From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:39228 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752228AbdHIATT (ORCPT ); Tue, 8 Aug 2017 20:19:19 -0400 Subject: Patch "packet: fix use-after-free in prb_retire_rx_blk_timer_expired()" has been added to the 4.4-stable tree To: xiyou.wangcong@gmail.com, davej@codemonkey.org.uk, davem@davemloft.net, dingtianhong@huawei.com, gregkh@linuxfoundation.org, liujian56@huawei.com, willemdebruijn.kernel@gmail.com Cc: , From: Date: Tue, 08 Aug 2017 17:19:00 -0700 Message-ID: <15022379408992@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled packet: fix use-after-free in prb_retire_rx_blk_timer_expired() to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: packet-fix-use-after-free-in-prb_retire_rx_blk_timer_expired.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Tue Aug 8 16:51:58 PDT 2017 From: WANG Cong Date: Mon, 24 Jul 2017 10:07:32 -0700 Subject: packet: fix use-after-free in prb_retire_rx_blk_timer_expired() From: WANG Cong [ Upstream commit c800aaf8d869f2b9b47b10c5c312fe19f0a94042 ] There are multiple reports showing we have a use-after-free in the timer prb_retire_rx_blk_timer_expired(), where we use struct tpacket_kbdq_core::pkbdq, a pg_vec, after it gets freed by free_pg_vec(). The interesting part is it is not freed via packet_release() but via packet_setsockopt(), which means we are not closing the socket. Looking into the big and fat function packet_set_ring(), this could happen if we satisfy the following conditions: 1. closing == 0, not on packet_release() path 2. req->tp_block_nr == 0, we don't allocate a new pg_vec 3. rx_ring->pg_vec is already set as V3, which means we already called packet_set_ring() wtih req->tp_block_nr > 0 previously 4. req->tp_frame_nr == 0, pass sanity check 5. po->mapped == 0, never called mmap() In this scenario we are clearing the old rx_ring->pg_vec, so we need to free this pg_vec, but we don't stop the timer on this path because of closing==0. The timer has to be stopped as long as we need to free pg_vec, therefore the check on closing!=0 is wrong, we should check pg_vec!=NULL instead. Thanks to liujian for testing different fixes. Reported-by: alexander.levin@verizon.com Reported-by: Dave Jones Reported-by: liujian (CE) Tested-by: liujian (CE) Cc: Ding Tianhong Cc: Willem de Bruijn Signed-off-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/packet/af_packet.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -4225,7 +4225,7 @@ static int packet_set_ring(struct sock * register_prot_hook(sk); } spin_unlock(&po->bind_lock); - if (closing && (po->tp_version > TPACKET_V2)) { + if (pg_vec && (po->tp_version > TPACKET_V2)) { /* Because we don't support block-based V3 on tx-ring */ if (!tx_ring) prb_shutdown_retire_blk_timer(po, rb_queue); Patches currently in stable-queue which might be from xiyou.wangcong@gmail.com are queue-4.4/packet-fix-use-after-free-in-prb_retire_rx_blk_timer_expired.patch queue-4.4/rtnetlink-allocate-more-memory-for-dev_set_mac_address.patch