32(file->image_bytes, 0, |
| 1523 | row_bytes, digits, file->height); |
| 1524 | } |
| 1525 | break; |
| 1526 | |
| 1527 | default: |
| 1528 | stop_invalid(file, "IHDR: interlace method"); |
| 1529 | } |
| 1530 | |
| 1531 | assert(file->image_digits >= 1 && file->image_digits <= 5); |
| 1532 | return 1; |
| 1533 | } |
| 1534 | |
| 1535 | /* PER-CHUNK CONTROL STRUCTURE |
| 1536 | * This structure is instantiated for each chunk, except for the IDAT chunks |
| 1537 | * where one chunk control structure is used for the whole of a single stream of |
| 1538 | * IDAT chunks (see the IDAT control structure below). |
| 1539 | */ |
| 1540 | struct chunk |
| 1541 | { |
| 1542 | /* ANCESTORS */ |
| 1543 | struct file * file; |
| 1544 | struct global * global; |
| 1545 | |
| 1546 | /* PUBLIC IDAT INFORMATION: SET BY THE ZLIB CODE */ |
| 1547 | udigit uncompressed_bytes[5]; |
| 1548 | int uncompressed_digits; |
| 1549 | udigit compressed_bytes[5]; |
| 1550 | int compressed_digits; |
| 1551 | |
| 1552 | /* PUBLIC PER-CHUNK INFORMATION: USED BY CHUNK READ CODE */ |
| 1553 | /* This information is filled in by chunk_init from the data in the file |
| 1554 | * control structure, but chunk_length may be changed later. |
| 1555 | */ |
| 1556 | fpos_t chunk_data_pos; /* Position of first byte of chunk data */ |
| 1557 | png_uint_32 chunk_length; /* From header (or modified below) */ |
| 1558 | png_uint_32 chunk_type; /* From header */ |
| 1559 | |
| 1560 | /* PUBLIC PER-CHUNK INFORMATION: FOR THE CHUNK WRITE CODE */ |
| 1561 | png_uint_32 write_crc; /* Output CRC (may differ from read_crc) */ |
| 1562 | png_uint_32 rewrite_offset; /* Count of bytes before rewrite. */ |
| 1563 | int rewrite_length; /* Number of bytes left to change */ |
| 1564 | png_byte rewrite_buffer[2]; /* Buffer of new byte values */ |
| 1565 | }; |
| 1566 | |
| 1567 | static void |
| 1568 | chunk_message(struct chunk *chunk, const char *message) |
| 1569 | { |
| 1570 | type_message(chunk->file, chunk->chunk_type, message); |
| 1571 | } |
| 1572 | |
| 1573 | static void |
| 1574 | chunk_end(struct chunk **chunk_var) |
| 1575 | { |
| 1576 | struct chunk *chunk = *chunk_var; |
| 1577 | |
| 1578 | *chunk_var = NULL; |
| 1579 | CLEAR(*chunk); |
| 1580 | } |
| 1581 | |
| 1582 | static void |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 1583 | chunk_init(struct chunk * const chunk, struct file * const file) |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 1584 | /* When a chunk is initialized the file length/type/pos are copied into the |
| 1585 | * corresponding chunk fields and the new chunk is registered in the file |
| 1586 | * structure. There can only be one chunk at a time. |
| 1587 | * |
| 1588 | * NOTE: this routine must onely be called from the file alloc routine! |
| 1589 | */ |
| 1590 | { |
| 1591 | assert(file->chunk == NULL); |
| 1592 | |
| 1593 | CLEAR(*chunk); |
| 1594 | |
| 1595 | chunk->file = file; |
| 1596 | chunk->global = file->global; |
| 1597 | |
| 1598 | chunk->chunk_data_pos = file->data_pos; |
| 1599 | chunk->chunk_length = file->length; |
| 1600 | chunk->chunk_type = file->type; |
| 1601 | |
| 1602 | /* Compresssed/uncompressed size information (from the zlib control structure |
| 1603 | * that is used to check the compressed data in a chunk.) |
| 1604 | */ |
| 1605 | chunk->uncompressed_digits = 0; |
| 1606 | chunk->compressed_digits = 0; |
| 1607 | |
| 1608 | file->chunk = chunk; |
| 1609 | } |
| 1610 | |
| 1611 | static png_uint_32 |
| 1612 | current_type(struct file *file, int code) |
| 1613 | /* Guess the actual chunk type that causes a stop() */ |
| 1614 | { |
| 1615 | /* This may return png_IDAT for errors detected (late) in the header; that |
| 1616 | * includes any inter-chunk consistency check that libpng performs. Assume |
| 1617 | * that if the chunk_type is png_IDAT and the file write count is 8 this is |
| 1618 | * what is happening. |
| 1619 | */ |
| 1620 | if (file->chunk != NULL) |
| 1621 | { |
| 1622 | png_uint_32 type = file->chunk->chunk_type; |
| 1623 | |
| 1624 | /* This is probably wrong for the excess IDATs case, because then libpng |
| 1625 | * whines about too many of them (apparently in some cases erroneously) |
| 1626 | * when the header is read. |
| 1627 | */ |
| 1628 | if (code <= LIBPNG_ERROR_CODE && type == png_IDAT && |
| 1629 | file->write_count == 8) |
| 1630 | type = 0; /* magic */ |
| 1631 | |
| 1632 | return type; |
| 1633 | } |
| 1634 | |
| 1635 | else |
| 1636 | return file->type; |
| 1637 | } |
| 1638 | |
| 1639 | static void |
| 1640 | setpos(struct chunk *chunk) |
| 1641 | /* Reset the position to 'chunk_data_pos' - the start of the data for this |
| 1642 | * chunk. As a side effect the read_count in the file is reset to 8, just |
| 1643 | * after the length/type header. |
| 1644 | */ |
| 1645 | { |
| 1646 | chunk->file->read_count = 8; |
| 1647 | file_setpos(chunk->file, &chunk->chunk_data_pos); |
| 1648 | } |
| 1649 | |
| 1650 | /* Specific chunk handling - called for each chunk header, all special chunk |
| 1651 | * processing is initiated in these functions. |
| 1652 | */ |
| 1653 | /* The next functions handle special processing for those chunks with LZ data, |
| 1654 | * the data is identified and checked for validity. If there are problems which |
| 1655 | * cannot be corrected the routines return false, otherwise true (although |
| 1656 | * modification to the zlib header may be required.) |
| 1657 | * |
| 1658 | * The compressed data is in zlib format (RFC1950) and consequently has a |
| 1659 | * minimum length of 7 bytes. |
| 1660 | */ |
| 1661 | static int zlib_check(struct file *file, png_uint_32 offset); |
| 1662 | |
| 1663 | static int |
| 1664 | process_zTXt_iCCP(struct file *file) |
| 1665 | /* zTXt and iCCP have exactly the same form - keyword, null, compression |
| 1666 | * method then compressed data. |
| 1667 | */ |
| 1668 | { |
| 1669 | struct chunk *chunk = file->chunk; |
| 1670 | png_uint_32 length; |
| 1671 | png_uint_32 index = 0; |
| 1672 | |
| 1673 | assert(chunk != NULL && file->idat == NULL); |
| 1674 | length = chunk->chunk_length; |
| 1675 | setpos(chunk); |
| 1676 | |
| 1677 | while (length >= 9) |
| 1678 | { |
| 1679 | --length; |
| 1680 | ++index; |
| 1681 | if (reread_byte(file) == 0) /* keyword null terminator */ |
| 1682 | { |
| 1683 | --length; |
| 1684 | ++index; |
| 1685 | (void)reread_byte(file); /* compression method */ |
| 1686 | return zlib_check(file, index); |
| 1687 | } |
| 1688 | } |
| 1689 | |
| 1690 | chunk_message(chunk, "too short"); |
| 1691 | return 0; /* skip */ |
| 1692 | } |
| 1693 | |
| 1694 | static int |
| 1695 | process_iTXt(struct file *file) |
| 1696 | { |
| 1697 | /* Like zTXt but more fields. */ |
| 1698 | struct chunk *chunk = file->chunk; |
| 1699 | png_uint_32 length; |
| 1700 | png_uint_32 index = 0; |
| 1701 | |
| 1702 | assert(chunk != NULL && file->idat == NULL); |
| 1703 | length = chunk->chunk_length; |
| 1704 | setpos(chunk); |
| 1705 | |
| 1706 | while (length >= 5) |
| 1707 | { |
| 1708 | --length; |
| 1709 | ++index; |
| 1710 | if (reread_byte(file) == 0) /* keyword null terminator */ |
| 1711 | { |
| 1712 | --length; |
| 1713 | ++index; |
| 1714 | if (reread_byte(file) == 0) /* uncompressed text */ |
| 1715 | return 1; /* nothing to check */ |
| 1716 | |
| 1717 | --length; |
| 1718 | ++index; |
| 1719 | (void)reread_byte(file); /* compression method */ |
| 1720 | |
| 1721 | /* Skip the language tag (null terminated). */ |
| 1722 | while (length >= 9) |
| 1723 | { |
| 1724 | --length; |
| 1725 | ++index; |
| 1726 | if (reread_byte(file) == 0) /* terminator */ |
| 1727 | { |
| 1728 | /* Skip the translated keyword */ |
| 1729 | while (length >= 8) |
| 1730 | { |
| 1731 | --length; |
| 1732 | ++index; |
| 1733 | if (reread_byte(file) == 0) /* terminator */ |
| 1734 | return zlib_check(file, index); |
| 1735 | } |
| 1736 | } |
| 1737 | } |
| 1738 | |
| 1739 | /* Ran out of bytes in the compressed case. */ |
| 1740 | break; |
| 1741 | } |
| 1742 | } |
| 1743 | |
| 1744 | log_error(file, INVALID_ERROR_CODE, "iTXt chunk length"); |
| 1745 | |
| 1746 | return 0; /* skip */ |
| 1747 | } |
| 1748 | |
| 1749 | /* IDAT READ/WRITE CONTROL STRUCTURE */ |
| 1750 | struct IDAT |
| 1751 | { |
| 1752 | /* ANCESTORS */ |
| 1753 | struct file * file; |
| 1754 | struct global * global; |
| 1755 | |
| 1756 | /* PROTECTED IDAT INFORMATION: SET BY THE IDAT READ CODE */ |
| 1757 | struct IDAT_list *idat_list_head; /* START of the list of IDAT information */ |
| 1758 | struct IDAT_list *idat_list_tail; /* *END* of the list of IDAT information */ |
| 1759 | |
| 1760 | /* PROTECTED IDAT INFORMATION: USED BY THE IDAT WRITE CODE */ |
| 1761 | struct IDAT_list *idat_cur; /* Current list entry */ |
| 1762 | unsigned int idat_count; /* And the *current* index into the list */ |
| 1763 | png_uint_32 idat_index; /* Index of *next* input byte to write */ |
| 1764 | png_uint_32 idat_length; /* Cache of current chunk length */ |
| 1765 | }; |
| 1766 | |
| 1767 | /* NOTE: there is currently no IDAT_reset, so a stream cannot contain more than |
| 1768 | * one IDAT sequence (i.e. MNG is not supported). |
| 1769 | */ |
| 1770 | |
| 1771 | static void |
| 1772 | IDAT_end(struct IDAT **idat_var) |
| 1773 | { |
| 1774 | struct IDAT *idat = *idat_var; |
| 1775 | struct file *file = idat->file; |
| 1776 | |
| 1777 | *idat_var = NULL; |
| 1778 | |
| 1779 | CLEAR(*idat); |
| 1780 | |
| 1781 | assert(file->chunk != NULL); |
| 1782 | chunk_end(&file->chunk); |
| 1783 | |
| 1784 | /* Regardless of why the IDAT was killed set the state back to CHUNKS (it may |
| 1785 | * already be CHUNKS because the state isn't changed until process_IDAT |
| 1786 | * returns; a stop will cause IDAT_end to be entered in state CHUNKS!) |
| 1787 | */ |
| 1788 | file->state = STATE_CHUNKS; |
| 1789 | } |
| 1790 | |
| 1791 | static void |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 1792 | IDAT_init(struct IDAT * const idat, struct file * const file) |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 1793 | /* When the chunk is png_IDAT instantiate an IDAT control structure in place |
| 1794 | * of a chunk control structure. The IDAT will instantiate a chunk control |
| 1795 | * structure using the file alloc routine. |
| 1796 | * |
| 1797 | * NOTE: this routine must only be called from the file alloc routine! |
| 1798 | */ |
| 1799 | { |
| 1800 | assert(file->chunk == NULL); |
| 1801 | assert(file->idat == NULL); |
| 1802 | |
| 1803 | CLEAR(*idat); |
| 1804 | |
| 1805 | idat->file = file; |
| 1806 | idat->global = file->global; |
| 1807 | |
| 1808 | /* Initialize the tail to the pre-allocated buffer and set the count to 0 |
| 1809 | * (empty.) |
| 1810 | */ |
| 1811 | idat->global->idat_cache.count = 0; |
| 1812 | idat->idat_list_head = idat->idat_list_tail = &idat->global->idat_cache; |
| 1813 | |
| 1814 | /* Now the chunk. The allocator calls the initializer of the new chunk and |
| 1815 | * stores the result in file->chunk: |
| 1816 | */ |
| 1817 | file->alloc(file, 0/*chunk*/); |
| 1818 | assert(file->chunk != NULL); |
| 1819 | |
| 1820 | /* And store this for cleanup (and to check for double alloc or failure to |
| 1821 | * free.) |
| 1822 | */ |
| 1823 | file->idat = idat; |
| 1824 | } |
| 1825 | |
| 1826 | static png_uint_32 |
| 1827 | rechunk_length(struct IDAT *idat) |
| 1828 | /* Return the length for the next IDAT chunk, taking into account |
| 1829 | * rechunking. |
| 1830 | */ |
| 1831 | { |
| 1832 | png_uint_32 len = idat->global->idat_max; |
| 1833 | |
| 1834 | if (len == 0) /* use original chunk lengths */ |
| 1835 | { |
| 1836 | const struct IDAT_list *cur; |
| 1837 | unsigned int count; |
| 1838 | |
| 1839 | if (idat->idat_index == 0) /* at the new chunk (first time) */ |
| 1840 | return idat->idat_length; /* use the cache */ |
| 1841 | |
| 1842 | /* Otherwise rechunk_length is called at the end of a chunk for the length |
| 1843 | * of the next one. |
| 1844 | */ |
| 1845 | cur = idat->idat_cur; |
| 1846 | count = idat->idat_count; |
| 1847 | |
| 1848 | assert(idat->idat_index == idat->idat_length && |
| 1849 | idat->idat_length == cur->lengths[count]); |
| 1850 | |
| 1851 | /* Return length of the *next* chunk */ |
| 1852 | if (++count < cur->count) |
| 1853 | return cur->lengths[count]; |
| 1854 | |
