1 /* auditfilter.c -- filtering of audit events
3 * Copyright 2003-2004 Red Hat, Inc.
4 * Copyright 2005 Hewlett-Packard Development Company, L.P.
5 * Copyright 2005 IBM Corporation
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.
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.
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
22 #include <linux/kernel.h>
23 #include <linux/audit.h>
24 #include <linux/kthread.h>
25 #include <linux/mutex.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>
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.
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
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]),
68 DEFINE_MUTEX(audit_filter_mutex);
70 static inline void audit_free_rule(struct audit_entry *e)
73 struct audit_krule *erule = &e->rule;
75 /* some rules don't have associated watches */
77 audit_put_watch(erule->watch);
79 for (i = 0; i < erule->field_count; i++) {
80 struct audit_field *f = &erule->fields[i];
82 security_audit_rule_free(f->lsm_rule);
85 kfree(erule->filterkey);
89 void audit_free_rule_rcu(struct rcu_head *head)
91 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
95 /* Initialize an audit filterlist entry. */
96 static inline struct audit_entry *audit_init_entry(u32 field_count)
98 struct audit_entry *entry;
99 struct audit_field *fields;
101 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
102 if (unlikely(!entry))
105 fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL);
106 if (unlikely(!fields)) {
110 entry->rule.fields = fields;
115 /* Unpack a filter field's string representation from user-space
117 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
121 if (!*bufp || (len == 0) || (len > *remain))
122 return ERR_PTR(-EINVAL);
124 /* Of the currently implemented string fields, PATH_MAX
125 * defines the longest valid length.
128 return ERR_PTR(-ENAMETOOLONG);
130 str = kmalloc(len + 1, GFP_KERNEL);
132 return ERR_PTR(-ENOMEM);
134 memcpy(str, *bufp, len);
142 /* Translate an inode field to kernel respresentation. */
143 static inline int audit_to_inode(struct audit_krule *krule,
144 struct audit_field *f)
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))
155 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
157 int __init audit_register_class(int class, unsigned *list)
159 __u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL);
162 while (*list != ~0U) {
163 unsigned n = *list++;
164 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
168 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
170 if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
178 int audit_match_class(int class, unsigned syscall)
180 if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
182 if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
184 return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
187 #ifdef CONFIG_AUDITSYSCALL
188 static inline int audit_match_class_bits(int class, u32 *mask)
192 if (classes[class]) {
193 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
194 if (mask[i] & classes[class][i])
200 static int audit_match_signal(struct audit_entry *entry)
202 struct audit_field *arch = entry->rule.arch_f;
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,
209 audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
213 switch(audit_classify_arch(arch->val)) {
215 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
217 case 1: /* 32bit on biarch */
218 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
226 /* Common user-space to kernel rule translation. */
227 static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
230 struct audit_entry *entry;
234 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
238 #ifdef CONFIG_AUDITSYSCALL
239 case AUDIT_FILTER_ENTRY:
240 if (rule->action == AUDIT_ALWAYS)
242 case AUDIT_FILTER_EXIT:
243 case AUDIT_FILTER_TASK:
245 case AUDIT_FILTER_USER:
246 case AUDIT_FILTER_TYPE:
249 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
250 printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
253 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
255 if (rule->field_count > AUDIT_MAX_FIELDS)
259 entry = audit_init_entry(rule->field_count);
