| 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/netlink.h> |
| 26 | #include <linux/selinux.h> |
| 27 | #include "audit.h" |
| 28 | |
| 29 | /* There are three lists of rules -- one to search at task creation |
| 30 | * time, one to search at syscall entry time, and another to search at |
| 31 | * syscall exit time. */ |
| 32 | struct list_head audit_filter_list[AUDIT_NR_FILTERS] = { |
| 33 | LIST_HEAD_INIT(audit_filter_list[0]), |
| 34 | LIST_HEAD_INIT(audit_filter_list[1]), |
| 35 | LIST_HEAD_INIT(audit_filter_list[2]), |
| 36 | LIST_HEAD_INIT(audit_filter_list[3]), |
| 37 | LIST_HEAD_INIT(audit_filter_list[4]), |
| 38 | LIST_HEAD_INIT(audit_filter_list[5]), |
| 39 | #if AUDIT_NR_FILTERS != 6 |
| 40 | #error Fix audit_filter_list initialiser |
| 41 | #endif |
| 42 | }; |
| 43 | |
| 44 | static inline void audit_free_rule(struct audit_entry *e) |
| 45 | { |
| 46 | int i; |
| 47 | if (e->rule.fields) |
| 48 | for (i = 0; i < e->rule.field_count; i++) { |
| 49 | struct audit_field *f = &e->rule.fields[i]; |
| 50 | kfree(f->se_str); |
| 51 | selinux_audit_rule_free(f->se_rule); |
| 52 | } |
| 53 | kfree(e->rule.fields); |
| 54 | kfree(e); |
| 55 | } |
| 56 | |
| 57 | static inline void audit_free_rule_rcu(struct rcu_head *head) |
| 58 | { |
| 59 | struct audit_entry *e = container_of(head, struct audit_entry, rcu); |
| 60 | audit_free_rule(e); |
| 61 | } |
| 62 | |
| 63 | /* Initialize an audit filterlist entry. */ |
| 64 | static inline struct audit_entry *audit_init_entry(u32 field_count) |
| 65 | { |
| 66 | struct audit_entry *entry; |
| 67 | struct audit_field *fields; |
| 68 | |
| 69 | entry = kzalloc(sizeof(*entry), GFP_KERNEL); |
| 70 | if (unlikely(!entry)) |
| 71 | return NULL; |
| 72 | |
| 73 | fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL); |
| 74 | if (unlikely(!fields)) { |
| 75 | kfree(entry); |
| 76 | return NULL; |
| 77 | } |
| 78 | entry->rule.fields = fields; |
| 79 | |
| 80 | return entry; |
| 81 | } |
| 82 | |
| 83 | /* Unpack a filter field's string representation from user-space |
| 84 | * buffer. */ |
| 85 | static char *audit_unpack_string(void **bufp, size_t *remain, size_t len) |
| 86 | { |
| 87 | char *str; |
| 88 | |
| 89 | if (!*bufp || (len == 0) || (len > *remain)) |
| 90 | return ERR_PTR(-EINVAL); |
| 91 | |
| 92 | /* Of the currently implemented string fields, PATH_MAX |
| 93 | * defines the longest valid length. |
| 94 | */ |
| 95 | if (len > PATH_MAX) |
| 96 | return ERR_PTR(-ENAMETOOLONG); |
| 97 | |
| 98 | str = kmalloc(len + 1, GFP_KERNEL); |
| 99 | if (unlikely(!str)) |
| 100 | return ERR_PTR(-ENOMEM); |
| 101 | |
| 102 | memcpy(str, *bufp, len); |
| 103 | str[len] = 0; |
| 104 | *bufp += len; |
| 105 | *remain -= len; |
| 106 | |
| 107 | return str; |
| 108 | } |
| 109 | |
| 110 | /* Common user-space to kernel rule translation. */ |
| 111 | static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule) |
| 112 | { |
| 113 | unsigned listnr; |
| 114 | struct audit_entry *entry; |
| 115 | int i, err; |
| 116 | |
| 117 | err = -EINVAL; |
| 118 | listnr = rule->flags & ~AUDIT_FILTER_PREPEND; |
| 119 | switch(listnr) { |
| 120 | default: |
| 121 | goto exit_err; |
| 122 | case AUDIT_FILTER_USER: |
| 123 | case AUDIT_FILTER_TYPE: |
| 124 | #ifdef CONFIG_AUDITSYSCALL |
| 125 | case AUDIT_FILTER_ENTRY: |
| 126 | case AUDIT_FILTER_EXIT: |
| 127 | case AUDIT_FILTER_TASK: |
| 128 | #endif |
| 129 | ; |
| 130 | } |
