- /* Public API */
-/* There are three lists of rules -- one to search at task creation
- * time, one to search at syscall entry time, and another to search at
- * syscall exit time. */
-static struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
- LIST_HEAD_INIT(audit_filter_list[0]),
- LIST_HEAD_INIT(audit_filter_list[1]),
- LIST_HEAD_INIT(audit_filter_list[2]),
- LIST_HEAD_INIT(audit_filter_list[3]),
- LIST_HEAD_INIT(audit_filter_list[4]),
-#if AUDIT_NR_FILTERS != 5
-#error Fix audit_filter_list initialiser
-#endif
-};
-
-struct audit_entry {
- struct list_head list;
- struct rcu_head rcu;
- struct audit_rule rule;
-};
-
-extern int audit_pid;
-
-/* Copy rule from user-space to kernel-space. Called from
- * audit_add_rule during AUDIT_ADD. */
-static inline int audit_copy_rule(struct audit_rule *d, struct audit_rule *s)
-{
- int i;
-
- if (s->action != AUDIT_NEVER
- && s->action != AUDIT_POSSIBLE
- && s->action != AUDIT_ALWAYS)
- return -1;
- if (s->field_count < 0 || s->field_count > AUDIT_MAX_FIELDS)
- return -1;
- if ((s->flags & ~AUDIT_FILTER_PREPEND) >= AUDIT_NR_FILTERS)
- return -1;
-
- d->flags = s->flags;
- d->action = s->action;
- d->field_count = s->field_count;
- for (i = 0; i < d->field_count; i++) {
- d->fields[i] = s->fields[i];
- d->values[i] = s->values[i];
- }
- for (i = 0; i < AUDIT_BITMASK_SIZE; i++) d->mask[i] = s->mask[i];
- return 0;
-}
-
-/* Check to see if two rules are identical. It is called from
- * audit_add_rule during AUDIT_ADD and
- * audit_del_rule during AUDIT_DEL. */
-static inline int audit_compare_rule(struct audit_rule *a, struct audit_rule *b)
-{
- int i;
-
- if (a->flags != b->flags)
- return 1;
-
- if (a->action != b->action)
- return 1;
-
- if (a->field_count != b->field_count)
- return 1;
-
- for (i = 0; i < a->field_count; i++) {
- if (a->fields[i] != b->fields[i]
- || a->values[i] != b->values[i])
- return 1;
- }
-
- for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
- if (a->mask[i] != b->mask[i])
- return 1;
-
- return 0;
-}
-
-/* Note that audit_add_rule and audit_del_rule are called via
- * audit_receive() in audit.c, and are protected by
- * audit_netlink_sem. */
-static inline int audit_add_rule(struct audit_rule *rule,
- struct list_head *list)
-{
- struct audit_entry *entry;
-
- /* Do not use the _rcu iterator here, since this is the only
- * addition routine. */
- list_for_each_entry(entry, list, list) {
- if (!audit_compare_rule(rule, &entry->rule)) {
- return -EEXIST;
- }
- }
-
- if (!(entry = kmalloc(sizeof(*entry), GFP_KERNEL)))
- return -ENOMEM;
- if (audit_copy_rule(&entry->rule, rule)) {
- kfree(entry);
- return -EINVAL;
- }
-
- if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
- entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
- list_add_rcu(&entry->list, list);
- } else {
- list_add_tail_rcu(&entry->list, list);
- }
-
- return 0;
-}
-
-static inline void audit_free_rule(struct rcu_head *head)
-{
- struct audit_entry *e = container_of(head, struct audit_entry, rcu);
- kfree(e);
-}
-
-/* Note that audit_add_rule and audit_del_rule are called via
- * audit_receive() in audit.c, and are protected by
- * audit_netlink_sem. */
-static inline int audit_del_rule(struct audit_rule *rule,
- struct list_head *list)
-{
- struct audit_entry *e;
-
- /* Do not use the _rcu iterator here, since this is the only
- * deletion routine. */
- list_for_each_entry(e, list, list) {
- if (!audit_compare_rule(rule, &e->rule)) {
- list_del_rcu(&e->list);
- call_rcu(&e->rcu, audit_free_rule);
- return 0;
- }
- }
- return -ENOENT; /* No matching rule */
-}
-
-static int audit_list_rules(void *_dest)
-{
- int pid, seq;
- int *dest = _dest;
- struct audit_entry *entry;
- int i;
-
- pid = dest[0];
- seq = dest[1];
- kfree(dest);
-
- down(&audit_netlink_sem);
-
- /* The *_rcu iterators not needed here because we are
- always called with audit_netlink_sem held. */
- for (i=0; i<AUDIT_NR_FILTERS; i++) {
- list_for_each_entry(entry, &audit_filter_list[i], list)
- audit_send_reply(pid, seq, AUDIT_LIST, 0, 1,
- &entry->rule, sizeof(entry->rule));
- }
- audit_send_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
-
- up(&audit_netlink_sem);
- return 0;
-}
-
-int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
- uid_t loginuid)
-{
- struct task_struct *tsk;
- int *dest;
- int err = 0;
- unsigned listnr;
-
- switch (type) {
- case AUDIT_LIST:
- /* We can't just spew out the rules here because we might fill
- * the available socket buffer space and deadlock waiting for
- * auditctl to read from it... which isn't ever going to
- * happen if we're actually running in the context of auditctl
- * trying to _send_ the stuff */
-
- dest = kmalloc(2 * sizeof(int), GFP_KERNEL);
- if (!dest)
- return -ENOMEM;
- dest[0] = pid;
- dest[1] = seq;
-
- tsk = kthread_run(audit_list_rules, dest, "audit_list_rules");
- if (IS_ERR(tsk)) {
- kfree(dest);
- err = PTR_ERR(tsk);
- }
- break;
- case AUDIT_ADD:
- listnr =((struct audit_rule *)data)->flags & ~AUDIT_FILTER_PREPEND;
- if (listnr >= AUDIT_NR_FILTERS)
- return -EINVAL;
-
- err = audit_add_rule(data, &audit_filter_list[listnr]);
- if (!err)
- audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
- "auid=%u added an audit rule\n", loginuid);
- break;
- case AUDIT_DEL:
- listnr =((struct audit_rule *)data)->flags & ~AUDIT_FILTER_PREPEND;
- if (listnr >= AUDIT_NR_FILTERS)
- return -EINVAL;
-
- err = audit_del_rule(data, &audit_filter_list[listnr]);
- if (!err)
- audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
- "auid=%u removed an audit rule\n", loginuid);
- break;
- default:
- return -EINVAL;
- }
-
- return err;
-}