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;
268 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
269 entry->rule.mask[i] = rule->mask[i];
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)];
276 if (!(*p & AUDIT_BIT(bit)))
278 *p &= ~AUDIT_BIT(bit);
282 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
283 entry->rule.mask[j] |= class[j];
293 static u32 audit_ops[] =
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,
305 static u32 audit_to_op(u32 op)
308 for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
313 /* check if an audit field is valid */
314 static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
318 if (entry->rule.listnr != AUDIT_FILTER_TYPE &&
319 entry->rule.listnr != AUDIT_FILTER_USER)
346 /* bit ops are only useful on syscall args */
347 if (f->op == Audit_bitmask || f->op == Audit_bittest)
354 case AUDIT_SUBJ_USER:
355 case AUDIT_SUBJ_ROLE:
356 case AUDIT_SUBJ_TYPE:
362 case AUDIT_OBJ_LEV_LOW:
363 case AUDIT_OBJ_LEV_HIGH:
366 case AUDIT_FILTERKEY:
368 /* arch is only allowed to be = or != */
370 if (f->op != Audit_not_equal && f->op != Audit_equal)
378 if (f->val & ~S_IFMT)
381 case AUDIT_FIELD_COMPARE:
382 if (f->val > AUDIT_MAX_FIELD_COMPARE)
389 /* Translate struct audit_rule_data to kernel's rule respresentation. */
390 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
394 struct audit_entry *entry;
396 size_t remain = datasz - sizeof(struct audit_rule_data);
400 entry = audit_to_entry_common((struct audit_rule *)data);
405 entry->rule.vers_ops = 2;
406 for (i = 0; i < data->field_count; i++) {
407 struct audit_field *f = &entry->rule.fields[i];
411 f->op = audit_to_op(data->fieldflags[i]);
412 if (f->op == Audit_bad)
415 f->type = data->fields[i];
416 f->val = data->values[i];
417 f->uid = INVALID_UID;
418 f->gid = INVALID_GID;
422 err = audit_field_valid(entry, f);
434 f->uid = make_kuid(current_user_ns(), f->val);
435 if (!uid_valid(f->uid))
443 f->gid = make_kgid(current_user_ns(), f->val);
444 if (!gid_valid(f->gid))
448 entry->rule.arch_f = f;
450 case AUDIT_SUBJ_USER:
451 case AUDIT_SUBJ_ROLE:
452 case AUDIT_SUBJ_TYPE:
458 case AUDIT_OBJ_LEV_LOW:
459 case AUDIT_OBJ_LEV_HIGH:
460 str = audit_unpack_string(&bufp, &remain, f->val);
463 entry->rule.buflen += f->val;
465 err = security_audit_rule_init(f->type, f->op, str,
466 (void **)&f->lsm_rule);
467 /* Keep currently invalid fields around in case they
468 * become valid after a policy reload. */
469 if (err == -EINVAL) {
470 printk(KERN_WARNING "audit rule for LSM "
471 "\'%s\' is invalid\n", str);
481 str = audit_unpack_string(&bufp, &remain, f->val);
484 entry->rule.buflen += f->val;
486 err = audit_to_watch(&entry->rule, str, f->val, f->op);
493 str = audit_unpack_string(&bufp, &remain, f->val);
496 entry->rule.buflen += f->val;
498 err = audit_make_tree(&entry->rule, str, f->op);
504 err = audit_to_inode(&entry->rule, f);
508 case AUDIT_FILTERKEY:
509 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
511 str = audit_unpack_string(&bufp, &remain, f->val);
514 entry->rule.buflen += f->val;
515 entry->rule.filterkey = str;
520 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
521 entry->rule.inode_f = NULL;
527 audit_free_rule(entry);
531 /* Pack a filter field's string representation into data block. */
532 static inline size_t audit_pack_string(void **bufp, const char *str)
534 size_t len = strlen(str);
536 memcpy(*bufp, str, len);
542 /* Translate kernel rule respresentation to struct audit_rule_data. */
543 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
545 struct audit_rule_data *data;
549 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
552 memset(data, 0, sizeof(*data));
554 data->flags = krule->flags | krule->listnr;
555 data->action = krule->action;
556 data->field_count = krule->field_count;
558 for (i = 0; i < data->field_count; i++) {
559 struct audit_field *f = &krule->fields[i];
561 data->fields[i] = f->type;
562 data->fieldflags[i] = audit_ops[f->op];
564 case AUDIT_SUBJ_USER:
565 case AUDIT_SUBJ_ROLE:
566 case AUDIT_SUBJ_TYPE:
572 case AUDIT_OBJ_LEV_LOW:
573 case AUDIT_OBJ_LEV_HIGH:
574 data->buflen += data->values[i] =
575 audit_pack_string(&bufp, f->lsm_str);
