| 1 | /* auditfilter.c -- filtering of audit events |
| 2 | * |
| 3 | * Copyright 2003-2004 Red Hat, Inc. |
| 4 | * Copyright 2005 Hewlett-Packard Development Company, L.P. |
| 5 | * Copyright 2005 IBM Corporation |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; either version 2 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License |
| 18 | * along with this program; if not, write to the Free Software |
| 19 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 20 | */ |
| 21 | |
| 22 | #include <linux/kernel.h> |
| 23 | #include <linux/audit.h> |
| 24 | #include <linux/kthread.h> |
| 25 | #include <linux/mutex.h> |
| 26 | #include <linux/fs.h> |
| 27 | #include <linux/namei.h> |
| 28 | #include <linux/netlink.h> |
| 29 | #include <linux/sched.h> |
| 30 | #include <linux/slab.h> |
| 31 | #include <linux/security.h> |
| 32 | #include "audit.h" |
| 33 | |
| 34 | /* |
| 35 | * Locking model: |
| 36 | * |
| 37 | * audit_filter_mutex: |
| 38 | * Synchronizes writes and blocking reads of audit's filterlist |
| 39 | * data. Rcu is used to traverse the filterlist and access |
| 40 | * contents of structs audit_entry, audit_watch and opaque |
| 41 | * LSM rules during filtering. If modified, these structures |
| 42 | * must be copied and replace their counterparts in the filterlist. |
| 43 | * An audit_parent struct is not accessed during filtering, so may |
| 44 | * be written directly provided audit_filter_mutex is held. |
| 45 | */ |
| 46 | |
| 47 | /* Audit filter lists, defined in <linux/audit.h> */ |
| 48 | struct list_head audit_filter_list[AUDIT_NR_FILTERS] = { |
| 49 | LIST_HEAD_INIT(audit_filter_list[0]), |
| 50 | LIST_HEAD_INIT(audit_filter_list[1]), |
| 51 | LIST_HEAD_INIT(audit_filter_list[2]), |
| 52 | LIST_HEAD_INIT(audit_filter_list[3]), |
| 53 | LIST_HEAD_INIT(audit_filter_list[4]), |
| 54 | LIST_HEAD_INIT(audit_filter_list[5]), |
| 55 | #if AUDIT_NR_FILTERS != 6 |
| 56 | #error Fix audit_filter_list initialiser |
| 57 | #endif |
| 58 | }; |
| 59 | static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = { |
| 60 | LIST_HEAD_INIT(audit_rules_list[0]), |
| 61 | LIST_HEAD_INIT(audit_rules_list[1]), |
| 62 | LIST_HEAD_INIT(audit_rules_list[2]), |
| 63 | LIST_HEAD_INIT(audit_rules_list[3]), |
| 64 | LIST_HEAD_INIT(audit_rules_list[4]), |
| 65 | LIST_HEAD_INIT(audit_rules_list[5]), |
| 66 | }; |
| 67 | |
| 68 | DEFINE_MUTEX(audit_filter_mutex); |
| 69 | |
| 70 | static inline void audit_free_rule(struct audit_entry *e) |
| 71 | { |
| 72 | int i; |
| 73 | struct audit_krule *erule = &e->rule; |
| 74 | |
| 75 | /* some rules don't have associated watches */ |
| 76 | if (erule->watch) |
| 77 | audit_put_watch(erule->watch); |
| 78 | if (erule->fields) |
| 79 | for (i = 0; i < erule->field_count; i++) { |
| 80 | struct audit_field *f = &erule->fields[i]; |
| 81 | kfree(f->lsm_str); |
| 82 | security_audit_rule_free(f->lsm_rule); |
| 83 | } |
| 84 | kfree(erule->fields); |
| 85 | kfree(erule->filterkey); |
| 86 | kfree(e); |
| 87 | } |
| 88 | |
| 89 | void audit_free_rule_rcu(struct rcu_head *head) |
| 90 | { |
| 91 | struct audit_entry *e = container_of(head, struct audit_entry, rcu); |
| 92 | audit_free_rule(e); |
| 93 | } |
| 94 | |
| 95 | /* Initialize an audit filterlist entry. */ |
| 96 | static inline struct audit_entry *audit_init_entry(u32 field_count) |
| 97 | { |
| 98 | struct audit_entry *entry; |
| 99 | struct audit_field *fields; |
| 100 | |
| 101 | entry = kzalloc(sizeof(*entry), GFP_KERNEL); |
| 102 | if (unlikely(!entry)) |
| 103 | return NULL; |
| 104 | |
| 105 | fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL); |
| 106 | if (unlikely(!fields)) { |
| 107 | kfree(entry); |
| 108 | return NULL; |
| 109 | } |
| 110 | entry->rule.fields = fields; |
| 111 | |
| 112 | return entry; |
| 113 | } |
| 114 | |
| 115 | /* Unpack a filter field's string representation from user-space |
| 116 | * buffer. */ |
| 117 | char *audit_unpack_string(void **bufp, size_t *remain, size_t len) |
| 118 | { |
| 119 | char *str; |
| 120 | |
| 121 | if (!*bufp || (len == 0) || (len > *remain)) |
| 122 | return ERR_PTR(-EINVAL); |
| 123 | |
| 124 | /* Of the currently implemented string fields, PATH_MAX |
| 125 | * defines the longest valid length. |
| 126 | */ |
| 127 | if (len > PATH_MAX) |
| 128 | return ERR_PTR(-ENAMETOOLONG); |
| 129 | |
| 130 | str = kmalloc(len + 1, GFP_KERNEL); |
| 131 | if (unlikely(!str)) |
| 132 | return ERR_PTR(-ENOMEM); |
| 133 | |
| 134 | memcpy(str, *bufp, len); |
| 135 | str[len] = 0; |
| 136 | *bufp += len; |
| 137 | *remain -= len; |
| 138 | |
| 139 | return str; |
| 140 | } |
| 141 | |
| 142 | /* Translate an inode field to kernel respresentation. */ |
| 143 | static inline int audit_to_inode(struct audit_krule *krule, |
| 144 | struct audit_field *f) |
| 145 | { |
| 146 | if (krule->listnr != AUDIT_FILTER_EXIT || |
| 147 | krule->watch || krule->inode_f || krule->tree || |
| 148 | (f->op != Audit_equal && f->op != Audit_not_equal)) |
| 149 | return -EINVAL; |
| 150 | |
| 151 | krule->inode_f = f; |
| 152 | return 0; |
| 153 | } |
| 154 | |
| 155 | static __u32 *classes[AUDIT_SYSCALL_CLASSES]; |
| 156 | |
| 157 | int __init audit_register_class(int class, unsigned *list) |
| 158 | { |
| 159 | __u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL); |
| 160 | if (!p) |
| 161 | return -ENOMEM; |
| 162 | while (*list != ~0U) { |
| 163 | unsigned n = *list++; |
| 164 | if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) { |
| 165 | kfree(p); |
| 166 | return -EINVAL; |
| 167 | } |
| 168 | p[AUDIT_WORD(n)] |= AUDIT_BIT(n); |
| 169 | } |
| 170 | if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) { |
