Denis Vlasenko | ac7d0e3 | 2007-10-08 19:32:12 +0000 | [diff] [blame] | 1 | /* vi: set sw=4 ts=4: */ |
| 2 | /* |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 3 | * Utility routines. |
Denis Vlasenko | ac7d0e3 | 2007-10-08 19:32:12 +0000 | [diff] [blame] | 4 | * |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 5 | * Copyright (C) tons of folks. Tracking down who wrote what |
| 6 | * isn't something I'm going to worry about... If you wrote something |
| 7 | * here, please feel free to acknowledge your work. |
Denis Vlasenko | ac7d0e3 | 2007-10-08 19:32:12 +0000 | [diff] [blame] | 8 | * |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 9 | * Based in part on code from sash, Copyright (c) 1999 by David I. Bell |
| 10 | * Permission has been granted to redistribute this code under the GPL. |
| 11 | * |
| 12 | * Licensed under GPLv2 or later, see file License in this tarball for details. |
Denis Vlasenko | ac7d0e3 | 2007-10-08 19:32:12 +0000 | [diff] [blame] | 13 | */ |
| 14 | |
| 15 | #include <assert.h> |
| 16 | #include "busybox.h" |
| 17 | |
| 18 | |
| 19 | /* Declare <applet>_main() */ |
| 20 | #define PROTOTYPES |
| 21 | #include "applets.h" |
| 22 | #undef PROTOTYPES |
| 23 | |
| 24 | #if ENABLE_SHOW_USAGE && !ENABLE_FEATURE_COMPRESS_USAGE |
| 25 | /* Define usage_messages[] */ |
| 26 | static const char usage_messages[] ALIGN1 = "" |
| 27 | #define MAKE_USAGE |
| 28 | #include "usage.h" |
| 29 | #include "applets.h" |
| 30 | ; |
| 31 | #undef MAKE_USAGE |
| 32 | #else |
| 33 | #define usage_messages 0 |
| 34 | #endif /* SHOW_USAGE */ |
| 35 | |
Denis Vlasenko | ac7d0e3 | 2007-10-08 19:32:12 +0000 | [diff] [blame] | 36 | |
Denis Vlasenko | 32b2a9f | 2008-02-22 22:43:22 +0000 | [diff] [blame] | 37 | /* Include generated applet names, pointers to <applet>_main, etc */ |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 38 | #include "applet_tables.h" |
Denis Vlasenko | ac7d0e3 | 2007-10-08 19:32:12 +0000 | [diff] [blame] | 39 | |
| 40 | |
| 41 | #if ENABLE_FEATURE_COMPRESS_USAGE |
| 42 | |
| 43 | #include "usage_compressed.h" |
| 44 | #include "unarchive.h" |
| 45 | |
| 46 | static const char *unpack_usage_messages(void) |
| 47 | { |
| 48 | char *outbuf = NULL; |
| 49 | bunzip_data *bd; |
| 50 | int i; |
| 51 | |
| 52 | i = start_bunzip(&bd, |
| 53 | /* src_fd: */ -1, |
| 54 | /* inbuf: */ packed_usage, |
| 55 | /* len: */ sizeof(packed_usage)); |
| 56 | /* read_bunzip can longjmp to start_bunzip, and ultimately |
| 57 | * end up here with i != 0 on read data errors! Not trivial */ |
| 58 | if (!i) { |
| 59 | /* Cannot use xmalloc: will leak bd in NOFORK case! */ |
| 60 | outbuf = malloc_or_warn(SIZEOF_usage_messages); |
| 61 | if (outbuf) |
| 62 | read_bunzip(bd, outbuf, SIZEOF_usage_messages); |
| 63 | } |
| 64 | dealloc_bunzip(bd); |
| 65 | return outbuf; |
| 66 | } |
| 67 | #define dealloc_usage_messages(s) free(s) |
| 68 | |
| 69 | #else |
| 70 | |
| 71 | #define unpack_usage_messages() usage_messages |
| 72 | #define dealloc_usage_messages(s) ((void)(s)) |
| 73 | |
| 74 | #endif /* FEATURE_COMPRESS_USAGE */ |
| 75 | |
| 76 | |
| 77 | void bb_show_usage(void) |
| 78 | { |
| 79 | if (ENABLE_SHOW_USAGE) { |
| 80 | const char *format_string; |
| 81 | const char *p; |
| 82 | const char *usage_string = p = unpack_usage_messages(); |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 83 | int ap = find_applet_by_name(applet_name); |
Denis Vlasenko | ac7d0e3 | 2007-10-08 19:32:12 +0000 | [diff] [blame] | 84 | |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 85 | if (ap < 0) /* never happens, paranoia */ |
Denis Vlasenko | ac7d0e3 | 2007-10-08 19:32:12 +0000 | [diff] [blame] | 86 | xfunc_die(); |
