From 1a4022f88d40e1255920b017556092ab926d7f66 Mon Sep 17 00:00:00 2001
From: Erez Zadok <ezk@fsl.cs.sunysb.edu>
Date: Sat, 21 May 2011 01:19:59 -0400
Subject: [PATCH] VFS: move BUG_ON test for symlink nd->depth after
current->link_count test
This solves a serious VFS-level bug in nested_symlink (which was
rewritten from do_follow_link), and follows the order of depth tests
that existed before.
The bug triggers a BUG_ON in fs/namei.c:1381, when running racer with
symlink and rename ops.
Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
Acked-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
fs/namei.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/namei.c b/fs/namei.c
index e3c4f112ebf7..6ff858c049c0 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1378,12 +1378,12 @@ static inline int nested_symlink(struct path *path, struct nameidata *nd)
{
int res;
- BUG_ON(nd->depth >= MAX_NESTED_LINKS);
if (unlikely(current->link_count >= MAX_NESTED_LINKS)) {
path_put_conditional(path, nd);
path_put(&nd->path);
return -ELOOP;
}
+ BUG_ON(nd->depth >= MAX_NESTED_LINKS);
nd->depth++;
current->link_count++;
--
GitLab