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authorMiklos Szeredi <mszeredi@suse.cz>2012-08-15 12:55:22 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-09-14 10:00:18 -0700
commit47b8bbd6c2aab324fa57f004f89abb40bb8478be (patch)
tree537905711303fcaad859a91e7351886ff792fd15
parentae2a5dd19bccd4fa52ee6bb78ad88b960d92c606 (diff)
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audit: fix refcounting in audit-tree
commit a2140fc0cb0325bb6384e788edd27b9a568714e2 upstream. Refcounting of fsnotify_mark in audit tree is broken. E.g: refcount create_chunk alloc_chunk 1 fsnotify_add_mark 2 untag_chunk fsnotify_get_mark 3 fsnotify_destroy_mark audit_tree_freeing_mark 2 fsnotify_put_mark 1 fsnotify_put_mark 0 via destroy_list fsnotify_mark_destroy -1 This was reported by various people as triggering Oops when stopping auditd. We could just remove the put_mark from audit_tree_freeing_mark() but that would break freeing via inode destruction. So this patch simply omits a put_mark after calling destroy_mark or adds a get_mark before. The additional get_mark is necessary where there's no other put_mark after fsnotify_destroy_mark() since it assumes that the caller is holding a reference (or the inode is keeping the mark pinned, not the case here AFAICS). Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reported-by: Valentin Avram <aval13@gmail.com> Reported-by: Peter Moody <pmoody@google.com> Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--kernel/audit_tree.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
index d52d247b07a..31fdc480b5c 100644
--- a/kernel/audit_tree.c
+++ b/kernel/audit_tree.c
@@ -250,7 +250,6 @@ static void untag_chunk(struct node *p)
spin_unlock(&hash_lock);
spin_unlock(&entry->lock);
fsnotify_destroy_mark(entry);
- fsnotify_put_mark(entry);
goto out;
}
@@ -293,7 +292,6 @@ static void untag_chunk(struct node *p)
spin_unlock(&hash_lock);
spin_unlock(&entry->lock);
fsnotify_destroy_mark(entry);
- fsnotify_put_mark(entry);
goto out;
Fallback:
@@ -332,6 +330,7 @@ static int create_chunk(struct inode *inode, struct audit_tree *tree)
spin_unlock(&hash_lock);
chunk->dead = 1;
spin_unlock(&entry->lock);
+ fsnotify_get_mark(entry);
fsnotify_destroy_mark(entry);
fsnotify_put_mark(entry);
return 0;
@@ -412,6 +411,7 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
spin_unlock(&chunk_entry->lock);
spin_unlock(&old_entry->lock);
+ fsnotify_get_mark(chunk_entry);
fsnotify_destroy_mark(chunk_entry);
fsnotify_put_mark(chunk_entry);
@@ -445,7 +445,6 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
spin_unlock(&old_entry->lock);
fsnotify_destroy_mark(old_entry);
fsnotify_put_mark(old_entry); /* pair to fsnotify_find mark_entry */
- fsnotify_put_mark(old_entry); /* and kill it */
return 0;
}