578 data->buflen += data->values[i] =
579 audit_pack_string(&bufp,
580 audit_watch_path(krule->watch));
583 data->buflen += data->values[i] =
584 audit_pack_string(&bufp,
585 audit_tree_path(krule->tree));
587 case AUDIT_FILTERKEY:
588 data->buflen += data->values[i] =
589 audit_pack_string(&bufp, krule->filterkey);
592 data->values[i] = f->val;
595 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
600 /* Compare two rules in kernel format. Considered success if rules
602 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
606 if (a->flags != b->flags ||
607 a->listnr != b->listnr ||
608 a->action != b->action ||
609 a->field_count != b->field_count)
612 for (i = 0; i < a->field_count; i++) {
613 if (a->fields[i].type != b->fields[i].type ||
614 a->fields[i].op != b->fields[i].op)
617 switch(a->fields[i].type) {
618 case AUDIT_SUBJ_USER:
619 case AUDIT_SUBJ_ROLE:
620 case AUDIT_SUBJ_TYPE:
626 case AUDIT_OBJ_LEV_LOW:
627 case AUDIT_OBJ_LEV_HIGH:
628 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
632 if (strcmp(audit_watch_path(a->watch),
633 audit_watch_path(b->watch)))
637 if (strcmp(audit_tree_path(a->tree),
638 audit_tree_path(b->tree)))
641 case AUDIT_FILTERKEY:
642 /* both filterkeys exist based on above type compare */
643 if (strcmp(a->filterkey, b->filterkey))
652 if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
660 if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
664 if (a->fields[i].val != b->fields[i].val)
669 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
670 if (a->mask[i] != b->mask[i])
676 /* Duplicate LSM field information. The lsm_rule is opaque, so must be
678 static inline int audit_dupe_lsm_field(struct audit_field *df,
679 struct audit_field *sf)
684 /* our own copy of lsm_str */
685 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
686 if (unlikely(!lsm_str))
688 df->lsm_str = lsm_str;
690 /* our own (refreshed) copy of lsm_rule */
691 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
692 (void **)&df->lsm_rule);
693 /* Keep currently invalid fields around in case they
694 * become valid after a policy reload. */
695 if (ret == -EINVAL) {
696 printk(KERN_WARNING "audit rule for LSM \'%s\' is "
697 "invalid\n", df->lsm_str);
704 /* Duplicate an audit rule. This will be a deep copy with the exception
705 * of the watch - that pointer is carried over. The LSM specific fields
706 * will be updated in the copy. The point is to be able to replace the old
707 * rule with the new rule in the filterlist, then free the old rule.
708 * The rlist element is undefined; list manipulations are handled apart from
709 * the initial copy. */
710 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
712 u32 fcount = old->field_count;
713 struct audit_entry *entry;
714 struct audit_krule *new;
718 entry = audit_init_entry(fcount);
719 if (unlikely(!entry))
720 return ERR_PTR(-ENOMEM);
723 new->vers_ops = old->vers_ops;
724 new->flags = old->flags;
725 new->listnr = old->listnr;
726 new->action = old->action;
727 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
728 new->mask[i] = old->mask[i];
729 new->prio = old->prio;
730 new->buflen = old->buflen;
731 new->inode_f = old->inode_f;
732 new->field_count = old->field_count;
735 * note that we are OK with not refcounting here; audit_match_tree()
736 * never dereferences tree and we can't get false positives there
737 * since we'd have to have rule gone from the list *and* removed
738 * before the chunks found by lookup had been allocated, i.e. before
739 * the beginning of list scan.
741 new->tree = old->tree;
742 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
744 /* deep copy this information, updating the lsm_rule fields, because
745 * the originals will all be freed when the old rule is freed. */
746 for (i = 0; i < fcount; i++) {
747 switch (new->fields[i].type) {
748 case AUDIT_SUBJ_USER:
749 case AUDIT_SUBJ_ROLE:
750 case AUDIT_SUBJ_TYPE:
756 case AUDIT_OBJ_LEV_LOW:
757 case AUDIT_OBJ_LEV_HIGH:
758 err = audit_dupe_lsm_field(&new->fields[i],
761 case AUDIT_FILTERKEY:
762 fk = kstrdup(old->filterkey, GFP_KERNEL);
769 audit_free_rule(entry);
775 audit_get_watch(old->watch);
776 new->watch = old->watch;
782 /* Find an existing audit rule.
