Stephen Smalley | f074036 | 2012-01-04 12:30:47 -0500 | [diff] [blame^] | 1 | #include <sys/types.h> |
| 2 | #include <unistd.h> |
| 3 | #include <string.h> |
| 4 | #include <stdio.h> |
| 5 | #include <stdlib.h> |
| 6 | #include <ctype.h> |
| 7 | #include <errno.h> |
| 8 | #include <pwd.h> |
| 9 | #include <grp.h> |
| 10 | #include <sys/types.h> |
| 11 | #include <sys/stat.h> |
| 12 | #include <fcntl.h> |
| 13 | #include <selinux/selinux.h> |
| 14 | #include <selinux/context.h> |
| 15 | #include <selinux/android.h> |
| 16 | #include "callbacks.h" |
| 17 | #include "selinux_internal.h" |
| 18 | |
| 19 | /* |
| 20 | * XXX Where should this configuration file be located? |
| 21 | * Needs to be accessible by zygote and installd when |
| 22 | * setting credentials for app processes and setting permissions |
| 23 | * on app data directories. |
| 24 | */ |
| 25 | #define SEAPP_CONTEXTS "/seapp_contexts" |
| 26 | |
| 27 | struct seapp_context { |
| 28 | /* input selectors */ |
| 29 | char isSystemServer; |
| 30 | char *user; |
| 31 | size_t len; |
| 32 | char prefix; |
| 33 | char *seinfo; |
| 34 | char *name; |
| 35 | /* outputs */ |
| 36 | char *domain; |
| 37 | char *type; |
| 38 | char *level; |
| 39 | char levelFromUid; |
| 40 | }; |
| 41 | |
| 42 | static int seapp_context_cmp(const void *A, const void *B) |
| 43 | { |
| 44 | const struct seapp_context **sp1 = A, **sp2 = B; |
| 45 | const struct seapp_context *s1 = *sp1, *s2 = *sp2; |
| 46 | |
| 47 | /* Give precedence to isSystemServer=true. */ |
| 48 | if (s1->isSystemServer != s2->isSystemServer) |
| 49 | return (s1->isSystemServer ? -1 : 1); |
| 50 | |
| 51 | /* Give precedence to a specified user= over an unspecified user=. */ |
| 52 | if (s1->user && !s2->user) |
| 53 | return -1; |
| 54 | if (!s1->user && s2->user) |
| 55 | return 1; |
| 56 | |
| 57 | if (s1->user) { |
| 58 | /* Give precedence to a fixed user= string over a prefix. */ |
| 59 | if (s1->prefix != s2->prefix) |
| 60 | return (s2->prefix ? -1 : 1); |
| 61 | |
| 62 | /* Give precedence to a longer prefix over a shorter prefix. */ |
| 63 | if (s1->prefix && s1->len != s2->len) |
| 64 | return (s1->len > s2->len) ? -1 : 1; |
| 65 | } |
| 66 | |
| 67 | /* Give precedence to a specified seinfo= over an unspecified seinfo=. */ |
| 68 | if (s1->seinfo && !s2->seinfo) |
| 69 | return -1; |
| 70 | if (!s1->seinfo && s2->seinfo) |
| 71 | return 1; |
| 72 | |
| 73 | /* Give precedence to a specified name= over an unspecified name=. */ |
| 74 | if (s1->name && !s2->name) |
| 75 | return -1; |
| 76 | if (!s1->name && s2->name) |
| 77 | return 1; |
| 78 | |
| 79 | /* Anything else has equal precedence. */ |
| 80 | return 0; |
| 81 | } |
| 82 | |
| 83 | static struct seapp_context **seapp_contexts = NULL; |
| 84 | static int nspec = 0; |
| 85 | |
| 86 | static void seapp_context_init(void) |
| 87 | { |
| 88 | FILE *fp; |
| 89 | char line_buf[BUFSIZ]; |
| 90 | const char *path = SEAPP_CONTEXTS; |
| 91 | char *token; |
| 92 | unsigned lineno; |
| 93 | struct seapp_context *cur; |
| 94 | char *p, *name = NULL, *value = NULL, *saveptr; |
| 95 | size_t len; |
| 96 | |
| 97 | fp = fopen(path, "r"); |
| 98 | if (!fp) { |
| 99 | selinux_log(SELINUX_ERROR, "%s: could not open %s", __FUNCTION__, path); |
| 100 | return; |
| 101 | } |
| 102 | |
| 103 | nspec = 0; |
| 104 | while (fgets(line_buf, sizeof line_buf - 1, fp)) { |
| 105 | p = line_buf; |