| 171 | kfree(p); |
| 172 | return -EINVAL; |
| 173 | } |
| 174 | classes[class] = p; |
| 175 | return 0; |
| 176 | } |
| 177 | |
| 178 | int audit_match_class(int class, unsigned syscall) |
| 179 | { |
| 180 | if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32)) |
| 181 | return 0; |
| 182 | if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class])) |
| 183 | return 0; |
| 184 | return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall); |
| 185 | } |
| 186 | |
| 187 | #ifdef CONFIG_AUDITSYSCALL |
| 188 | static inline int audit_match_class_bits(int class, u32 *mask) |
| 189 | { |
| 190 | int i; |
| 191 | |
| 192 | if (classes[class]) { |
| 193 | for (i = 0; i < AUDIT_BITMASK_SIZE; i++) |
| 194 | if (mask[i] & classes[class][i]) |
| 195 | return 0; |
| 196 | } |
| 197 | return 1; |
| 198 | } |
| 199 | |
| 200 | static int audit_match_signal(struct audit_entry *entry) |
| 201 | { |
| 202 | struct audit_field *arch = entry->rule.arch_f; |
| 203 | |
| 204 | if (!arch) { |
| 205 | /* When arch is unspecified, we must check both masks on biarch |
| 206 | * as syscall number alone is ambiguous. */ |
| 207 | return (audit_match_class_bits(AUDIT_CLASS_SIGNAL, |
| 208 | entry->rule.mask) && |
| 209 | audit_match_class_bits(AUDIT_CLASS_SIGNAL_32, |
| 210 | entry->rule.mask)); |
| 211 | } |
| 212 | |
| 213 | switch(audit_classify_arch(arch->val)) { |
| 214 | case 0: /* native */ |
| 215 | return (audit_match_class_bits(AUDIT_CLASS_SIGNAL, |
| 216 | entry->rule.mask)); |
| 217 | case 1: /* 32bit on biarch */ |
| 218 | return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32, |
| 219 | entry->rule.mask)); |
| 220 | default: |
| 221 | return 1; |
| 222 | } |
| 223 | } |
| 224 | #endif |
| 225 | |
| 226 | /* Common user-space to kernel rule translation. */ |
| 227 | static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule) |
| 228 | { |
| 229 | unsigned listnr; |
| 230 | struct audit_entry *entry; |
| 231 | int i, err; |
| 232 | |
| 233 | err = -EINVAL; |
| 234 | listnr = rule->flags & ~AUDIT_FILTER_PREPEND; |
| 235 | switch(listnr) { |
| 236 | default: |
| 237 | goto exit_err; |
| 238 | #ifdef CONFIG_AUDITSYSCALL |
| 239 | case AUDIT_FILTER_ENTRY: |
| 240 | if (rule->action == AUDIT_ALWAYS) |
| 241 | goto exit_err; |
| 242 | case AUDIT_FILTER_EXIT: |
| 243 | case AUDIT_FILTER_TASK: |
| 244 | #endif |
| 245 | case AUDIT_FILTER_USER: |
| 246 | case AUDIT_FILTER_TYPE: |
| 247 | ; |
| 248 | } |
| 249 | if (unlikely(rule->action == AUDIT_POSSIBLE)) { |
| 250 | printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n"); |
| 251 | goto exit_err; |
| 252 | } |
| 253 | if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS) |
| 254 | goto exit_err; |
| 255 | if (rule->field_count > AUDIT_MAX_FIELDS) |
| 256 | goto exit_err; |
| 257 | |
| 258 | err = -ENOMEM; |
| 259 | entry = audit_init_entry(rule->field_count); |
| 260 | if (!entry) |
| 261 | goto exit_err; |
| 262 | |
| 263 | entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND; |
| 264 | entry->rule.listnr = listnr; |
| 265 | entry->rule.action = rule->action; |
| 266 | entry->rule.field_count = rule->field_count; |
| 267 | |
| 268 | for (i = 0; i < AUDIT_BITMASK_SIZE; i++) |
| 269 | entry->rule.mask[i] = rule->mask[i]; |
| 270 | |
| 271 | for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) { |
| 272 | int bit = AUDIT_BITMASK_SIZE * 32 - i - 1; |
| 273 | __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)]; |
| 274 | __u32 *class; |
| 275 | |
| 276 | if (!(*p & AUDIT_BIT(bit))) |
| 277 | continue; |
| 278 | *p &= ~AUDIT_BIT(bit); |
| 279 | class = classes[i]; |
| 280 | if (class) { |
| 281 | int j; |
| 282 | for (j = 0; j < AUDIT_BITMASK_SIZE; j++) |
| 283 | entry->rule.mask[j] |= class[j]; |
| 284 | } |
| 285 | } |
| 286 | |
| 287 | return entry; |
| 288 | |
| 289 | exit_err: |
| 290 | return ERR_PTR(err); |
| 291 | } |
| 292 | |
| 293 | static u32 audit_ops[] = |
| 294 | { |
| 295 | [Audit_equal] = AUDIT_EQUAL, |
| 296 | [Audit_not_equal] = AUDIT_NOT_EQUAL, |
| 297 | [Audit_bitmask] = AUDIT_BIT_MASK, |
| 298 | [Audit_bittest] = AUDIT_BIT_TEST, |
| 299 | [Audit_lt] = AUDIT_LESS_THAN, |
| 300 | [Audit_gt] = AUDIT_GREATER_THAN, |
| 301 | [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL, |
| 302 | [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL, |
| 303 | }; |
| 304 | |
| 305 | static u32 audit_to_op(u32 op) |
| 306 | { |
| 307 | u32 n; |
| 308 | for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++) |
| 309 | ; |
| 310 | return n; |
| 311 | } |
| 312 | |
| 313 | |
| 314 | /* Translate struct audit_rule to kernel's rule respresentation. |
| 315 | * Exists for backward compatibility with userspace. */ |
| 316 | static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule) |
| 317 | { |
| 318 | struct audit_entry *entry; |
| 319 | int err = 0; |
| 320 | int i; |
| 321 | |
| 322 | entry = audit_to_entry_common(rule); |
| 323 | if (IS_ERR(entry)) |
| 324 | goto exit_nofree; |
| 325 | |
| 326 | for (i = 0; i < rule->field_count; i++) { |
| 327 | struct audit_field *f = &entry->rule.fields[i]; |
| 328 | u32 n; |
| 329 | |
| 330 | n = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS); |
| 331 | |
| 332 | /* Support for legacy operators where |
| 333 | * AUDIT_NEGATE bit signifies != and otherwise assumes == */ |
| 334 | if (n & AUDIT_NEGATE) |
| 335 | f->op = Audit_not_equal; |
| 336 | else if (!n) |
| 337 | f->op = Audit_equal; |
| 338 | else |
| 339 | f->op = audit_to_op(n); |
| 340 | |
| 341 | entry->rule.vers_ops = (n & AUDIT_OPERATORS) ? 2 : 1; |
| 342 | |
| 343 | f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS); |
