Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame^] | 1 | /* $OpenBSD: bufaux.c,v 1.50 2010/08/31 09:58:37 djm Exp $ */ |
| 2 | /* |
| 3 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
| 4 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| 5 | * All rights reserved |
| 6 | * Auxiliary functions for storing and retrieving various data types to/from |
| 7 | * Buffers. |
| 8 | * |
| 9 | * As far as I am concerned, the code I have written for this software |
| 10 | * can be used freely for any purpose. Any derived versions of this |
| 11 | * software must be clearly marked as such, and if the derived work is |
| 12 | * incompatible with the protocol description in the RFC file, it must be |
| 13 | * called by a name other than "ssh" or "Secure Shell". |
| 14 | * |
| 15 | * |
| 16 | * SSH2 packet format added by Markus Friedl |
| 17 | * Copyright (c) 2000 Markus Friedl. All rights reserved. |
| 18 | * |
| 19 | * Redistribution and use in source and binary forms, with or without |
| 20 | * modification, are permitted provided that the following conditions |
| 21 | * are met: |
| 22 | * 1. Redistributions of source code must retain the above copyright |
| 23 | * notice, this list of conditions and the following disclaimer. |
| 24 | * 2. Redistributions in binary form must reproduce the above copyright |
| 25 | * notice, this list of conditions and the following disclaimer in the |
| 26 | * documentation and/or other materials provided with the distribution. |
| 27 | * |
| 28 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 29 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 30 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 31 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 32 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 33 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 34 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 35 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 36 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 37 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 38 | */ |
| 39 | |
| 40 | #include "includes.h" |
| 41 | |
| 42 | #include <sys/types.h> |
| 43 | |
| 44 | #include <openssl/bn.h> |
| 45 | |
| 46 | #include <string.h> |
| 47 | #include <stdarg.h> |
| 48 | |
| 49 | #include "xmalloc.h" |
| 50 | #include "buffer.h" |
| 51 | #include "log.h" |
| 52 | #include "misc.h" |
| 53 | |
| 54 | /* |
| 55 | * Returns integers from the buffer (msb first). |
| 56 | */ |
| 57 | |
| 58 | int |
| 59 | buffer_get_short_ret(u_short *ret, Buffer *buffer) |
| 60 | { |
| 61 | u_char buf[2]; |
| 62 | |
| 63 | if (buffer_get_ret(buffer, (char *) buf, 2) == -1) |
| 64 | return (-1); |
| 65 | *ret = get_u16(buf); |
| 66 | return (0); |
| 67 | } |
| 68 | |
| 69 | u_short |
| 70 | buffer_get_short(Buffer *buffer) |
| 71 | { |
| 72 | u_short ret; |
| 73 | |
| 74 | if (buffer_get_short_ret(&ret, buffer) == -1) |
| 75 | fatal("buffer_get_short: buffer error"); |
| 76 | |
| 77 | return (ret); |
| 78 | } |
| 79 | |
| 80 | int |
| 81 | buffer_get_int_ret(u_int *ret, Buffer *buffer) |
| 82 | { |
| 83 | u_char buf[4]; |
| 84 | |
| 85 | if (buffer_get_ret(buffer, (char *) buf, 4) == -1) |
| 86 | return (-1); |
| 87 | if (ret != NULL) |
| 88 | *ret = get_u32(buf); |
| 89 | return (0); |
| 90 | } |
| 91 | |