| 87 | |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 88 | while (ap) { |
Denis Vlasenko | ac7d0e3 | 2007-10-08 19:32:12 +0000 | [diff] [blame] | 89 | while (*p++) continue; |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 90 | ap--; |
Denis Vlasenko | ac7d0e3 | 2007-10-08 19:32:12 +0000 | [diff] [blame] | 91 | } |
| 92 | |
| 93 | fprintf(stderr, "%s multi-call binary\n", bb_banner); |
| 94 | format_string = "\nUsage: %s %s\n\n"; |
| 95 | if (*p == '\b') |
| 96 | format_string = "\nNo help available.\n\n"; |
| 97 | fprintf(stderr, format_string, applet_name, p); |
| 98 | dealloc_usage_messages((char*)usage_string); |
| 99 | } |
| 100 | xfunc_die(); |
| 101 | } |
| 102 | |
| 103 | |
Denis Vlasenko | 745cd17 | 2007-11-29 03:31:20 +0000 | [diff] [blame] | 104 | /* NB: any char pointer will work as well, not necessarily applet_names */ |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 105 | static int applet_name_compare(const void *name, const void *v) |
Denis Vlasenko | ac7d0e3 | 2007-10-08 19:32:12 +0000 | [diff] [blame] | 106 | { |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 107 | int i = (const char *)v - applet_names; |
| 108 | return strcmp(name, APPLET_NAME(i)); |
Denis Vlasenko | ac7d0e3 | 2007-10-08 19:32:12 +0000 | [diff] [blame] | 109 | } |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 110 | int find_applet_by_name(const char *name) |
Denis Vlasenko | ac7d0e3 | 2007-10-08 19:32:12 +0000 | [diff] [blame] | 111 | { |
| 112 | /* Do a binary search to find the applet entry given the name. */ |
Denis Vlasenko | 745cd17 | 2007-11-29 03:31:20 +0000 | [diff] [blame] | 113 | const char *p; |
| 114 | p = bsearch(name, applet_names, ARRAY_SIZE(applet_main), 1, applet_name_compare); |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 115 | if (!p) |
| 116 | return -1; |
| 117 | return p - applet_names; |
Denis Vlasenko | ac7d0e3 | 2007-10-08 19:32:12 +0000 | [diff] [blame] | 118 | } |
| 119 | |
| 120 | |
| 121 | #ifdef __GLIBC__ |
| 122 | /* Make it reside in R/W memory: */ |
| 123 | int *const bb_errno __attribute__ ((section (".data"))); |
| 124 | #endif |
| 125 | |
Denis Vlasenko | 68404f1 | 2008-03-17 09:00:54 +0000 | [diff] [blame] | 126 | void lbb_prepare(const char *applet |
| 127 | USE_FEATURE_INDIVIDUAL(, char **argv)) |
Denis Vlasenko | ac7d0e3 | 2007-10-08 19:32:12 +0000 | [diff] [blame] | 128 | { |
| 129 | #ifdef __GLIBC__ |
| 130 | (*(int **)&bb_errno) = __errno_location(); |
Denis Vlasenko | 574f2f4 | 2008-02-27 18:41:59 +0000 | [diff] [blame] | 131 | barrier(); |
Denis Vlasenko | ac7d0e3 | 2007-10-08 19:32:12 +0000 | [diff] [blame] | 132 | #endif |
Denis Vlasenko | 15cb4a4 | 2007-10-11 10:06:26 +0000 | [diff] [blame] | 133 | applet_name = applet; |
Denis Vlasenko | ac7d0e3 | 2007-10-08 19:32:12 +0000 | [diff] [blame] | 134 | |
| 135 | /* Set locale for everybody except 'init' */ |
| 136 | if (ENABLE_LOCALE_SUPPORT && getpid() != 1) |
| 137 | setlocale(LC_ALL, ""); |
| 138 | |
Denis Vlasenko | 82d38da | 2007-10-10 14:38:47 +0000 | [diff] [blame] | 139 | #if ENABLE_FEATURE_INDIVIDUAL |
| 140 | /* Redundant for busybox (run_applet_and_exit covers that case) |
| 141 | * but needed for "individual applet" mode */ |
Denis Vlasenko | d419a9f | 2007-10-08 20:45:42 +0000 | [diff] [blame] | 142 | if (argv[1] && strcmp(argv[1], "--help") == 0) |
Denis Vlasenko | ac7d0e3 | 2007-10-08 19:32:12 +0000 | [diff] [blame] | 143 | bb_show_usage(); |
Denis Vlasenko | 82d38da | 2007-10-10 14:38:47 +0000 | [diff] [blame] | 144 | #endif |
Denis Vlasenko | ac7d0e3 | 2007-10-08 19:32:12 +0000 | [diff] [blame] | 145 | } |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 146 | |
| 147 | /* The code below can well be in applets/applets.c, as it is used only |