| 344 | f->val = rule->values[i]; |
| 345 | |
| 346 | err = -EINVAL; |
| 347 | if (f->op == Audit_bad) |
| 348 | goto exit_free; |
| 349 | |
| 350 | switch(f->type) { |
| 351 | default: |
| 352 | goto exit_free; |
| 353 | case AUDIT_PID: |
| 354 | case AUDIT_UID: |
| 355 | case AUDIT_EUID: |
| 356 | case AUDIT_SUID: |
| 357 | case AUDIT_FSUID: |
| 358 | case AUDIT_GID: |
| 359 | case AUDIT_EGID: |
| 360 | case AUDIT_SGID: |
| 361 | case AUDIT_FSGID: |
| 362 | case AUDIT_LOGINUID: |
| 363 | case AUDIT_PERS: |
| 364 | case AUDIT_MSGTYPE: |
| 365 | case AUDIT_PPID: |
| 366 | case AUDIT_DEVMAJOR: |
| 367 | case AUDIT_DEVMINOR: |
| 368 | case AUDIT_EXIT: |
| 369 | case AUDIT_SUCCESS: |
| 370 | /* bit ops are only useful on syscall args */ |
| 371 | if (f->op == Audit_bitmask || f->op == Audit_bittest) |
| 372 | goto exit_free; |
| 373 | break; |
| 374 | case AUDIT_ARG0: |
| 375 | case AUDIT_ARG1: |
| 376 | case AUDIT_ARG2: |
| 377 | case AUDIT_ARG3: |
| 378 | break; |
| 379 | /* arch is only allowed to be = or != */ |
| 380 | case AUDIT_ARCH: |
| 381 | if (f->op != Audit_not_equal && f->op != Audit_equal) |
| 382 | goto exit_free; |
| 383 | entry->rule.arch_f = f; |
| 384 | break; |
| 385 | case AUDIT_PERM: |
| 386 | if (f->val & ~15) |
| 387 | goto exit_free; |
| 388 | break; |
| 389 | case AUDIT_FILETYPE: |
| 390 | if (f->val & ~S_IFMT) |
| 391 | goto exit_free; |
| 392 | break; |
| 393 | case AUDIT_INODE: |
| 394 | err = audit_to_inode(&entry->rule, f); |
| 395 | if (err) |
| 396 | goto exit_free; |
| 397 | break; |
| 398 | } |
| 399 | } |
| 400 | |
| 401 | if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal) |
| 402 | entry->rule.inode_f = NULL; |
| 403 | |
| 404 | exit_nofree: |
| 405 | return entry; |
| 406 | |
| 407 | exit_free: |
| 408 | audit_free_rule(entry); |
| 409 | return ERR_PTR(err); |
| 410 | } |
| 411 | |
| 412 | /* Translate struct audit_rule_data to kernel's rule respresentation. */ |
| 413 | static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data, |
| 414 | size_t datasz) |
| 415 | { |
| 416 | int err = 0; |
| 417 | struct audit_entry *entry; |
| 418 | void *bufp; |
| 419 | size_t remain = datasz - sizeof(struct audit_rule_data); |
| 420 | int i; |
| 421 | char *str; |
| 422 | |
| 423 | entry = audit_to_entry_common((struct audit_rule *)data); |
| 424 | if (IS_ERR(entry)) |
| 425 | goto exit_nofree; |
| 426 | |
| 427 | bufp = data->buf; |
| 428 | entry->rule.vers_ops = 2; |
| 429 | for (i = 0; i < data->field_count; i++) { |
| 430 | struct audit_field *f = &entry->rule.fields[i]; |
| 431 | |
| 432 | err = -EINVAL; |
| 433 | |
| 434 | f->op = audit_to_op(data->fieldflags[i]); |
| 435 | if (f->op == Audit_bad) |
| 436 | goto exit_free; |
| 437 | |
| 438 | f->type = data->fields[i]; |
| 439 | f->val = data->values[i]; |
| 440 | f->lsm_str = NULL; |
| 441 | f->lsm_rule = NULL; |
| 442 | switch(f->type) { |
| 443 | case AUDIT_PID: |
| 444 | case AUDIT_UID: |
| 445 | case AUDIT_EUID: |
| 446 | case AUDIT_SUID: |
| 447 | case AUDIT_FSUID: |
| 448 | case AUDIT_GID: |
| 449 | case AUDIT_EGID: |
| 450 | case AUDIT_SGID: |
| 451 | case AUDIT_FSGID: |
| 452 | case AUDIT_LOGINUID: |
| 453 | case AUDIT_PERS: |
| 454 | case AUDIT_MSGTYPE: |
| 455 | case AUDIT_PPID: |
| 456 | case AUDIT_DEVMAJOR: |
| 457 | case AUDIT_DEVMINOR: |
| 458 | case AUDIT_EXIT: |
| 459 | case AUDIT_SUCCESS: |
| 460 | case AUDIT_ARG0: |
| 461 | case AUDIT_ARG1: |
| 462 | case AUDIT_ARG2: |
| 463 | case AUDIT_ARG3: |
| 464 | case AUDIT_OBJ_UID: |
| 465 | case AUDIT_OBJ_GID: |
| 466 | break; |
| 467 | case AUDIT_ARCH: |
| 468 | entry->rule.arch_f = f; |
| 469 | break; |
| 470 | case AUDIT_SUBJ_USER: |
| 471 | case AUDIT_SUBJ_ROLE: |
| 472 | case AUDIT_SUBJ_TYPE: |
| 473 | case AUDIT_SUBJ_SEN: |
| 474 | case AUDIT_SUBJ_CLR: |
| 475 | case AUDIT_OBJ_USER: |
| 476 | case AUDIT_OBJ_ROLE: |
| 477 | case AUDIT_OBJ_TYPE: |
| 478 | case AUDIT_OBJ_LEV_LOW: |
| 479 | case AUDIT_OBJ_LEV_HIGH: |
| 480 | str = audit_unpack_string(&bufp, &remain, f->val); |
| 481 | if (IS_ERR(str)) |
| 482 | goto exit_free; |
| 483 | entry->rule.buflen += f->val; |
| 484 | |
| 485 | err = security_audit_rule_init(f->type, f->op, str, |
| 486 | (void **)&f->lsm_rule); |
| 487 | /* Keep currently invalid fields around in case they |
| 488 | * become valid after a policy reload. */ |
| 489 | if (err == -EINVAL) { |
| 490 | printk(KERN_WARNING "audit rule for LSM " |
| 491 | "\'%s\' is invalid\n", str); |
| 492 | err = 0; |
| 493 | } |
| 494 | if (err) { |
| 495 | kfree(str); |
| 496 | goto exit_free; |
| 497 | } else |
| 498 | f->lsm_str = str; |
| 499 | break; |
| 500 | case AUDIT_WATCH: |
| 501 | str = audit_unpack_string(&bufp, &remain, f->val); |
| 502 | if (IS_ERR(str)) |
| 503 | goto exit_free; |
| 504 | entry->rule.buflen += f->val; |
| 505 | |
| 506 | err = audit_to_watch(&entry->rule, str, f->val, f->op); |
| 507 | if (err) { |
| 508 | kfree(str); |
| 509 | goto exit_free; |
| 510 | } |
| 511 | break; |
| 512 | case AUDIT_DIR: |
| 513 | str = audit_unpack_string(&bufp, &remain, f->val); |
| 514 | if (IS_ERR(str)) |
| 515 | goto exit_free; |
| 516 | entry->rule.buflen += f->val; |
| 517 | |
| 518 | err = audit_make_tree(&entry->rule, str, f->op); |
| 519 | kfree(str); |
| 520 | if (err) |
| 521 | goto exit_free; |
| 522 | break; |
| 523 | case AUDIT_INODE: |
| 524 | err = audit_to_inode(&entry->rule, f); |
| 525 | if (err) |
| 526 | goto exit_free; |
| 527 | break; |
| 528 | case AUDIT_FILTERKEY: |
| 529 | if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN) |
| 530 | goto exit_free; |
| 531 | str = audit_unpack_string(&bufp, &remain, f->val); |
| 532 | if (IS_ERR(str)) |
| 533 | goto exit_free; |