| 92 | u_int |
| 93 | buffer_get_int(Buffer *buffer) |
| 94 | { |
| 95 | u_int ret; |
| 96 | |
| 97 | if (buffer_get_int_ret(&ret, buffer) == -1) |
| 98 | fatal("buffer_get_int: buffer error"); |
| 99 | |
| 100 | return (ret); |
| 101 | } |
| 102 | |
| 103 | int |
| 104 | buffer_get_int64_ret(u_int64_t *ret, Buffer *buffer) |
| 105 | { |
| 106 | u_char buf[8]; |
| 107 | |
| 108 | if (buffer_get_ret(buffer, (char *) buf, 8) == -1) |
| 109 | return (-1); |
| 110 | if (ret != NULL) |
| 111 | *ret = get_u64(buf); |
| 112 | return (0); |
| 113 | } |
| 114 | |
| 115 | u_int64_t |
| 116 | buffer_get_int64(Buffer *buffer) |
| 117 | { |
| 118 | u_int64_t ret; |
| 119 | |
| 120 | if (buffer_get_int64_ret(&ret, buffer) == -1) |
| 121 | fatal("buffer_get_int: buffer error"); |
| 122 | |
| 123 | return (ret); |
| 124 | } |
| 125 | |
| 126 | /* |
| 127 | * Stores integers in the buffer, msb first. |
| 128 | */ |
| 129 | void |
| 130 | buffer_put_short(Buffer *buffer, u_short value) |
| 131 | { |
| 132 | char buf[2]; |
| 133 | |
| 134 | put_u16(buf, value); |
| 135 | buffer_append(buffer, buf, 2); |
| 136 | } |
| 137 | |
| 138 | void |
| 139 | buffer_put_int(Buffer *buffer, u_int value) |
| 140 | { |
| 141 | char buf[4]; |
| 142 | |
| 143 | put_u32(buf, value); |
| 144 | buffer_append(buffer, buf, 4); |
| 145 | } |
| 146 | |
| 147 | void |
| 148 | buffer_put_int64(Buffer *buffer, u_int64_t value) |
| 149 | { |
| 150 | char buf[8]; |
| 151 | |
| 152 | put_u64(buf, value); |
| 153 | buffer_append(buffer, buf, 8); |
| 154 | } |
| 155 | |
| 156 | /* |
| 157 | * Returns an arbitrary binary string from the buffer. The string cannot |
| 158 | * be longer than 256k. The returned value points to memory allocated |
| 159 | * with xmalloc; it is the responsibility of the calling function to free |
| 160 | * the data. If length_ptr is non-NULL, the length of the returned data |
| 161 | * will be stored there. A null character will be automatically appended |
| 162 | * to the returned string, and is not counted in length. |
| 163 | */ |
| 164 | void * |
| 165 | buffer_get_string_ret(Buffer *buffer, u_int *length_ptr) |
| 166 | { |
| 167 | u_char *value; |
| 168 | u_int len; |
| 169 | |
| 170 | /* Get the length. */ |
| 171 | if (buffer_get_int_ret(&len, buffer) != 0) { |
| 172 | error("buffer_get_string_ret: cannot extract length"); |
| 173 | return (NULL); |
| 174 | } |
| 175 | if (len > 256 * 1024) { |
| 176 | error("buffer_get_string_ret: bad string length %u", len); |
| 177 | return (NULL); |
| 178 | } |
| 179 | /* Allocate space for the string. Add one byte for a null character. */ |
| 180 | value = xmalloc(len + 1); |
| 181 | /* Get the string. */ |
| 182 | if (buffer_get_ret(buffer, value, len) == -1) { |
| 183 | error("buffer_get_string_ret: buffer_get failed"); |
| 184 | xfree(value); |
| 185 | return (NULL); |
| 186 | } |
| 187 | /* Append a null character to make processing easier. */ |
| 188 | value[len] = '\0'; |
| 189 | /* Optionally return the length of the string. */ |
| 190 | if (length_ptr) |
| 191 | *length_ptr = len; |
| 192 | return (value); |
| 193 | } |
| 194 | |
| 195 | void * |
| 196 | buffer_get_string(Buffer *buffer, u_int *length_ptr) |
| 197 | { |
| 198 | void *ret; |
| 199 | |
| 200 | if ((ret = buffer_get_string_ret(buffer, length_ptr)) == NULL) |