783 * Caller must hold audit_filter_mutex to prevent stale rule data. */
784 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
785 struct list_head **p)
787 struct audit_entry *e, *found = NULL;
788 struct list_head *list;
791 if (entry->rule.inode_f) {
792 h = audit_hash_ino(entry->rule.inode_f->val);
793 *p = list = &audit_inode_hash[h];
794 } else if (entry->rule.watch) {
795 /* we don't know the inode number, so must walk entire hash */
796 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
797 list = &audit_inode_hash[h];
798 list_for_each_entry(e, list, list)
799 if (!audit_compare_rule(&entry->rule, &e->rule)) {
806 *p = list = &audit_filter_list[entry->rule.listnr];
809 list_for_each_entry(e, list, list)
810 if (!audit_compare_rule(&entry->rule, &e->rule)) {
819 static u64 prio_low = ~0ULL/2;
820 static u64 prio_high = ~0ULL/2 - 1;
822 /* Add rule to given filterlist if not a duplicate. */
823 static inline int audit_add_rule(struct audit_entry *entry)
825 struct audit_entry *e;
826 struct audit_watch *watch = entry->rule.watch;
827 struct audit_tree *tree = entry->rule.tree;
828 struct list_head *list;
830 #ifdef CONFIG_AUDITSYSCALL
833 /* If either of these, don't count towards total */
834 if (entry->rule.listnr == AUDIT_FILTER_USER ||
835 entry->rule.listnr == AUDIT_FILTER_TYPE)
839 mutex_lock(&audit_filter_mutex);
840 e = audit_find_rule(entry, &list);
842 mutex_unlock(&audit_filter_mutex);
844 /* normally audit_add_tree_rule() will free it on failure */
846 audit_put_tree(tree);
851 /* audit_filter_mutex is dropped and re-taken during this call */
852 err = audit_add_watch(&entry->rule, &list);
854 mutex_unlock(&audit_filter_mutex);
859 err = audit_add_tree_rule(&entry->rule);
861 mutex_unlock(&audit_filter_mutex);
866 entry->rule.prio = ~0ULL;
867 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
868 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
869 entry->rule.prio = ++prio_high;
871 entry->rule.prio = --prio_low;
874 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
875 list_add(&entry->rule.list,
876 &audit_rules_list[entry->rule.listnr]);
877 list_add_rcu(&entry->list, list);
878 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
880 list_add_tail(&entry->rule.list,
881 &audit_rules_list[entry->rule.listnr]);
882 list_add_tail_rcu(&entry->list, list);
884 #ifdef CONFIG_AUDITSYSCALL
888 if (!audit_match_signal(entry))
891 mutex_unlock(&audit_filter_mutex);
897 audit_put_watch(watch); /* tmp watch, matches initial get */
901 /* Remove an existing rule from filterlist. */
902 static inline int audit_del_rule(struct audit_entry *entry)
904 struct audit_entry *e;
905 struct audit_watch *watch = entry->rule.watch;
906 struct audit_tree *tree = entry->rule.tree;
907 struct list_head *list;
909 #ifdef CONFIG_AUDITSYSCALL
912 /* If either of these, don't count towards total */
913 if (entry->rule.listnr == AUDIT_FILTER_USER ||
914 entry->rule.listnr == AUDIT_FILTER_TYPE)
918 mutex_lock(&audit_filter_mutex);
919 e = audit_find_rule(entry, &list);
921 mutex_unlock(&audit_filter_mutex);
927 audit_remove_watch_rule(&e->rule);
930 audit_remove_tree_rule(&e->rule);
932 list_del_rcu(&e->list);
933 list_del(&e->rule.list);
934 call_rcu(&e->rcu, audit_free_rule_rcu);
936 #ifdef CONFIG_AUDITSYSCALL
940 if (!audit_match_signal(entry))
943 mutex_unlock(&audit_filter_mutex);
947 audit_put_watch(watch); /* match initial get */
949 audit_put_tree(tree); /* that's the temporary one */
954 /* List rules using struct audit_rule_data. */
955 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
958 struct audit_krule *r;
961 /* This is a blocking read, so use audit_filter_mutex instead of rcu
962 * iterator to sync with list writers. */
963 for (i=0; i<AUDIT_NR_FILTERS; i++) {
964 list_for_each_entry(r, &audit_rules_list[i], list) {
965 struct audit_rule_data *data;
967 data = audit_krule_to_data(r);
970 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
971 data, sizeof(*data) + data->buflen);
973 skb_queue_tail(q, skb);