| 534 | entry->rule.buflen += f->val; |
| 535 | entry->rule.filterkey = str; |
| 536 | break; |
| 537 | case AUDIT_PERM: |
| 538 | if (f->val & ~15) |
| 539 | goto exit_free; |
| 540 | break; |
| 541 | case AUDIT_FILETYPE: |
| 542 | if (f->val & ~S_IFMT) |
| 543 | goto exit_free; |
| 544 | break; |
| 545 | case AUDIT_FIELD_COMPARE: |
| 546 | if (f->val > AUDIT_MAX_FIELD_COMPARE) |
| 547 | goto exit_free; |
| 548 | break; |
| 549 | default: |
| 550 | goto exit_free; |
| 551 | } |
| 552 | } |
| 553 | |
| 554 | if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal) |
| 555 | entry->rule.inode_f = NULL; |
| 556 | |
| 557 | exit_nofree: |
| 558 | return entry; |
| 559 | |
| 560 | exit_free: |
| 561 | audit_free_rule(entry); |
| 562 | return ERR_PTR(err); |
| 563 | } |
| 564 | |
| 565 | /* Pack a filter field's string representation into data block. */ |
| 566 | static inline size_t audit_pack_string(void **bufp, const char *str) |
| 567 | { |
| 568 | size_t len = strlen(str); |
| 569 | |
| 570 | memcpy(*bufp, str, len); |
| 571 | *bufp += len; |
| 572 | |
| 573 | return len; |
| 574 | } |
| 575 | |
| 576 | /* Translate kernel rule respresentation to struct audit_rule. |
| 577 | * Exists for backward compatibility with userspace. */ |
| 578 | static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule) |
| 579 | { |
| 580 | struct audit_rule *rule; |
| 581 | int i; |
| 582 | |
| 583 | rule = kzalloc(sizeof(*rule), GFP_KERNEL); |
| 584 | if (unlikely(!rule)) |
| 585 | return NULL; |
| 586 | |
| 587 | rule->flags = krule->flags | krule->listnr; |
| 588 | rule->action = krule->action; |
| 589 | rule->field_count = krule->field_count; |
| 590 | for (i = 0; i < rule->field_count; i++) { |
| 591 | rule->values[i] = krule->fields[i].val; |
| 592 | rule->fields[i] = krule->fields[i].type; |
| 593 | |
| 594 | if (krule->vers_ops == 1) { |
| 595 | if (krule->fields[i].op == Audit_not_equal) |
| 596 | rule->fields[i] |= AUDIT_NEGATE; |
| 597 | } else { |
| 598 | rule->fields[i] |= audit_ops[krule->fields[i].op]; |
| 599 | } |
| 600 | } |
| 601 | for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i]; |
| 602 | |
| 603 | return rule; |
| 604 | } |
| 605 | |
| 606 | /* Translate kernel rule respresentation to struct audit_rule_data. */ |
| 607 | static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule) |
| 608 | { |
| 609 | struct audit_rule_data *data; |
| 610 | void *bufp; |
| 611 | int i; |
| 612 | |
| 613 | data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL); |
| 614 | if (unlikely(!data)) |
| 615 | return NULL; |
| 616 | memset(data, 0, sizeof(*data)); |
| 617 | |
| 618 | data->flags = krule->flags | krule->listnr; |
| 619 | data->action = krule->action; |
| 620 | data->field_count = krule->field_count; |
| 621 | bufp = data->buf; |
| 622 | for (i = 0; i < data->field_count; i++) { |
| 623 | struct audit_field *f = &krule->fields[i]; |
| 624 | |
| 625 | data->fields[i] = f->type; |
| 626 | data->fieldflags[i] = audit_ops[f->op]; |
| 627 | switch(f->type) { |
| 628 | case AUDIT_SUBJ_USER: |
| 629 | case AUDIT_SUBJ_ROLE: |
| 630 | case AUDIT_SUBJ_TYPE: |
| 631 | case AUDIT_SUBJ_SEN: |
| 632 | case AUDIT_SUBJ_CLR: |
| 633 | case AUDIT_OBJ_USER: |
| 634 | case AUDIT_OBJ_ROLE: |
| 635 | case AUDIT_OBJ_TYPE: |
| 636 | case AUDIT_OBJ_LEV_LOW: |
| 637 | case AUDIT_OBJ_LEV_HIGH: |
| 638 | data->buflen += data->values[i] = |
| 639 | audit_pack_string(&bufp, f->lsm_str); |
| 640 | break; |
| 641 | case AUDIT_WATCH: |
| 642 | data->buflen += data->values[i] = |
| 643 | audit_pack_string(&bufp, |
| 644 | audit_watch_path(krule->watch)); |
| 645 | break; |
| 646 | case AUDIT_DIR: |
| 647 | data->buflen += data->values[i] = |
| 648 | audit_pack_string(&bufp, |
| 649 | audit_tree_path(krule->tree)); |
| 650 | break; |
| 651 | case AUDIT_FILTERKEY: |
| 652 | data->buflen += data->values[i] = |
| 653 | audit_pack_string(&bufp, krule->filterkey); |
| 654 | break; |
| 655 | default: |
| 656 | data->values[i] = f->val; |
| 657 | } |
| 658 | } |
| 659 | for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i]; |
| 660 | |
| 661 | return data; |
| 662 | } |
| 663 | |
| 664 | /* Compare two rules in kernel format. Considered success if rules |
| 665 | * don't match. */ |
| 666 | static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b) |
| 667 | { |
| 668 | int i; |
| 669 | |
| 670 | if (a->flags != b->flags || |
| 671 | a->listnr != b->listnr || |
| 672 | a->action != b->action || |
| 673 | a->field_count != b->field_count) |
| 674 | return 1; |
| 675 | |
| 676 | for (i = 0; i < a->field_count; i++) { |
| 677 | if (a->fields[i].type != b->fields[i].type || |
| 678 | a->fields[i].op != b->fields[i].op) |
| 679 | return 1; |
| 680 | |
| 681 | switch(a->fields[i].type) { |
| 682 | case AUDIT_SUBJ_USER: |
| 683 | case AUDIT_SUBJ_ROLE: |
| 684 | case AUDIT_SUBJ_TYPE: |
| 685 | case AUDIT_SUBJ_SEN: |
| 686 | case AUDIT_SUBJ_CLR: |
| 687 | case AUDIT_OBJ_USER: |
| 688 | case AUDIT_OBJ_ROLE: |
| 689 | case AUDIT_OBJ_TYPE: |
| 690 | case AUDIT_OBJ_LEV_LOW: |
| 691 | case AUDIT_OBJ_LEV_HIGH: |
| 692 | if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str)) |
| 693 | return 1; |
| 694 | break; |
| 695 | case AUDIT_WATCH: |
| 696 | if (strcmp(audit_watch_path(a->watch), |
| 697 | audit_watch_path(b->watch))) |
| 698 | return 1; |
| 699 | break; |
| 700 | case AUDIT_DIR: |
| 701 | if (strcmp(audit_tree_path(a->tree), |
| 702 | audit_tree_path(b->tree))) |
| 703 | return 1; |
| 704 | break; |
| 705 | case AUDIT_FILTERKEY: |
| 706 | /* both filterkeys exist based on above type compare */ |
| 707 | if (strcmp(a->filterkey, b->filterkey)) |
| 708 | return 1; |