| 1855 | /* End of this list */ |
| 1856 | assert(cur != idat->idat_list_tail); |
| 1857 | cur = cur->next; |
| 1858 | assert(cur != NULL && cur->count > 0); |
| 1859 | return cur->lengths[0]; |
| 1860 | } |
| 1861 | |
| 1862 | else /* rechunking */ |
| 1863 | { |
| 1864 | /* The chunk size is the lesser of file->idat_max and the number |
| 1865 | * of remaining bytes. |
| 1866 | */ |
| 1867 | png_uint_32 have = idat->idat_length - idat->idat_index; |
| 1868 | |
| 1869 | if (len > have) |
| 1870 | { |
| 1871 | struct IDAT_list *cur = idat->idat_cur; |
| 1872 | unsigned int j = idat->idat_count+1; /* the next IDAT in the list */ |
| 1873 | |
| 1874 | do |
| 1875 | { |
| 1876 | /* Add up the remaining bytes. This can't overflow because the |
| 1877 | * individual lengths are always <= 0x7fffffff, so when we add two |
| 1878 | * of them overflow is not possible. |
| 1879 | */ |
| 1880 | assert(cur != NULL); |
| 1881 | |
| 1882 | for (;;) |
| 1883 | { |
| 1884 | /* NOTE: IDAT_list::count here, not IDAT_list::length */ |
| 1885 | for (; j < cur->count; ++j) |
| 1886 | { |
| 1887 | have += cur->lengths[j]; |
| 1888 | if (len <= have) |
| 1889 | return len; |
| 1890 | } |
| 1891 | |
| 1892 | /* If this was the end return the count of the available bytes */ |
| 1893 | if (cur == idat->idat_list_tail) |
| 1894 | return have; |
| 1895 | |
| 1896 | cur = cur->next; |
| 1897 | j = 0; |
| 1898 | } |
| 1899 | } |
| 1900 | while (len > have); |
| 1901 | } |
| 1902 | |
| 1903 | return len; |
| 1904 | } |
| 1905 | } |
| 1906 | |
| 1907 | static int |
| 1908 | process_IDAT(struct file *file) |
| 1909 | /* Process the IDAT stream, this is the more complex than the preceding |
| 1910 | * cases because the compressed data is spread across multiple IDAT chunks |
| 1911 | * (typically). Rechunking of the data is not handled here; all this |
| 1912 | * function does is establish whether the zlib header needs to be modified. |
| 1913 | * |
| 1914 | * Initially the function returns false, indicating that the chunk should not |
| 1915 | * be written. It does this until the last IDAT chunk is passed in, then it |
| 1916 | * checks the zlib data and returns true. |
| 1917 | * |
| 1918 | * It does not return false on a fatal error; it calls stop instead. |
| 1919 | * |
| 1920 | * The caller must have an instantiated (IDAT) control structure and it must |
| 1921 | * have extent over the whole read of the IDAT stream. For a PNG this means |
| 1922 | * the whole PNG read, for MNG it could have lesser extent. |
| 1923 | */ |
| 1924 | { |
| 1925 | struct IDAT_list *list; |
| 1926 | |
| 1927 | assert(file->idat != NULL && file->chunk != NULL); |
| 1928 | |
| 1929 | /* We need to first check the entire sequence of IDAT chunks to ensure the |
| 1930 | * stream is in sync. Do this by building a list of all the chunks and |
| 1931 | * recording the length of each because the length may have been fixed up by |
| 1932 | * sync_stream below. |
| 1933 | * |
| 1934 | * At the end of the list of chunks, where the type of the next chunk is not |
| 1935 | * png_IDAT, process the whole stream using the list data to check validity |
| 1936 | * then return control to the start and rewrite everything. |
| 1937 | */ |
| 1938 | list = file->idat->idat_list_tail; |
| 1939 | |
| 1940 | if (list->count == list->length) |
| 1941 | { |
| 1942 | list = IDAT_list_extend(list); |
| 1943 | |
| 1944 | if (list == NULL) |
| 1945 | stop(file, READ_ERROR_CODE, "out of memory"); |
| 1946 | |
| 1947 | /* Move to the next block */ |
| 1948 | list->count = 0; |
| 1949 | file->idat->idat_list_tail = list; |
| 1950 | } |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 1951 | |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 1952 | /* And fill in the next IDAT information buffer. */ |
| 1953 | list->lengths[(list->count)++] = file->chunk->chunk_length; |
| 1954 | |
| 1955 | /* The type of the next chunk was recorded in the file control structure by |
| 1956 | * the caller, if this is png_IDAT return 'skip' to the caller. |
| 1957 | */ |
| 1958 | if (file->type == png_IDAT) |
| 1959 | return 0; /* skip this for the moment */ |
| 1960 | |
| 1961 | /* This is the final IDAT chunk, so run the tests to check for the too far |
| 1962 | * back error and possibly optimize the window bits. This means going back |
| 1963 | * to the start of the first chunk data, which is stored in the original |
| 1964 | * chunk allocation. |
| 1965 | */ |
| 1966 | setpos(file->chunk); |
| 1967 | |
| 1968 | if (zlib_check(file, 0)) |
| 1969 | { |
| 1970 | struct IDAT *idat; |
| 1971 | int cmp; |
| 1972 | |
| 1973 | /* The IDAT stream was successfully uncompressed; see whether it |
| 1974 | * contained the correct number of bytes of image data. |
| 1975 | */ |
| 1976 | cmp = uarb_cmp(file->image_bytes, file->image_digits, |
| 1977 | file->chunk->uncompressed_bytes, file->chunk->uncompressed_digits); |
| 1978 | |
| 1979 | if (cmp < 0) |
| 1980 | type_message(file, png_IDAT, "extra uncompressed data"); |
| 1981 | |
| 1982 | else if (cmp > 0) |
| 1983 | stop(file, LIBPNG_ERROR_CODE, "IDAT: uncompressed data too small"); |
| 1984 | |
| 1985 | /* Return the stream to the start of the first IDAT chunk; the length |
| 1986 | * is set in the write case below but the input chunk variables must be |
| 1987 | * set (once) here: |
| 1988 | */ |
| 1989 | setpos(file->chunk); |
| 1990 | |
| 1991 | idat = file->idat; |
| 1992 | idat->idat_cur = idat->idat_list_head; |
| 1993 | idat->idat_length = idat->idat_cur->lengths[0]; |
| 1994 | idat->idat_count = 0; /* Count of chunks read in current list */ |
| 1995 | idat->idat_index = 0; /* Index into chunk data */ |
| 1996 | |
| 1997 | /* Update the chunk length to the correct value for the IDAT chunk: */ |
| 1998 | file->chunk->chunk_length = rechunk_length(idat); |
| 1999 | |
| 2000 | /* Change the state to writing IDAT chunks */ |
| 2001 | file->state = STATE_IDAT; |
| 2002 | |
| 2003 | return 1; |
| 2004 | } |
| 2005 | |
| 2006 | else /* Failure to decompress the IDAT stream; give up. */ |
| 2007 | stop(file, ZLIB_ERROR_CODE, "could not uncompress IDAT"); |
| 2008 | } |
| 2009 | |
| 2010 | /* ZLIB CONTROL STRUCTURE */ |
| 2011 | struct zlib |
| 2012 | { |
| 2013 | /* ANCESTORS */ |
| 2014 | struct IDAT * idat; /* NOTE: May be NULL */ |
| 2015 | struct chunk * chunk; |
| 2016 | struct file * file; |
| 2017 | struct global *global; |
| 2018 | |
| 2019 | /* GLOBAL ZLIB INFORMATION: SET BY THE CALLER */ |
| 2020 | png_uint_32 rewrite_offset; |
| 2021 | |
| 2022 | /* GLOBAL ZLIB INFORMATION: SET BY THE ZLIB READ CODE */ |
| 2023 | udigit compressed_bytes[5]; |
| 2024 | int compressed_digits; |
| 2025 | udigit uncompressed_bytes[5]; |
| 2026 | int uncompressed_digits; |
| 2027 | int file_bits; /* window bits from the file */ |
| 2028 | int ok_bits; /* Set <16 on a successful read */ |
| 2029 | int cksum; /* Set on a checksum error */ |
| 2030 | |
| 2031 | /* PROTECTED ZLIB INFORMATION: USED BY THE ZLIB ROUTINES */ |
| 2032 | z_stream z; |
| 2033 | png_uint_32 extra_bytes; /* Count of extra compressed bytes */ |
| 2034 | int state; |
| 2035 | int rc; /* Last return code */ |
| 2036 | int window_bits; /* 0 if no change */ |
| 2037 | png_byte header[2]; |
| 2038 | }; |
| 2039 | |
| 2040 | static const char * |
| 2041 | zlib_flevel(struct zlib *zlib) |
| 2042 | { |
| 2043 | switch (zlib->header[1] >> 6) |
| 2044 | { |
| 2045 | case 0: return "supfast"; |
| 2046 | case 1: return "stdfast"; |
| 2047 | case 2: return "default"; |
| 2048 | case 3: return "maximum"; |
| 2049 | default: assert(UNREACHED); |
| 2050 | } |
| 2051 | |
| 2052 | return "COMPILER BUG"; |
| 2053 | } |
| 2054 | |
| 2055 | static const char * |
| 2056 | zlib_rc(struct zlib *zlib) |
| 2057 | /* Return a string for the zlib return code */ |
| 2058 | { |
| 2059 | switch (zlib->rc) |
| 2060 | { |
| 2061 | case Z_OK: return "Z_OK"; |
| 2062 | case Z_STREAM_END: return "Z_STREAM_END"; |
| 2063 | case Z_NEED_DICT: return "Z_NEED_DICT"; |
| 2064 | case Z_ERRNO: return "Z_ERRNO"; |
| 2065 | case Z_STREAM_ERROR: return "Z_STREAM_ERROR"; |
| 2066 | case Z_DATA_ERROR: return "Z_DATA_ERROR"; |
| 2067 | case Z_MEM_ERROR: return "Z_MEM_ERROR"; |
| 2068 | case Z_BUF_ERROR: return "Z_BUF_ERROR"; |
| 2069 | case Z_VERSION_ERROR: return "Z_VERSION_ERROR"; |
| 2070 | default: return "Z_*INVALID_RC*"; |
| 2071 | } |
| 2072 | } |
| 2073 | |
| 2074 | static void |
| 2075 | zlib_message(struct zlib *zlib, int unexpected) |
| 2076 | /* Output a message given a zlib rc */ |
| 2077 | { |
| 2078 | if (zlib->global->errors) |
| 2079 | { |
| 2080 | const char *reason = zlib->z.msg; |
| 2081 | |
| 2082 | if (reason == NULL) |
| 2083 | reason = "[no message]"; |
| 2084 | |
| 2085 | fputs(zlib->file->file_name, stderr); |
| 2086 | type_sep(stderr); |
| 2087 | type_name(zlib->chunk->chunk_type, stderr); |
| 2088 | fprintf(stderr, ": %szlib error: %d (%s) (%s)\n", |
| 2089 | unexpected ? "unexpected " : "", zlib->rc, zlib_rc(zlib), reason); |
| 2090 | } |
| 2091 | } |
| 2092 | |
| 2093 | static void |
| 2094 | zlib_end(struct zlib *zlib) |
| 2095 | { |
| 2096 | /* Output the summary line now; this ensures a summary line always gets |
| 2097 | * output regardless of the manner of exit. |
| 2098 | */ |
| 2099 | if (!zlib->global->quiet) |
| 2100 | { |
| 2101 | if (zlib->ok_bits < 16) /* stream was read ok */ |
| 2102 | { |
| 2103 | const char *reason; |
| 2104 | |
| 2105 | if (zlib->cksum) |
| 2106 | reason = "CHK"; /* checksum error */ |
| 2107 | |
| 2108 | else if (zlib->ok_bits > zlib->file_bits) |
| 2109 | reason = "TFB"; /* fixing a too-far-back error */ |
| 2110 | |
| 2111 | else if (zlib->ok_bits == zlib->file_bits) |
| 2112 | reason = "OK "; |
| 2113 | |
| 2114 | else |
| 2115 | reason = "OPT"; /* optimizing window bits */ |
| 2116 | |
| 2117 | /* SUMMARY FORMAT (for a successful zlib inflate): |
| 2118 | * |
| 2119 | * IDAT reason flevel file-bits ok-bits compressed uncompressed file |
| 2120 | */ |
| 2121 | type_name(zlib->chunk->chunk_type, stdout); |
| 2122 | printf(" %s %s %d %d ", reason, zlib_flevel(zlib), zlib->file_bits, |
| 2123 | zlib->ok_bits); |
| 2124 | uarb_print(zlib->compressed_bytes, zlib->compressed_digits, stdout); |
| 2125 | putc(' ', stdout); |
| 2126 | uarb_print(zlib->uncompressed_bytes, zlib->uncompressed_digits, |
| 2127 | stdout); |
| 2128 | putc(' ', stdout); |
| 2129 | fputs(zlib->file->file_name, stdout); |
| 2130 | putc('\n', stdout); |
| 2131 | } |
| 2132 | |
| 2133 | else |
| 2134 | { |
| 2135 | /* This is a zlib read error; the chunk will be skipped. For an IDAT |
| 2136 | * stream this will also cause a fatal read error (via stop()). |
| 2137 | * |
| 2138 | * SUMMARY FORMAT: |
| 2139 | * |
| 2140 | * IDAT SKP flevel file-bits z-rc compressed message file |
| 2141 | * |
| 2142 | * z-rc is the zlib failure code; message is the error message with |
| 2143 | * spaces replaced by '-'. The compressed byte count indicates where |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 2144 | * in the zlib stream the error occurred. |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 2145 | */ |
| 2146 | type_name(zlib->chunk->chunk_type, stdout); |
| 2147 | printf(" SKP %s %d %s ", zlib_flevel(zlib), zlib->file_bits, |
| 2148 | zlib_rc(zlib)); |
| 2149 | uarb_print(zlib->compressed_bytes, zlib->compressed_digits, stdout); |
| 2150 | putc(' ', stdout); |
| 2151 | emit_string(zlib->z.msg ? zlib->z.msg : "[no_message]", stdout); |
| 2152 | putc(' ', stdout); |
| 2153 | fputs(zlib->file->file_name, stdout); |
| 2154 | putc('\n', stdout); |
| 2155 | } |
| 2156 | } |
| 2157 | |
| 2158 | if (zlib->state >= 0) |
| 2159 | { |
| 2160 | zlib->rc = inflateEnd(&zlib->z); |
| 2161 | |
| 2162 | if (zlib->rc != Z_OK) |
| 2163 | zlib_message(zlib, 1/*unexpected*/); |
| 2164 | } |
| 2165 | |
| 2166 | CLEAR(*zlib); |
| 2167 | } |
| 2168 | |
| 2169 | static int |
| 2170 | zlib_reset(struct zlib *zlib, int window_bits) |
| 2171 | /* Reinitializes a zlib with a different window_bits */ |
| 2172 | { |
| 2173 | assert(zlib->state >= 0); /* initialized by zlib_init */ |
| 2174 | |
| 2175 | zlib->z.next_in = Z_NULL; |
| 2176 | zlib->z.avail_in = 0; |
| 2177 | zlib->z.next_out = Z_NULL; |
| 2178 | zlib->z.avail_out = 0; |
| 2179 | |
| 2180 | zlib->window_bits = window_bits; |
