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authorAl Viro <viro@zeniv.linux.org.uk>2016-02-28 03:31:01 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2016-02-28 03:31:01 +0300
commita7f775428b8f5808815c0e3004020cedb94cbe3b (patch)
tree44e2bed48f96a5e9918280e518448daab65ea44f
parentd4565649b6d6923369112758212b851adc407f0c (diff)
downloadlinux-a7f775428b8f5808815c0e3004020cedb94cbe3b.tar.xz
should_follow_link(): validate ->d_seq after having decided to follow
... otherwise d_is_symlink() above might have nothing to do with the inode value we've got. Cc: stable@vger.kernel.org # v4.2+ Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--fs/namei.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/namei.c b/fs/namei.c
index e0881c0bd228..65a0e9d1ea48 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1712,6 +1712,11 @@ static inline int should_follow_link(struct nameidata *nd, struct path *link,
return 0;
if (!follow)
return 0;
+ /* make sure that d_is_symlink above matches inode */
+ if (nd->flags & LOOKUP_RCU) {
+ if (read_seqcount_retry(&link->dentry->d_seq, seq))
+ return -ECHILD;
+ }
return pick_link(nd, link, inode, seq);
}