| 106 | while (isspace(*p)) |
| 107 | p++; |
| 108 | if (*p == '#' || *p == 0) |
| 109 | continue; |
| 110 | nspec++; |
| 111 | } |
| 112 | |
| 113 | seapp_contexts = calloc(nspec, sizeof(struct seapp_context *)); |
| 114 | if (!seapp_contexts) |
| 115 | goto oom; |
| 116 | |
| 117 | rewind(fp); |
| 118 | nspec = 0; |
| 119 | lineno = 1; |
| 120 | while (fgets(line_buf, sizeof line_buf - 1, fp)) { |
| 121 | len = strlen(line_buf); |
| 122 | if (line_buf[len - 1] == '\n') |
| 123 | line_buf[len - 1] = 0; |
| 124 | p = line_buf; |
| 125 | while (isspace(*p)) |
| 126 | p++; |
| 127 | if (*p == '#' || *p == 0) |
| 128 | continue; |
| 129 | |
| 130 | cur = calloc(1, sizeof(struct seapp_context)); |
| 131 | if (!cur) |
| 132 | goto oom; |
| 133 | |
| 134 | token = strtok_r(p, " \t", &saveptr); |
| 135 | if (!token) |
| 136 | goto err; |
| 137 | |
| 138 | while (1) { |
| 139 | name = token; |
| 140 | value = strchr(name, '='); |
| 141 | if (!value) |
| 142 | goto err; |
| 143 | *value++ = 0; |
| 144 | |
| 145 | if (!strcasecmp(name, "isSystemServer")) { |
| 146 | if (!strcasecmp(value, "true")) |
| 147 | cur->isSystemServer = 1; |
| 148 | else if (!strcasecmp(value, "false")) |
| 149 | cur->isSystemServer = 0; |
| 150 | else { |
| 151 | goto err; |
| 152 | } |
| 153 | } else if (!strcasecmp(name, "user")) { |
| 154 | cur->user = strdup(value); |
| 155 | if (!cur->user) |
| 156 | goto oom; |
| 157 | cur->len = strlen(cur->user); |
| 158 | if (cur->user[cur->len-1] == '*') |
| 159 | cur->prefix = 1; |
| 160 | } else if (!strcasecmp(name, "seinfo")) { |
| 161 | cur->seinfo = strdup(value); |
| 162 | if (!cur->seinfo) |
| 163 | goto oom; |
| 164 | } else if (!strcasecmp(name, "name")) { |
| 165 | cur->name = strdup(value); |
| 166 | if (!cur->name) |
| 167 | goto oom; |
| 168 | } else if (!strcasecmp(name, "domain")) { |
| 169 | cur->domain = strdup(value); |
| 170 | if (!cur->domain) |
| 171 | goto oom; |
| 172 | } else if (!strcasecmp(name, "type")) { |
| 173 | cur->type = strdup(value); |
| 174 | if (!cur->type) |
| 175 | goto oom; |
| 176 | } else if (!strcasecmp(name, "levelFromUid")) { |
| 177 | if (!strcasecmp(value, "true")) |
| 178 | cur->levelFromUid = 1; |
| 179 | else if (!strcasecmp(value, "false")) |
| 180 | cur->levelFromUid = 0; |
| 181 | else { |
| 182 | goto err; |
| 183 | } |
| 184 | } else if (!strcasecmp(name, "level")) { |
| 185 | cur->level = strdup(value); |
| 186 | if (!cur->level) |
| 187 | goto oom; |
| 188 | } else |
| 189 | goto err; |
| 190 | |
| 191 | token = strtok_r(NULL, " \t", &saveptr); |
| 192 | if (!token) |
| 193 | break; |
| 194 | } |
| 195 | |
| 196 | seapp_contexts[nspec] = cur; |
| 197 | nspec++; |
| 198 | lineno++; |
| 199 | } |
| 200 | |
| 201 | qsort(seapp_contexts, nspec, sizeof(struct seapp_context *), |
| 202 | seapp_context_cmp); |
| 203 | |
| 204 | #if DEBUG |
| 205 | { |
| 206 | int i; |
| 207 | for (i = 0; i < nspec; i++) { |
| 208 | cur = seapp_contexts[i]; |
| 209 | selinux_log(SELINUX_INFO, "%s: isSystemServer=%s user=%s seinfo=%s name=%s -> domain=%s type=%s level=%s levelFromUid=%s", |
| 210 | __FUNCTION__, |
| 211 | cur->isSystemServer ? "true" : "false", |
| 212 | cur->user, cur->seinfo, cur->name, |
| 213 | cur->domain, cur->type, cur->level, |
| 214 | cur->levelFromUid ? "true" : "false"); |
| 215 | } |
| 216 | } |
| 217 | #endif |
| 218 | |
| 219 | out: |
| 220 | fclose(fp); |