| 2181 | zlib->compressed_digits = 0; |
| 2182 | zlib->uncompressed_digits = 0; |
| 2183 | |
| 2184 | zlib->state = 0; /* initialized, once */ |
| 2185 | zlib->rc = inflateReset2(&zlib->z, 0); |
| 2186 | if (zlib->rc != Z_OK) |
| 2187 | { |
| 2188 | zlib_message(zlib, 1/*unexpected*/); |
| 2189 | return 0; |
| 2190 | } |
| 2191 | |
| 2192 | return 1; |
| 2193 | } |
| 2194 | |
| 2195 | static int |
| 2196 | zlib_init(struct zlib *zlib, struct IDAT *idat, struct chunk *chunk, |
| 2197 | int window_bits, png_uint_32 offset) |
| 2198 | /* Initialize a zlib_control; the result is true/false */ |
| 2199 | { |
| 2200 | CLEAR(*zlib); |
| 2201 | |
| 2202 | zlib->idat = idat; |
| 2203 | zlib->chunk = chunk; |
| 2204 | zlib->file = chunk->file; |
| 2205 | zlib->global = chunk->global; |
| 2206 | zlib->rewrite_offset = offset; /* never changed for this zlib */ |
| 2207 | |
| 2208 | /* *_out does not need to be set: */ |
| 2209 | zlib->z.next_in = Z_NULL; |
| 2210 | zlib->z.avail_in = 0; |
| 2211 | zlib->z.zalloc = Z_NULL; |
| 2212 | zlib->z.zfree = Z_NULL; |
| 2213 | zlib->z.opaque = Z_NULL; |
| 2214 | |
| 2215 | zlib->state = -1; |
| 2216 | zlib->window_bits = window_bits; |
| 2217 | |
| 2218 | zlib->compressed_digits = 0; |
| 2219 | zlib->uncompressed_digits = 0; |
| 2220 | |
| 2221 | /* These values are sticky across reset (in addition to the stuff in the |
| 2222 | * first block, which is actually constant.) |
| 2223 | */ |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 2224 | zlib->file_bits = 24; |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 2225 | zlib->ok_bits = 16; /* unset */ |
| 2226 | zlib->cksum = 0; /* set when a checksum error is detected */ |
| 2227 | |
| 2228 | /* '0' means use the header; inflateInit2 should always succeed because it |
| 2229 | * does nothing apart from allocating the internal zstate. |
| 2230 | */ |
| 2231 | zlib->rc = inflateInit2(&zlib->z, 0); |
| 2232 | if (zlib->rc != Z_OK) |
| 2233 | { |
| 2234 | zlib_message(zlib, 1/*unexpected*/); |
| 2235 | return 0; |
| 2236 | } |
| 2237 | |
| 2238 | else |
| 2239 | { |
| 2240 | zlib->state = 0; /* initialized */ |
| 2241 | return 1; |
| 2242 | } |
| 2243 | } |
| 2244 | |
| 2245 | static int |
| 2246 | max_window_bits(uarbc size, int ndigits) |
| 2247 | /* Return the zlib stream window bits required for data of the given size. */ |
| 2248 | { |
| 2249 | png_uint_16 cb; |
| 2250 | |
| 2251 | if (ndigits > 1) |
| 2252 | return 15; |
| 2253 | |
| 2254 | cb = size[0]; |
| 2255 | |
| 2256 | if (cb > 16384) return 15; |
| 2257 | if (cb > 8192) return 14; |
| 2258 | if (cb > 4096) return 13; |
| 2259 | if (cb > 2048) return 12; |
| 2260 | if (cb > 1024) return 11; |
| 2261 | if (cb > 512) return 10; |
| 2262 | if (cb > 256) return 9; |
| 2263 | return 8; |
| 2264 | } |
| 2265 | |
| 2266 | static int |
| 2267 | zlib_advance(struct zlib *zlib, png_uint_32 nbytes) |
| 2268 | /* Read nbytes compressed bytes; the stream will be initialized if required. |
| 2269 | * Bytes are always being reread and errors are fatal. The return code is as |
| 2270 | * follows: |
| 2271 | * |
| 2272 | * -1: saw the "too far back" error |
| 2273 | * 0: ok, keep going |
| 2274 | * 1: saw Z_STREAM_END (zlib->extra_bytes indicates too much data) |
| 2275 | * 2: a zlib error that cannot be corrected (error message already |
| 2276 | * output if required.) |
| 2277 | */ |
| 2278 | # define ZLIB_TOO_FAR_BACK (-1) |
| 2279 | # define ZLIB_OK 0 |
| 2280 | # define ZLIB_STREAM_END 1 |
| 2281 | # define ZLIB_FATAL 2 |
| 2282 | { |
| 2283 | int state = zlib->state; |
| 2284 | int endrc = ZLIB_OK; |
| 2285 | png_uint_32 in_bytes = 0; |
| 2286 | struct file *file = zlib->file; |
| 2287 | |
| 2288 | assert(state >= 0); |
| 2289 | |
| 2290 | while (in_bytes < nbytes && endrc == ZLIB_OK) |
| 2291 | { |
| 2292 | png_uint_32 out_bytes; |
| 2293 | int flush; |
| 2294 | png_byte bIn = reread_byte(file); |
| 2295 | png_byte bOut; |
| 2296 | |
| 2297 | switch (state) |
| 2298 | { |
| 2299 | case 0: /* first header byte */ |
| 2300 | { |
| 2301 | int file_bits = 8+(bIn >> 4); |
| 2302 | int new_bits = zlib->window_bits; |
| 2303 | |
| 2304 | zlib->file_bits = file_bits; |
| 2305 | |
| 2306 | /* Check against the existing value - it may not need to be |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 2307 | * changed. Note that a bogus file_bits is allowed through once, |
| 2308 | * to see if it works, but the window_bits value is set to 15, |
| 2309 | * the maximum. |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 2310 | */ |
| 2311 | if (new_bits == 0) /* no change */ |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 2312 | zlib->window_bits = ((file_bits > 15) ? 15 : file_bits); |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 2313 | |
| 2314 | else if (new_bits != file_bits) /* rewrite required */ |
| 2315 | bIn = (png_byte)((bIn & 0xf) + ((new_bits-8) << 4)); |
| 2316 | } |
| 2317 | |
| 2318 | zlib->header[0] = bIn; |
| 2319 | zlib->state = state = 1; |
| 2320 | break; |
| 2321 | |
| 2322 | case 1: /* second header byte */ |
| 2323 | { |
| 2324 | int b2 = bIn & 0xe0; /* top 3 bits */ |
| 2325 | |
| 2326 | /* The checksum calculation, on the first 11 bits: */ |
| 2327 | b2 += 0x1f - ((zlib->header[0] << 8) + b2) % 0x1f; |
| 2328 | |
| 2329 | /* Update the checksum byte if required: */ |
| 2330 | if (bIn != b2) |
| 2331 | { |
| 2332 | /* If the first byte wasn't changed this indicates an error in |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 2333 | * the checksum calculation; signal this by setting 'cksum'. |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 2334 | */ |
| 2335 | if (zlib->file_bits == zlib->window_bits) |
| 2336 | zlib->cksum = 1; |
| 2337 | |
| 2338 | bIn = (png_byte)b2; |
| 2339 | } |
| 2340 | } |
| 2341 | |
| 2342 | zlib->header[1] = bIn; |
| 2343 | zlib->state = state = 2; |
| 2344 | break; |
| 2345 | |
| 2346 | default: /* After the header bytes */ |
| 2347 | break; |
| 2348 | } |
| 2349 | |
| 2350 | /* For some streams, perhaps only those compressed with 'superfast |
| 2351 | * compression' (which results in a lot of copying) Z_BUF_ERROR can happen |
| 2352 | * immediately after all output has been flushed on the next input byte. |
| 2353 | * This is handled below when Z_BUF_ERROR is detected by adding an output |
| 2354 | * byte. |
| 2355 | */ |
| 2356 | zlib->z.next_in = &bIn; |
| 2357 | zlib->z.avail_in = 1; |
| 2358 | zlib->z.next_out = &bOut; |
| 2359 | zlib->z.avail_out = 0; /* Initially */ |
| 2360 | |
| 2361 | /* Initially use Z_NO_FLUSH in an attempt to persuade zlib to look at this |
| 2362 | * byte without confusing what is going on with output. |
| 2363 | */ |
| 2364 | flush = Z_NO_FLUSH; |
| 2365 | out_bytes = 0; |
| 2366 | |
| 2367 | /* NOTE: expression 3 is only evaluted on 'continue', because of the |
| 2368 | * 'break' at the end of this loop below. |
| 2369 | */ |
| 2370 | for (;endrc == ZLIB_OK; |
| 2371 | flush = Z_SYNC_FLUSH, |
| 2372 | zlib->z.next_out = &bOut, |
| 2373 | zlib->z.avail_out = 1, |
| 2374 | ++out_bytes) |
| 2375 | { |
| 2376 | zlib->rc = inflate(&zlib->z, flush); |
| 2377 | out_bytes -= zlib->z.avail_out; |
| 2378 | |
| 2379 | switch (zlib->rc) |
| 2380 | { |
| 2381 | case Z_BUF_ERROR: |
| 2382 | if (zlib->z.avail_out == 0) |
| 2383 | continue; /* Try another output byte. */ |
| 2384 | |
| 2385 | if (zlib->z.avail_in == 0) |
| 2386 | break; /* Try another input byte */ |
| 2387 | |
| 2388 | /* Both avail_out and avail_in are 1 yet zlib returned a code |
| 2389 | * indicating no progress was possible. This is unexpected. |
| 2390 | */ |
| 2391 | zlib_message(zlib, 1/*unexpected*/); |
| 2392 | endrc = ZLIB_FATAL; /* stop processing */ |
| 2393 | break; |
| 2394 | |
| 2395 | case Z_OK: |
| 2396 | /* Zlib is supposed to have made progress: */ |
| 2397 | assert(zlib->z.avail_out == 0 || zlib->z.avail_in == 0); |
| 2398 | continue; |
| 2399 | |
| 2400 | case Z_STREAM_END: |
| 2401 | /* This is the successful end. */ |
| 2402 | zlib->state = 3; /* end of stream */ |
| 2403 | endrc = ZLIB_STREAM_END; |
| 2404 | break; |
| 2405 | |
| 2406 | case Z_NEED_DICT: |
| 2407 | zlib_message(zlib, 0/*stream error*/); |
| 2408 | endrc = ZLIB_FATAL; |
| 2409 | break; |
| 2410 | |
| 2411 | case Z_DATA_ERROR: |
| 2412 | /* The too far back error can be corrected, others cannot: */ |
| 2413 | if (zlib->z.msg != NULL && |
| 2414 | strcmp(zlib->z.msg, "invalid distance too far back") == 0) |
| 2415 | { |
| 2416 | endrc = ZLIB_TOO_FAR_BACK; |
| 2417 | break; |
| 2418 | } |
| 2419 | /* FALL THROUGH */ |
| 2420 | |
| 2421 | default: |
| 2422 | zlib_message(zlib, 0/*stream error*/); |
| 2423 | endrc = ZLIB_FATAL; |
| 2424 | break; |
| 2425 | } /* switch (inflate rc) */ |
| 2426 | |
| 2427 | /* Control gets here when further output is not possible; endrc may |
| 2428 | * still be ZLIB_OK if more input is required. |
| 2429 | */ |
| 2430 | break; |
| 2431 | } /* for (output bytes) */ |
| 2432 | |
| 2433 | /* Keep a running count of output byte produced: */ |
| 2434 | zlib->uncompressed_digits = uarb_add32(zlib->uncompressed_bytes, |
| 2435 | zlib->uncompressed_digits, out_bytes); |
| 2436 | |
| 2437 | /* Keep going, the loop will terminate when endrc is no longer set to |
| 2438 | * ZLIB_OK or all the input bytes have been consumed; meanwhile keep |
| 2439 | * adding input bytes. |
| 2440 | */ |
| 2441 | assert(zlib->z.avail_in == 0 || endrc != ZLIB_OK); |
| 2442 | |
| 2443 | in_bytes += 1 - zlib->z.avail_in; |
| 2444 | } /* while (input bytes) */ |
| 2445 | |
| 2446 | assert(in_bytes == nbytes || endrc != ZLIB_OK); |
| 2447 | |
| 2448 | /* Update the running total of input bytes consumed */ |
| 2449 | zlib->compressed_digits = uarb_add32(zlib->compressed_bytes, |
| 2450 | zlib->compressed_digits, in_bytes - zlib->z.avail_in); |
| 2451 | |
| 2452 | /* At the end of the stream update the chunk with the accumulated |
| 2453 | * information if it is an improvement: |
| 2454 | */ |
| 2455 | if (endrc == ZLIB_STREAM_END && zlib->window_bits < zlib->ok_bits) |
| 2456 | { |
| 2457 | struct chunk *chunk = zlib->chunk; |
| 2458 | |
| 2459 | chunk->uncompressed_digits = uarb_copy(chunk->uncompressed_bytes, |
| 2460 | zlib->uncompressed_bytes, zlib->uncompressed_digits); |
| 2461 | chunk->compressed_digits = uarb_copy(chunk->compressed_bytes, |
| 2462 | zlib->compressed_bytes, zlib->compressed_digits); |
| 2463 | chunk->rewrite_buffer[0] = zlib->header[0]; |
| 2464 | chunk->rewrite_buffer[1] = zlib->header[1]; |
| 2465 | |
| 2466 | if (zlib->window_bits != zlib->file_bits || zlib->cksum) |
| 2467 | { |
| 2468 | /* A rewrite is required */ |
| 2469 | chunk->rewrite_offset = zlib->rewrite_offset; |
| 2470 | chunk->rewrite_length = 2; |
| 2471 | } |
| 2472 | |
| 2473 | else |
| 2474 | { |
| 2475 | chunk->rewrite_offset = 0; |
| 2476 | chunk->rewrite_length = 0; |
| 2477 | } |
| 2478 | |
| 2479 | if (in_bytes < nbytes) |
| 2480 | chunk_message(chunk, "extra compressed data"); |
| 2481 | |
| 2482 | zlib->extra_bytes = nbytes - in_bytes; |
| 2483 | zlib->ok_bits = zlib->window_bits; |
| 2484 | } |
| 2485 | |
| 2486 | return endrc; |
| 2487 | } |
| 2488 | |
| 2489 | static int |
| 2490 | zlib_run(struct zlib *zlib) |
| 2491 | /* Like zlib_advance but also handles a stream of IDAT chunks. */ |
| 2492 | { |
| 2493 | /* The 'extra_bytes' field is set by zlib_advance if there is extra |
| 2494 | * compressed data in the chunk it handles (if it sees Z_STREAM_END before |
| 2495 | * all the input data has been used.) This function uses the value to update |
| 2496 | * the correct chunk length, so the problem should only ever be detected once |
| 2497 | * for each chunk. zlib_advance outputs the error message, though see the |
| 2498 | * IDAT specific check below. |
| 2499 | */ |
| 2500 | zlib->extra_bytes = 0; |
| 2501 | |
| 2502 | if (zlib->idat != NULL) |
| 2503 | { |
| 2504 | struct IDAT_list *list = zlib->idat->idat_list_head; |
| 2505 | struct IDAT_list *last = zlib->idat->idat_list_tail; |
| 2506 | int skip = 0; |
| 2507 | |
| 2508 | /* 'rewrite_offset' is the offset of the LZ data within the chunk, for |
| 2509 | * IDAT it should be 0: |
| 2510 | */ |
| 2511 | assert(zlib->rewrite_offset == 0); |
| 2512 | |
| 2513 | /* Process each IDAT_list in turn; the caller has left the stream |
