1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * security/tomoyo/audit.c 4 * 5 * Copyright (C) 2005-2011 NTT DATA CORPORATION 6 */ 7 8 #include "common.h" 9 #include <linux/slab.h> 10 11 /** 12 * tomoyo_print_bprm - Print "struct linux_binprm" for auditing. 13 * 14 * @bprm: Pointer to "struct linux_binprm". 15 * @dump: Pointer to "struct tomoyo_page_dump". 16 * 17 * Returns the contents of @bprm on success, NULL otherwise. 18 * 19 * This function uses kzalloc(), so caller must kfree() if this function 20 * didn't return NULL. 21 */ 22 static char *tomoyo_print_bprm(struct linux_binprm *bprm, 23 struct tomoyo_page_dump *dump) 24 { 25 static const int tomoyo_buffer_len = 4096 * 2; 26 char *buffer = kzalloc(tomoyo_buffer_len, GFP_NOFS); 27 char *cp; 28 char *last_start; 29 int len; 30 unsigned long pos = bprm->p; 31 int offset = pos % PAGE_SIZE; 32 int argv_count = bprm->argc; 33 int envp_count = bprm->envc; 34 bool truncated = false; 35 36 if (!buffer) 37 return NULL; 38 len = snprintf(buffer, tomoyo_buffer_len - 1, "argv[]={ "); 39 cp = buffer + len; 40 if (!argv_count) { 41 memmove(cp, "} envp[]={ ", 11); 42 cp += 11; 43 } 44 last_start = cp; 45 while (argv_count || envp_count) { 46 if (!tomoyo_dump_page(bprm, pos, dump)) 47 goto out; 48 pos += PAGE_SIZE - offset; 49 /* Read. */ 50 while (offset < PAGE_SIZE) { 51 const char *kaddr = dump->data; 52 const unsigned char c = kaddr[offset++]; 53 54 if (cp == last_start) 55 *cp++ = '"'; 56 if (cp >= buffer + tomoyo_buffer_len - 32) { 57 /* Reserve some room for "..." string. */ 58 truncated = true; 59 } else if (c == '\\') { 60 *cp++ = '\\'; 61 *cp++ = '\\'; 62 } else if (c > ' ' && c < 127) { 63 *cp++ = c; 64 } else if (!c) { 65 *cp++ = '"'; 66 *cp++ = ' '; 67 last_start = cp; 68 } else { 69 *cp++ = '\\'; 70 *cp++ = (c >> 6) + '0'; 71 *cp++ = ((c >> 3) & 7) + '0'; 72 *cp++ = (c & 7) + '0'; 73 } 74 if (c) 75 continue; 76 if (argv_count) { 77 if (--argv_count == 0) { 78 if (truncated) { 79 cp = last_start; 80 memmove(cp, "... ", 4); 81 cp += 4; 82 } 83 memmove(cp, "} envp[]={ ", 11); 84 cp += 11; 85 last_start = cp; 86 truncated = false; 87 } 88 } else if (envp_count) { 89 if (--envp_count == 0) { 90 if (truncated) { 91 cp = last_start; 92 memmove(cp, "... ", 4); 93 cp += 4; 94 } 95 } 96 } 97 if (!argv_count && !envp_count) 98 break; 99 } 100 offset = 0; 101 } 102 *cp++ = '}'; 103 *cp = '\0'; 104 return buffer; 105 out: 106 snprintf(buffer, tomoyo_buffer_len - 1, 107 "argv[]={ ... } envp[]= { ... }"); 108 return buffer; 109 } 110 111 /** 112 * tomoyo_filetype - Get string representation of file type. 113 * 114 * @mode: Mode value for stat(). 115 * 116 * Returns file type string. 117 */ 118 static inline const char *tomoyo_filetype(const umode_t mode) 119 { 120 switch (mode & S_IFMT) { 121 case S_IFREG: 122 case 0: 123 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FILE]; 124 case S_IFDIR: 125 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_DIRECTORY]; 126 case S_IFLNK: 127 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SYMLINK]; 128 case S_IFIFO: 129 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FIFO]; 130 case S_IFSOCK: 131 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SOCKET]; 132 case S_IFBLK: 133 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_BLOCK_DEV]; 134 case S_IFCHR: 135 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_CHAR_DEV]; 136 } 137 return "unknown"; /* This should not happen. */ 138 } 139 140 /** 141 * tomoyo_print_header - Get header line of audit log. 142 * 143 * @r: Pointer to "struct tomoyo_request_info". 