| 709 | break; |
| 710 | default: |
| 711 | if (a->fields[i].val != b->fields[i].val) |
| 712 | return 1; |
| 713 | } |
| 714 | } |
| 715 | |
| 716 | for (i = 0; i < AUDIT_BITMASK_SIZE; i++) |
| 717 | if (a->mask[i] != b->mask[i]) |
| 718 | return 1; |
| 719 | |
| 720 | return 0; |
| 721 | } |
| 722 | |
| 723 | /* Duplicate LSM field information. The lsm_rule is opaque, so must be |
| 724 | * re-initialized. */ |
| 725 | static inline int audit_dupe_lsm_field(struct audit_field *df, |
| 726 | struct audit_field *sf) |
| 727 | { |
| 728 | int ret = 0; |
| 729 | char *lsm_str; |
| 730 | |
| 731 | /* our own copy of lsm_str */ |
| 732 | lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL); |
| 733 | if (unlikely(!lsm_str)) |
| 734 | return -ENOMEM; |
| 735 | df->lsm_str = lsm_str; |
| 736 | |
| 737 | /* our own (refreshed) copy of lsm_rule */ |
| 738 | ret = security_audit_rule_init(df->type, df->op, df->lsm_str, |
| 739 | (void **)&df->lsm_rule); |
| 740 | /* Keep currently invalid fields around in case they |
| 741 | * become valid after a policy reload. */ |
| 742 | if (ret == -EINVAL) { |
| 743 | printk(KERN_WARNING "audit rule for LSM \'%s\' is " |
| 744 | "invalid\n", df->lsm_str); |
| 745 | ret = 0; |
| 746 | } |
| 747 | |
| 748 | return ret; |
| 749 | } |
| 750 | |
| 751 | /* Duplicate an audit rule. This will be a deep copy with the exception |
| 752 | * of the watch - that pointer is carried over. The LSM specific fields |
| 753 | * will be updated in the copy. The point is to be able to replace the old |
| 754 | * rule with the new rule in the filterlist, then free the old rule. |
| 755 | * The rlist element is undefined; list manipulations are handled apart from |
| 756 | * the initial copy. */ |
| 757 | struct audit_entry *audit_dupe_rule(struct audit_krule *old) |
| 758 | { |
| 759 | u32 fcount = old->field_count; |
| 760 | struct audit_entry *entry; |
| 761 | struct audit_krule *new; |
| 762 | char *fk; |
| 763 | int i, err = 0; |
| 764 | |
| 765 | entry = audit_init_entry(fcount); |
| 766 | if (unlikely(!entry)) |
| 767 | return ERR_PTR(-ENOMEM); |
| 768 | |
| 769 | new = &entry->rule; |
| 770 | new->vers_ops = old->vers_ops; |
| 771 | new->flags = old->flags; |
| 772 | new->listnr = old->listnr; |
| 773 | new->action = old->action; |
| 774 | for (i = 0; i < AUDIT_BITMASK_SIZE; i++) |
| 775 | new->mask[i] = old->mask[i]; |
| 776 | new->prio = old->prio; |
| 777 | new->buflen = old->buflen; |
| 778 | new->inode_f = old->inode_f; |
| 779 | new->field_count = old->field_count; |
| 780 | |
| 781 | /* |
| 782 | * note that we are OK with not refcounting here; audit_match_tree() |
| 783 | * never dereferences tree and we can't get false positives there |
| 784 | * since we'd have to have rule gone from the list *and* removed |
| 785 | * before the chunks found by lookup had been allocated, i.e. before |
| 786 | * the beginning of list scan. |
| 787 | */ |
| 788 | new->tree = old->tree; |
| 789 | memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount); |
| 790 | |
| 791 | /* deep copy this information, updating the lsm_rule fields, because |
| 792 | * the originals will all be freed when the old rule is freed. */ |
| 793 | for (i = 0; i < fcount; i++) { |
| 794 | switch (new->fields[i].type) { |
| 795 | case AUDIT_SUBJ_USER: |
| 796 | case AUDIT_SUBJ_ROLE: |
| 797 | case AUDIT_SUBJ_TYPE: |
| 798 | case AUDIT_SUBJ_SEN: |
| 799 | case AUDIT_SUBJ_CLR: |
| 800 | case AUDIT_OBJ_USER: |
| 801 | case AUDIT_OBJ_ROLE: |
| 802 | case AUDIT_OBJ_TYPE: |
| 803 | case AUDIT_OBJ_LEV_LOW: |
| 804 | case AUDIT_OBJ_LEV_HIGH: |
| 805 | err = audit_dupe_lsm_field(&new->fields[i], |
| 806 | &old->fields[i]); |
| 807 | break; |
| 808 | case AUDIT_FILTERKEY: |
| 809 | fk = kstrdup(old->filterkey, GFP_KERNEL); |
| 810 | if (unlikely(!fk)) |
| 811 | err = -ENOMEM; |
| 812 | else |
| 813 | new->filterkey = fk; |
| 814 | } |
| 815 | if (err) { |
| 816 | audit_free_rule(entry); |
| 817 | return ERR_PTR(err); |
| 818 | } |
| 819 | } |
| 820 | |
| 821 | if (old->watch) { |
| 822 | audit_get_watch(old->watch); |
| 823 | new->watch = old->watch; |
| 824 | } |
| 825 | |
| 826 | return entry; |
| 827 | } |
| 828 | |
| 829 | /* Find an existing audit rule. |
| 830 | * Caller must hold audit_filter_mutex to prevent stale rule data. */ |
| 831 | static struct audit_entry *audit_find_rule(struct audit_entry *entry, |
| 832 | struct list_head **p) |
| 833 | { |
| 834 | struct audit_entry *e, *found = NULL; |
| 835 | struct list_head *list; |
| 836 | int h; |
| 837 | |
| 838 | if (entry->rule.inode_f) { |
| 839 | h = audit_hash_ino(entry->rule.inode_f->val); |
| 840 | *p = list = &audit_inode_hash[h]; |
| 841 | } else if (entry->rule.watch) { |
| 842 | /* we don't know the inode number, so must walk entire hash */ |
| 843 | for (h = 0; h < AUDIT_INODE_BUCKETS; h++) { |
| 844 | list = &audit_inode_hash[h]; |
| 845 | list_for_each_entry(e, list, list) |
| 846 | if (!audit_compare_rule(&entry->rule, &e->rule)) { |
| 847 | found = e; |
| 848 | goto out; |
| 849 | } |
| 850 | } |
| 851 | goto out; |
| 852 | } else { |
| 853 | *p = list = &audit_filter_list[entry->rule.listnr]; |
| 854 | } |
| 855 | |
| 856 | list_for_each_entry(e, list, list) |
| 857 | if (!audit_compare_rule(&entry->rule, &e->rule)) { |
| 858 | found = e; |
| 859 | goto out; |
| 860 | } |
| 861 | |
| 862 | out: |
| 863 | return found; |
| 864 | } |
| 865 | |
| 866 | static u64 prio_low = ~0ULL/2; |
| 867 | static u64 prio_high = ~0ULL/2 - 1; |
| 868 | |
| 869 | /* Add rule to given filterlist if not a duplicate. */ |
| 870 | static inline int audit_add_rule(struct audit_entry *entry) |
| 871 | { |