| 2514 | * positioned at the start of the first IDAT chunk data. |
| 2515 | */ |
| 2516 | for (;;) |
| 2517 | { |
| 2518 | const unsigned int count = list->count; |
| 2519 | unsigned int i; |
| 2520 | |
| 2521 | for (i = 0; i<count; ++i) |
| 2522 | { |
| 2523 | int rc; |
| 2524 | |
| 2525 | if (skip > 0) /* Skip CRC and next IDAT header */ |
| 2526 | skip_12(zlib->file); |
| 2527 | |
| 2528 | skip = 12; /* for the next time */ |
| 2529 | |
| 2530 | rc = zlib_advance(zlib, list->lengths[i]); |
| 2531 | |
| 2532 | switch (rc) |
| 2533 | { |
| 2534 | case ZLIB_OK: /* keep going */ |
| 2535 | break; |
| 2536 | |
| 2537 | case ZLIB_STREAM_END: /* stop */ |
| 2538 | /* There may be extra chunks; if there are and one of them is |
| 2539 | * not zero length output the 'extra data' message. Only do |
| 2540 | * this check if errors are being output. |
| 2541 | */ |
| 2542 | if (zlib->global->errors && zlib->extra_bytes == 0) |
| 2543 | { |
| 2544 | struct IDAT_list *check = list; |
| 2545 | int j = i+1, jcount = count; |
| 2546 | |
| 2547 | for (;;) |
| 2548 | { |
| 2549 | for (; j<jcount; ++j) |
| 2550 | if (check->lengths[j] > 0) |
| 2551 | { |
| 2552 | chunk_message(zlib->chunk, |
| 2553 | "extra compressed data"); |
| 2554 | goto end_check; |
| 2555 | } |
| 2556 | |
| 2557 | if (check == last) |
| 2558 | break; |
| 2559 | |
| 2560 | check = check->next; |
| 2561 | jcount = check->count; |
| 2562 | j = 0; |
| 2563 | } |
| 2564 | } |
| 2565 | |
| 2566 | end_check: |
| 2567 | /* Terminate the list at the current position, reducing the |
| 2568 | * length of the last IDAT too if required. |
| 2569 | */ |
| 2570 | list->lengths[i] -= zlib->extra_bytes; |
| 2571 | list->count = i+1; |
| 2572 | zlib->idat->idat_list_tail = list; |
| 2573 | /* FALL THROUGH */ |
| 2574 | |
| 2575 | default: |
| 2576 | return rc; |
| 2577 | } |
| 2578 | } |
| 2579 | |
| 2580 | /* At the end of the compressed data and Z_STREAM_END was not seen. */ |
| 2581 | if (list == last) |
| 2582 | return ZLIB_OK; |
| 2583 | |
| 2584 | list = list->next; |
| 2585 | } |
| 2586 | } |
| 2587 | |
| 2588 | else |
| 2589 | { |
| 2590 | struct chunk *chunk = zlib->chunk; |
| 2591 | int rc; |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 2592 | |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 2593 | assert(zlib->rewrite_offset < chunk->chunk_length); |
| 2594 | |
| 2595 | rc = zlib_advance(zlib, chunk->chunk_length - zlib->rewrite_offset); |
| 2596 | |
| 2597 | /* The extra bytes in the chunk are handled now by adjusting the chunk |
| 2598 | * length to exclude them; the zlib data is always stored at the end of |
| 2599 | * the PNG chunk (although clearly this is not necessary.) zlib_advance |
| 2600 | * has already output a warning message. |
| 2601 | */ |
| 2602 | chunk->chunk_length -= zlib->extra_bytes; |
| 2603 | return rc; |
| 2604 | } |
| 2605 | } |
| 2606 | |
| 2607 | static int /* global function; not a member function */ |
| 2608 | zlib_check(struct file *file, png_uint_32 offset) |
| 2609 | /* Check the stream of zlib compressed data in either idat (if given) or (if |
| 2610 | * not) chunk. In fact it is zlib_run that handles the difference in reading |
| 2611 | * a single chunk and a list of IDAT chunks. |
| 2612 | * |
| 2613 | * In either case the input file must be positioned at the first byte of zlib |
| 2614 | * compressed data (the first header byte). |
| 2615 | * |
| 2616 | * The return value is true on success, including the case where the zlib |
| 2617 | * header may need to be rewritten, and false on an unrecoverable error. |
| 2618 | * |
| 2619 | * In the case of IDAT chunks 'offset' should be 0. |
| 2620 | */ |
| 2621 | { |
| 2622 | fpos_t start_pos; |
| 2623 | struct zlib zlib; |
| 2624 | |
| 2625 | /* Record the start of the LZ data to allow a re-read. */ |
| 2626 | file_getpos(file, &start_pos); |
| 2627 | |
| 2628 | /* First test the existing (file) window bits: */ |
| 2629 | if (zlib_init(&zlib, file->idat, file->chunk, 0/*window bits*/, offset)) |
| 2630 | { |
| 2631 | int min_bits, max_bits, rc; |
| 2632 | |
| 2633 | /* The first run using the existing window bits. */ |
| 2634 | rc = zlib_run(&zlib); |
| 2635 | |
| 2636 | switch (rc) |
| 2637 | { |
| 2638 | case ZLIB_TOO_FAR_BACK: |
| 2639 | /* too far back error */ |
| 2640 | file->status_code |= TOO_FAR_BACK; |
| 2641 | min_bits = zlib.window_bits + 1; |
| 2642 | max_bits = 15; |
| 2643 | break; |
| 2644 | |
| 2645 | case ZLIB_STREAM_END: |
| 2646 | if (!zlib.global->optimize_zlib && |
| 2647 | zlib.window_bits == zlib.file_bits && !zlib.cksum) |
| 2648 | { |
| 2649 | /* The trivial case where the stream is ok and optimization was |
| 2650 | * not requested. |
| 2651 | */ |
| 2652 | zlib_end(&zlib); |
| 2653 | return 1; |
| 2654 | } |
| 2655 | |
| 2656 | max_bits = max_window_bits(zlib.uncompressed_bytes, |
| 2657 | zlib.uncompressed_digits); |
| 2658 | if (zlib.ok_bits < max_bits) |
| 2659 | max_bits = zlib.ok_bits; |
| 2660 | min_bits = 8; |
| 2661 | |
| 2662 | /* cksum is set if there is an error in the zlib header checksum |
| 2663 | * calculation in the original file (and this may be the only reason |
| 2664 | * a rewrite is required). We can't rely on the file window bits in |
| 2665 | * this case, so do the optimization anyway. |
| 2666 | */ |
| 2667 | if (zlib.cksum) |
| 2668 | chunk_message(zlib.chunk, "zlib checkum"); |
| 2669 | break; |
| 2670 | |
| 2671 | |
| 2672 | case ZLIB_OK: |
| 2673 | /* Truncated stream; unrecoverable, gets converted to ZLIB_FATAL */ |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 2674 | zlib.z.msg = PNGZ_MSG_CAST("[truncated]"); |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 2675 | zlib_message(&zlib, 0/*expected*/); |
| 2676 | /* FALL THROUGH */ |
| 2677 | |
| 2678 | default: |
| 2679 | /* Unrecoverable error; skip the chunk; a zlib_message has already |
| 2680 | * been output. |
| 2681 | */ |
| 2682 | zlib_end(&zlib); |
| 2683 | return 0; |
| 2684 | } |
| 2685 | |
| 2686 | /* Optimize window bits or fix a too-far-back error. min_bits and |
| 2687 | * max_bits have been set appropriately, ok_bits records the bit value |
| 2688 | * known to work. |
| 2689 | */ |
| 2690 | while (min_bits < max_bits || max_bits < zlib.ok_bits/*if 16*/) |
| 2691 | { |
| 2692 | int test_bits = (min_bits + max_bits) >> 1; |
| 2693 | |
| 2694 | if (zlib_reset(&zlib, test_bits)) |
| 2695 | { |
| 2696 | file_setpos(file, &start_pos); |
| 2697 | rc = zlib_run(&zlib); |
| 2698 | |
| 2699 | switch (rc) |
| 2700 | { |
| 2701 | case ZLIB_TOO_FAR_BACK: |
| 2702 | min_bits = test_bits+1; |
| 2703 | if (min_bits > max_bits) |
| 2704 | { |
| 2705 | /* This happens when the stream really is damaged and it |
| 2706 | * contains a distance code that addresses bytes before |
| 2707 | * the start of the uncompressed data. |
| 2708 | */ |
| 2709 | assert(test_bits == 15); |
| 2710 | |
| 2711 | /* Output the error that wasn't output before: */ |
| 2712 | if (zlib.z.msg == NULL) |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 2713 | zlib.z.msg = PNGZ_MSG_CAST( |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 2714 | "invalid distance too far back"); |
| 2715 | zlib_message(&zlib, 0/*stream error*/); |
| 2716 | zlib_end(&zlib); |
| 2717 | return 0; |
| 2718 | } |
| 2719 | break; |
| 2720 | |
| 2721 | case ZLIB_STREAM_END: /* success */ |
| 2722 | max_bits = test_bits; |
| 2723 | break; |
| 2724 | |
| 2725 | default: |
| 2726 | /* A fatal error; this happens if a too-far-back error was |
| 2727 | * hiding a more serious error, zlib_advance has already |
| 2728 | * output a zlib_message. |
| 2729 | */ |
| 2730 | zlib_end(&zlib); |
| 2731 | return 0; |
| 2732 | } |
| 2733 | } |
| 2734 | |
| 2735 | else /* inflateReset2 failed */ |
| 2736 | { |
| 2737 | zlib_end(&zlib); |
| 2738 | return 0; |
| 2739 | } |
| 2740 | } |
| 2741 | |
| 2742 | /* The loop guarantees this */ |
| 2743 | assert(zlib.ok_bits == max_bits); |
| 2744 | zlib_end(&zlib); |
| 2745 | return 1; |
| 2746 | } |
| 2747 | |
| 2748 | else /* zlib initialization failed - skip the chunk */ |
| 2749 | { |
| 2750 | zlib_end(&zlib); |
| 2751 | return 0; |
| 2752 | } |
| 2753 | } |
| 2754 | |
| 2755 | /***************************** LIBPNG CALLBACKS *******************************/ |
| 2756 | /* The strategy here is to run a regular libpng PNG file read but examine the |
| 2757 | * input data (from the file) before passing it to libpng so as to be aware of |
| 2758 | * the state we expect libpng to be in. Warning and error callbacks are also |
| 2759 | * intercepted so that they can be quieted and interpreted. Interpretation |
| 2760 | * depends on a somewhat risky string match for known error messages; let us |
| 2761 | * hope that this can be fixed in the next version of libpng. |
| 2762 | * |
| 2763 | * The control structure is pointed to by the libpng error pointer. It contains |
| 2764 | * that set of structures which must persist across multiple read callbacks, |
| 2765 | * which is pretty much everything except the 'zlib' control structure. |
| 2766 | * |
| 2767 | * The file structure is instantiated in the caller of the per-file routine, but |
| 2768 | * the per-file routine contains the chunk and IDAT control structures. |
| 2769 | */ |
| 2770 | /* The three routines read_chunk, process_chunk and sync_stream can only be |
| 2771 | * called via a call to read_chunk and only exit at a return from process_chunk. |
| 2772 | * These routines could have been written as one confusing large routine, |
| 2773 | * instead this code relies on the compiler to do tail call elimination. The |
| 2774 | * possible calls are as follows: |
| 2775 | * |
| 2776 | * read_chunk |
| 2777 | * -> sync_stream |
| 2778 | * -> process_chunk |
| 2779 | * -> process_chunk |
| 2780 | * -> read_chunk |
| 2781 | * returns |
| 2782 | */ |
| 2783 | static void read_chunk(struct file *file); |
| 2784 | static void |
| 2785 | process_chunk(struct file *file, png_uint_32 file_crc, png_uint_32 next_length, |
| 2786 | png_uint_32 next_type) |
| 2787 | /* Called when the chunk data has been read, next_length and next_type |
| 2788 | * will be set for the next chunk (or 0 if this is IEND). |
| 2789 | * |
| 2790 | * When this routine returns, chunk_length and chunk_type will be set for the |
| 2791 | * next chunk to write because if a chunk is skipped this return calls back |
| 2792 | * to read_chunk. |
| 2793 | */ |
| 2794 | { |
| 2795 | const png_uint_32 type = file->type; |
| 2796 | |
| 2797 | if (file->global->verbose > 1) |
| 2798 | { |
| 2799 | fputs(" ", stderr); |
| 2800 | type_name(file->type, stderr); |
| 2801 | fprintf(stderr, " %lu 0x%.8x 0x%.8x\n", (unsigned long)file->length, |
| 2802 | file->crc ^ 0xffffffff, file_crc); |
| 2803 | } |
| 2804 | |
| 2805 | /* The basic structure seems correct but the CRC may not match, in this |
| 2806 | * case assume that it is simply a bad CRC, either wrongly calculated or |
| 2807 | * because of damaged stream data. |
| 2808 | */ |
| 2809 | if ((file->crc ^ 0xffffffff) != file_crc) |
| 2810 | { |
| 2811 | /* The behavior is set by the 'skip' setting; if it is anything other |
| 2812 | * than SKIP_BAD_CRC ignore the bad CRC and return the chunk, with a |
| 2813 | * corrected CRC and possibly processed, to libpng. Otherwise skip the |
| 2814 | * chunk, which will result in a fatal error if the chunk is critical. |
| 2815 | */ |
| 2816 | file->status_code |= CRC_ERROR; |
| 2817 | |
| 2818 | /* Ignore the bad CRC */ |
| 2819 | if (file->global->skip != SKIP_BAD_CRC) |
| 2820 | type_message(file, type, "bad CRC"); |
| 2821 | |
| 2822 | /* This will cause an IEND with a bad CRC to stop */ |
| 2823 | else if (CRITICAL(type)) |
| 2824 | stop(file, READ_ERROR_CODE, "bad CRC in critical chunk"); |
| 2825 | |
| 2826 | else |
| 2827 | { |
| 2828 | type_message(file, type, "skipped: bad CRC"); |
| 2829 | |
| 2830 | /* NOTE: this cannot be reached for IEND because it is critical. */ |
| 2831 | goto skip_chunk; |
| 2832 | } |
| 2833 | } |
| 2834 | |
| 2835 | /* Check for other 'skip' cases and handle these; these only apply to |
| 2836 | * ancillary chunks (and not tRNS, which should probably have been a critical |
| 2837 | * chunk.) |
| 2838 | */ |
| 2839 | if (skip_chunk_type(file->global, type)) |
| 2840 | goto skip_chunk; |
| 2841 | |
| 2842 | /* The chunk may still be skipped if problems are detected in the LZ data, |