144 * 145 * Returns string representation. 146 * 147 * This function uses kmalloc(), so caller must kfree() if this function 148 * didn't return NULL. 149 */ 150 static char *tomoyo_print_header(struct tomoyo_request_info *r) 151 { 152 struct tomoyo_time stamp; 153 const pid_t gpid = task_pid_nr(current); 154 struct tomoyo_obj_info *obj = r->obj; 155 static const int tomoyo_buffer_len = 4096; 156 char *buffer = kmalloc(tomoyo_buffer_len, GFP_NOFS); 157 int pos; 158 u8 i; 159 160 if (!buffer) 161 return NULL; 162 163 tomoyo_convert_time(ktime_get_real_seconds(), &stamp); 164 165 pos = snprintf(buffer, tomoyo_buffer_len - 1, 166 "#%04u/%02u/%02u %02u:%02u:%02u# profile=%u mode=%s granted=%s (global-pid=%u) task={ pid=%u ppid=%u uid=%u gid=%u euid=%u egid=%u suid=%u sgid=%u fsuid=%u fsgid=%u }", 167 stamp.year, stamp.month, stamp.day, stamp.hour, 168 stamp.min, stamp.sec, r->profile, tomoyo_mode[r->mode], 169 str_yes_no(r->granted), gpid, tomoyo_sys_getpid(), 170 tomoyo_sys_getppid(), 171 from_kuid(&init_user_ns, current_uid()), 172 from_kgid(&init_user_ns, current_gid()), 173 from_kuid(&init_user_ns, current_euid()), 174 from_kgid(&init_user_ns, current_egid()), 175 from_kuid(&init_user_ns, current_suid()), 176 from_kgid(&init_user_ns, current_sgid()), 177 from_kuid(&init_user_ns, current_fsuid()), 178 from_kgid(&init_user_ns, current_fsgid())); 179 if (!obj) 180 goto no_obj_info; 181 if (!obj->validate_done) { 182 tomoyo_get_attributes(obj); 183 obj->validate_done = true; 184 } 185 for (i = 0; i < TOMOYO_MAX_PATH_STAT; i++) { 186 struct tomoyo_mini_stat *stat; 187 unsigned int dev; 188 umode_t mode; 189 190 if (!obj->stat_valid[i]) 191 continue; 192 stat = &obj->stat[i]; 193 dev = stat->dev; 194 mode = stat->mode; 195 if (i & 1) { 196 pos += snprintf(buffer + pos, 197 tomoyo_buffer_len - 1 - pos, 198 " path%u.parent={ uid=%u gid=%u ino=%lu perm=0%o }", 199 (i >> 1) + 1, 200 from_kuid(&init_user_ns, stat->uid), 201 from_kgid(&init_user_ns, stat->gid), 202 (unsigned long)stat->ino, 203 stat->mode & S_IALLUGO); 204 continue; 205 } 206 pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos, 207 " path%u={ uid=%u gid=%u ino=%lu major=%u minor=%u perm=0%o type=%s", 208 (i >> 1) + 1, 209 from_kuid(&init_user_ns, stat->uid), 210 from_kgid(&init_user_ns, stat->gid), 211 (unsigned long)stat->ino, 212 MAJOR(dev), MINOR(dev), 213 mode & S_IALLUGO, tomoyo_filetype(mode)); 214 if (S_ISCHR(mode) || S_ISBLK(mode)) { 215 dev = stat->rdev; 216 pos += snprintf(buffer + pos, 217 tomoyo_buffer_len - 1 - pos, 218 " dev_major=%u dev_minor=%u", 219 MAJOR(dev), MINOR(dev)); 220 } 221 pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos, 222 " }"); 223 } 224 no_obj_info: 225 if (pos < tomoyo_buffer_len - 1) 226 return buffer; 227 kfree(buffer); 228 return NULL; 229 } 230 231 /** 232 * tomoyo_init_log - Allocate buffer for audit logs. 233 * 234 * @r: Pointer to "struct tomoyo_request_info". 235 * @len: Buffer size needed for @fmt and @args. 236 * @fmt: The printf()'s format string. 237 * @args: va_list structure for @fmt. 238 * 239 * Returns pointer to allocated memory. 