| 872 | struct audit_entry *e; |
| 873 | struct audit_watch *watch = entry->rule.watch; |
| 874 | struct audit_tree *tree = entry->rule.tree; |
| 875 | struct list_head *list; |
| 876 | int err; |
| 877 | #ifdef CONFIG_AUDITSYSCALL |
| 878 | int dont_count = 0; |
| 879 | |
| 880 | /* If either of these, don't count towards total */ |
| 881 | if (entry->rule.listnr == AUDIT_FILTER_USER || |
| 882 | entry->rule.listnr == AUDIT_FILTER_TYPE) |
| 883 | dont_count = 1; |
| 884 | #endif |
| 885 | |
| 886 | mutex_lock(&audit_filter_mutex); |
| 887 | e = audit_find_rule(entry, &list); |
| 888 | if (e) { |
| 889 | mutex_unlock(&audit_filter_mutex); |
| 890 | err = -EEXIST; |
| 891 | /* normally audit_add_tree_rule() will free it on failure */ |
| 892 | if (tree) |
| 893 | audit_put_tree(tree); |
| 894 | goto error; |
| 895 | } |
| 896 | |
| 897 | if (watch) { |
| 898 | /* audit_filter_mutex is dropped and re-taken during this call */ |
| 899 | err = audit_add_watch(&entry->rule, &list); |
| 900 | if (err) { |
| 901 | mutex_unlock(&audit_filter_mutex); |
| 902 | goto error; |
| 903 | } |
| 904 | } |
| 905 | if (tree) { |
| 906 | err = audit_add_tree_rule(&entry->rule); |
| 907 | if (err) { |
| 908 | mutex_unlock(&audit_filter_mutex); |
| 909 | goto error; |
| 910 | } |
| 911 | } |
| 912 | |
| 913 | entry->rule.prio = ~0ULL; |
| 914 | if (entry->rule.listnr == AUDIT_FILTER_EXIT) { |
| 915 | if (entry->rule.flags & AUDIT_FILTER_PREPEND) |
| 916 | entry->rule.prio = ++prio_high; |
| 917 | else |
| 918 | entry->rule.prio = --prio_low; |
| 919 | } |
| 920 | |
| 921 | if (entry->rule.flags & AUDIT_FILTER_PREPEND) { |
| 922 | list_add(&entry->rule.list, |
| 923 | &audit_rules_list[entry->rule.listnr]); |
| 924 | list_add_rcu(&entry->list, list); |
| 925 | entry->rule.flags &= ~AUDIT_FILTER_PREPEND; |
| 926 | } else { |
| 927 | list_add_tail(&entry->rule.list, |
| 928 | &audit_rules_list[entry->rule.listnr]); |
| 929 | list_add_tail_rcu(&entry->list, list); |
| 930 | } |
| 931 | #ifdef CONFIG_AUDITSYSCALL |
| 932 | if (!dont_count) |
| 933 | audit_n_rules++; |
| 934 | |
| 935 | if (!audit_match_signal(entry)) |
| 936 | audit_signals++; |
| 937 | #endif |
| 938 | mutex_unlock(&audit_filter_mutex); |
| 939 | |
| 940 | return 0; |
| 941 | |
| 942 | error: |
| 943 | if (watch) |
| 944 | audit_put_watch(watch); /* tmp watch, matches initial get */ |
| 945 | return err; |
| 946 | } |
| 947 | |
| 948 | /* Remove an existing rule from filterlist. */ |
| 949 | static inline int audit_del_rule(struct audit_entry *entry) |
| 950 | { |
| 951 | struct audit_entry *e; |
| 952 | struct audit_watch *watch = entry->rule.watch; |
| 953 | struct audit_tree *tree = entry->rule.tree; |
| 954 | struct list_head *list; |
| 955 | int ret = 0; |
| 956 | #ifdef CONFIG_AUDITSYSCALL |
| 957 | int dont_count = 0; |
| 958 | |
| 959 | /* If either of these, don't count towards total */ |
| 960 | if (entry->rule.listnr == AUDIT_FILTER_USER || |
| 961 | entry->rule.listnr == AUDIT_FILTER_TYPE) |
| 962 | dont_count = 1; |
| 963 | #endif |
| 964 | |
| 965 | mutex_lock(&audit_filter_mutex); |
| 966 | e = audit_find_rule(entry, &list); |
| 967 | if (!e) { |
| 968 | mutex_unlock(&audit_filter_mutex); |
| 969 | ret = -ENOENT; |
| 970 | goto out; |
| 971 | } |
| 972 | |
| 973 | if (e->rule.watch) |
| 974 | audit_remove_watch_rule(&e->rule); |
| 975 | |
| 976 | if (e->rule.tree) |
| 977 | audit_remove_tree_rule(&e->rule); |
| 978 | |
| 979 | list_del_rcu(&e->list); |
| 980 | list_del(&e->rule.list); |
| 981 | call_rcu(&e->rcu, audit_free_rule_rcu); |
| 982 | |
| 983 | #ifdef CONFIG_AUDITSYSCALL |
| 984 | if (!dont_count) |
| 985 | audit_n_rules--; |
| 986 | |
| 987 | if (!audit_match_signal(entry)) |
| 988 | audit_signals--; |
| 989 | #endif |
| 990 | mutex_unlock(&audit_filter_mutex); |
| 991 | |
| 992 | out: |
| 993 | if (watch) |
| 994 | audit_put_watch(watch); /* match initial get */ |
| 995 | if (tree) |
| 996 | audit_put_tree(tree); /* that's the temporary one */ |
| 997 | |
| 998 | return ret; |
| 999 | } |
| 1000 | |
| 1001 | /* List rules using struct audit_rule. Exists for backward |
| 1002 | * compatibility with userspace. */ |
| 1003 | static void audit_list(int pid, int seq, struct sk_buff_head *q) |
| 1004 | { |
| 1005 | struct sk_buff *skb; |
| 1006 | struct audit_krule *r; |
| 1007 | int i; |
| 1008 | |
| 1009 | /* This is a blocking read, so use audit_filter_mutex instead of rcu |
| 1010 | * iterator to sync with list writers. */ |
| 1011 | for (i=0; i<AUDIT_NR_FILTERS; i++) { |
| 1012 | list_for_each_entry(r, &audit_rules_list[i], list) { |
| 1013 | struct audit_rule *rule; |
| 1014 | |
| 1015 | rule = audit_krule_to_rule(r); |
| 1016 | if (unlikely(!rule)) |
| 1017 | break; |
| 1018 | skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1, |
| 1019 | rule, sizeof(*rule)); |
| 1020 | if (skb) |
| 1021 | skb_queue_tail(q, skb); |
| 1022 | kfree(rule); |
| 1023 | } |
| 1024 | } |
| 1025 | skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0); |
| 1026 | if (skb) |
| 1027 | skb_queue_tail(q, skb); |
| 1028 | } |
| 1029 | |
| 1030 | /* List rules using struct audit_rule_data. */ |
| 1031 | static void audit_list_rules(int pid, int seq, struct sk_buff_head *q) |
| 1032 | { |
| 1033 | struct sk_buff *skb; |
| 1034 | struct audit_krule *r; |
| 1035 | int i; |
| 1036 | |
| 1037 | /* This is a blocking read, so use audit_filter_mutex instead of rcu |
| 1038 | * iterator to sync with list writers. */ |
| 1039 | for (i=0; i<AUDIT_NR_FILTERS; i++) { |
| 1040 | list_for_each_entry(r, &audit_rules_list[i], list) { |
| 1041 | struct audit_rule_data *data; |
| 1042 | |
| 1043 | data = audit_krule_to_data(r); |
