From: Al Viro <viro@zeniv.linux.org.uk>
Date: Wed, 5 Aug 2015 03:23:50 +0000 (-0400)
Subject: may_follow_link() should use nd->inode
X-Git-Tag: v4.2-rc7~29^2
X-Git-Url: http://git.cascardo.eti.br/?a=commitdiff_plain;h=aa65fa35ba6b589a12a6025739c2d935dd743b5a;p=cascardo%2Flinux.git

may_follow_link() should use nd->inode

Now that we can get there in RCU mode, we shouldn't play with
nd->path.dentry->d_inode - it's not guaranteed to be stable.
Use nd->inode instead.

Reported-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---

diff --git a/fs/namei.c b/fs/namei.c
index fbbcf0993312..1c2105ed20c5 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -879,7 +879,7 @@ static inline int may_follow_link(struct nameidata *nd)
 		return 0;
 
 	/* Allowed if parent directory not sticky and world-writable. */
-	parent = nd->path.dentry->d_inode;
+	parent = nd->inode;
 	if ((parent->i_mode & (S_ISVTX|S_IWOTH)) != (S_ISVTX|S_IWOTH))
 		return 0;