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Fix rule eviction order for AUDIT_DIR

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If syscall removes the root of subtree being watched, we
definitely do not want the rules refering that subtree
to be destroyed without the syscall in question having
a chance to match them.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
2009-06-24 00:02:38 -04:00
parent 9d96098510
commit 916d75761c
4 changed files with 72 additions and 23 deletions
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56
kernel/audit_tree.c
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@@ -2,6 +2,7 @@
#include <linux/inotify.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/kthread.h>
struct audit_tree;
struct audit_chunk;
@@ -517,6 +518,8 @@ static void trim_marked(struct audit_tree *tree)
}
}
static void audit_schedule_prune(void);
/* called with audit_filter_mutex */
int audit_remove_tree_rule(struct audit_krule *rule)
{
@@ -822,10 +825,11 @@ int audit_tag_tree(char *old, char *new)
/*
* That gets run when evict_chunk() ends up needing to kill audit_tree.
* Runs from a separate thread, with audit_cmd_mutex held.
* Runs from a separate thread.
*/
void audit_prune_trees(void)
static int prune_tree_thread(void *unused)
{
mutex_lock(&audit_cmd_mutex);
mutex_lock(&audit_filter_mutex);
while (!list_empty(&prune_list)) {
@@ -842,6 +846,40 @@ void audit_prune_trees(void)
}
mutex_unlock(&audit_filter_mutex);
mutex_unlock(&audit_cmd_mutex);
return 0;
}
static void audit_schedule_prune(void)
{
kthread_run(prune_tree_thread, NULL, "audit_prune_tree");
}
/*
* ... and that one is done if evict_chunk() decides to delay until the end
* of syscall. Runs synchronously.
*/
void audit_kill_trees(struct list_head *list)
{
mutex_lock(&audit_cmd_mutex);
mutex_lock(&audit_filter_mutex);
while (!list_empty(list)) {
struct audit_tree *victim;
victim = list_entry(list->next, struct audit_tree, list);
kill_rules(victim);
list_del_init(&victim->list);
mutex_unlock(&audit_filter_mutex);
prune_one(victim);
mutex_lock(&audit_filter_mutex);
}
mutex_unlock(&audit_filter_mutex);
mutex_unlock(&audit_cmd_mutex);
}
/*
@@ -852,6 +890,8 @@ void audit_prune_trees(void)
static void evict_chunk(struct audit_chunk *chunk)
{
struct audit_tree *owner;
struct list_head *postponed = audit_killed_trees();
int need_prune = 0;
int n;
if (chunk->dead)
@@ -867,15 +907,21 @@ static void evict_chunk(struct audit_chunk *chunk)
owner->root = NULL;
list_del_init(&owner->same_root);
spin_unlock(&hash_lock);
kill_rules(owner);
list_move(&owner->list, &prune_list);
audit_schedule_prune();
if (!postponed) {
kill_rules(owner);
list_move(&owner->list, &prune_list);
need_prune = 1;
} else {
list_move(&owner->list, postponed);
}
spin_lock(&hash_lock);
}
list_del_rcu(&chunk->hash);
for (n = 0; n < chunk->count; n++)
list_del_init(&chunk->owners[n].list);
spin_unlock(&hash_lock);
if (need_prune)
audit_schedule_prune();
mutex_unlock(&audit_filter_mutex);
}