| 131 | if (rule->action != AUDIT_NEVER && rule->action != AUDIT_POSSIBLE && |
| 132 | rule->action != AUDIT_ALWAYS) |
| 133 | goto exit_err; |
| 134 | if (rule->field_count > AUDIT_MAX_FIELDS) |
| 135 | goto exit_err; |
| 136 | |
| 137 | err = -ENOMEM; |
| 138 | entry = audit_init_entry(rule->field_count); |
| 139 | if (!entry) |
| 140 | goto exit_err; |
| 141 | |
| 142 | entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND; |
| 143 | entry->rule.listnr = listnr; |
| 144 | entry->rule.action = rule->action; |
| 145 | entry->rule.field_count = rule->field_count; |
| 146 | |
| 147 | for (i = 0; i < AUDIT_BITMASK_SIZE; i++) |
| 148 | entry->rule.mask[i] = rule->mask[i]; |
| 149 | |
| 150 | return entry; |
| 151 | |
| 152 | exit_err: |
| 153 | return ERR_PTR(err); |
| 154 | } |
| 155 | |
| 156 | /* Translate struct audit_rule to kernel's rule respresentation. |
| 157 | * Exists for backward compatibility with userspace. */ |
| 158 | static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule) |
| 159 | { |
| 160 | struct audit_entry *entry; |
| 161 | int err = 0; |
| 162 | int i; |
| 163 | |
| 164 | entry = audit_to_entry_common(rule); |
| 165 | if (IS_ERR(entry)) |
| 166 | goto exit_nofree; |
| 167 | |
| 168 | for (i = 0; i < rule->field_count; i++) { |
| 169 | struct audit_field *f = &entry->rule.fields[i]; |
| 170 | |
| 171 | f->op = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS); |
| 172 | f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS); |
| 173 | f->val = rule->values[i]; |
| 174 | |
| 175 | if (f->type & AUDIT_UNUSED_BITS || |
| 176 | f->type == AUDIT_SE_USER || |
| 177 | f->type == AUDIT_SE_ROLE || |
| 178 | f->type == AUDIT_SE_TYPE || |
| 179 | f->type == AUDIT_SE_SEN || |
| 180 | f->type == AUDIT_SE_CLR) { |
| 181 | err = -EINVAL; |
| 182 | goto exit_free; |
| 183 | } |
| 184 | |
| 185 | entry->rule.vers_ops = (f->op & AUDIT_OPERATORS) ? 2 : 1; |
| 186 | |
| 187 | /* Support for legacy operators where |
| 188 | * AUDIT_NEGATE bit signifies != and otherwise assumes == */ |
| 189 | if (f->op & AUDIT_NEGATE) |
| 190 | f->op = AUDIT_NOT_EQUAL; |
| 191 | else if (!f->op) |
| 192 | f->op = AUDIT_EQUAL; |
| 193 | else if (f->op == AUDIT_OPERATORS) { |
| 194 | err = -EINVAL; |
| 195 | goto exit_free; |
| 196 | } |
| 197 | } |
| 198 | |
| 199 | exit_nofree: |
| 200 | return entry; |
| 201 | |
| 202 | exit_free: |
| 203 | audit_free_rule(entry); |
| 204 | return ERR_PTR(err); |
| 205 | } |
| 206 | |
| 207 | /* Translate struct audit_rule_data to kernel's rule respresentation. */ |
| 208 | static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data, |
| 209 | size_t datasz) |
| 210 | { |
| 211 | int err = 0; |
| 212 | struct audit_entry *entry; |
| 213 | void *bufp; |
| 214 | size_t remain = datasz - sizeof(struct audit_rule_data); |
| 215 | int i; |
| 216 | char *str; |
| 217 | |
| 218 | entry = audit_to_entry_common((struct audit_rule *)data); |
| 219 | if (IS_ERR(entry)) |
| 220 | goto exit_nofree; |
| 221 | |
| 222 | bufp = data->buf; |
| 223 | entry->rule.vers_ops = 2; |
| 224 | for (i = 0; i < data->field_count; i++) { |
| 225 | struct audit_field *f = &entry->rule.fields[i]; |
| 226 | |
| 227 | err = -EINVAL; |
| 228 | if (!(data->fieldflags[i] & AUDIT_OPERATORS) || |
| 229 | data->fieldflags[i] & ~AUDIT_OPERATORS) |
| 230 | goto exit_free; |
| 231 | |
| 232 | f->op = data->fieldflags[i] & AUDIT_OPERATORS; |
| 233 | f->type = data->fields[i]; |