| 1044 | if (unlikely(!data)) |
| 1045 | break; |
| 1046 | skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1, |
| 1047 | data, sizeof(*data) + data->buflen); |
| 1048 | if (skb) |
| 1049 | skb_queue_tail(q, skb); |
| 1050 | kfree(data); |
| 1051 | } |
| 1052 | } |
| 1053 | skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0); |
| 1054 | if (skb) |
| 1055 | skb_queue_tail(q, skb); |
| 1056 | } |
| 1057 | |
| 1058 | /* Log rule additions and removals */ |
| 1059 | static void audit_log_rule_change(uid_t loginuid, u32 sessionid, u32 sid, |
| 1060 | char *action, struct audit_krule *rule, |
| 1061 | int res) |
| 1062 | { |
| 1063 | struct audit_buffer *ab; |
| 1064 | |
| 1065 | if (!audit_enabled) |
| 1066 | return; |
| 1067 | |
| 1068 | ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); |
| 1069 | if (!ab) |
| 1070 | return; |
| 1071 | audit_log_format(ab, "auid=%u ses=%u", loginuid, sessionid); |
| 1072 | if (sid) { |
| 1073 | char *ctx = NULL; |
| 1074 | u32 len; |
| 1075 | if (security_secid_to_secctx(sid, &ctx, &len)) |
| 1076 | audit_log_format(ab, " ssid=%u", sid); |
| 1077 | else { |
| 1078 | audit_log_format(ab, " subj=%s", ctx); |
| 1079 | security_release_secctx(ctx, len); |
| 1080 | } |
| 1081 | } |
| 1082 | audit_log_format(ab, " op="); |
| 1083 | audit_log_string(ab, action); |
| 1084 | audit_log_key(ab, rule->filterkey); |
| 1085 | audit_log_format(ab, " list=%d res=%d", rule->listnr, res); |
| 1086 | audit_log_end(ab); |
| 1087 | } |
| 1088 | |
| 1089 | /** |
| 1090 | * audit_receive_filter - apply all rules to the specified message type |
| 1091 | * @type: audit message type |
| 1092 | * @pid: target pid for netlink audit messages |
| 1093 | * @uid: target uid for netlink audit messages |
| 1094 | * @seq: netlink audit message sequence (serial) number |
| 1095 | * @data: payload data |
| 1096 | * @datasz: size of payload data |
| 1097 | * @loginuid: loginuid of sender |
| 1098 | * @sessionid: sessionid for netlink audit message |
| 1099 | * @sid: SE Linux Security ID of sender |
| 1100 | */ |
| 1101 | int audit_receive_filter(int type, int pid, int seq, void *data, |
| 1102 | size_t datasz, uid_t loginuid, u32 sessionid, u32 sid) |
| 1103 | { |
| 1104 | struct task_struct *tsk; |
| 1105 | struct audit_netlink_list *dest; |
| 1106 | int err = 0; |
| 1107 | struct audit_entry *entry; |
| 1108 | |
| 1109 | switch (type) { |
| 1110 | case AUDIT_LIST: |
| 1111 | case AUDIT_LIST_RULES: |
| 1112 | /* We can't just spew out the rules here because we might fill |
| 1113 | * the available socket buffer space and deadlock waiting for |
| 1114 | * auditctl to read from it... which isn't ever going to |
| 1115 | * happen if we're actually running in the context of auditctl |
| 1116 | * trying to _send_ the stuff */ |
| 1117 | |
| 1118 | dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL); |
| 1119 | if (!dest) |
| 1120 | return -ENOMEM; |
| 1121 | dest->pid = pid; |
| 1122 | skb_queue_head_init(&dest->q); |
| 1123 | |
| 1124 | mutex_lock(&audit_filter_mutex); |
| 1125 | if (type == AUDIT_LIST) |
| 1126 | audit_list(pid, seq, &dest->q); |
| 1127 | else |
| 1128 | audit_list_rules(pid, seq, &dest->q); |
| 1129 | mutex_unlock(&audit_filter_mutex); |
| 1130 | |
| 1131 | tsk = kthread_run(audit_send_list, dest, "audit_send_list"); |
| 1132 | if (IS_ERR(tsk)) { |
| 1133 | skb_queue_purge(&dest->q); |
| 1134 | kfree(dest); |
| 1135 | err = PTR_ERR(tsk); |
| 1136 | } |
| 1137 | break; |
| 1138 | case AUDIT_ADD: |
| 1139 | case AUDIT_ADD_RULE: |
| 1140 | if (type == AUDIT_ADD) |
| 1141 | entry = audit_rule_to_entry(data); |
| 1142 | else |
| 1143 | entry = audit_data_to_entry(data, datasz); |
| 1144 | if (IS_ERR(entry)) |
| 1145 | return PTR_ERR(entry); |
| 1146 | |
| 1147 | err = audit_add_rule(entry); |
| 1148 | audit_log_rule_change(loginuid, sessionid, sid, "add rule", |
| 1149 | &entry->rule, !err); |
| 1150 | |
| 1151 | if (err) |
| 1152 | audit_free_rule(entry); |
| 1153 | break; |
| 1154 | case AUDIT_DEL: |
| 1155 | case AUDIT_DEL_RULE: |
| 1156 | if (type == AUDIT_DEL) |
| 1157 | entry = audit_rule_to_entry(data); |
| 1158 | else |
| 1159 | entry = audit_data_to_entry(data, datasz); |
| 1160 | if (IS_ERR(entry)) |
| 1161 | return PTR_ERR(entry); |
| 1162 | |
| 1163 | err = audit_del_rule(entry); |
| 1164 | audit_log_rule_change(loginuid, sessionid, sid, "remove rule", |
| 1165 | &entry->rule, !err); |
| 1166 | |
| 1167 | audit_free_rule(entry); |
| 1168 | break; |
| 1169 | default: |
| 1170 | return -EINVAL; |
| 1171 | } |
| 1172 | |
| 1173 | return err; |
| 1174 | } |
| 1175 | |
| 1176 | int audit_comparator(u32 left, u32 op, u32 right) |
| 1177 | { |
| 1178 | switch (op) { |
| 1179 | case Audit_equal: |
| 1180 | return (left == right); |
| 1181 | case Audit_not_equal: |
| 1182 | return (left != right); |
| 1183 | case Audit_lt: |
| 1184 | return (left < right); |
| 1185 | case Audit_le: |
| 1186 | return (left <= right); |
| 1187 | case Audit_gt: |
| 1188 | return (left > right); |
| 1189 | case Audit_ge: |
| 1190 | return (left >= right); |
| 1191 | case Audit_bitmask: |
| 1192 | return (left & right); |
| 1193 | case Audit_bittest: |
| 1194 | return ((left & right) == right); |
| 1195 | default: |
| 1196 | BUG(); |
| 1197 | return 0; |
| 1198 | } |
| 1199 | } |
| 1200 | |
| 1201 | /* Compare given dentry name with last component in given path, |
| 1202 | * return of 0 indicates a match. */ |
| 1203 | int audit_compare_dname_path(const char *dname, const char *path, |
| 1204 | int *dirlen) |
| 1205 | { |
| 1206 | int dlen, plen; |
| 1207 | const char *p; |
| 1208 | |
| 1209 | if (!dname || !path) |
