Commit 916d7576 authored by Al Viro's avatar Al Viro

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: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 9d960985
......@@ -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)
{
......
......@@ -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;
......@@ -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);
}
......
......@@ -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;
}
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