| 2843 | * however the LZ data check requires a chunk. Handle this by instantiating |
| 2844 | * a chunk unless an IDAT is already instantiated (IDAT control structures |
| 2845 | * instantiate their own chunk.) |
| 2846 | */ |
| 2847 | if (type != png_IDAT) |
| 2848 | file->alloc(file, 0/*chunk*/); |
| 2849 | |
| 2850 | else if (file->idat == NULL) |
| 2851 | file->alloc(file, 1/*IDAT*/); |
| 2852 | |
| 2853 | else |
| 2854 | { |
| 2855 | /* The chunk length must be updated for process_IDAT */ |
| 2856 | assert(file->chunk != NULL); |
| 2857 | assert(file->chunk->chunk_type == png_IDAT); |
| 2858 | file->chunk->chunk_length = file->length; |
| 2859 | } |
| 2860 | |
| 2861 | /* Record the 'next' information too, now that the original values for |
| 2862 | * this chunk have been copied. Notice that the IDAT chunks only make a |
| 2863 | * copy of the position of the first chunk, this is fine - process_IDAT does |
| 2864 | * not need the position of this chunk. |
| 2865 | */ |
| 2866 | file->length = next_length; |
| 2867 | file->type = next_type; |
| 2868 | getpos(file); |
| 2869 | |
| 2870 | /* Do per-type processing, note that if this code does not return from the |
| 2871 | * function the chunk will be skipped. The rewrite is cancelled here so that |
| 2872 | * it can be set in the per-chunk processing. |
| 2873 | */ |
| 2874 | file->chunk->rewrite_length = 0; |
| 2875 | file->chunk->rewrite_offset = 0; |
| 2876 | switch (type) |
| 2877 | { |
| 2878 | default: |
| 2879 | return; |
| 2880 | |
| 2881 | case png_IHDR: |
| 2882 | /* Read this now and update the control structure with the information |
| 2883 | * it contains. The header is validated completely to ensure this is a |
| 2884 | * PNG. |
| 2885 | */ |
| 2886 | { |
| 2887 | struct chunk *chunk = file->chunk; |
| 2888 | |
| 2889 | if (chunk->chunk_length != 13) |
| 2890 | stop_invalid(file, "IHDR length"); |
| 2891 | |
| 2892 | /* Read all the IHDR information and validate it. */ |
| 2893 | setpos(chunk); |
| 2894 | file->width = reread_4(file); |
| 2895 | file->height = reread_4(file); |
| 2896 | file->bit_depth = reread_byte(file); |
| 2897 | file->color_type = reread_byte(file); |
| 2898 | file->compression_method = reread_byte(file); |
| 2899 | file->filter_method = reread_byte(file); |
| 2900 | file->interlace_method = reread_byte(file); |
| 2901 | |
| 2902 | /* This validates all the fields, and calls stop_invalid if |
| 2903 | * there is a problem. |
| 2904 | */ |
| 2905 | calc_image_size(file); |
| 2906 | } |
| 2907 | return; |
| 2908 | |
| 2909 | /* Ancillary chunks that require further processing: */ |
| 2910 | case png_zTXt: case png_iCCP: |
| 2911 | if (process_zTXt_iCCP(file)) |
| 2912 | return; |
| 2913 | chunk_end(&file->chunk); |
| 2914 | file_setpos(file, &file->data_pos); |
| 2915 | break; |
| 2916 | |
| 2917 | case png_iTXt: |
| 2918 | if (process_iTXt(file)) |
| 2919 | return; |
| 2920 | chunk_end(&file->chunk); |
| 2921 | file_setpos(file, &file->data_pos); |
| 2922 | break; |
| 2923 | |
| 2924 | case png_IDAT: |
| 2925 | if (process_IDAT(file)) |
| 2926 | return; |
| 2927 | /* First pass: */ |
| 2928 | assert(next_type == png_IDAT); |
| 2929 | break; |
| 2930 | } |
| 2931 | |
| 2932 | /* Control reaches this point if the chunk must be skipped. For chunks other |
| 2933 | * than IDAT this means that the zlib compressed data is fatally damanged and |
| 2934 | * the chunk will not be passed to libpng. For IDAT it means that the end of |
| 2935 | * the IDAT stream has not yet been reached and we must handle the next |
| 2936 | * (IDAT) chunk. If the LZ data in an IDAT stream cannot be read 'stop' must |
| 2937 | * be used to halt parsing of the PNG. |
| 2938 | */ |
| 2939 | read_chunk(file); |
| 2940 | return; |
| 2941 | |
| 2942 | /* This is the generic code to skip the current chunk; simply jump to the |
| 2943 | * next one. |
| 2944 | */ |
| 2945 | skip_chunk: |
| 2946 | file->length = next_length; |
| 2947 | file->type = next_type; |
| 2948 | getpos(file); |
| 2949 | read_chunk(file); |
| 2950 | } |
| 2951 | |
| 2952 | static png_uint_32 |
| 2953 | get32(png_bytep buffer, int offset) |
| 2954 | /* Read a 32-bit value from an 8-byte circular buffer (used only below). |
| 2955 | */ |
| 2956 | { |
| 2957 | return |
| 2958 | (buffer[ offset & 7] << 24) + |
| 2959 | (buffer[(offset+1) & 7] << 16) + |
| 2960 | (buffer[(offset+2) & 7] << 8) + |
| 2961 | (buffer[(offset+3) & 7] ); |
| 2962 | } |
| 2963 | |
| 2964 | static void |
| 2965 | sync_stream(struct file *file) |
| 2966 | /* The stream seems to be messed up, attempt to resync from the current chunk |
| 2967 | * header. Executes stop on a fatal error, otherwise calls process_chunk. |
| 2968 | */ |
| 2969 | { |
| 2970 | png_uint_32 file_crc; |
| 2971 | |
| 2972 | file->status_code |= STREAM_ERROR; |
| 2973 | |
| 2974 | if (file->global->verbose) |
| 2975 | { |
| 2976 | fputs(" SYNC ", stderr); |
| 2977 | type_name(file->type, stderr); |
| 2978 | putc('\n', stderr); |
| 2979 | } |
| 2980 | |
| 2981 | /* Return to the start of the chunk data */ |
| 2982 | file_setpos(file, &file->data_pos); |
| 2983 | file->read_count = 8; |
| 2984 | |
| 2985 | if (read_4(file, &file_crc) == 4) /* else completely truncated */ |
| 2986 | { |
| 2987 | /* Ignore the recorded chunk length, proceed through the data looking for |
| 2988 | * a leading sequence of bytes that match the CRC in the following four |
| 2989 | * bytes. Each time a match is found check the next 8 bytes for a valid |
| 2990 | * length, chunk-type pair. |
| 2991 | */ |
| 2992 | png_uint_32 length; |
| 2993 | png_uint_32 type = file->type; |
| 2994 | png_uint_32 crc = crc_init_4(type); |
| 2995 | png_byte buffer[8]; |
| 2996 | unsigned int nread = 0, nused = 0; |
| 2997 | |
| 2998 | for (length=0; length <= 0x7fffffff; ++length) |
| 2999 | { |
| 3000 | int ch; |
| 3001 | |
| 3002 | if ((crc ^ 0xffffffff) == file_crc) |
| 3003 | { |
| 3004 | /* A match on the CRC; for IEND this is sufficient, but for anything |
| 3005 | * else expect a following chunk header. |
| 3006 | */ |
| 3007 | if (type == png_IEND) |
| 3008 | { |
| 3009 | file->length = length; |
| 3010 | process_chunk(file, file_crc, 0, 0); |
| 3011 | return; |
| 3012 | } |
| 3013 | |
| 3014 | else |
| 3015 | { |
| 3016 | /* Need 8 bytes */ |
| 3017 | while (nread < 8+nused) |
| 3018 | { |
| 3019 | ch = read_byte(file); |
| 3020 | if (ch == EOF) |
| 3021 | goto truncated; |
| 3022 | buffer[(nread++) & 7] = (png_byte)ch; |
| 3023 | } |
| 3024 | |
| 3025 | /* Prevent overflow */ |
| 3026 | nread -= nused & ~7; |
| 3027 | nused -= nused & ~7; /* or, nused &= 7 ;-) */ |
| 3028 | |
| 3029 | /* Examine the 8 bytes for a valid chunk header. */ |
| 3030 | { |
| 3031 | png_uint_32 next_length = get32(buffer, nused); |
| 3032 | |
| 3033 | if (next_length < 0x7fffffff) |
| 3034 | { |
| 3035 | png_uint_32 next_type = get32(buffer, nused+4); |
| 3036 | |
| 3037 | if (chunk_type_valid(next_type)) |
| 3038 | { |
| 3039 | file->read_count -= 8; |
| 3040 | process_chunk(file, file_crc, next_length, next_type); |
| 3041 | return; |
| 3042 | } |
| 3043 | } |
| 3044 | |
| 3045 | /* Not valid, keep going. */ |
| 3046 | } |
| 3047 | } |
| 3048 | } |
| 3049 | |
| 3050 | /* This catches up with the circular buffer which gets filled above |
| 3051 | * while checking a chunk header. This code is slightly tricky - if |
| 3052 | * the chunk_type is IEND the buffer will never be used, if it is not |
| 3053 | * the code will always read ahead exactly 8 bytes and pass this on to |
| 3054 | * process_chunk. So the invariant that IEND leaves the file position |
| 3055 | * after the IEND CRC and other chunk leave it after the *next* chunk |
| 3056 | * header is not broken. |
| 3057 | */ |
| 3058 | if (nread <= nused) |
| 3059 | { |
| 3060 | ch = read_byte(file); |
| 3061 | |
| 3062 | if (ch == EOF) |
| 3063 | goto truncated; |
| 3064 | } |
| 3065 | |
| 3066 | else |
| 3067 | ch = buffer[(++nused) & 7]; |
| 3068 | |
| 3069 | crc = crc_one_byte(crc, file_crc >> 24); |
| 3070 | file_crc = (file_crc << 8) + ch; |
| 3071 | } |
| 3072 | |
| 3073 | /* Control gets to here if when 0x7fffffff bytes (plus 8) have been read, |
| 3074 | * ok, treat this as a damaged stream too: |
| 3075 | */ |
| 3076 | } |
| 3077 | |
| 3078 | truncated: |
| 3079 | stop(file, READ_ERROR_CODE, "damaged PNG stream"); |
| 3080 | } |
| 3081 | |
| 3082 | static void |
| 3083 | read_chunk(struct file *file) |
| 3084 | /* On entry file::data_pos must be set to the position of the first byte |
| 3085 | * of the chunk data *and* the input file must be at this position. This |
| 3086 | * routine (via process_chunk) instantiates a chunk or IDAT control structure |
| 3087 | * based on file::length and file::type and also resets these fields and |
| 3088 | * file::data_pos for the chunk after this one. For an IDAT chunk the whole |
| 3089 | * stream of IDATs will be read, until something other than an IDAT is |
| 3090 | * encountered, and the file fields will be set for the chunk after the end |
| 3091 | * of the stream of IDATs. |
| 3092 | * |
| 3093 | * For IEND the file::type field will be set to 0, and nothing beyond the end |
| 3094 | * of the IEND chunk will have been read. |
| 3095 | */ |
| 3096 | { |
| 3097 | png_uint_32 length = file->length; |
| 3098 | png_uint_32 type = file->type; |
| 3099 | |
| 3100 | /* After IEND file::type is set to 0, if libpng attempts to read |
| 3101 | * more data at this point this is a bug in libpng. |
| 3102 | */ |
| 3103 | if (type == 0) |
| 3104 | stop(file, UNEXPECTED_ERROR_CODE, "read beyond IEND"); |
| 3105 | |
| 3106 | if (file->global->verbose > 2) |
| 3107 | { |
| 3108 | fputs(" ", stderr); |
| 3109 | type_name(type, stderr); |
| 3110 | fprintf(stderr, " %lu\n", (unsigned long)length); |
| 3111 | } |
| 3112 | |
| 3113 | /* Start the read_crc calculation with the chunk type, then read to the end |
| 3114 | * of the chunk data (without processing it in any way) to check that it is |
| 3115 | * all there and calculate the CRC. |
| 3116 | */ |
| 3117 | file->crc = crc_init_4(type); |
| 3118 | if (crc_read_many(file, length)) /* else it was truncated */ |
| 3119 | { |
| 3120 | png_uint_32 file_crc; /* CRC read from file */ |
| 3121 | unsigned int nread = read_4(file, &file_crc); |
| 3122 | |
| 3123 | if (nread == 4) |
| 3124 | { |
| 3125 | if (type != png_IEND) /* do not read beyond IEND */ |
| 3126 | { |
| 3127 | png_uint_32 next_length; |
| 3128 | |
| 3129 | nread += read_4(file, &next_length); |
| 3130 | if (nread == 8 && next_length <= 0x7fffffff) |
| 3131 | { |
| 3132 | png_uint_32 next_type; |
| 3133 | |
| 3134 | nread += read_4(file, &next_type); |
| 3135 | |
| 3136 | if (nread == 12 && chunk_type_valid(next_type)) |
| 3137 | { |
| 3138 | /* Adjust the read count back to the correct value for this |
| 3139 | * chunk. |
| 3140 | */ |
| 3141 | file->read_count -= 8; |
| 3142 | process_chunk(file, file_crc, next_length, next_type); |
| 3143 | return; |
| 3144 | } |
| 3145 | } |
| 3146 | } |
| 3147 | |
| 3148 | else /* IEND */ |
| 3149 | { |
| 3150 | process_chunk(file, file_crc, 0, 0); |
| 3151 | return; |
| 3152 | } |
| 3153 | } |
| 3154 | } |
| 3155 | |
| 3156 | /* Control gets to here if the the stream seems invalid or damaged in some |
| 3157 | * way. Either there was a problem reading all the expected data (this |
| 3158 | * chunk's data, its CRC and the length and type of the next chunk) or the |
| 3159 | * next chunk length/type are invalid. Notice that the cases that end up |
| 3160 | * here all correspond to cases that would otherwise terminate the read of |
| 3161 | * the PNG file. |
| 3162 | */ |
| 3163 | sync_stream(file); |
| 3164 | } |
| 3165 | |
| 3166 | /* This returns a file* from a png_struct in an implementation specific way. */ |
| 3167 | static struct file *get_control(png_const_structrp png_ptr); |
| 3168 | |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 3169 | static void PNGCBAPI |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3170 | error_handler(png_structp png_ptr, png_const_charp message) |
| 3171 | { |
| 3172 | stop(get_control(png_ptr), LIBPNG_ERROR_CODE, message); |
| 3173 | } |