| 1210 | return 1; |
| 1211 | |
| 1212 | dlen = strlen(dname); |
| 1213 | plen = strlen(path); |
| 1214 | if (plen < dlen) |
| 1215 | return 1; |
| 1216 | |
| 1217 | /* disregard trailing slashes */ |
| 1218 | p = path + plen - 1; |
| 1219 | while ((*p == '/') && (p > path)) |
| 1220 | p--; |
| 1221 | |
| 1222 | /* find last path component */ |
| 1223 | p = p - dlen + 1; |
| 1224 | if (p < path) |
| 1225 | return 1; |
| 1226 | else if (p > path) { |
| 1227 | if (*--p != '/') |
| 1228 | return 1; |
| 1229 | else |
| 1230 | p++; |
| 1231 | } |
| 1232 | |
| 1233 | /* return length of path's directory component */ |
| 1234 | if (dirlen) |
| 1235 | *dirlen = p - path; |
| 1236 | return strncmp(p, dname, dlen); |
| 1237 | } |
| 1238 | |
| 1239 | static int audit_filter_user_rules(struct audit_krule *rule, |
| 1240 | enum audit_state *state) |
| 1241 | { |
| 1242 | int i; |
| 1243 | |
| 1244 | for (i = 0; i < rule->field_count; i++) { |
| 1245 | struct audit_field *f = &rule->fields[i]; |
| 1246 | int result = 0; |
| 1247 | u32 sid; |
| 1248 | |
| 1249 | switch (f->type) { |
| 1250 | case AUDIT_PID: |
| 1251 | result = audit_comparator(task_pid_vnr(current), f->op, f->val); |
| 1252 | break; |
| 1253 | case AUDIT_UID: |
| 1254 | result = audit_comparator(current_uid(), f->op, f->val); |
| 1255 | break; |
| 1256 | case AUDIT_GID: |
| 1257 | result = audit_comparator(current_gid(), f->op, f->val); |
| 1258 | break; |
| 1259 | case AUDIT_LOGINUID: |
| 1260 | result = audit_comparator(audit_get_loginuid(current), |
| 1261 | f->op, f->val); |
| 1262 | break; |
| 1263 | case AUDIT_SUBJ_USER: |
| 1264 | case AUDIT_SUBJ_ROLE: |
| 1265 | case AUDIT_SUBJ_TYPE: |
| 1266 | case AUDIT_SUBJ_SEN: |
| 1267 | case AUDIT_SUBJ_CLR: |
| 1268 | if (f->lsm_rule) { |
| 1269 | security_task_getsecid(current, &sid); |
| 1270 | result = security_audit_rule_match(sid, |
| 1271 | f->type, |
| 1272 | f->op, |
| 1273 | f->lsm_rule, |
| 1274 | NULL); |
| 1275 | } |
| 1276 | break; |
| 1277 | } |
| 1278 | |
| 1279 | if (!result) |
| 1280 | return 0; |
| 1281 | } |
| 1282 | switch (rule->action) { |
| 1283 | case AUDIT_NEVER: *state = AUDIT_DISABLED; break; |
| 1284 | case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break; |
| 1285 | } |
| 1286 | return 1; |
| 1287 | } |
| 1288 | |
| 1289 | int audit_filter_user(void) |
| 1290 | { |
| 1291 | enum audit_state state = AUDIT_DISABLED; |
| 1292 | struct audit_entry *e; |
| 1293 | int ret = 1; |
| 1294 | |
| 1295 | rcu_read_lock(); |
| 1296 | list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) { |
| 1297 | if (audit_filter_user_rules(&e->rule, &state)) { |
| 1298 | if (state == AUDIT_DISABLED) |
| 1299 | ret = 0; |
| 1300 | break; |
| 1301 | } |
| 1302 | } |
| 1303 | rcu_read_unlock(); |
| 1304 | |
| 1305 | return ret; /* Audit by default */ |
| 1306 | } |
| 1307 | |
| 1308 | int audit_filter_type(int type) |
| 1309 | { |
| 1310 | struct audit_entry *e; |
| 1311 | int result = 0; |
| 1312 | |
| 1313 | rcu_read_lock(); |
| 1314 | if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE])) |
| 1315 | goto unlock_and_return; |
| 1316 | |
| 1317 | list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE], |
| 1318 | list) { |
| 1319 | int i; |
| 1320 | for (i = 0; i < e->rule.field_count; i++) { |
| 1321 | struct audit_field *f = &e->rule.fields[i]; |
| 1322 | if (f->type == AUDIT_MSGTYPE) { |
| 1323 | result = audit_comparator(type, f->op, f->val); |
| 1324 | if (!result) |
| 1325 | break; |
| 1326 | } |
| 1327 | } |
| 1328 | if (result) |
| 1329 | goto unlock_and_return; |
| 1330 | } |
| 1331 | unlock_and_return: |
| 1332 | rcu_read_unlock(); |
| 1333 | return result; |
| 1334 | } |
| 1335 | |
| 1336 | static int update_lsm_rule(struct audit_krule *r) |
| 1337 | { |
| 1338 | struct audit_entry *entry = container_of(r, struct audit_entry, rule); |
| 1339 | struct audit_entry *nentry; |
| 1340 | int err = 0; |
| 1341 | |
| 1342 | if (!security_audit_rule_known(r)) |
| 1343 | return 0; |
| 1344 | |
| 1345 | nentry = audit_dupe_rule(r); |
| 1346 | if (IS_ERR(nentry)) { |
| 1347 | /* save the first error encountered for the |
| 1348 | * return value */ |
| 1349 | err = PTR_ERR(nentry); |
| 1350 | audit_panic("error updating LSM filters"); |
| 1351 | if (r->watch) |
| 1352 | list_del(&r->rlist); |
| 1353 | list_del_rcu(&entry->list); |
| 1354 | list_del(&r->list); |
| 1355 | } else { |
| 1356 | if (r->watch || r->tree) |
| 1357 | list_replace_init(&r->rlist, &nentry->rule.rlist); |
| 1358 | list_replace_rcu(&entry->list, &nentry->list); |
| 1359 | list_replace(&r->list, &nentry->rule.list); |
| 1360 | } |
| 1361 | call_rcu(&entry->rcu, audit_free_rule_rcu); |
| 1362 | |
| 1363 | return err; |
| 1364 | } |
| 1365 | |
| 1366 | /* This function will re-initialize the lsm_rule field of all applicable rules. |
| 1367 | * It will traverse the filter lists serarching for rules that contain LSM |
| 1368 | * specific filter fields. When such a rule is found, it is copied, the |
| 1369 | * LSM field is re-initialized, and the old rule is replaced with the |
| 1370 | * updated rule. */ |
| 1371 | int audit_update_lsm_rules(void) |
| 1372 | { |
| 1373 | struct audit_krule *r, *n; |
| 1374 | int i, err = 0; |
| 1375 | |
| 1376 | /* audit_filter_mutex synchronizes the writers */ |
| 1377 | mutex_lock(&audit_filter_mutex); |
| 1378 | |
| 1379 | for (i = 0; i < AUDIT_NR_FILTERS; i++) { |
| 1380 | list_for_each_entry_safe(r, n, &audit_rules_list[i], list) { |
| 1381 | int res = update_lsm_rule(r); |
| 1382 | if (!err) |
| 1383 | err = res; |
| 1384 | } |
| 1385 | } |
| 1386 | mutex_unlock(&audit_filter_mutex); |
| 1387 | |
| 1388 | return err; |
| 1389 | } |