| 234 | f->val = data->values[i]; |
| 235 | f->se_str = NULL; |
| 236 | f->se_rule = NULL; |
| 237 | switch(f->type) { |
| 238 | case AUDIT_SE_USER: |
| 239 | case AUDIT_SE_ROLE: |
| 240 | case AUDIT_SE_TYPE: |
| 241 | case AUDIT_SE_SEN: |
| 242 | case AUDIT_SE_CLR: |
| 243 | str = audit_unpack_string(&bufp, &remain, f->val); |
| 244 | if (IS_ERR(str)) |
| 245 | goto exit_free; |
| 246 | entry->rule.buflen += f->val; |
| 247 | |
| 248 | err = selinux_audit_rule_init(f->type, f->op, str, |
| 249 | &f->se_rule); |
| 250 | /* Keep currently invalid fields around in case they |
| 251 | * become valid after a policy reload. */ |
| 252 | if (err == -EINVAL) { |
| 253 | printk(KERN_WARNING "audit rule for selinux " |
| 254 | "\'%s\' is invalid\n", str); |
| 255 | err = 0; |
| 256 | } |
| 257 | if (err) { |
| 258 | kfree(str); |
| 259 | goto exit_free; |
| 260 | } else |
| 261 | f->se_str = str; |
| 262 | break; |
| 263 | } |
| 264 | } |
| 265 | |
| 266 | exit_nofree: |
| 267 | return entry; |
| 268 | |
| 269 | exit_free: |
| 270 | audit_free_rule(entry); |
| 271 | return ERR_PTR(err); |
| 272 | } |
| 273 | |
| 274 | /* Pack a filter field's string representation into data block. */ |
| 275 | static inline size_t audit_pack_string(void **bufp, char *str) |
| 276 | { |
| 277 | size_t len = strlen(str); |
| 278 | |
| 279 | memcpy(*bufp, str, len); |
| 280 | *bufp += len; |
| 281 | |
| 282 | return len; |
| 283 | } |
| 284 | |
| 285 | /* Translate kernel rule respresentation to struct audit_rule. |
| 286 | * Exists for backward compatibility with userspace. */ |
| 287 | static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule) |
| 288 | { |
| 289 | struct audit_rule *rule; |
| 290 | int i; |
| 291 | |
| 292 | rule = kmalloc(sizeof(*rule), GFP_KERNEL); |
| 293 | if (unlikely(!rule)) |
| 294 | return NULL; |
| 295 | memset(rule, 0, sizeof(*rule)); |
| 296 | |
| 297 | rule->flags = krule->flags | krule->listnr; |
| 298 | rule->action = krule->action; |
| 299 | rule->field_count = krule->field_count; |
| 300 | for (i = 0; i < rule->field_count; i++) { |
| 301 | rule->values[i] = krule->fields[i].val; |
| 302 | rule->fields[i] = krule->fields[i].type; |
| 303 | |
| 304 | if (krule->vers_ops == 1) { |
| 305 | if (krule->fields[i].op & AUDIT_NOT_EQUAL) |
| 306 | rule->fields[i] |= AUDIT_NEGATE; |
| 307 | } else { |
| 308 | rule->fields[i] |= krule->fields[i].op; |
| 309 | } |
| 310 | } |
| 311 | for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i]; |
| 312 | |
| 313 | return rule; |
| 314 | } |
| 315 | |
| 316 | /* Translate kernel rule respresentation to struct audit_rule_data. */ |
| 317 | static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule) |
| 318 | { |
| 319 | struct audit_rule_data *data; |
| 320 | void *bufp; |
| 321 | int i; |
| 322 | |
| 323 | data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL); |
| 324 | if (unlikely(!data)) |
| 325 | return NULL; |
| 326 | memset(data, 0, sizeof(*data)); |
| 327 | |
| 328 | data->flags = krule->flags | krule->listnr; |
| 329 | data->action = krule->action; |
| 330 | data->field_count = krule->field_count; |
| 331 | bufp = data->buf; |
| 332 | for (i = 0; i < data->field_count; i++) { |
| 333 | struct audit_field *f = &krule->fields[i]; |
| 334 | |
| 335 | data->fields[i] = f->type; |
| 336 | data->fieldflags[i] = f->op; |
| 337 | switch(f->type) { |
| 338 | case AUDIT_SE_USER: |
| 339 | case AUDIT_SE_ROLE: |