| 3174 | |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 3175 | static void PNGCBAPI |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3176 | warning_handler(png_structp png_ptr, png_const_charp message) |
| 3177 | { |
| 3178 | struct file *file = get_control(png_ptr); |
| 3179 | |
| 3180 | if (file->global->warnings) |
| 3181 | emit_error(file, LIBPNG_WARNING_CODE, message); |
| 3182 | } |
| 3183 | |
| 3184 | /* Read callback - this is where the work gets done to check the stream before |
| 3185 | * passing it to libpng |
| 3186 | */ |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 3187 | static void PNGCBAPI |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3188 | read_callback(png_structp png_ptr, png_bytep buffer, size_t count) |
| 3189 | /* Return 'count' bytes to libpng in 'buffer' */ |
| 3190 | { |
| 3191 | struct file *file = get_control(png_ptr); |
| 3192 | png_uint_32 type, length; /* For the chunk be *WRITTEN* */ |
| 3193 | struct chunk *chunk; |
| 3194 | |
| 3195 | /* libpng should always ask for at least one byte */ |
| 3196 | if (count == 0) |
| 3197 | stop(file, UNEXPECTED_ERROR_CODE, "read callback for 0 bytes"); |
| 3198 | |
| 3199 | /* The callback always reads ahead by 8 bytes - the signature or chunk header |
| 3200 | * - these bytes are stored in chunk_length and chunk_type. This block is |
| 3201 | * executed once for the signature and once for the first chunk right at the |
| 3202 | * start. |
| 3203 | */ |
| 3204 | if (file->read_count < 8) |
| 3205 | { |
| 3206 | assert(file->read_count == 0); |
| 3207 | assert((file->status_code & TRUNCATED) == 0); |
| 3208 | |
| 3209 | (void)read_4(file, &file->length); |
| 3210 | |
| 3211 | if (file->read_count == 4) |
| 3212 | (void)read_4(file, &file->type); |
| 3213 | |
| 3214 | if (file->read_count < 8) |
| 3215 | { |
| 3216 | assert((file->status_code & TRUNCATED) != 0); |
| 3217 | stop(file, READ_ERROR_CODE, "not a PNG (too short)"); |
| 3218 | } |
| 3219 | |
| 3220 | if (file->state == STATE_SIGNATURE) |
| 3221 | { |
| 3222 | if (file->length != sig1 || file->type != sig2) |
| 3223 | stop(file, LIBPNG_ERROR_CODE, "not a PNG (signature)"); |
| 3224 | |
| 3225 | /* Else write it (this is the initialization of write_count, prior to |
| 3226 | * this it contains CLEAR garbage.) |
| 3227 | */ |
| 3228 | file->write_count = 0; |
| 3229 | } |
| 3230 | |
| 3231 | else |
| 3232 | { |
| 3233 | assert(file->state == STATE_CHUNKS); |
| 3234 | |
| 3235 | /* The first chunk must be a well formed IHDR (this could be relaxed to |
| 3236 | * use the checks in process_chunk, but that seems unnecessary.) |
| 3237 | */ |
| 3238 | if (file->length != 13 || file->type != png_IHDR) |
| 3239 | stop(file, LIBPNG_ERROR_CODE, "not a PNG (IHDR)"); |
| 3240 | |
| 3241 | /* The position of the data must be stored too */ |
| 3242 | getpos(file); |
| 3243 | } |
| 3244 | } |
| 3245 | |
| 3246 | /* Retrieve previous state (because the read callbacks are made pretty much |
| 3247 | * byte-by-byte in the sequential reader prior to 1.7). |
| 3248 | */ |
| 3249 | chunk = file->chunk; |
| 3250 | |
| 3251 | if (chunk != NULL) |
| 3252 | { |
| 3253 | length = chunk->chunk_length; |
| 3254 | type = chunk->chunk_type; |
| 3255 | } |
| 3256 | |
| 3257 | else |
| 3258 | { |
| 3259 | /* This is the signature case; for IDAT and other chunks these values will |
| 3260 | * be overwritten when read_chunk is called below. |
| 3261 | */ |
| 3262 | length = file->length; |
| 3263 | type = file->type; |
| 3264 | } |
| 3265 | |
| 3266 | do |
| 3267 | { |
| 3268 | png_uint_32 b; |
| 3269 | |
| 3270 | /* Complete the read of a chunk; as a side effect this also instantiates |
| 3271 | * a chunk control structure and sets the file length/type/data_pos fields |
| 3272 | * for the *NEXT* chunk header. |
| 3273 | * |
| 3274 | * NOTE: at an IDAT any following IDAT chunks will also be read and the |
| 3275 | * next_ fields will refer to the chunk after the last IDAT. |
| 3276 | * |
| 3277 | * NOTE: read_chunk only returns when it has read a chunk that must now be |
| 3278 | * written. |
| 3279 | */ |
| 3280 | if (file->state != STATE_SIGNATURE && chunk == NULL) |
| 3281 | { |
| 3282 | assert(file->read_count == 8); |
| 3283 | assert(file->idat == NULL); |
| 3284 | read_chunk(file); |
| 3285 | chunk = file->chunk; |
| 3286 | assert(chunk != NULL); |
| 3287 | |
| 3288 | /* Do the initialization that was not done before. */ |
| 3289 | length = chunk->chunk_length; |
| 3290 | type = chunk->chunk_type; |
| 3291 | |
| 3292 | /* And start writing the new chunk. */ |
| 3293 | file->write_count = 0; |
| 3294 | } |
| 3295 | |
| 3296 | /* The chunk_ fields describe a chunk that must be written, or hold the |
| 3297 | * signature. Write the header first. In the signature case this |
| 3298 | * rewrites the signature. |
| 3299 | */ |
| 3300 | switch (file->write_count) |
| 3301 | { |
| 3302 | case 0: b = length >> 24; break; |
| 3303 | case 1: b = length >> 16; break; |
| 3304 | case 2: b = length >> 8; break; |
| 3305 | case 3: b = length ; break; |
| 3306 | |
| 3307 | case 4: b = type >> 24; break; |
| 3308 | case 5: b = type >> 16; break; |
| 3309 | case 6: b = type >> 8; break; |
| 3310 | case 7: b = type ; break; |
| 3311 | |
| 3312 | case 8: |
| 3313 | /* The header has been written. If this is really the signature |
| 3314 | * that's all that is required and we can go to normal chunk |
| 3315 | * processing. |
| 3316 | */ |
| 3317 | if (file->state == STATE_SIGNATURE) |
| 3318 | { |
| 3319 | /* The signature has been written, the tail call to read_callback |
| 3320 | * below (it's just a goto to the start with a decent compiler) |
| 3321 | * will read the IHDR header ahead and validate it. |
| 3322 | */ |
| 3323 | assert(length == sig1 && type == sig2); |
| 3324 | file->read_count = 0; /* Forces a header read */ |
| 3325 | file->state = STATE_CHUNKS; /* IHDR: checked above */ |
| 3326 | read_callback(png_ptr, buffer, count); |
| 3327 | return; |
| 3328 | } |
| 3329 | |
| 3330 | else |
| 3331 | { |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 3332 | assert(chunk != NULL); |
| 3333 | |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3334 | /* Set up for write, notice that repositioning the input stream |
| 3335 | * is only necessary if something is to be read from it. Also |
| 3336 | * notice that for the IDAT stream this must only happen once - |
| 3337 | * on the first IDAT - to get back to the start of the list and |
| 3338 | * this is done inside process_IDAT: |
| 3339 | */ |
| 3340 | chunk->write_crc = crc_init_4(type); |
| 3341 | if (file->state != STATE_IDAT && length > 0) |
| 3342 | setpos(chunk); |
| 3343 | } |
| 3344 | /* FALL THROUGH */ |
| 3345 | |
| 3346 | default: |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 3347 | assert(chunk != NULL); |
| 3348 | |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3349 | /* NOTE: the arithmetic below overflows and gives a large positive |
| 3350 | * png_uint_32 value until the whole chunk data has been written. |
| 3351 | */ |
| 3352 | switch (file->write_count - length) |
| 3353 | { |
| 3354 | /* Write the chunk data, normally this just comes from |
| 3355 | * the file. The only exception is for that part of a |
| 3356 | * chunk which is zlib data and which must be rewritten, |
| 3357 | * and IDAT chunks which can be completely |
| 3358 | * reconstructed. |
| 3359 | */ |
| 3360 | default: |
| 3361 | if (file->state == STATE_IDAT) |
| 3362 | { |
| 3363 | struct IDAT *idat = file->idat; |
| 3364 | |
| 3365 | assert(idat != NULL); |
| 3366 | |
| 3367 | /* Read an IDAT byte from the input stream of IDAT chunks. |
| 3368 | * Because the IDAT stream can be re-chunked this stream is |
| 3369 | * held in the struct IDAT members. The chunk members, in |
| 3370 | * particular chunk_length (and therefore the length local) |
| 3371 | * refer to the output chunk. |
| 3372 | */ |
| 3373 | while (idat->idat_index >= idat->idat_length) |
| 3374 | { |
| 3375 | /* Advance one chunk */ |
| 3376 | struct IDAT_list *cur = idat->idat_cur; |
| 3377 | |
| 3378 | assert(idat->idat_index == idat->idat_length); |
| 3379 | assert(cur != NULL && cur->count > 0); |
| 3380 | |
| 3381 | /* NOTE: IDAT_list::count here, not IDAT_list::length */ |
| 3382 | if (++(idat->idat_count) >= cur->count) |
| 3383 | { |
| 3384 | assert(idat->idat_count == cur->count); |
| 3385 | |
| 3386 | /* Move on to the next IDAT_list: */ |
| 3387 | cur = cur->next; |
| 3388 | |
| 3389 | /* This is an internal error - read beyond the end of |
| 3390 | * the pre-calculated stream. |
| 3391 | */ |
| 3392 | if (cur == NULL || cur->count == 0) |
| 3393 | stop(file, UNEXPECTED_ERROR_CODE, |
| 3394 | "read beyond end of IDAT"); |
| 3395 | |
| 3396 | idat->idat_count = 0; |
| 3397 | idat->idat_cur = cur; |
| 3398 | } |
| 3399 | |
| 3400 | idat->idat_index = 0; |
| 3401 | /* Zero length IDAT chunks are permitted, so the length |
| 3402 | * here may be 0. |
| 3403 | */ |
| 3404 | idat->idat_length = cur->lengths[idat->idat_count]; |
| 3405 | |
| 3406 | /* And skip 12 bytes to the next chunk data */ |
| 3407 | skip_12(file); |
| 3408 | } |
| 3409 | |
| 3410 | /* The index is always that of the next byte, the rest of |
| 3411 | * the information is always the current IDAT chunk and the |
| 3412 | * current list. |
| 3413 | */ |
| 3414 | ++(idat->idat_index); |
| 3415 | } |
| 3416 | |
| 3417 | /* Read the byte from the stream. */ |
| 3418 | b = reread_byte(file); |
| 3419 | |
| 3420 | /* If the byte must be rewritten handle that here */ |
| 3421 | if (chunk->rewrite_length > 0) |
| 3422 | { |
| 3423 | if (chunk->rewrite_offset > 0) |
| 3424 | --(chunk->rewrite_offset); |
| 3425 | |
| 3426 | else |
| 3427 | { |
| 3428 | b = chunk->rewrite_buffer[0]; |
| 3429 | memmove(chunk->rewrite_buffer, chunk->rewrite_buffer+1, |
| 3430 | (sizeof chunk->rewrite_buffer)- |
| 3431 | (sizeof chunk->rewrite_buffer[0])); |
| 3432 | |
| 3433 | --(chunk->rewrite_length); |
| 3434 | } |
| 3435 | } |
| 3436 | |
| 3437 | chunk->write_crc = crc_one_byte(chunk->write_crc, b); |
| 3438 | break; |
| 3439 | |
| 3440 | /* The CRC is written at: |
| 3441 | * |
| 3442 | * chunk_write == chunk_length+8..chunk_length+11 |
| 3443 | * |
| 3444 | * so 8 to 11. The CRC is not (yet) conditioned. |
| 3445 | */ |
| 3446 | case 8: b = chunk->write_crc >> 24; goto write_crc; |
| 3447 | case 9: b = chunk->write_crc >> 16; goto write_crc; |
| 3448 | case 10: b = chunk->write_crc >> 8; goto write_crc; |
| 3449 | case 11: |
| 3450 | /* This must happen before the chunk_end below: */ |
| 3451 | b = chunk->write_crc; |
| 3452 | |
| 3453 | if (file->global->verbose > 2) |
| 3454 | { |
| 3455 | fputs(" ", stderr); |
| 3456 | type_name(type, stderr); |
| 3457 | fprintf(stderr, " %lu 0x%.8x\n", (unsigned long)length, |
| 3458 | chunk->write_crc ^ 0xffffffff); |
| 3459 | } |
| 3460 | |
| 3461 | /* The IDAT stream is written without a call to read_chunk |
| 3462 | * until the end is reached. rechunk_length() calculates the |
| 3463 | * length of the output chunks. Control gets to this point at |
| 3464 | * the end of an *output* chunk - the length calculated by |
| 3465 | * rechunk_length. If this corresponds to the end of the |
| 3466 | * input stream stop writing IDAT chunks, otherwise continue. |
| 3467 | */ |
| 3468 | if (file->state == STATE_IDAT && |
| 3469 | (file->idat->idat_index < file->idat->idat_length || |
| 3470 | 1+file->idat->idat_count < file->idat->idat_cur->count || |
| 3471 | file->idat->idat_cur != file->idat->idat_list_tail)) |
| 3472 | { |
| 3473 | /* Write another IDAT chunk. Call rechunk_length to |
| 3474 | * calculate the length required. |
| 3475 | */ |
| 3476 | length = chunk->chunk_length = rechunk_length(file->idat); |
| 3477 | assert(type == png_IDAT); |
| 3478 | file->write_count = 0; /* for the new chunk */ |
| 3479 | --(file->write_count); /* fake out the increment below */ |
| 3480 | } |
| 3481 | |
| 3482 | else |
| 3483 | { |
| 3484 | /* Entered at the end of a non-IDAT chunk and at the end of |
| 3485 | * the IDAT stream. The rewrite should have been cleared. |
| 3486 | */ |
| 3487 | if (chunk->rewrite_length > 0 || chunk->rewrite_offset > 0) |
| 3488 | stop(file, UNEXPECTED_ERROR_CODE, "pending rewrite"); |
| 3489 | |
| 3490 | /* This is the last byte so reset chunk_read for the next |
| 3491 | * chunk and move the input file to the position after the |
