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authorAl Viro <viro@zeniv.linux.org.uk>2009-06-24 00:02:38 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2009-06-24 00:02:38 -0400
commit916d75761c971b6e630a26bd4ba472e90ac9a4b9 (patch)
tree3a4b18d0d29c1d12f64fefbb2bc5559813a686f7 /kernel
parent9d9609851003ebed15957f0f2ce18492739ee124 (diff)
downloadlinux-2.6.34-ux500-916d75761c971b6e630a26bd4ba472e90ac9a4b9.tar.gz
Fix rule eviction order for AUDIT_DIR
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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/audit.c17
-rw-r--r--kernel/audit.h7
-rw-r--r--kernel/audit_tree.c56
-rw-r--r--kernel/auditsc.c15
4 files changed, 72 insertions, 23 deletions
diff --git a/kernel/audit.c b/kernel/audit.c
index 6194c50e203..defc2e6f1e3 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -133,7 +133,7 @@ static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
/* Serialize requests from userspace. */
-static DEFINE_MUTEX(audit_cmd_mutex);
+DEFINE_MUTEX(audit_cmd_mutex);
/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
* audit records. Since printk uses a 1024 byte buffer, this buffer
@@ -505,21 +505,6 @@ int audit_send_list(void *_dest)
return 0;
}
-#ifdef CONFIG_AUDIT_TREE
-static int prune_tree_thread(void *unused)
-{
- mutex_lock(&audit_cmd_mutex);
- audit_prune_trees();
- mutex_unlock(&audit_cmd_mutex);
- return 0;
-}
-
-void audit_schedule_prune(void)
-{
- kthread_run(prune_tree_thread, NULL, "audit_prune_tree");
-}
-#endif
-
struct sk_buff *audit_make_reply(int pid, int seq, int type, int done,
int multi, void *payload, int size)
{
diff --git a/kernel/audit.h b/kernel/audit.h
index bb1c0d69db0..208687be4f3 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -128,10 +128,9 @@ extern int audit_add_tree_rule(struct audit_krule *);
extern int audit_remove_tree_rule(struct audit_krule *);
extern void audit_trim_trees(void);
extern int audit_tag_tree(char *old, char *new);
-extern void audit_schedule_prune(void);
-extern void audit_prune_trees(void);
extern const char *audit_tree_path(struct audit_tree *);
extern void audit_put_tree(struct audit_tree *);
+extern void audit_kill_trees(struct list_head *);
#else
#define audit_remove_tree_rule(rule) BUG()
#define audit_add_tree_rule(rule) -EINVAL
@@ -140,6 +139,7 @@ extern void audit_put_tree(struct audit_tree *);
#define audit_put_tree(tree) (void)0
#define audit_tag_tree(old, new) -EINVAL
#define audit_tree_path(rule) "" /* never called */
+#define audit_kill_trees(list) BUG()
#endif
extern char *audit_unpack_string(void **, size_t *, size_t);
@@ -158,7 +158,10 @@ static inline int audit_signal_info(int sig, struct task_struct *t)
return 0;
}
extern void audit_filter_inodes(struct task_struct *, struct audit_context *);
+extern struct list_head *audit_killed_trees(void);
#else
#define audit_signal_info(s,t) AUDIT_DISABLED
#define audit_filter_inodes(t,c) AUDIT_DISABLED
#endif
+
+extern struct mutex audit_cmd_mutex;
diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
index 3ff0731284a..2451dc6f328 100644
--- a/kernel/audit_tree.c
+++ b/kernel/audit_tree.c
@@ -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);
}
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 2de95d1582b..68d3c6a0ecd 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -199,6 +199,7 @@ struct audit_context {
struct audit_tree_refs *trees, *first_trees;
int tree_count;
+ struct list_head killed_trees;
int type;
union {
@@ -853,6 +854,7 @@ static inline struct audit_context *audit_alloc_context(enum audit_state state)
if (!(context = kmalloc(sizeof(*context), GFP_KERNEL)))
return NULL;
audit_zero_context(context, state);
+ INIT_LIST_HEAD(&context->killed_trees);
return context;
}
@@ -1545,6 +1547,8 @@ void audit_free(struct task_struct *tsk)
/* that can happen only if we are called from do_exit() */
if (context->in_syscall && context->current_state == AUDIT_RECORD_CONTEXT)
audit_log_exit(context, tsk);
+ if (!list_empty(&context->killed_trees))
+ audit_kill_trees(&context->killed_trees);
audit_free_context(context);
}
@@ -1688,6 +1692,9 @@ void audit_syscall_exit(int valid, long return_code)
context->in_syscall = 0;
context->prio = context->state == AUDIT_RECORD_CONTEXT ? ~0ULL : 0;
+ if (!list_empty(&context->killed_trees))
+ audit_kill_trees(&context->killed_trees);
+
if (context->previous) {
struct audit_context *new_context = context->previous;
context->previous = NULL;
@@ -2521,3 +2528,11 @@ void audit_core_dumps(long signr)
audit_log_format(ab, " sig=%ld", signr);
audit_log_end(ab);
}
+
+struct list_head *audit_killed_trees(void)
+{
+ struct audit_context *ctx = current->audit_context;
+ if (likely(!ctx || !ctx->in_syscall))
+ return NULL;
+ return &ctx->killed_trees;
+}