240 * 241 * This function uses kzalloc(), so caller must kfree() if this function 242 * didn't return NULL. 243 */ 244 char *tomoyo_init_log(struct tomoyo_request_info *r, int len, const char *fmt, 245 va_list args) 246 { 247 char *buf = NULL; 248 char *bprm_info = NULL; 249 const char *header = NULL; 250 char *realpath = NULL; 251 const char *symlink = NULL; 252 int pos; 253 const char *domainname = r->domain->domainname->name; 254 255 header = tomoyo_print_header(r); 256 if (!header) 257 return NULL; 258 /* +10 is for '\n' etc. and '\0'. */ 259 len += strlen(domainname) + strlen(header) + 10; 260 if (r->ee) { 261 struct file *file = r->ee->bprm->file; 262 263 realpath = tomoyo_realpath_from_path(&file->f_path); 264 bprm_info = tomoyo_print_bprm(r->ee->bprm, &r->ee->dump); 265 if (!realpath || !bprm_info) 266 goto out; 267 /* +80 is for " exec={ realpath=\"%s\" argc=%d envc=%d %s }" */ 268 len += strlen(realpath) + 80 + strlen(bprm_info); 269 } else if (r->obj && r->obj->symlink_target) { 270 symlink = r->obj->symlink_target->name; 271 /* +18 is for " symlink.target=\"%s\"" */ 272 len += 18 + strlen(symlink); 273 } 274 len = kmalloc_size_roundup(len); 275 buf = kzalloc(len, GFP_NOFS); 276 if (!buf) 277 goto out; 278 len--; 279 pos = snprintf(buf, len, "%s", header); 280 if (realpath) { 281 struct linux_binprm *bprm = r->ee->bprm; 282 283 pos += snprintf(buf + pos, len - pos, 284 " exec={ realpath=\"%s\" argc=%d envc=%d %s }", 285 realpath, bprm->argc, bprm->envc, bprm_info); 286 } else if (symlink) 287 pos += snprintf(buf + pos, len - pos, " symlink.target=\"%s\"", 288 symlink); 289 pos += snprintf(buf + pos, len - pos, "\n%s\n", domainname); 290 vsnprintf(buf + pos, len - pos, fmt, args); 291 out: 292 kfree(realpath); 293 kfree(bprm_info); 294 kfree(header); 295 return buf; 296 } 297 298 /* Wait queue for /sys/kernel/security/tomoyo/audit. */ 299 static DECLARE_WAIT_QUEUE_HEAD(tomoyo_log_wait); 300 301 /* Structure for audit log. */ 302 struct tomoyo_log { 303 struct list_head list; 304 char *log; 305 int size; 306 }; 307 308 /* The list for "struct tomoyo_log". */ 309 static LIST_HEAD(tomoyo_log); 310 311 /* Lock for "struct list_head tomoyo_log". */ 312 static DEFINE_SPINLOCK(tomoyo_log_lock); 313 314 /* Length of "struct list_head tomoyo_log". */ 315 static unsigned int tomoyo_log_count; 316 317 /** 318 * tomoyo_get_audit - Get audit mode. 319 * 320 * @ns: Pointer to "struct tomoyo_policy_namespace". 321 * @profile: Profile number. 322 * @index: Index number of functionality. 323 * @matched_acl: Pointer to "struct tomoyo_acl_info". 324 * @is_granted: True if granted log, false otherwise. 325 * 326 * Returns true if this request should be audited, false otherwise. 327 */ 328 static bool tomoyo_get_audit(const struct tomoyo_policy_namespace *ns, 329 const u8 profile, const u8 index, 330 const struct tomoyo_acl_info *matched_acl, 331 const bool is_granted) 332 { 333 u8 mode; 334 const u8 category = tomoyo_index2category[index] + 335 TOMOYO_MAX_MAC_INDEX; 336 struct tomoyo_profile *p; 337 338 if (!tomoyo_policy_loaded) 339 return false; 340 p = tomoyo_profile(ns, profile); 341 if (tomoyo_log_count >= p->pref[TOMOYO_PREF_MAX_AUDIT_LOG]) 342 return false; 343 if (is_granted && matched_acl && matched_acl->cond && 344 matched_acl->cond->grant_log != TOMOYO_GRANTLOG_AUTO) 345 return matched_acl->cond->grant_log == TOMOYO_GRANTLOG_YES; 346 mode = p->config[index]; 347 if (mode == TOMOYO_CONFIG_USE_DEFAULT) 348 mode = p->config[category]; 349 if (mode == TOMOYO_CONFIG_USE_DEFAULT) 350 mode = p->default_config; 351 if (is_granted) 352 return mode & TOMOYO_CONFIG_WANT_GRANT_LOG; 353 return mode & TOMOYO_CONFIG_WANT_REJECT_LOG; 354 } 355 356 /** 357 * tomoyo_write_log2 - Write an audit log. 358 * 359 * @r: Pointer to "struct tomoyo_request_info". 