From f391d6ee002ea022c62dc0b09d0578f3ccce81be Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Fri, 18 Nov 2022 14:48:00 +0300 Subject: [PATCH] cifs: Use after free in debug code This debug code dereferences "old_iface" after it was already freed by the call to release_iface(). Re-order the debugging to avoid this issue. Fixes: b54034a73baf ("cifs: during reconnect, update interface if necessary") Cc: stable@vger.kernel.org # 5.19+ Reviewed-by: Paulo Alcantara (SUSE) Signed-off-by: Dan Carpenter Signed-off-by: Steve French --- fs/cifs/sess.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c index 92e4278ec35d53..9e7d9f0baa18a1 100644 --- a/fs/cifs/sess.c +++ b/fs/cifs/sess.c @@ -302,14 +302,14 @@ cifs_chan_update_iface(struct cifs_ses *ses, struct TCP_Server_Info *server) /* now drop the ref to the current iface */ if (old_iface && iface) { - kref_put(&old_iface->refcount, release_iface); cifs_dbg(FYI, "replacing iface: %pIS with %pIS\n", &old_iface->sockaddr, &iface->sockaddr); - } else if (old_iface) { kref_put(&old_iface->refcount, release_iface); + } else if (old_iface) { cifs_dbg(FYI, "releasing ref to iface: %pIS\n", &old_iface->sockaddr); + kref_put(&old_iface->refcount, release_iface); } else { WARN_ON(!iface); cifs_dbg(FYI, "adding new iface: %pIS\n", &iface->sockaddr);