| 148 | * for busybox binary, not "individual" binaries. |
| 149 | * However, keeping it here and linking it into libbusybox.so |
| 150 | * (together with remaining tiny applets/applets.o) |
| 151 | * makes it possible to avoid --whole-archive at link time. |
| 152 | * This makes (shared busybox) + libbusybox smaller. |
| 153 | * (--gc-sections would be even better....) |
| 154 | */ |
| 155 | |
| 156 | const char *applet_name; |
| 157 | #if !BB_MMU |
| 158 | bool re_execed; |
| 159 | #endif |
| 160 | |
| 161 | USE_FEATURE_SUID(static uid_t ruid;) /* real uid */ |
| 162 | |
| 163 | #if ENABLE_FEATURE_SUID_CONFIG |
| 164 | |
| 165 | /* applets[] is const, so we have to define this "override" structure */ |
| 166 | static struct BB_suid_config { |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 167 | int m_applet; |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 168 | uid_t m_uid; |
| 169 | gid_t m_gid; |
| 170 | mode_t m_mode; |
| 171 | struct BB_suid_config *m_next; |
| 172 | } *suid_config; |
| 173 | |
| 174 | static bool suid_cfg_readable; |
| 175 | |
| 176 | /* check if u is member of group g */ |
| 177 | static int ingroup(uid_t u, gid_t g) |
| 178 | { |
| 179 | struct group *grp = getgrgid(g); |
| 180 | |
| 181 | if (grp) { |
| 182 | char **mem; |
| 183 | |
| 184 | for (mem = grp->gr_mem; *mem; mem++) { |
| 185 | struct passwd *pwd = getpwnam(*mem); |
| 186 | |
| 187 | if (pwd && (pwd->pw_uid == u)) |
| 188 | return 1; |
| 189 | } |
| 190 | } |
| 191 | return 0; |
| 192 | } |
| 193 | |
| 194 | /* This should probably be a libbb routine. In that case, |
| 195 | * I'd probably rename it to something like bb_trimmed_slice. |
| 196 | */ |
| 197 | static char *get_trimmed_slice(char *s, char *e) |
| 198 | { |
| 199 | /* First, consider the value at e to be nul and back up until we |
| 200 | * reach a non-space char. Set the char after that (possibly at |
| 201 | * the original e) to nul. */ |
| 202 | while (e-- > s) { |
| 203 | if (!isspace(*e)) { |
| 204 | break; |
| 205 | } |
| 206 | } |
| 207 | e[1] = '\0'; |
| 208 | |
| 209 | /* Next, advance past all leading space and return a ptr to the |
| 210 | * first non-space char; possibly the terminating nul. */ |
| 211 | return skip_whitespace(s); |
| 212 | } |
| 213 | |
| 214 | /* Don't depend on the tools to combine strings. */ |
| 215 | static const char config_file[] ALIGN1 = "/etc/busybox.conf"; |
| 216 | |
| 217 | /* We don't supply a value for the nul, so an index adjustment is |
| 218 | * necessary below. Also, we use unsigned short here to save some |
| 219 | * space even though these are really mode_t values. */ |
| 220 | static const unsigned short mode_mask[] ALIGN2 = { |
| 221 | /* SST sst xxx --- */ |
| 222 | S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* user */ |
| 223 | S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* group */ |
| 224 | 0, S_IXOTH, S_IXOTH, 0 /* other */ |
| 225 | }; |
| 226 | |
| 227 | #define parse_error(x) do { errmsg = x; goto pe_label; } while (0) |
| 228 | |
| 229 | static void parse_config_file(void) |
| 230 | { |
| 231 | struct BB_suid_config *sct_head; |
| 232 | struct BB_suid_config *sct; |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 233 | int applet_no; |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 234 | FILE *f; |
| 235 | const char *errmsg; |
| 236 | char *s; |
| 237 | char *e; |
| 238 | int i; |
| 239 | unsigned lc; |
| 240 | smallint section; |
| 241 | char buffer[256]; |
| 242 | struct stat st; |
| 243 | |
| 244 | assert(!suid_config); /* Should be set to NULL by bss init. */ |
| 245 | |
| 246 | ruid = getuid(); |
| 247 | if (ruid == 0) /* run by root - don't need to even read config file */ |