| 221 | return; |
| 222 | |
| 223 | err: |
| 224 | selinux_log(SELINUX_ERROR, "%s: Error reading %s, line %u, name %s, value %s\n", |
| 225 | __FUNCTION__, path, lineno, name, value); |
| 226 | goto out; |
| 227 | oom: |
| 228 | selinux_log(SELINUX_ERROR, |
| 229 | "%s: Out of memory\n", __FUNCTION__); |
| 230 | goto out; |
| 231 | } |
| 232 | |
| 233 | static pthread_once_t once = PTHREAD_ONCE_INIT; |
| 234 | |
| 235 | int selinux_android_setfilecon(const char *pkgdir, |
| 236 | const char *name, |
| 237 | uid_t uid) |
| 238 | { |
| 239 | char *orig_ctx_str = NULL, *ctx_str; |
| 240 | context_t ctx = NULL; |
| 241 | struct passwd *pw; |
| 242 | struct seapp_context *cur; |
| 243 | int i, rc; |
| 244 | |
| 245 | if (is_selinux_enabled() <= 0) |
| 246 | return 0; |
| 247 | |
| 248 | __selinux_once(once, seapp_context_init); |
| 249 | |
| 250 | rc = getfilecon(pkgdir, &ctx_str); |
| 251 | if (rc < 0) |
| 252 | goto err; |
| 253 | |
| 254 | ctx = context_new(ctx_str); |
| 255 | orig_ctx_str = ctx_str; |
| 256 | if (!ctx) |
| 257 | goto oom; |
| 258 | |
| 259 | pw = getpwuid(uid); |
| 260 | if (!pw) |
| 261 | goto err; |
| 262 | |
| 263 | for (i = 0; i < nspec; i++) { |
| 264 | cur = seapp_contexts[i]; |
| 265 | |
| 266 | /* isSystemServer=true is only for app process labeling. */ |
| 267 | if (cur->isSystemServer) |
| 268 | continue; |
| 269 | |
| 270 | if (cur->user) { |
| 271 | if (cur->prefix) { |
| 272 | if (strncasecmp(pw->pw_name, cur->user, cur->len-1)) |
| 273 | continue; |
| 274 | } else { |
| 275 | if (strcasecmp(pw->pw_name, cur->user)) |
| 276 | continue; |
| 277 | } |
| 278 | } |
| 279 | |
| 280 | /* seinfo= is ignored / not available for file labeling. */ |
| 281 | |
| 282 | if (cur->name) { |
| 283 | if (!name || strcasecmp(name, cur->name)) |
| 284 | continue; |
| 285 | } |
| 286 | |
| 287 | if (!cur->type) |
| 288 | continue; |
| 289 | |
| 290 | if (context_type_set(ctx, cur->type)) |
| 291 | goto oom; |
| 292 | |
| 293 | if (cur->levelFromUid && !strncmp(pw->pw_name, "app_", 4)) { |
| 294 | char level[255]; |
| 295 | unsigned long id; |
| 296 | |
| 297 | /* Only supported for app UIDs. */ |
| 298 | id = strtoul(pw->pw_name + 4, NULL, 10); |
| 299 | snprintf(level, sizeof level, "%s:c%lu", |
| 300 | context_range_get(ctx), id); |
| 301 | if (context_range_set(ctx, level)) |
| 302 | goto oom; |
| 303 | } else if (cur->level) { |
| 304 | if (context_range_set(ctx, cur->level)) |
| 305 | goto oom; |
| 306 | } |
| 307 | |
| 308 | break; |
| 309 | } |
| 310 | |
| 311 | ctx_str = context_str(ctx); |
| 312 | if (!ctx_str) |
| 313 | goto oom; |
| 314 | |
| 315 | rc = security_check_context(ctx_str); |
| 316 | if (rc < 0) |
| 317 | goto err; |
| 318 | |
| 319 | if (strcmp(ctx_str, orig_ctx_str)) { |
| 320 | rc = setfilecon(pkgdir, ctx_str); |
| 321 | if (rc < 0) |
| 322 | goto err; |
| 323 | } |
| 324 | |
| 325 | rc = 0; |
| 326 | out: |
| 327 | freecon(orig_ctx_str); |
| 328 | context_free(ctx); |
| 329 | return rc; |
| 330 | err: |
| 331 | selinux_log(SELINUX_ERROR, "%s: Error setting context for pkgdir %s, uid %d: %s\n", |
| 332 | __FUNCTION__, pkgdir, uid, strerror(errno)); |
| 333 | rc = -1; |
| 334 | goto out; |
| 335 | oom: |
| 336 | selinux_log(SELINUX_ERROR, "%s: Out of memory\n", __FUNCTION__); |
| 337 | rc = -1; |
| 338 | goto out; |
| 339 | } |
| 340 | |
| 341 | int selinux_android_setcontext(uid_t uid, |
| 342 | int isSystemServer, |
