From 6f4b352f004c696439c5b5d75a4edc3d0823e770 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 27 Feb 2016 19:31:01 -0500 Subject: [PATCH] should_follow_link(): validate ->d_seq after having decided to follow commit a7f775428b8f5808815c0e3004020cedb94cbe3b upstream. ... otherwise d_is_symlink() above might have nothing to do with the inode value we've got. Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman --- fs/namei.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/namei.c b/fs/namei.c index f26cecbd6e73..930b51d6308b 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1711,6 +1711,11 @@ 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); } -- 2.34.1