| 248 | return; |
| 249 | |
| 250 | if ((stat(config_file, &st) != 0) /* No config file? */ |
| 251 | || !S_ISREG(st.st_mode) /* Not a regular file? */ |
| 252 | || (st.st_uid != 0) /* Not owned by root? */ |
| 253 | || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */ |
| 254 | || !(f = fopen(config_file, "r")) /* Cannot open? */ |
| 255 | ) { |
| 256 | return; |
| 257 | } |
| 258 | |
| 259 | suid_cfg_readable = 1; |
| 260 | sct_head = NULL; |
| 261 | section = lc = 0; |
| 262 | |
| 263 | while (1) { |
| 264 | s = buffer; |
| 265 | |
| 266 | if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */ |
Denis Vlasenko | d02db89 | 2008-03-17 09:05:21 +0000 | [diff] [blame] | 267 | // why? |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 268 | if (ferror(f)) { /* Make sure it wasn't a read error. */ |
| 269 | parse_error("reading"); |
| 270 | } |
| 271 | fclose(f); |
| 272 | suid_config = sct_head; /* Success, so set the pointer. */ |
| 273 | return; |
| 274 | } |
| 275 | |
| 276 | lc++; /* Got a (partial) line. */ |
| 277 | |
| 278 | /* If a line is too long for our buffer, we consider it an error. |
| 279 | * The following test does mistreat one corner case though. |
| 280 | * If the final line of the file does not end with a newline and |
| 281 | * yet exactly fills the buffer, it will be treated as too long |
| 282 | * even though there isn't really a problem. But it isn't really |
| 283 | * worth adding code to deal with such an unlikely situation, and |
| 284 | * we do err on the side of caution. Besides, the line would be |
| 285 | * too long if it did end with a newline. */ |
| 286 | if (!strchr(s, '\n') && !feof(f)) { |
| 287 | parse_error("line too long"); |
| 288 | } |
| 289 | |
| 290 | /* Trim leading and trailing whitespace, ignoring comments, and |
| 291 | * check if the resulting string is empty. */ |
| 292 | s = get_trimmed_slice(s, strchrnul(s, '#')); |
| 293 | if (!*s) { |
| 294 | continue; |
| 295 | } |
| 296 | |
| 297 | /* Check for a section header. */ |
| 298 | |
| 299 | if (*s == '[') { |
| 300 | /* Unlike the old code, we ignore leading and trailing |
| 301 | * whitespace for the section name. We also require that |
| 302 | * there are no stray characters after the closing bracket. */ |
| 303 | e = strchr(s, ']'); |
| 304 | if (!e /* Missing right bracket? */ |
| 305 | || e[1] /* Trailing characters? */ |
| 306 | || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */ |
| 307 | ) { |
| 308 | parse_error("section header"); |
| 309 | } |
| 310 | /* Right now we only have one section so just check it. |
| 311 | * If more sections are added in the future, please don't |
| 312 | * resort to cascading ifs with multiple strcasecmp calls. |
| 313 | * That kind of bloated code is all too common. A loop |
| 314 | * and a string table would be a better choice unless the |
| 315 | * number of sections is very small. */ |
| 316 | if (strcasecmp(s, "SUID") == 0) { |
| 317 | section = 1; |
| 318 | continue; |
| 319 | } |
| 320 | section = -1; /* Unknown section so set to skip. */ |
| 321 | continue; |
| 322 | } |
| 323 | |
| 324 | /* Process sections. */ |
| 325 | |
| 326 | if (section == 1) { /* SUID */ |
| 327 | /* Since we trimmed leading and trailing space above, we're |
| 328 | * now looking for strings of the form |
| 329 | * <key>[::space::]*=[::space::]*<value> |
| 330 | * where both key and value could contain inner whitespace. */ |
| 331 | |
| 332 | /* First get the key (an applet name in our case). */ |
| 333 | e = strchr(s, '='); |
| 334 | if (e) { |
| 335 | s = get_trimmed_slice(s, e); |
| 336 | } |
| 337 | if (!e || !*s) { /* Missing '=' or empty key. */ |
| 338 | parse_error("keyword"); |
| 339 | } |
| 340 | |