| 340 | case AUDIT_SE_TYPE: |
| 341 | case AUDIT_SE_SEN: |
| 342 | case AUDIT_SE_CLR: |
| 343 | data->buflen += data->values[i] = |
| 344 | audit_pack_string(&bufp, f->se_str); |
| 345 | break; |
| 346 | default: |
| 347 | data->values[i] = f->val; |
| 348 | } |
| 349 | } |
| 350 | for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i]; |
| 351 | |
| 352 | return data; |
| 353 | } |
| 354 | |
| 355 | /* Compare two rules in kernel format. Considered success if rules |
| 356 | * don't match. */ |
| 357 | static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b) |
| 358 | { |
| 359 | int i; |
| 360 | |
| 361 | if (a->flags != b->flags || |
| 362 | a->listnr != b->listnr || |
| 363 | a->action != b->action || |
| 364 | a->field_count != b->field_count) |
| 365 | return 1; |
| 366 | |
| 367 | for (i = 0; i < a->field_count; i++) { |
| 368 | if (a->fields[i].type != b->fields[i].type || |
| 369 | a->fields[i].op != b->fields[i].op) |
| 370 | return 1; |
| 371 | |
| 372 | switch(a->fields[i].type) { |
| 373 | case AUDIT_SE_USER: |
| 374 | case AUDIT_SE_ROLE: |
| 375 | case AUDIT_SE_TYPE: |
| 376 | case AUDIT_SE_SEN: |
| 377 | case AUDIT_SE_CLR: |
| 378 | if (strcmp(a->fields[i].se_str, b->fields[i].se_str)) |
| 379 | return 1; |
| 380 | break; |
| 381 | default: |
| 382 | if (a->fields[i].val != b->fields[i].val) |
| 383 | return 1; |
| 384 | } |
| 385 | } |
| 386 | |
| 387 | for (i = 0; i < AUDIT_BITMASK_SIZE; i++) |
| 388 | if (a->mask[i] != b->mask[i]) |
| 389 | return 1; |
| 390 | |
| 391 | return 0; |
| 392 | } |
| 393 | |
| 394 | /* Duplicate selinux field information. The se_rule is opaque, so must be |
| 395 | * re-initialized. */ |
| 396 | static inline int audit_dupe_selinux_field(struct audit_field *df, |
| 397 | struct audit_field *sf) |
| 398 | { |
| 399 | int ret = 0; |
| 400 | char *se_str; |
| 401 | |
| 402 | /* our own copy of se_str */ |
| 403 | se_str = kstrdup(sf->se_str, GFP_KERNEL); |
| 404 | if (unlikely(IS_ERR(se_str))) |
| 405 | return -ENOMEM; |
| 406 | df->se_str = se_str; |
| 407 | |
| 408 | /* our own (refreshed) copy of se_rule */ |
| 409 | ret = selinux_audit_rule_init(df->type, df->op, df->se_str, |
| 410 | &df->se_rule); |
| 411 | /* Keep currently invalid fields around in case they |
| 412 | * become valid after a policy reload. */ |
| 413 | if (ret == -EINVAL) { |
| 414 | printk(KERN_WARNING "audit rule for selinux \'%s\' is " |
| 415 | "invalid\n", df->se_str); |
| 416 | ret = 0; |
| 417 | } |
| 418 | |
| 419 | return ret; |
| 420 | } |
| 421 | |
| 422 | /* Duplicate an audit rule. This will be a deep copy with the exception |
| 423 | * of the watch - that pointer is carried over. The selinux specific fields |
| 424 | * will be updated in the copy. The point is to be able to replace the old |
| 425 | * rule with the new rule in the filterlist, then free the old rule. */ |
| 426 | static struct audit_entry *audit_dupe_rule(struct audit_krule *old) |
| 427 | { |
| 428 | u32 fcount = old->field_count; |
| 429 | struct audit_entry *entry; |
| 430 | struct audit_krule *new; |
| 431 | int i, err = 0; |
| 432 | |
| 433 | entry = audit_init_entry(fcount); |
| 434 | if (unlikely(!entry)) |
| 435 | return ERR_PTR(-ENOMEM); |
| 436 | |
| 437 | new = &entry->rule; |
| 438 | new->vers_ops = old->vers_ops; |
| 439 | new->flags = old->flags; |
| 440 | new->listnr = old->listnr; |
| 441 | new->action = old->action; |
| 442 | for (i = 0; i < AUDIT_BITMASK_SIZE; i++) |