977 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
979 skb_queue_tail(q, skb);
982 /* Log rule additions and removals */
983 static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
985 struct audit_buffer *ab;
986 uid_t loginuid = from_kuid(&init_user_ns, audit_get_loginuid(current));
987 u32 sessionid = audit_get_sessionid(current);
993 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
996 audit_log_format(ab, "auid=%u ses=%u" ,loginuid, sessionid);
997 security_task_getsecid(current, &sid);
1001 if (security_secid_to_secctx(sid, &ctx, &len))
1002 audit_log_format(ab, " ssid=%u", sid);
1004 audit_log_format(ab, " subj=%s", ctx);
1005 security_release_secctx(ctx, len);
1008 audit_log_format(ab, " op=");
1009 audit_log_string(ab, action);
1010 audit_log_key(ab, rule->filterkey);
1011 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1016 * audit_receive_filter - apply all rules to the specified message type
1017 * @type: audit message type
1018 * @pid: target pid for netlink audit messages
1019 * @seq: netlink audit message sequence (serial) number
1020 * @data: payload data
1021 * @datasz: size of payload data
1022 * @loginuid: loginuid of sender
1023 * @sessionid: sessionid for netlink audit message
1024 * @sid: SE Linux Security ID of sender
1026 int audit_receive_filter(int type, int pid, int seq, void *data, size_t datasz)
1028 struct task_struct *tsk;
1029 struct audit_netlink_list *dest;
1031 struct audit_entry *entry;
1034 case AUDIT_LIST_RULES:
1035 /* We can't just spew out the rules here because we might fill
1036 * the available socket buffer space and deadlock waiting for
1037 * auditctl to read from it... which isn't ever going to
1038 * happen if we're actually running in the context of auditctl
1039 * trying to _send_ the stuff */
1041 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1045 skb_queue_head_init(&dest->q);
1047 mutex_lock(&audit_filter_mutex);
1048 audit_list_rules(pid, seq, &dest->q);
1049 mutex_unlock(&audit_filter_mutex);
1051 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1053 skb_queue_purge(&dest->q);
1058 case AUDIT_ADD_RULE:
1059 entry = audit_data_to_entry(data, datasz);
1061 return PTR_ERR(entry);
1063 err = audit_add_rule(entry);
1064 audit_log_rule_change("add rule", &entry->rule, !err);
1066 audit_free_rule(entry);
1068 case AUDIT_DEL_RULE:
1069 entry = audit_data_to_entry(data, datasz);
1071 return PTR_ERR(entry);
1073 err = audit_del_rule(entry);
1074 audit_log_rule_change("remove rule", &entry->rule, !err);
1075 audit_free_rule(entry);
1084 int audit_comparator(u32 left, u32 op, u32 right)
1088 return (left == right);
1089 case Audit_not_equal:
1090 return (left != right);
1092 return (left < right);
1094 return (left <= right);
1096 return (left > right);
1098 return (left >= right);
1100 return (left & right);
1102 return ((left & right) == right);
1109 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1113 return uid_eq(left, right);
1114 case Audit_not_equal:
1115 return !uid_eq(left, right);
1117 return uid_lt(left, right);
1119 return uid_lte(left, right);
1121 return uid_gt(left, right);
1123 return uid_gte(left, right);
1132 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1136 return gid_eq(left, right);
1137 case Audit_not_equal:
1138 return !gid_eq(left, right);
1140 return gid_lt(left, right);
1142 return gid_lte(left, right);
1144 return gid_gt(left, right);
1146 return gid_gte(left, right);
1156 * parent_len - find the length of the parent portion of a pathname
1157 * @path: pathname of which to determine length
1159 int parent_len(const char *path)
1164 plen = strlen(path);
1169 /* disregard trailing slashes */
1170 p = path + plen - 1;
1171 while ((*p == '/') && (p > path))
1174 /* walk backward until we find the next slash or hit beginning */
1175 while ((*p != '/') && (p > path))
1178 /* did we find a slash? Then increment to include it in path */
1186 * audit_compare_dname_path - compare given dentry name with last component in
1187 * given path. Return of 0 indicates a match.