| 341 | /* Ok, we have an applet name. Process the rhs if this |
| 342 | * applet is currently built in and ignore it otherwise. |
| 343 | * Note: this can hide config file bugs which only pop |
| 344 | * up when the busybox configuration is changed. */ |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 345 | applet_no = find_applet_by_name(s); |
| 346 | if (applet_no >= 0) { |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 347 | /* Note: We currently don't check for duplicates! |
| 348 | * The last config line for each applet will be the |
| 349 | * one used since we insert at the head of the list. |
| 350 | * I suppose this could be considered a feature. */ |
| 351 | sct = xmalloc(sizeof(struct BB_suid_config)); |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 352 | sct->m_applet = applet_no; |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 353 | sct->m_mode = 0; |
| 354 | sct->m_next = sct_head; |
| 355 | sct_head = sct; |
| 356 | |
| 357 | /* Get the specified mode. */ |
| 358 | |
| 359 | e = skip_whitespace(e+1); |
| 360 | |
| 361 | for (i = 0; i < 3; i++) { |
| 362 | /* There are 4 chars + 1 nul for each of user/group/other. */ |
| 363 | static const char mode_chars[] ALIGN1 = "Ssx-\0" "Ssx-\0" "Ttx-"; |
| 364 | |
| 365 | const char *q; |
| 366 | q = strchrnul(mode_chars + 5*i, *e++); |
| 367 | if (!*q) { |
| 368 | parse_error("mode"); |
| 369 | } |
| 370 | /* Adjust by -i to account for nul. */ |
| 371 | sct->m_mode |= mode_mask[(q - mode_chars) - i]; |
| 372 | } |
| 373 | |
| 374 | /* Now get the the user/group info. */ |
| 375 | |
| 376 | s = skip_whitespace(e); |
| 377 | |
| 378 | /* Note: we require whitespace between the mode and the |
| 379 | * user/group info. */ |
| 380 | if ((s == e) || !(e = strchr(s, '.'))) { |
| 381 | parse_error("<uid>.<gid>"); |
| 382 | } |
| 383 | *e++ = '\0'; |
| 384 | |
| 385 | /* We can't use get_ug_id here since it would exit() |
| 386 | * if a uid or gid was not found. Oh well... */ |
| 387 | sct->m_uid = bb_strtoul(s, NULL, 10); |
| 388 | if (errno) { |
| 389 | struct passwd *pwd = getpwnam(s); |
| 390 | if (!pwd) { |
| 391 | parse_error("user"); |
| 392 | } |
| 393 | sct->m_uid = pwd->pw_uid; |
| 394 | } |
| 395 | |
| 396 | sct->m_gid = bb_strtoul(e, NULL, 10); |
| 397 | if (errno) { |
| 398 | struct group *grp; |
| 399 | grp = getgrnam(e); |
| 400 | if (!grp) { |
| 401 | parse_error("group"); |
| 402 | } |
| 403 | sct->m_gid = grp->gr_gid; |
| 404 | } |
| 405 | } |
| 406 | continue; |
| 407 | } |
| 408 | |
| 409 | /* Unknown sections are ignored. */ |
| 410 | |
| 411 | /* Encountering configuration lines prior to seeing a |
| 412 | * section header is treated as an error. This is how |
| 413 | * the old code worked, but it may not be desirable. |
| 414 | * We may want to simply ignore such lines in case they |
| 415 | * are used in some future version of busybox. */ |
| 416 | if (!section) { |
| 417 | parse_error("keyword outside section"); |
| 418 | } |
| 419 | |
| 420 | } /* while (1) */ |
| 421 | |
| 422 | pe_label: |
| 423 | fprintf(stderr, "Parse error in %s, line %d: %s\n", |
| 424 | config_file, lc, errmsg); |
| 425 | |
| 426 | fclose(f); |
| 427 | /* Release any allocated memory before returning. */ |
| 428 | while (sct_head) { |
| 429 | sct = sct_head->m_next; |
| 430 | free(sct_head); |
| 431 | sct_head = sct; |
| 432 | } |
| 433 | } |
| 434 | #else |
| 435 | static inline void parse_config_file(void) |
| 436 | { |
| 437 | USE_FEATURE_SUID(ruid = getuid();) |
| 438 | } |
| 439 | #endif /* FEATURE_SUID_CONFIG */ |
| 440 | |
| 441 | |
| 442 | #if ENABLE_FEATURE_SUID |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 443 | static void check_suid(int applet_no) |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 444 | { |