| 201 | fatal("buffer_get_string: buffer error"); |
| 202 | return (ret); |
| 203 | } |
| 204 | |
| 205 | char * |
| 206 | buffer_get_cstring_ret(Buffer *buffer, u_int *length_ptr) |
| 207 | { |
| 208 | u_int length; |
| 209 | char *cp, *ret = buffer_get_string_ret(buffer, &length); |
| 210 | |
| 211 | if (ret == NULL) |
| 212 | return NULL; |
| 213 | if ((cp = memchr(ret, '\0', length)) != NULL) { |
| 214 | /* XXX allow \0 at end-of-string for a while, remove later */ |
| 215 | if (cp == ret + length - 1) |
| 216 | error("buffer_get_cstring_ret: string contains \\0"); |
| 217 | else { |
| 218 | bzero(ret, length); |
| 219 | xfree(ret); |
| 220 | return NULL; |
| 221 | } |
| 222 | } |
| 223 | if (length_ptr != NULL) |
| 224 | *length_ptr = length; |
| 225 | return ret; |
| 226 | } |
| 227 | |
| 228 | char * |
| 229 | buffer_get_cstring(Buffer *buffer, u_int *length_ptr) |
| 230 | { |
| 231 | char *ret; |
| 232 | |
| 233 | if ((ret = buffer_get_cstring_ret(buffer, length_ptr)) == NULL) |
| 234 | fatal("buffer_get_cstring: buffer error"); |
| 235 | return ret; |
| 236 | } |
| 237 | |
| 238 | void * |
| 239 | buffer_get_string_ptr_ret(Buffer *buffer, u_int *length_ptr) |
| 240 | { |
| 241 | void *ptr; |
| 242 | u_int len; |
| 243 | |
| 244 | if (buffer_get_int_ret(&len, buffer) != 0) |
| 245 | return NULL; |
| 246 | if (len > 256 * 1024) { |
| 247 | error("buffer_get_string_ptr: bad string length %u", len); |
| 248 | return NULL; |
| 249 | } |
| 250 | ptr = buffer_ptr(buffer); |
| 251 | buffer_consume(buffer, len); |
| 252 | if (length_ptr) |
| 253 | *length_ptr = len; |
| 254 | return (ptr); |
| 255 | } |
| 256 | |
| 257 | void * |
| 258 | buffer_get_string_ptr(Buffer *buffer, u_int *length_ptr) |
| 259 | { |
| 260 | void *ret; |
| 261 | |
| 262 | if ((ret = buffer_get_string_ptr_ret(buffer, length_ptr)) == NULL) |
| 263 | fatal("buffer_get_string_ptr: buffer error"); |
| 264 | return (ret); |
| 265 | } |
| 266 | |
| 267 | /* |
| 268 | * Stores and arbitrary binary string in the buffer. |
| 269 | */ |
| 270 | void |
| 271 | buffer_put_string(Buffer *buffer, const void *buf, u_int len) |
| 272 | { |
| 273 | buffer_put_int(buffer, len); |
| 274 | buffer_append(buffer, buf, len); |
| 275 | } |
| 276 | void |
| 277 | buffer_put_cstring(Buffer *buffer, const char *s) |
| 278 | { |
| 279 | if (s == NULL) |
| 280 | fatal("buffer_put_cstring: s == NULL"); |
| 281 | buffer_put_string(buffer, s, strlen(s)); |
| 282 | } |
| 283 | |
| 284 | /* |
| 285 | * Returns a character from the buffer (0 - 255). |
| 286 | */ |
| 287 | int |
| 288 | buffer_get_char_ret(char *ret, Buffer *buffer) |
| 289 | { |
| 290 | if (buffer_get_ret(buffer, ret, 1) == -1) { |
| 291 | error("buffer_get_char_ret: buffer_get_ret failed"); |
| 292 | return (-1); |
| 293 | } |
| 294 | return (0); |
| 295 | } |
| 296 | |
| 297 | int |
| 298 | buffer_get_char(Buffer *buffer) |
| 299 | { |
| 300 | char ch; |
| 301 | |
| 302 | if (buffer_get_char_ret(&ch, buffer) == -1) |
| 303 | fatal("buffer_get_char: buffer error"); |
| 304 | return (u_char) ch; |
| 305 | } |
| 306 | |
| 307 | /* |
| 308 | * Stores a character in the buffer. |
| 309 | */ |
| 310 | void |
| 311 | buffer_put_char(Buffer *buffer, int value) |
| 312 | { |
| 313 | char ch = value; |
| 314 | |
| 315 | buffer_append(buffer, &ch, 1); |
| 316 | } |