Messages in this thread Patch in this message | | | From | Kamal Mostafa <> | Subject | [PATCH 4.2.y-ckt 217/273] should_follow_link(): validate ->d_seq after having decided to follow | Date | Mon, 7 Mar 2016 14:50:08 -0800 |
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4.2.8-ckt5 -stable review patch. If anyone has any objections, please let me know.
---8<------------------------------------------------------------
From: Al Viro <viro@zeniv.linux.org.uk>
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 <viro@zeniv.linux.org.uk> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- fs/namei.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/fs/namei.c b/fs/namei.c index 1047096..414561f 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1714,6 +1714,11 @@ 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); } -- 2.7.0
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