| 443 | new->mask[i] = old->mask[i]; |
| 444 | new->buflen = old->buflen; |
| 445 | new->field_count = old->field_count; |
| 446 | memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount); |
| 447 | |
| 448 | /* deep copy this information, updating the se_rule fields, because |
| 449 | * the originals will all be freed when the old rule is freed. */ |
| 450 | for (i = 0; i < fcount; i++) { |
| 451 | switch (new->fields[i].type) { |
| 452 | case AUDIT_SE_USER: |
| 453 | case AUDIT_SE_ROLE: |
| 454 | case AUDIT_SE_TYPE: |
| 455 | case AUDIT_SE_SEN: |
| 456 | case AUDIT_SE_CLR: |
| 457 | err = audit_dupe_selinux_field(&new->fields[i], |
| 458 | &old->fields[i]); |
| 459 | } |
| 460 | if (err) { |
| 461 | audit_free_rule(entry); |
| 462 | return ERR_PTR(err); |
| 463 | } |
| 464 | } |
| 465 | |
| 466 | return entry; |
| 467 | } |
| 468 | |
| 469 | /* Add rule to given filterlist if not a duplicate. Protected by |
| 470 | * audit_netlink_mutex. */ |
| 471 | static inline int audit_add_rule(struct audit_entry *entry, |
| 472 | struct list_head *list) |
| 473 | { |
| 474 | struct audit_entry *e; |
| 475 | |
| 476 | /* Do not use the _rcu iterator here, since this is the only |
| 477 | * addition routine. */ |
| 478 | list_for_each_entry(e, list, list) { |
| 479 | if (!audit_compare_rule(&entry->rule, &e->rule)) |
| 480 | return -EEXIST; |
| 481 | } |
| 482 | |
| 483 | if (entry->rule.flags & AUDIT_FILTER_PREPEND) { |
| 484 | list_add_rcu(&entry->list, list); |
| 485 | } else { |
| 486 | list_add_tail_rcu(&entry->list, list); |
| 487 | } |
| 488 | |
| 489 | return 0; |
| 490 | } |
| 491 | |
| 492 | /* Remove an existing rule from filterlist. Protected by |
| 493 | * audit_netlink_mutex. */ |
| 494 | static inline int audit_del_rule(struct audit_entry *entry, |
| 495 | struct list_head *list) |
| 496 | { |
| 497 | struct audit_entry *e; |
| 498 | |
| 499 | /* Do not use the _rcu iterator here, since this is the only |
| 500 | * deletion routine. */ |
| 501 | list_for_each_entry(e, list, list) { |
| 502 | if (!audit_compare_rule(&entry->rule, &e->rule)) { |
| 503 | list_del_rcu(&e->list); |
| 504 | call_rcu(&e->rcu, audit_free_rule_rcu); |
| 505 | return 0; |
| 506 | } |
| 507 | } |
| 508 | return -ENOENT; /* No matching rule */ |
| 509 | } |
| 510 | |
| 511 | /* List rules using struct audit_rule. Exists for backward |
| 512 | * compatibility with userspace. */ |
| 513 | static void audit_list(int pid, int seq, struct sk_buff_head *q) |
| 514 | { |
| 515 | struct sk_buff *skb; |
| 516 | struct audit_entry *entry; |
| 517 | int i; |
| 518 | |
| 519 | /* The *_rcu iterators not needed here because we are |
| 520 | always called with audit_netlink_mutex held. */ |
| 521 | for (i=0; i<AUDIT_NR_FILTERS; i++) { |
| 522 | list_for_each_entry(entry, &audit_filter_list[i], list) { |
| 523 | struct audit_rule *rule; |
| 524 | |
| 525 | rule = audit_krule_to_rule(&entry->rule); |
| 526 | if (unlikely(!rule)) |
| 527 | break; |
| 528 | skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1, |
| 529 | rule, sizeof(*rule)); |
| 530 | if (skb) |
| 531 | skb_queue_tail(q, skb); |
| 532 | kfree(rule); |
| 533 | } |
| 534 | } |
| 535 | skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0); |
| 536 | if (skb) |
| 537 | skb_queue_tail(q, skb); |
| 538 | } |
| 539 | |
| 540 | /* List rules using struct audit_rule_data. */ |
| 541 | static void audit_list_rules(int pid, int seq, struct sk_buff_head *q) |