1188 * @dname: dentry name that we're comparing
1189 * @path: full pathname that we're comparing
1190 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
1191 * here indicates that we must compute this value.
1193 int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1198 dlen = strlen(dname);
1199 pathlen = strlen(path);
1203 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1204 if (pathlen - parentlen != dlen)
1207 p = path + parentlen;
1209 return strncmp(p, dname, dlen);
1212 static int audit_filter_user_rules(struct audit_krule *rule, int type,
1213 enum audit_state *state)
1217 for (i = 0; i < rule->field_count; i++) {
1218 struct audit_field *f = &rule->fields[i];
1224 result = audit_comparator(task_pid_vnr(current), f->op, f->val);
1227 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1230 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1232 case AUDIT_LOGINUID:
1233 result = audit_uid_comparator(audit_get_loginuid(current),
1237 result = audit_comparator(type, f->op, f->val);
1239 case AUDIT_SUBJ_USER:
1240 case AUDIT_SUBJ_ROLE:
1241 case AUDIT_SUBJ_TYPE:
1242 case AUDIT_SUBJ_SEN:
1243 case AUDIT_SUBJ_CLR:
1245 security_task_getsecid(current, &sid);
1246 result = security_audit_rule_match(sid,
1258 switch (rule->action) {
1259 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1260 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1265 int audit_filter_user(int type)
1267 enum audit_state state = AUDIT_DISABLED;
1268 struct audit_entry *e;
1272 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1273 if (audit_filter_user_rules(&e->rule, type, &state)) {
1274 if (state == AUDIT_DISABLED)
1281 return ret; /* Audit by default */
1284 int audit_filter_type(int type)
1286 struct audit_entry *e;
1290 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1291 goto unlock_and_return;
1293 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1296 for (i = 0; i < e->rule.field_count; i++) {
1297 struct audit_field *f = &e->rule.fields[i];
1298 if (f->type == AUDIT_MSGTYPE) {
1299 result = audit_comparator(type, f->op, f->val);
1305 goto unlock_and_return;
1312 static int update_lsm_rule(struct audit_krule *r)
1314 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1315 struct audit_entry *nentry;
1318 if (!security_audit_rule_known(r))
1321 nentry = audit_dupe_rule(r);
1322 if (IS_ERR(nentry)) {
1323 /* save the first error encountered for the
1325 err = PTR_ERR(nentry);
1326 audit_panic("error updating LSM filters");
1328 list_del(&r->rlist);
1329 list_del_rcu(&entry->list);
1332 if (r->watch || r->tree)
1333 list_replace_init(&r->rlist, &nentry->rule.rlist);
1334 list_replace_rcu(&entry->list, &nentry->list);
1335 list_replace(&r->list, &nentry->rule.list);
1337 call_rcu(&entry->rcu, audit_free_rule_rcu);
1342 /* This function will re-initialize the lsm_rule field of all applicable rules.
1343 * It will traverse the filter lists serarching for rules that contain LSM
1344 * specific filter fields. When such a rule is found, it is copied, the
1345 * LSM field is re-initialized, and the old rule is replaced with the
1347 int audit_update_lsm_rules(void)
1349 struct audit_krule *r, *n;
1352 /* audit_filter_mutex synchronizes the writers */
1353 mutex_lock(&audit_filter_mutex);
1355 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1356 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1357 int res = update_lsm_rule(r);
1362 mutex_unlock(&audit_filter_mutex);