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) <pc@cjr.nz>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index 92e4278ec35d536714a440a6193c35a9721ec5eb..9e7d9f0baa18a133eb1afd76a4916d7f47d00dd2 100644 (file)
--- 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);