| 542 | { |
| 543 | struct sk_buff *skb; |
| 544 | struct audit_entry *e; |
| 545 | int i; |
| 546 | |
| 547 | /* The *_rcu iterators not needed here because we are |
| 548 | always called with audit_netlink_mutex held. */ |
| 549 | for (i=0; i<AUDIT_NR_FILTERS; i++) { |
| 550 | list_for_each_entry(e, &audit_filter_list[i], list) { |
| 551 | struct audit_rule_data *data; |
| 552 | |
| 553 | data = audit_krule_to_data(&e->rule); |
| 554 | if (unlikely(!data)) |
| 555 | break; |
| 556 | skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1, |
| 557 | data, sizeof(*data)); |
| 558 | if (skb) |
| 559 | skb_queue_tail(q, skb); |
| 560 | kfree(data); |
| 561 | } |
| 562 | } |
| 563 | skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0); |
| 564 | if (skb) |
| 565 | skb_queue_tail(q, skb); |
| 566 | } |
| 567 | |
| 568 | /** |
| 569 | * audit_receive_filter - apply all rules to the specified message type |
| 570 | * @type: audit message type |
| 571 | * @pid: target pid for netlink audit messages |
| 572 | * @uid: target uid for netlink audit messages |
| 573 | * @seq: netlink audit message sequence (serial) number |
| 574 | * @data: payload data |
| 575 | * @datasz: size of payload data |
| 576 | * @loginuid: loginuid of sender |
| 577 | * @sid: SE Linux Security ID of sender |
| 578 | */ |
| 579 | int audit_receive_filter(int type, int pid, int uid, int seq, void *data, |
| 580 | size_t datasz, uid_t loginuid, u32 sid) |
| 581 | { |
| 582 | struct task_struct *tsk; |
| 583 | struct audit_netlink_list *dest; |
| 584 | int err = 0; |
| 585 | struct audit_entry *entry; |
| 586 | |
| 587 | switch (type) { |
| 588 | case AUDIT_LIST: |
| 589 | case AUDIT_LIST_RULES: |
| 590 | /* We can't just spew out the rules here because we might fill |
| 591 | * the available socket buffer space and deadlock waiting for |
| 592 | * auditctl to read from it... which isn't ever going to |
| 593 | * happen if we're actually running in the context of auditctl |
| 594 | * trying to _send_ the stuff */ |
| 595 | |
| 596 | dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL); |
| 597 | if (!dest) |
| 598 | return -ENOMEM; |
| 599 | dest->pid = pid; |
| 600 | skb_queue_head_init(&dest->q); |
| 601 | |
| 602 | if (type == AUDIT_LIST) |
| 603 | audit_list(pid, seq, &dest->q); |
| 604 | else |
| 605 | audit_list_rules(pid, seq, &dest->q); |
| 606 | |
| 607 | tsk = kthread_run(audit_send_list, dest, "audit_send_list"); |
| 608 | if (IS_ERR(tsk)) { |
| 609 | skb_queue_purge(&dest->q); |
| 610 | kfree(dest); |
| 611 | err = PTR_ERR(tsk); |
| 612 | } |
| 613 | break; |
| 614 | case AUDIT_ADD: |
| 615 | case AUDIT_ADD_RULE: |
| 616 | if (type == AUDIT_ADD) |
| 617 | entry = audit_rule_to_entry(data); |
| 618 | else |
| 619 | entry = audit_data_to_entry(data, datasz); |
| 620 | if (IS_ERR(entry)) |
| 621 | return PTR_ERR(entry); |
| 622 | |
| 623 | err = audit_add_rule(entry, |
| 624 | &audit_filter_list[entry->rule.listnr]); |
| 625 | if (sid) { |
| 626 | char *ctx = NULL; |
| 627 | u32 len; |
| 628 | if (selinux_ctxid_to_string(sid, &ctx, &len)) { |
| 629 | /* Maybe call audit_panic? */ |
| 630 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, |
| 631 | "auid=%u ssid=%u add rule to list=%d res=%d", |
| 632 | loginuid, sid, entry->rule.listnr, !err); |
| 633 | } else |
| 634 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, |