| 445 | gid_t rgid; /* real gid */ |
| 446 | |
| 447 | if (ruid == 0) /* set by parse_config_file() */ |
| 448 | return; /* run by root - no need to check more */ |
| 449 | rgid = getgid(); |
| 450 | |
| 451 | #if ENABLE_FEATURE_SUID_CONFIG |
| 452 | if (suid_cfg_readable) { |
| 453 | uid_t uid; |
| 454 | struct BB_suid_config *sct; |
| 455 | mode_t m; |
| 456 | |
| 457 | for (sct = suid_config; sct; sct = sct->m_next) { |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 458 | if (sct->m_applet == applet_no) |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 459 | goto found; |
| 460 | } |
Denis Vlasenko | 15ca51e | 2007-10-29 19:25:45 +0000 | [diff] [blame] | 461 | goto check_need_suid; |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 462 | found: |
| 463 | m = sct->m_mode; |
| 464 | if (sct->m_uid == ruid) |
| 465 | /* same uid */ |
| 466 | m >>= 6; |
| 467 | else if ((sct->m_gid == rgid) || ingroup(ruid, sct->m_gid)) |
| 468 | /* same group / in group */ |
| 469 | m >>= 3; |
| 470 | |
| 471 | if (!(m & S_IXOTH)) /* is x bit not set ? */ |
| 472 | bb_error_msg_and_die("you have no permission to run this applet!"); |
| 473 | |
| 474 | /* _both_ sgid and group_exec have to be set for setegid */ |
| 475 | if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) |
| 476 | rgid = sct->m_gid; |
| 477 | /* else (no setegid) we will set egid = rgid */ |
| 478 | |
| 479 | /* We set effective AND saved ids. If saved-id is not set |
| 480 | * like we do below, seteiud(0) can still later succeed! */ |
| 481 | if (setresgid(-1, rgid, rgid)) |
| 482 | bb_perror_msg_and_die("setresgid"); |
| 483 | |
| 484 | /* do we have to set effective uid? */ |
| 485 | uid = ruid; |
| 486 | if (sct->m_mode & S_ISUID) |
| 487 | uid = sct->m_uid; |
| 488 | /* else (no seteuid) we will set euid = ruid */ |
| 489 | |
| 490 | if (setresuid(-1, uid, uid)) |
| 491 | bb_perror_msg_and_die("setresuid"); |
| 492 | return; |
| 493 | } |
| 494 | #if !ENABLE_FEATURE_SUID_CONFIG_QUIET |
| 495 | { |
| 496 | static bool onetime = 0; |
| 497 | |
| 498 | if (!onetime) { |
| 499 | onetime = 1; |
| 500 | fprintf(stderr, "Using fallback suid method\n"); |
| 501 | } |
| 502 | } |
| 503 | #endif |
Denis Vlasenko | 15ca51e | 2007-10-29 19:25:45 +0000 | [diff] [blame] | 504 | check_need_suid: |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 505 | #endif |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 506 | if (APPLET_SUID(applet_no) == _BB_SUID_ALWAYS) { |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 507 | /* Real uid is not 0. If euid isn't 0 too, suid bit |
| 508 | * is most probably not set on our executable */ |
| 509 | if (geteuid()) |
Denis Vlasenko | 15ca51e | 2007-10-29 19:25:45 +0000 | [diff] [blame] | 510 | bb_error_msg_and_die("must be suid to work properly"); |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 511 | } else if (APPLET_SUID(applet_no) == _BB_SUID_NEVER) { |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 512 | xsetgid(rgid); /* drop all privileges */ |
| 513 | xsetuid(ruid); |
| 514 | } |
| 515 | } |
| 516 | #else |
| 517 | #define check_suid(x) ((void)0) |
| 518 | #endif /* FEATURE_SUID */ |
| 519 | |
| 520 | |
| 521 | #if ENABLE_FEATURE_INSTALLER |
| 522 | /* create (sym)links for each applet */ |
| 523 | static void install_links(const char *busybox, int use_symbolic_links) |
| 524 | { |
| 525 | /* directory table |
| 526 | * this should be consistent w/ the enum, |
| 527 | * busybox.h::bb_install_loc_t, or else... */ |
| 528 | static const char usr_bin [] ALIGN1 = "/usr/bin"; |
| 529 | static const char usr_sbin[] ALIGN1 = "/usr/sbin"; |
| 530 | static const char *const install_dir[] = { |