| 343 | const char *seinfo, |
| 344 | const char *name) |
| 345 | { |
| 346 | char *orig_ctx_str = NULL, *ctx_str; |
| 347 | context_t ctx = NULL; |
| 348 | unsigned long id; |
| 349 | struct passwd *pw; |
| 350 | struct seapp_context *cur; |
| 351 | int i, rc; |
| 352 | |
| 353 | if (is_selinux_enabled() <= 0) |
| 354 | return 0; |
| 355 | |
| 356 | __selinux_once(once, seapp_context_init); |
| 357 | |
| 358 | rc = getcon(&ctx_str); |
| 359 | if (rc) |
| 360 | goto err; |
| 361 | |
| 362 | ctx = context_new(ctx_str); |
| 363 | orig_ctx_str = ctx_str; |
| 364 | if (!ctx) |
| 365 | goto oom; |
| 366 | |
| 367 | pw = getpwuid(uid); |
| 368 | if (!pw) |
| 369 | goto err; |
| 370 | |
| 371 | for (i = 0; i < nspec; i++) { |
| 372 | cur = seapp_contexts[i]; |
| 373 | if (cur->isSystemServer != isSystemServer) |
| 374 | continue; |
| 375 | if (cur->user) { |
| 376 | if (cur->prefix) { |
| 377 | if (strncasecmp(pw->pw_name, cur->user, cur->len-1)) |
| 378 | continue; |
| 379 | } else { |
| 380 | if (strcasecmp(pw->pw_name, cur->user)) |
| 381 | continue; |
| 382 | } |
| 383 | } |
| 384 | if (cur->seinfo) { |
| 385 | if (!seinfo || strcasecmp(seinfo, cur->seinfo)) |
| 386 | continue; |
| 387 | } |
| 388 | if (cur->name) { |
| 389 | if (!name || strcasecmp(name, cur->name)) |
| 390 | continue; |
| 391 | } |
| 392 | |
| 393 | if (!cur->domain) |
| 394 | continue; |
| 395 | |
| 396 | if (context_type_set(ctx, cur->domain)) |
| 397 | goto oom; |
| 398 | |
| 399 | if (cur->levelFromUid && !strncmp(pw->pw_name, "app_", 4)) { |
| 400 | char level[255]; |
| 401 | unsigned long id; |
| 402 | |
| 403 | /* Only supported for app UIDs. */ |
| 404 | id = strtoul(pw->pw_name + 4, NULL, 10); |
| 405 | snprintf(level, sizeof level, "%s:c%lu", |
| 406 | context_range_get(ctx), id); |
| 407 | if (context_range_set(ctx, level)) |
| 408 | goto oom; |
| 409 | } else if (cur->level) { |
| 410 | if (context_range_set(ctx, cur->level)) |
| 411 | goto oom; |
| 412 | } |
| 413 | |
| 414 | break; |
| 415 | } |
| 416 | |
| 417 | if (i == nspec) { |
| 418 | /* |
| 419 | * No match. |
| 420 | * Fail to prevent staying in the zygote's context. |
| 421 | */ |
| 422 | selinux_log(SELINUX_ERROR, |
| 423 | "%s: No match for app with uid %d, seinfo %s, name %s\n", |
| 424 | __FUNCTION__, uid, seinfo, name); |
| 425 | rc = -1; |
| 426 | goto out; |
| 427 | } |
| 428 | |
| 429 | ctx_str = context_str(ctx); |
| 430 | if (!ctx_str) |
| 431 | goto oom; |
| 432 | |
| 433 | rc = security_check_context(ctx_str); |
| 434 | if (rc < 0) |
| 435 | goto err; |
| 436 | |
| 437 | if (strcmp(ctx_str, orig_ctx_str)) { |
| 438 | rc = setcon(ctx_str); |
| 439 | if (rc < 0) |
| 440 | goto err; |
| 441 | } |
| 442 | |
| 443 | rc = 0; |
| 444 | out: |
| 445 | freecon(orig_ctx_str); |
| 446 | context_free(ctx); |
| 447 | return rc; |
| 448 | err: |
| 449 | if (isSystemServer) |
| 450 | selinux_log(SELINUX_ERROR, |
| 451 | "%s: Error setting context for system server: %s\n", |
| 452 | __FUNCTION__, strerror(errno)); |
| 453 | else |
| 454 | selinux_log(SELINUX_ERROR, |
| 455 | "%s: Error setting context for app with uid %d, seinfo %s: %s\n", |
| 456 | __FUNCTION__, uid, seinfo, strerror(errno)); |
| 457 | |
| 458 | rc = -1; |
| 459 | goto out; |
| 460 | oom: |
| 461 | selinux_log(SELINUX_ERROR, "%s: Out of memory\n", __FUNCTION__); |
| 462 | rc = -1; |
| 463 | goto out; |
| 464 | } |
| 465 | |