| 635 | "auid=%u subj=%s add rule to list=%d res=%d", |
| 636 | loginuid, ctx, entry->rule.listnr, !err); |
| 637 | kfree(ctx); |
| 638 | } else |
| 639 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, |
| 640 | "auid=%u add rule to list=%d res=%d", |
| 641 | loginuid, entry->rule.listnr, !err); |
| 642 | |
| 643 | if (err) |
| 644 | audit_free_rule(entry); |
| 645 | break; |
| 646 | case AUDIT_DEL: |
| 647 | case AUDIT_DEL_RULE: |
| 648 | if (type == AUDIT_DEL) |
| 649 | entry = audit_rule_to_entry(data); |
| 650 | else |
| 651 | entry = audit_data_to_entry(data, datasz); |
| 652 | if (IS_ERR(entry)) |
| 653 | return PTR_ERR(entry); |
| 654 | |
| 655 | err = audit_del_rule(entry, |
| 656 | &audit_filter_list[entry->rule.listnr]); |
| 657 | |
| 658 | if (sid) { |
| 659 | char *ctx = NULL; |
| 660 | u32 len; |
| 661 | if (selinux_ctxid_to_string(sid, &ctx, &len)) { |
| 662 | /* Maybe call audit_panic? */ |
| 663 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, |
| 664 | "auid=%u ssid=%u remove rule from list=%d res=%d", |
| 665 | loginuid, sid, entry->rule.listnr, !err); |
| 666 | } else |
| 667 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, |
| 668 | "auid=%u subj=%s remove rule from list=%d res=%d", |
| 669 | loginuid, ctx, entry->rule.listnr, !err); |
| 670 | kfree(ctx); |
| 671 | } else |
| 672 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, |
| 673 | "auid=%u remove rule from list=%d res=%d", |
| 674 | loginuid, entry->rule.listnr, !err); |
| 675 | |
| 676 | audit_free_rule(entry); |
| 677 | break; |
| 678 | default: |
| 679 | return -EINVAL; |
| 680 | } |
| 681 | |
| 682 | return err; |
| 683 | } |
| 684 | |
| 685 | int audit_comparator(const u32 left, const u32 op, const u32 right) |
| 686 | { |
| 687 | switch (op) { |
| 688 | case AUDIT_EQUAL: |
| 689 | return (left == right); |
| 690 | case AUDIT_NOT_EQUAL: |
| 691 | return (left != right); |
| 692 | case AUDIT_LESS_THAN: |
| 693 | return (left < right); |
| 694 | case AUDIT_LESS_THAN_OR_EQUAL: |
| 695 | return (left <= right); |
| 696 | case AUDIT_GREATER_THAN: |
| 697 | return (left > right); |
| 698 | case AUDIT_GREATER_THAN_OR_EQUAL: |
| 699 | return (left >= right); |
| 700 | } |
| 701 | BUG(); |
| 702 | return 0; |
| 703 | } |
| 704 | |
| 705 | |
| 706 | |
| 707 | static int audit_filter_user_rules(struct netlink_skb_parms *cb, |
| 708 | struct audit_krule *rule, |
| 709 | enum audit_state *state) |
| 710 | { |
| 711 | int i; |
| 712 | |
| 713 | for (i = 0; i < rule->field_count; i++) { |
| 714 | struct audit_field *f = &rule->fields[i]; |
| 715 | int result = 0; |
| 716 | |
| 717 | switch (f->type) { |
| 718 | case AUDIT_PID: |
| 719 | result = audit_comparator(cb->creds.pid, f->op, f->val); |
| 720 | break; |
| 721 | case AUDIT_UID: |
| 722 | result = audit_comparator(cb->creds.uid, f->op, f->val); |
| 723 | break; |
| 724 | case AUDIT_GID: |
| 725 | result = audit_comparator(cb->creds.gid, f->op, f->val); |
| 726 | break; |
| 727 | case AUDIT_LOGINUID: |
| 728 | result = audit_comparator(cb->loginuid, f->op, f->val); |
| 729 | break; |
| 730 | } |
| 731 | |
| 732 | if (!result) |
| 733 | return 0; |
| 734 | } |
| 735 | switch (rule->action) { |
| 736 | case AUDIT_NEVER: *state = AUDIT_DISABLED; break; |
| 737 | case AUDIT_POSSIBLE: *state = AUDIT_BUILD_CONTEXT; break; |
| 738 | case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break; |
| 739 | } |
| 740 | return 1; |
| 741 | } |
| 742 | |