| 531 | &usr_bin [8], /* "", equivalent to "/" for concat_path_file() */ |
| 532 | &usr_bin [4], /* "/bin" */ |
| 533 | &usr_sbin[4], /* "/sbin" */ |
| 534 | usr_bin, |
| 535 | usr_sbin |
| 536 | }; |
| 537 | |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 538 | int (*lf)(const char *, const char *); |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 539 | char *fpc; |
| 540 | int i; |
| 541 | int rc; |
| 542 | |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 543 | lf = link; |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 544 | if (use_symbolic_links) |
| 545 | lf = symlink; |
| 546 | |
Denis Vlasenko | 745cd17 | 2007-11-29 03:31:20 +0000 | [diff] [blame] | 547 | for (i = 0; i < ARRAY_SIZE(applet_main); i++) { |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 548 | fpc = concat_path_file( |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 549 | install_dir[APPLET_INSTALL_LOC(i)], |
| 550 | APPLET_NAME(i)); |
Denis Vlasenko | 745cd17 | 2007-11-29 03:31:20 +0000 | [diff] [blame] | 551 | // debug: bb_error_msg("%slinking %s to busybox", |
| 552 | // use_symbolic_links ? "sym" : "", fpc); |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 553 | rc = lf(busybox, fpc); |
| 554 | if (rc != 0 && errno != EEXIST) { |
| 555 | bb_simple_perror_msg(fpc); |
| 556 | } |
| 557 | free(fpc); |
| 558 | } |
| 559 | } |
| 560 | #else |
| 561 | #define install_links(x,y) ((void)0) |
| 562 | #endif /* FEATURE_INSTALLER */ |
| 563 | |
| 564 | /* If we were called as "busybox..." */ |
| 565 | static int busybox_main(char **argv) |
| 566 | { |
| 567 | if (!argv[1]) { |
| 568 | /* Called without arguments */ |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 569 | const char *a; |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 570 | int col, output_width; |
| 571 | help: |
| 572 | output_width = 80; |
| 573 | if (ENABLE_FEATURE_AUTOWIDTH) { |
| 574 | /* Obtain the terminal width */ |
| 575 | get_terminal_width_height(0, &output_width, NULL); |
| 576 | } |
| 577 | /* leading tab and room to wrap */ |
| 578 | output_width -= sizeof("start-stop-daemon, ") + 8; |
| 579 | |
| 580 | printf("%s multi-call binary\n", bb_banner); /* reuse const string... */ |
Denis Vlasenko | fcfb5c0 | 2007-12-24 12:16:24 +0000 | [diff] [blame] | 581 | printf("Copyright (C) 1998-2007 Erik Andersen, Rob Landley, Denys Vlasenko\n" |
| 582 | "and others. Licensed under GPLv2.\n" |
| 583 | "See source distribution for full notice.\n" |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 584 | "\n" |
| 585 | "Usage: busybox [function] [arguments]...\n" |
Denis Vlasenko | fcfb5c0 | 2007-12-24 12:16:24 +0000 | [diff] [blame] | 586 | " or: function [arguments]...\n" |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 587 | "\n" |
| 588 | "\tBusyBox is a multi-call binary that combines many common Unix\n" |
| 589 | "\tutilities into a single executable. Most people will create a\n" |
| 590 | "\tlink to busybox for each function they wish to use and BusyBox\n" |
| 591 | "\twill act like whatever it was invoked as!\n" |
Denis Vlasenko | fcfb5c0 | 2007-12-24 12:16:24 +0000 | [diff] [blame] | 592 | "\n" |
| 593 | "Currently defined functions:\n"); |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 594 | col = 0; |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 595 | a = applet_names; |
| 596 | while (*a) { |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 597 | if (col > output_width) { |
| 598 | puts(","); |
| 599 | col = 0; |
| 600 | } |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 601 | col += printf("%s%s", (col ? ", " : "\t"), a); |
| 602 | a += strlen(a) + 1; |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 603 | } |