360 * @len: Buffer size needed for @fmt and @args. 361 * @fmt: The printf()'s format string. 362 * @args: va_list structure for @fmt. 363 * 364 * Returns nothing. 365 */ 366 void tomoyo_write_log2(struct tomoyo_request_info *r, int len, const char *fmt, 367 va_list args) 368 { 369 char *buf; 370 struct tomoyo_log *entry; 371 bool quota_exceeded = false; 372 373 if (!tomoyo_get_audit(r->domain->ns, r->profile, r->type, 374 r->matched_acl, r->granted)) 375 goto out; 376 buf = tomoyo_init_log(r, len, fmt, args); 377 if (!buf) 378 goto out; 379 entry = kzalloc(sizeof(*entry), GFP_NOFS); 380 if (!entry) { 381 kfree(buf); 382 goto out; 383 } 384 entry->log = buf; 385 len = kmalloc_size_roundup(strlen(buf) + 1); 386 /* 387 * The entry->size is used for memory quota checks. 388 * Don't go beyond strlen(entry->log). 389 */ 390 entry->size = len + kmalloc_size_roundup(sizeof(*entry)); 391 spin_lock(&tomoyo_log_lock); 392 if (tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT] && 393 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] + entry->size >= 394 tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT]) { 395 quota_exceeded = true; 396 } else { 397 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] += entry->size; 398 list_add_tail(&entry->list, &tomoyo_log); 399 tomoyo_log_count++; 400 } 401 spin_unlock(&tomoyo_log_lock); 402 if (quota_exceeded) { 403 kfree(buf); 404 kfree(entry); 405 goto out; 406 } 407 wake_up(&tomoyo_log_wait); 408 out: 409 return; 410 } 411 412 /** 413 * tomoyo_write_log - Write an audit log. 414 * 415 * @r: Pointer to "struct tomoyo_request_info". 416 * @fmt: The printf()'s format string, followed by parameters. 417 * 418 * Returns nothing. 419 */ 420 void tomoyo_write_log(struct tomoyo_request_info *r, const char *fmt, ...) 421 { 422 va_list args; 423 int len; 424 425 va_start(args, fmt); 426 len = vsnprintf(NULL, 0, fmt, args) + 1; 427 va_end(args); 428 va_start(args, fmt); 429 tomoyo_write_log2(r, len, fmt, args); 430 va_end(args); 431 } 432 433 /** 434 * tomoyo_read_log - Read an audit log. 435 * 436 * @head: Pointer to "struct tomoyo_io_buffer". 437 * 438 * Returns nothing. 439 */ 440 void tomoyo_read_log(struct tomoyo_io_buffer *head) 441 { 442 struct tomoyo_log *ptr = NULL; 443 444 if (head->r.w_pos) 445 return; 446 kfree(head->read_buf); 447 head->read_buf = NULL; 448 spin_lock(&tomoyo_log_lock); 449 if (!list_empty(&tomoyo_log)) { 450 ptr = list_entry(tomoyo_log.next, typeof(*ptr), list); 451 list_del(&ptr->list); 452 tomoyo_log_count--; 453 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] -= ptr->size; 454 } 455 spin_unlock(&tomoyo_log_lock); 456 if (ptr) { 457 head->read_buf = ptr->log; 458 head->r.w[head->r.w_pos++] = head->read_buf; 459 kfree(ptr); 460 } 461 } 462 463 /** 464 * tomoyo_poll_log - Wait for an audit log. 465 * 466 * @file: Pointer to "struct file". 467 * @wait: Pointer to "poll_table". Maybe NULL. 468 * 469 * Returns EPOLLIN | EPOLLRDNORM when ready to read an audit log. 470 */ 471 __poll_t tomoyo_poll_log(struct file *file, poll_table *wait) 472 { 473 if (tomoyo_log_count) 474 return EPOLLIN | EPOLLRDNORM; 475 poll_wait(file, &tomoyo_log_wait, wait); 476 if (tomoyo_log_count) 477 return EPOLLIN | EPOLLRDNORM; 478 return 0; 479 } 480