cifs: Fix server use-after-free in cifs_chan_skip_or_disable()

When a secondary channel is no longer supported by the server,
cifs_chan_skip_or_disable() drops the channel reference with
cifs_put_tcp_session() and then continues to use the server pointer by
calling cifs_signal_cifsd_for_reconnect() on it and reading its
primary_server pointer. cifs_put_tcp_session() can drop the last
reference of the channel and tear it down, so both the channel and the
primary server (whose reference is also dropped by
cifs_put_tcp_session()) can be freed before they are signaled for
reconnect.

Signal the channel and the primary server and capture the primary
server pointer before dropping the channel reference with
cifs_put_tcp_session().

Fixes: f591062bdbf4 ("cifs: handle servers that still advertise multichannel after disabling")
Cc: stable@vger.kernel.org
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>

0 files changed, 0 insertions, 0 deletions