| 604 | puts("\n"); |
| 605 | return 0; |
| 606 | } |
| 607 | |
| 608 | if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) { |
| 609 | const char *busybox; |
| 610 | busybox = xmalloc_readlink(bb_busybox_exec_path); |
| 611 | if (!busybox) |
| 612 | busybox = bb_busybox_exec_path; |
| 613 | /* -s makes symlinks */ |
| 614 | install_links(busybox, argv[2] && strcmp(argv[2], "-s") == 0); |
| 615 | return 0; |
| 616 | } |
| 617 | |
| 618 | if (strcmp(argv[1], "--help") == 0) { |
| 619 | /* "busybox --help [<applet>]" */ |
| 620 | if (!argv[2]) |
| 621 | goto help; |
| 622 | /* convert to "<applet> --help" */ |
| 623 | argv[0] = argv[2]; |
| 624 | argv[2] = NULL; |
| 625 | } else { |
| 626 | /* "busybox <applet> arg1 arg2 ..." */ |
| 627 | argv++; |
| 628 | } |
| 629 | /* We support "busybox /a/path/to/applet args..." too. Allows for |
| 630 | * "#!/bin/busybox"-style wrappers */ |
| 631 | applet_name = bb_get_last_path_component_nostrip(argv[0]); |
| 632 | run_applet_and_exit(applet_name, argv); |
| 633 | bb_error_msg_and_die("applet not found"); |
| 634 | } |
| 635 | |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 636 | void run_applet_no_and_exit(int applet_no, char **argv) |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 637 | { |
| 638 | int argc = 1; |
| 639 | |
| 640 | while (argv[argc]) |
| 641 | argc++; |
| 642 | |
| 643 | /* Reinit some shared global data */ |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 644 | xfunc_error_retval = EXIT_FAILURE; |
| 645 | |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 646 | applet_name = APPLET_NAME(applet_no); |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 647 | if (argc == 2 && !strcmp(argv[1], "--help")) |
| 648 | bb_show_usage(); |
| 649 | if (ENABLE_FEATURE_SUID) |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 650 | check_suid(applet_no); |
Denis Vlasenko | 745cd17 | 2007-11-29 03:31:20 +0000 | [diff] [blame] | 651 | exit(applet_main[applet_no](argc, argv)); |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 652 | } |
| 653 | |
| 654 | void run_applet_and_exit(const char *name, char **argv) |
| 655 | { |
Denis Vlasenko | 1aa7e47 | 2007-11-28 06:49:03 +0000 | [diff] [blame] | 656 | int applet = find_applet_by_name(name); |
| 657 | if (applet >= 0) |
| 658 | run_applet_no_and_exit(applet, argv); |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 659 | if (!strncmp(name, "busybox", 7)) |
| 660 | exit(busybox_main(argv)); |
| 661 | } |
| 662 | |
| 663 | |
| 664 | #if ENABLE_BUILD_LIBBUSYBOX |
Denis Vlasenko | 85c2471 | 2008-03-17 09:04:04 +0000 | [diff] [blame] | 665 | int lbb_main(char **argv) |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 666 | #else |
Denis Vlasenko | 68404f1 | 2008-03-17 09:00:54 +0000 | [diff] [blame] | 667 | int main(int argc ATTRIBUTE_UNUSED, char **argv) |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 668 | #endif |
| 669 | { |
Denis Vlasenko | 68404f1 | 2008-03-17 09:00:54 +0000 | [diff] [blame] | 670 | lbb_prepare("busybox" USE_FEATURE_INDIVIDUAL(, argv)); |
Denis Vlasenko | 724d196 | 2007-10-10 14:41:07 +0000 | [diff] [blame] | 671 | |
| 672 | #if !BB_MMU |
| 673 | /* NOMMU re-exec trick sets high-order bit in first byte of name */ |
| 674 | if (argv[0][0] & 0x80) { |
| 675 | re_execed = 1; |
| 676 | argv[0][0] &= 0x7f; |
| 677 | } |
| 678 | #endif |
| 679 | applet_name = argv[0]; |
| 680 | if (applet_name[0] == '-') |
| 681 | applet_name++; |
| 682 | applet_name = bb_basename(applet_name); |
| 683 | |
| 684 | parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */ |
| 685 | |
| 686 | run_applet_and_exit(applet_name, argv); |
| 687 | bb_error_msg_and_die("applet not found"); |
| 688 | } |