| 3492 | * *next* chunk header if required. |
| 3493 | */ |
| 3494 | file->read_count = 8; |
| 3495 | file_setpos(file, &file->data_pos); |
| 3496 | |
| 3497 | if (file->idat == NULL) |
| 3498 | chunk_end(&file->chunk); |
| 3499 | |
| 3500 | else |
| 3501 | IDAT_end(&file->idat); |
| 3502 | } |
| 3503 | |
| 3504 | write_crc: |
| 3505 | b ^= 0xff; /* conditioning */ |
| 3506 | break; |
| 3507 | } |
| 3508 | break; |
| 3509 | } |
| 3510 | |
| 3511 | /* Write one byte */ |
| 3512 | b &= 0xff; |
| 3513 | *buffer++ = (png_byte)b; |
| 3514 | --count; |
| 3515 | write_byte(file, (png_byte)b); /* increments chunk_write */ |
| 3516 | } |
| 3517 | while (count > 0); |
| 3518 | } |
| 3519 | |
| 3520 | /* Bundle the file and an uninitialized chunk and IDAT control structure |
| 3521 | * together to allow implementation of the chunk/IDAT allocate routine. |
| 3522 | */ |
| 3523 | struct control |
| 3524 | { |
| 3525 | struct file file; |
| 3526 | struct chunk chunk; |
| 3527 | struct IDAT idat; |
| 3528 | }; |
| 3529 | |
| 3530 | static int |
| 3531 | control_end(struct control *control) |
| 3532 | { |
| 3533 | return file_end(&control->file); |
| 3534 | } |
| 3535 | |
| 3536 | static struct file * |
| 3537 | get_control(png_const_structrp png_ptr) |
| 3538 | { |
| 3539 | /* This just returns the (file*). The chunk and idat control structures |
| 3540 | * don't always exist. |
| 3541 | */ |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 3542 | struct control *control = voidcast(struct control*, |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3543 | png_get_error_ptr(png_ptr)); |
| 3544 | return &control->file; |
| 3545 | } |
| 3546 | |
| 3547 | static void |
| 3548 | allocate(struct file *file, int allocate_idat) |
| 3549 | { |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 3550 | struct control *control = voidcast(struct control*, file->alloc_ptr); |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3551 | |
| 3552 | if (allocate_idat) |
| 3553 | { |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3554 | assert(file->idat == NULL); |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 3555 | IDAT_init(&control->idat, file); |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3556 | } |
| 3557 | |
| 3558 | else /* chunk */ |
| 3559 | { |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3560 | assert(file->chunk == NULL); |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 3561 | chunk_init(&control->chunk, file); |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3562 | } |
| 3563 | } |
| 3564 | |
| 3565 | static int |
| 3566 | control_init(struct control *control, struct global *global, |
| 3567 | const char *file_name, const char *out_name) |
| 3568 | /* This wraps file_init(&control::file) and simply returns the result from |
| 3569 | * file_init. |
| 3570 | */ |
| 3571 | { |
| 3572 | return file_init(&control->file, global, file_name, out_name, control, |
| 3573 | allocate); |
| 3574 | } |
| 3575 | |
| 3576 | static int |
| 3577 | read_png(struct control *control) |
| 3578 | /* Read a PNG, return 0 on success else an error (status) code; a bit mask as |
| 3579 | * defined for file::status_code as above. |
| 3580 | */ |
| 3581 | { |
| 3582 | png_structp png_ptr; |
| 3583 | png_infop info_ptr = NULL; |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3584 | volatile int rc; |
| 3585 | |
| 3586 | png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, control, |
| 3587 | error_handler, warning_handler); |
| 3588 | |
| 3589 | if (png_ptr == NULL) |
| 3590 | { |
| 3591 | /* This is not really expected. */ |
| 3592 | log_error(&control->file, LIBPNG_ERROR_CODE, "OOM allocating png_struct"); |
| 3593 | control->file.status_code |= INTERNAL_ERROR; |
| 3594 | return LIBPNG_ERROR_CODE; |
| 3595 | } |
| 3596 | |
| 3597 | rc = setjmp(control->file.jmpbuf); |
| 3598 | if (rc == 0) |
| 3599 | { |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 3600 | # ifdef PNG_SET_USER_LIMITS_SUPPORTED |
| 3601 | /* Remove any limits on the size of PNG files that can be read, |
| 3602 | * without this we may reject files based on built-in safety |
| 3603 | * limits. |
| 3604 | */ |
| 3605 | png_set_user_limits(png_ptr, 0x7fffffff, 0x7fffffff); |
| 3606 | png_set_chunk_cache_max(png_ptr, 0); |
| 3607 | png_set_chunk_malloc_max(png_ptr, 0); |
| 3608 | # endif |
| 3609 | |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3610 | png_set_read_fn(png_ptr, control, read_callback); |
| 3611 | |
| 3612 | info_ptr = png_create_info_struct(png_ptr); |
| 3613 | if (info_ptr == NULL) |
| 3614 | png_error(png_ptr, "OOM allocating info structure"); |
| 3615 | |
| 3616 | if (control->file.global->verbose) |
| 3617 | fprintf(stderr, " INFO\n"); |
| 3618 | |
| 3619 | png_read_info(png_ptr, info_ptr); |
| 3620 | |
| 3621 | { |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 3622 | png_uint_32 height = png_get_image_height(png_ptr, info_ptr); |
| 3623 | int passes = png_set_interlace_handling(png_ptr); |
| 3624 | int pass; |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3625 | |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 3626 | png_start_read_image(png_ptr); |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3627 | |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 3628 | for (pass = 0; pass < passes; ++pass) |
| 3629 | { |
| 3630 | png_uint_32 y = height; |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3631 | |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 3632 | /* NOTE: this skips asking libpng to return either version of |
| 3633 | * the image row, but libpng still reads the rows. |
| 3634 | */ |
| 3635 | while (y-- > 0) |
| 3636 | png_read_row(png_ptr, NULL, NULL); |
| 3637 | } |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3638 | } |
| 3639 | |
| 3640 | if (control->file.global->verbose) |
| 3641 | fprintf(stderr, " END\n"); |
| 3642 | |
| 3643 | /* Make sure to read to the end of the file: */ |
| 3644 | png_read_end(png_ptr, info_ptr); |
| 3645 | } |
| 3646 | |
| 3647 | png_destroy_read_struct(&png_ptr, &info_ptr, NULL); |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3648 | return rc; |
| 3649 | } |
| 3650 | |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 3651 | static int |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3652 | one_file(struct global *global, const char *file_name, const char *out_name) |
| 3653 | { |
| 3654 | int rc; |
| 3655 | struct control control; |
| 3656 | |
| 3657 | if (global->verbose) |
| 3658 | fprintf(stderr, "FILE %s -> %s\n", file_name, |
| 3659 | out_name ? out_name : "<none>"); |
| 3660 | |
| 3661 | /* Although control_init can return a failure code the structure is always |
| 3662 | * initialized, so control_end can be used to accumulate any status codes. |
| 3663 | */ |
| 3664 | rc = control_init(&control, global, file_name, out_name); |
| 3665 | |
| 3666 | if (rc == 0) |
| 3667 | rc = read_png(&control); |
| 3668 | |
| 3669 | rc |= control_end(&control); |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 3670 | |
| 3671 | return rc; |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3672 | } |
| 3673 | |
| 3674 | static void |
| 3675 | usage(const char *prog) |
| 3676 | { |
| 3677 | /* ANSI C-90 limits strings to 509 characters, so use a string array: */ |
| 3678 | size_t i; |
| 3679 | static const char *usage_string[] = { |
| 3680 | " Tests, optimizes and optionally fixes the zlib header in PNG files.", |
| 3681 | " Optionally, when fixing, strips ancilliary chunks from the file.", |
| 3682 | 0, |
| 3683 | "OPTIONS", |
| 3684 | " OPERATION", |
| 3685 | " By default files are just checked for readability with a summary of the", |
| 3686 | " of zlib issues founds for each compressed chunk and the IDAT stream in", |
| 3687 | " the file.", |
| 3688 | " --optimize (-o):", |
| 3689 | " Find the smallest deflate window size for the compressed data.", |
| 3690 | " --strip=[none|crc|unsafe|unused|transform|color|all]:", |
| 3691 | " none (default): Retain all chunks.", |
| 3692 | " crc: Remove chunks with a bad CRC.", |
| 3693 | " unsafe: Remove chunks that may be unsafe to retain if the image data", |
| 3694 | " is modified. This is set automatically if --max is given but", |
| 3695 | " may be cancelled by a later --strip=none.", |
| 3696 | " unused: Remove chunks not used by libpng when decoding an image.", |
| 3697 | " This retains any chunks that might be used by libpng image", |
| 3698 | " transformations.", |
| 3699 | " transform: unused+bKGD.", |
| 3700 | " color: transform+iCCP and cHRM.", |
| 3701 | " all: color+gAMA and sRGB.", |
| 3702 | " Only ancillary chunks are ever removed. In addition the tRNS and sBIT", |
| 3703 | " chunks are never removed as they affect exact interpretation of the", |
| 3704 | " image pixel values. The following known chunks are treated specially", |
| 3705 | " by the above options:", |
| 3706 | " gAMA, sRGB [all]: These specify the gamma encoding used for the pixel", |
| 3707 | " values.", |
| 3708 | " cHRM, iCCP [color]: These specify how colors are encoded. iCCP also", |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 3709 | " specifies the exact encoding of a pixel value; however, in", |
| 3710 | " practice most programs will ignore it.", |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3711 | " bKGD [transform]: This is used by libpng transforms." |
| 3712 | " --max=<number>:", |
| 3713 | " Use IDAT chunks sized <number>. If no number is given the the IDAT", |
| 3714 | " chunks will be the maximum size permitted; 2^31-1 bytes. If the option", |
| 3715 | " is omitted the original chunk sizes will not be changed. When the", |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 3716 | " option is given --strip=unsafe is set automatically. This may be", |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3717 | " cancelled if you know that all unknown unsafe-to-copy chunks really are", |
| 3718 | " safe to copy across an IDAT size change. This is true of all chunks", |
| 3719 | " that have ever been formally proposed as PNG extensions.", |
| 3720 | " MESSAGES", |
| 3721 | " By default the program only outputs summaries for each file.", |
| 3722 | " --quiet (-q):", |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 3723 | " Do not output the summaries except for files that cannot be read. With", |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3724 | " two --quiets these are not output either.", |
| 3725 | " --errors (-e):", |
| 3726 | " Output errors from libpng and the program (except too-far-back).", |
| 3727 | " --warnings (-w):", |
| 3728 | " Output warnings from libpng.", |
| 3729 | " OUTPUT", |
| 3730 | " By default nothing is written.", |
| 3731 | " --out=<file>:", |
| 3732 | " Write the optimized/corrected version of the next PNG to <file>. This", |
| 3733 | " overrides the following two options", |
| 3734 | " --suffix=<suffix>:", |
| 3735 | " Set --out=<name><suffix> for all following files unless overridden on", |
| 3736 | " a per-file basis by explicit --out.", |
| 3737 | " --prefix=<prefix>:", |
| 3738 | " Set --out=<prefix><name> for all the following files unless overridden", |
| 3739 | " on a per-file basis by explicit --out.", |
| 3740 | " These two options can be used together to produce a suffix and prefix.", |
| 3741 | " INTERNAL OPTIONS", |
| 3742 | #if 0 /*NYI*/ |
| 3743 | #ifdef PNG_MAXIMUM_INFLATE_WINDOW |
| 3744 | " --test:", |
| 3745 | " Test the PNG_MAXIMUM_INFLATE_WINDOW option. Setting this disables", |
| 3746 | " output as this would produce a broken file.", |
| 3747 | #endif |
| 3748 | #endif |
| 3749 | 0, |
| 3750 | "EXIT CODES", |
| 3751 | " *** SUBJECT TO CHANGE ***", |
| 3752 | " The program exit code is value in the range 0..127 holding a bit mask of", |
| 3753 | " the following codes. Notice that the results for each file are combined", |
| 3754 | " together - check one file at a time to get a meaningful error code!", |
| 3755 | " 0x01: The zlib too-far-back error existed in at least one chunk.", |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 3756 | " 0x02: At least one chunk had a CRC error.", |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3757 | " 0x04: A chunk length was incorrect.", |
| 3758 | " 0x08: The file was truncated.", |