| 743 | int audit_filter_user(struct netlink_skb_parms *cb, int type) |
| 744 | { |
| 745 | struct audit_entry *e; |
| 746 | enum audit_state state; |
| 747 | int ret = 1; |
| 748 | |
| 749 | rcu_read_lock(); |
| 750 | list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) { |
| 751 | if (audit_filter_user_rules(cb, &e->rule, &state)) { |
| 752 | if (state == AUDIT_DISABLED) |
| 753 | ret = 0; |
| 754 | break; |
| 755 | } |
| 756 | } |
| 757 | rcu_read_unlock(); |
| 758 | |
| 759 | return ret; /* Audit by default */ |
| 760 | } |
| 761 | |
| 762 | int audit_filter_type(int type) |
| 763 | { |
| 764 | struct audit_entry *e; |
| 765 | int result = 0; |
| 766 | |
| 767 | rcu_read_lock(); |
| 768 | if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE])) |
| 769 | goto unlock_and_return; |
| 770 | |
| 771 | list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE], |
| 772 | list) { |
| 773 | int i; |
| 774 | for (i = 0; i < e->rule.field_count; i++) { |
| 775 | struct audit_field *f = &e->rule.fields[i]; |
| 776 | if (f->type == AUDIT_MSGTYPE) { |
| 777 | result = audit_comparator(type, f->op, f->val); |
| 778 | if (!result) |
| 779 | break; |
| 780 | } |
| 781 | } |
| 782 | if (result) |
| 783 | goto unlock_and_return; |
| 784 | } |
| 785 | unlock_and_return: |
| 786 | rcu_read_unlock(); |
| 787 | return result; |
| 788 | } |
| 789 | |
| 790 | /* Check to see if the rule contains any selinux fields. Returns 1 if there |
| 791 | are selinux fields specified in the rule, 0 otherwise. */ |
| 792 | static inline int audit_rule_has_selinux(struct audit_krule *rule) |
| 793 | { |
| 794 | int i; |
| 795 | |
| 796 | for (i = 0; i < rule->field_count; i++) { |
| 797 | struct audit_field *f = &rule->fields[i]; |
| 798 | switch (f->type) { |
| 799 | case AUDIT_SE_USER: |
| 800 | case AUDIT_SE_ROLE: |
| 801 | case AUDIT_SE_TYPE: |
| 802 | case AUDIT_SE_SEN: |
| 803 | case AUDIT_SE_CLR: |
| 804 | return 1; |
| 805 | } |
| 806 | } |
| 807 | |
| 808 | return 0; |
| 809 | } |
| 810 | |
| 811 | /* This function will re-initialize the se_rule field of all applicable rules. |
| 812 | * It will traverse the filter lists serarching for rules that contain selinux |
| 813 | * specific filter fields. When such a rule is found, it is copied, the |
| 814 | * selinux field is re-initialized, and the old rule is replaced with the |
| 815 | * updated rule. */ |
| 816 | int selinux_audit_rule_update(void) |
| 817 | { |
| 818 | struct audit_entry *entry, *n, *nentry; |
| 819 | int i, err = 0; |
| 820 | |
| 821 | /* audit_netlink_mutex synchronizes the writers */ |
| 822 | mutex_lock(&audit_netlink_mutex); |
| 823 | |
| 824 | for (i = 0; i < AUDIT_NR_FILTERS; i++) { |
| 825 | list_for_each_entry_safe(entry, n, &audit_filter_list[i], list) { |
| 826 | if (!audit_rule_has_selinux(&entry->rule)) |
| 827 | continue; |
| 828 | |
| 829 | nentry = audit_dupe_rule(&entry->rule); |
| 830 | if (unlikely(IS_ERR(nentry))) { |
| 831 | /* save the first error encountered for the |
| 832 | * return value */ |
| 833 | if (!err) |
| 834 | err = PTR_ERR(nentry); |
| 835 | audit_panic("error updating selinux filters"); |
| 836 | list_del_rcu(&entry->list); |
| 837 | } else { |
| 838 | list_replace_rcu(&entry->list, &nentry->list); |
| 839 | } |
| 840 | call_rcu(&entry->rcu, audit_free_rule_rcu); |
| 841 | } |
| 842 | } |
| 843 | |
| 844 | mutex_unlock(&audit_netlink_mutex); |
| 845 | |
| 846 | return err; |
| 847 | } |