| 3759 | " Errors less than 16 are potentially recoverable, for a single file if the", |
| 3760 | " exit code is less than 16 the file could be read (with corrections if a", |
| 3761 | " non-zero code is returned).", |
| 3762 | " 0x10: The file could not be read, even with corrections.", |
| 3763 | " 0x20: The output file could not be written.", |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 3764 | " 0x40: An unexpected, potentially internal, error occurred.", |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3765 | " If the command line arguments are incorrect the program exits with exit", |
| 3766 | " 255. Some older operating systems only support 7-bit exit codes, on those", |
| 3767 | " systems it is suggested that this program is first tested by supplying", |
| 3768 | " invalid arguments.", |
| 3769 | 0, |
| 3770 | "DESCRIPTION", |
| 3771 | " " PROGRAM_NAME ":", |
| 3772 | " checks each PNG file on the command line for errors. By default errors are", |
| 3773 | " not output and the program just returns an exit code and prints a summary.", |
| 3774 | " With the --quiet (-q) option the summaries are suppressed too and the", |
| 3775 | " program only outputs unexpected errors (internal errors and file open", |
| 3776 | " errors).", |
| 3777 | " Various known problems in PNG files are fixed while the file is being read", |
| 3778 | " The exit code says what problems were fixed. In particular the zlib error:", |
| 3779 | 0, |
| 3780 | " \"invalid distance too far back\"", |
| 3781 | 0, |
| 3782 | " caused by an incorrect optimization of a zlib stream is fixed in any", |
| 3783 | " compressed chunk in which it is encountered. An integrity problem of the", |
| 3784 | " PNG stream caused by a bug in libpng which wrote an incorrect chunk length", |
| 3785 | " is also fixed. Chunk CRC errors are automatically fixed up.", |
| 3786 | 0, |
| 3787 | " Setting one of the \"OUTPUT\" options causes the possibly modified file to", |
| 3788 | " be written to a new file.", |
| 3789 | 0, |
| 3790 | " Notice that some PNG files with the zlib optimization problem can still be", |
| 3791 | " read by libpng under some circumstances. This program will still detect", |
| 3792 | " and, if requested, correct the error.", |
| 3793 | 0, |
| 3794 | " The program will reliably process all files on the command line unless", |
| 3795 | " either an invalid argument causes the usage message (this message) to be", |
| 3796 | " produced or the program crashes.", |
| 3797 | 0, |
| 3798 | " The summary lines describe issues encountered with the zlib compressed", |
| 3799 | " stream of a chunk. They have the following format, which is SUBJECT TO", |
| 3800 | " CHANGE in the future:", |
| 3801 | 0, |
| 3802 | " chunk reason comp-level p1 p2 p3 p4 file", |
| 3803 | 0, |
| 3804 | " p1 through p4 vary according to the 'reason'. There are always 8 space", |
| 3805 | " separated fields. Reasons specific formats are:", |
| 3806 | 0, |
| 3807 | " chunk ERR status code read-errno write-errno message file", |
| 3808 | " chunk SKP comp-level file-bits zlib-rc compressed message file", |
| 3809 | " chunk ??? comp-level file-bits ok-bits compressed uncompress file", |
| 3810 | 0, |
| 3811 | " The various fields are", |
| 3812 | 0, |
| 3813 | "$1 chunk: The chunk type of a chunk in the file or 'HEAD' if a problem", |
| 3814 | " is reported by libpng at the start of the IDAT stream.", |
| 3815 | "$2 reason: One of:", |
| 3816 | " CHK: A zlib header checksum was detected and fixed.", |
| 3817 | " TFB: The zlib too far back error was detected and fixed.", |
| 3818 | " OK : No errors were detected in the zlib stream and optimization", |
| 3819 | " was not requested, or was not possible.", |
| 3820 | " OPT: The zlib stream window bits value could be improved (and was).", |
| 3821 | " SKP: The chunk was skipped because of a zlib issue (zlib-rc) with", |
| 3822 | " explanation 'message'", |
| 3823 | " ERR: The read of the file was aborted. The parameters explain why.", |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 3824 | "$3 status: For 'ERR' the accumulated status code from 'EXIT CODES' above.", |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3825 | " This is printed as a 2 digit hexadecimal value", |
| 3826 | " comp-level: The recorded compression level (FLEVEL) of a zlib stream", |
| 3827 | " expressed as a string {supfast,stdfast,default,maximum}", |
| 3828 | "$4 code: The file exit code; where stop was called, as a fairly terse", |
| 3829 | " string {warning,libpng,zlib,invalid,read,write,unexpected}.", |
| 3830 | " file-bits: The zlib window bits recorded in the file.", |
| 3831 | "$5 read-errno: A system errno value from a read translated by strerror(3).", |
| 3832 | " zlib-rc: A zlib return code as a string (see zlib.h).", |
| 3833 | " ok-bits: The smallest zlib window bits value that works.", |
| 3834 | "$6 write-errno:A system errno value from a write translated by strerror(3).", |
| 3835 | " compressed: The count of compressed bytes in the zlib stream, when the", |
| 3836 | " reason is 'SKP'; this is a count of the bytes read from the", |
| 3837 | " stream when the fatal error was encountered.", |
| 3838 | "$7 message: An error message (spaces replaced by _, as in all parameters),", |
| 3839 | " uncompress: The count of bytes from uncompressing the zlib stream; this", |
| 3840 | " may not be the same as the number of bytes in the image.", |
| 3841 | "$8 file: The name of the file (this may contain spaces).", |
| 3842 | }; |
| 3843 | |
| 3844 | fprintf(stderr, "Usage: %s {[options] png-file}\n", prog); |
| 3845 | |
| 3846 | for (i=0; i < (sizeof usage_string)/(sizeof usage_string[0]); ++i) |
| 3847 | { |
| 3848 | if (usage_string[i] != 0) |
| 3849 | fputs(usage_string[i], stderr); |
| 3850 | |
| 3851 | fputc('\n', stderr); |
| 3852 | } |
| 3853 | |
| 3854 | exit(255); |
| 3855 | } |
| 3856 | |
| 3857 | int |
| 3858 | main(int argc, const char **argv) |
| 3859 | { |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 3860 | char temp_name[FILENAME_MAX+1]; |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3861 | const char * prog = *argv; |
| 3862 | const char * outfile = NULL; |
| 3863 | const char * suffix = NULL; |
| 3864 | const char * prefix = NULL; |
| 3865 | int done = 0; /* if at least one file is processed */ |
| 3866 | struct global global; |
| 3867 | |
| 3868 | global_init(&global); |
| 3869 | |
| 3870 | while (--argc > 0) |
| 3871 | { |
| 3872 | ++argv; |
| 3873 | |
| 3874 | if (strcmp(*argv, "--debug") == 0) |
| 3875 | { |
| 3876 | /* To help debugging problems: */ |
| 3877 | global.errors = global.warnings = 1; |
| 3878 | global.quiet = 0; |
| 3879 | global.verbose = 7; |
| 3880 | } |
| 3881 | |
| 3882 | else if (strncmp(*argv, "--max=", 6) == 0) |
| 3883 | { |
| 3884 | global.idat_max = (png_uint_32)atol(6+*argv); |
| 3885 | |
| 3886 | if (global.skip < SKIP_UNSAFE) |
| 3887 | global.skip = SKIP_UNSAFE; |
| 3888 | } |
| 3889 | |
| 3890 | else if (strcmp(*argv, "--max") == 0) |
| 3891 | { |
| 3892 | global.idat_max = 0x7fffffff; |
| 3893 | |
| 3894 | if (global.skip < SKIP_UNSAFE) |
| 3895 | global.skip = SKIP_UNSAFE; |
| 3896 | } |
| 3897 | |
| 3898 | else if (strcmp(*argv, "--optimize") == 0 || strcmp(*argv, "-o") == 0) |
| 3899 | global.optimize_zlib = 1; |
| 3900 | |
| 3901 | else if (strncmp(*argv, "--out=", 6) == 0) |
| 3902 | outfile = 6+*argv; |
| 3903 | |
| 3904 | else if (strncmp(*argv, "--suffix=", 9) == 0) |
| 3905 | suffix = 9+*argv; |
| 3906 | |
| 3907 | else if (strncmp(*argv, "--prefix=", 9) == 0) |
| 3908 | prefix = 9+*argv; |
| 3909 | |
| 3910 | else if (strcmp(*argv, "--strip=none") == 0) |
| 3911 | global.skip = SKIP_NONE; |
| 3912 | |
| 3913 | else if (strcmp(*argv, "--strip=crc") == 0) |
| 3914 | global.skip = SKIP_BAD_CRC; |
| 3915 | |
| 3916 | else if (strcmp(*argv, "--strip=unsafe") == 0) |
| 3917 | global.skip = SKIP_UNSAFE; |
| 3918 | |
| 3919 | else if (strcmp(*argv, "--strip=unused") == 0) |
| 3920 | global.skip = SKIP_UNUSED; |
| 3921 | |
| 3922 | else if (strcmp(*argv, "--strip=transform") == 0) |
| 3923 | global.skip = SKIP_TRANSFORM; |
| 3924 | |
| 3925 | else if (strcmp(*argv, "--strip=color") == 0) |
| 3926 | global.skip = SKIP_COLOR; |
| 3927 | |
| 3928 | else if (strcmp(*argv, "--strip=all") == 0) |
| 3929 | global.skip = SKIP_ALL; |
| 3930 | |
| 3931 | else if (strcmp(*argv, "--errors") == 0 || strcmp(*argv, "-e") == 0) |
| 3932 | global.errors = 1; |
| 3933 | |
| 3934 | else if (strcmp(*argv, "--warnings") == 0 || strcmp(*argv, "-w") == 0) |
| 3935 | global.warnings = 1; |
| 3936 | |
| 3937 | else if (strcmp(*argv, "--quiet") == 0 || strcmp(*argv, "-q") == 0) |
| 3938 | { |
| 3939 | if (global.quiet) |
| 3940 | global.quiet = 2; |
| 3941 | |
| 3942 | else |
| 3943 | global.quiet = 1; |
| 3944 | } |
| 3945 | |
| 3946 | else if (strcmp(*argv, "--verbose") == 0 || strcmp(*argv, "-v") == 0) |
| 3947 | ++global.verbose; |
| 3948 | |
| 3949 | #if 0 |
| 3950 | /* NYI */ |
| 3951 | # ifdef PNG_MAXIMUM_INFLATE_WINDOW |
| 3952 | else if (strcmp(*argv, "--test") == 0) |
| 3953 | ++set_option; |
| 3954 | # endif |
| 3955 | #endif |
| 3956 | |
| 3957 | else if ((*argv)[0] == '-') |
| 3958 | usage(prog); |
| 3959 | |
| 3960 | else |
| 3961 | { |
| 3962 | size_t outlen = strlen(*argv); |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 3963 | |
| 3964 | if (outfile == NULL) /* else this takes precedence */ |
| 3965 | { |
| 3966 | /* Consider the prefix/suffix options */ |
| 3967 | if (prefix != NULL) |
| 3968 | { |
| 3969 | size_t prefixlen = strlen(prefix); |
| 3970 | |
| 3971 | if (prefixlen+outlen > FILENAME_MAX) |
| 3972 | { |
| 3973 | fprintf(stderr, "%s: output file name too long: %s%s%s\n", |
| 3974 | prog, prefix, *argv, suffix ? suffix : ""); |
| 3975 | global.status_code |= WRITE_ERROR; |
| 3976 | continue; |
| 3977 | } |
| 3978 | |
| 3979 | memcpy(temp_name, prefix, prefixlen); |
| 3980 | memcpy(temp_name+prefixlen, *argv, outlen); |
| 3981 | outlen += prefixlen; |
| 3982 | outfile = temp_name; |
| 3983 | } |
| 3984 | |
| 3985 | else if (suffix != NULL) |
| 3986 | memcpy(temp_name, *argv, outlen); |
| 3987 | |
| 3988 | temp_name[outlen] = 0; |
| 3989 | |
| 3990 | if (suffix != NULL) |
| 3991 | { |
| 3992 | size_t suffixlen = strlen(suffix); |
| 3993 | |
| 3994 | if (outlen+suffixlen > FILENAME_MAX) |
| 3995 | { |
| 3996 | fprintf(stderr, "%s: output file name too long: %s%s\n", |
| 3997 | prog, *argv, suffix); |
| 3998 | global.status_code |= WRITE_ERROR; |
| 3999 | continue; |
| 4000 | } |
| 4001 | |
| 4002 | memcpy(temp_name+outlen, suffix, suffixlen); |
| 4003 | outlen += suffixlen; |
| 4004 | temp_name[outlen] = 0; |
| 4005 | outfile = temp_name; |
| 4006 | } |
| 4007 | } |
| 4008 | |
| 4009 | (void)one_file(&global, *argv, outfile); |
| 4010 | ++done; |
| 4011 | outfile = NULL; |
| 4012 | } |
| 4013 | } |
| 4014 | |
| 4015 | if (!done) |
| 4016 | usage(prog); |
| 4017 | |
| 4018 | return global_end(&global); |
| 4019 | } |
| 4020 | |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 4021 | #else /* ZLIB_VERNUM < 0x1240 */ |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 4022 | int |
| 4023 | main(void) |
| 4024 | { |
| 4025 | fprintf(stderr, |
| 4026 | "pngfix needs libpng with a zlib >=1.2.4 (not 0x%x)\n", |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 4027 | ZLIB_VERNUM); |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 4028 | return 77; |
| 4029 | } |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 4030 | #endif /* ZLIB_VERNUM */ |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 4031 | |
| 4032 | #else /* No read support */ |
| 4033 | |
| 4034 | int |
| 4035 | main(void) |
| 4036 | { |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 4037 | fprintf(stderr, "pngfix does not work without read deinterlace support\n"); |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 4038 | return 77; |
| 4039 | } |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 4040 | #endif /* PNG_READ_SUPPORTED && PNG_EASY_ACCESS_SUPPORTED */ |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 4041 | #else /* No setjmp support */ |
| 4042 | int |
| 4043 | main(void) |
| 4044 | { |
| 4045 | fprintf(stderr, "pngfix does not work without setjmp support\n"); |
| 4046 | return 77; |
| 4047 | } |
| 4048 | #endif /* PNG_SETJMP_SUPPORTED */ |
| 4049 | |