From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, NORMAL_HTTP_TO_IP,NUMERIC_HTTP_ADDR,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6F6F6C7618B for ; Sat, 27 Jul 2019 11:40:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3D9442082E for ; Sat, 27 Jul 2019 11:40:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564227658; bh=TYNJ1YsSH65sXPDM7fG4T/T4XSM5LGIykM1kF9l2qh4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=E7L0GSL8raAQbUq09Q+SYtxuxZos8hIAmKUoOeY2ImHpXvxJ1njqZ8XxpEDIX238V bk4lHPg7EBq5gVGNt/fG5781zwE5kKwlkwcXWXTP/B64xMCEBqdqq8zgVNynVuHCV/ rH/EYDIiugHNbt8GX88gzCJefmMGTrysnvzwT6II= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728835AbfG0LkG (ORCPT ); Sat, 27 Jul 2019 07:40:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:50122 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725975AbfG0LkF (ORCPT ); Sat, 27 Jul 2019 07:40:05 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C5C842082E; Sat, 27 Jul 2019 11:40:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564227604; bh=TYNJ1YsSH65sXPDM7fG4T/T4XSM5LGIykM1kF9l2qh4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=0lmmf3USQeflX1ETKKdgyMqeLJ3DnGchN4sqwjN7J6yZ/TQERPjpn/GUyOkOoeM/W 9bamC46vEGVH+amKq7Kk+dsG/KKVlcy6ZKgsGDX8jSoWmLPX93ws7b/tzTJiMwiL8Z fUWJulYEVZC6ID/6q5vWGoWCOZ0GYY6rH7TTpr5c= Date: Sat, 27 Jul 2019 13:40:01 +0200 From: Greg KH To: maowenan Cc: stable@vger.kernel.org, davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 4.4 stable net] net: tcp: Fix use-after-free in tcp_write_xmit Message-ID: <20190727114001.GA6685@kroah.com> References: <20190724091715.137033-1-maowenan@huawei.com> <20190724110524.GA4472@kroah.com> <495c2d12-2c18-3498-52a0-71e9e8a05576@huawei.com> <02a3860d-4ad8-0ba9-e488-9a149de55b3b@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <02a3860d-4ad8-0ba9-e488-9a149de55b3b@huawei.com> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Sat, Jul 27, 2019 at 07:22:30PM +0800, maowenan wrote: > > > On 2019/7/27 18:44, maowenan wrote: > > > > > > On 2019/7/24 20:13, maowenan wrote: > >> > >> > >> On 2019/7/24 19:05, Greg KH wrote: > >>> On Wed, Jul 24, 2019 at 05:17:15PM +0800, Mao Wenan wrote: > >>>> There is one report about tcp_write_xmit use-after-free with version 4.4.136: > >>>> > >>>> BUG: KASAN: use-after-free in tcp_skb_pcount include/net/tcp.h:796 [inline] > >>>> BUG: KASAN: use-after-free in tcp_init_tso_segs net/ipv4/tcp_output.c:1619 [inline] > >>>> BUG: KASAN: use-after-free in tcp_write_xmit+0x3fc2/0x4cb0 net/ipv4/tcp_output.c:2056 > >>>> Read of size 2 at addr ffff8801d6fc87b0 by task syz-executor408/4195 > >>>> > >>>> CPU: 0 PID: 4195 Comm: syz-executor408 Not tainted 4.4.136-gfb7e319 #59 > >>>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > >>>> 0000000000000000 7d8f38ecc03be946 ffff8801d73b7710 ffffffff81e0edad > >>>> ffffea00075bf200 ffff8801d6fc87b0 0000000000000000 ffff8801d6fc87b0 > >>>> dffffc0000000000 ffff8801d73b7748 ffffffff815159b6 ffff8801d6fc87b0 > >>>> Call Trace: > >>>> [] __dump_stack lib/dump_stack.c:15 [inline] > >>>> [] dump_stack+0xc1/0x124 lib/dump_stack.c:51 > >>>> [] print_address_description+0x6c/0x216 mm/kasan/report.c:252 > >>>> [] kasan_report_error mm/kasan/report.c:351 [inline] > >>>> [] kasan_report.cold.7+0x175/0x2f7 mm/kasan/report.c:408 > >>>> [] __asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:427 > >>>> [] tcp_skb_pcount include/net/tcp.h:796 [inline] > >>>> [] tcp_init_tso_segs net/ipv4/tcp_output.c:1619 [inline] > >>>> [] tcp_write_xmit+0x3fc2/0x4cb0 net/ipv4/tcp_output.c:2056 > >>>> [] __tcp_push_pending_frames+0xa0/0x290 net/ipv4/tcp_output.c:2307 > >>>> [] tcp_send_fin+0x176/0xab0 net/ipv4/tcp_output.c:2883 > >>>> [] tcp_close+0xca0/0xf70 net/ipv4/tcp.c:2112 > >>>> [] inet_release+0xff/0x1d0 net/ipv4/af_inet.c:435 > >>>> [] sock_release+0x96/0x1c0 net/socket.c:586 > >>>> [] sock_close+0x16/0x20 net/socket.c:1037 > >>>> [] __fput+0x235/0x6f0 fs/file_table.c:208 > >>>> [] ____fput+0x15/0x20 fs/file_table.c:244 > >>>> [] task_work_run+0x10f/0x190 kernel/task_work.c:115 > >>>> [] exit_task_work include/linux/task_work.h:21 [inline] > >>>> [] do_exit+0x9e5/0x26b0 kernel/exit.c:759 > >>>> [] do_group_exit+0x111/0x330 kernel/exit.c:889 > >>>> [] get_signal+0x4ec/0x14b0 kernel/signal.c:2321 > >>>> [] do_signal+0x8b/0x1d30 arch/x86/kernel/signal.c:712 > >>>> [] exit_to_usermode_loop+0x11a/0x160 arch/x86/entry/common.c:248 > >>>> [] prepare_exit_to_usermode arch/x86/entry/common.c:283 [inline] > >>>> [] syscall_return_slowpath+0x1b5/0x1f0 arch/x86/entry/common.c:348 > >>>> [] int_ret_from_sys_call+0x25/0xa3 > >>>> > >>>> Allocated by task 4194: > >>>> [] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63 > >>>> [] save_stack+0x43/0xd0 mm/kasan/kasan.c:512 > >>>> [] set_track mm/kasan/kasan.c:524 [inline] > >>>> [] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:616 > >>>> [] kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:554 > >>>> [] slab_post_alloc_hook mm/slub.c:1349 [inline] > >>>> [] slab_alloc_node mm/slub.c:2615 [inline] > >>>> [] slab_alloc mm/slub.c:2623 [inline] > >>>> [] kmem_cache_alloc+0xbe/0x2a0 mm/slub.c:2628 > >>>> [] kmem_cache_alloc_node include/linux/slab.h:350 [inline] > >>>> [] __alloc_skb+0xe6/0x600 net/core/skbuff.c:218 > >>>> [] alloc_skb_fclone include/linux/skbuff.h:856 [inline] > >>>> [] sk_stream_alloc_skb+0xa3/0x5d0 net/ipv4/tcp.c:833 > >>>> [] tcp_sendmsg+0xd34/0x2b00 net/ipv4/tcp.c:1178 > >>>> [] inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:755 > >>>> [] sock_sendmsg_nosec net/socket.c:625 [inline] > >>>> [] sock_sendmsg+0xcc/0x110 net/socket.c:635 > >>>> [] SYSC_sendto+0x21c/0x370 net/socket.c:1665 > >>>> [] SyS_sendto+0x40/0x50 net/socket.c:1633 > >>>> [] entry_SYSCALL_64_fastpath+0x22/0x9e > >>>> > >>>> Freed by task 4194: > >>>> [] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63 > >>>> [] save_stack+0x43/0xd0 mm/kasan/kasan.c:512 > >>>> [] set_track mm/kasan/kasan.c:524 [inline] > >>>> [] kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:589 > >>>> [] slab_free_hook mm/slub.c:1383 [inline] > >>>> [] slab_free_freelist_hook mm/slub.c:1405 [inline] > >>>> [] slab_free mm/slub.c:2859 [inline] > >>>> [] kmem_cache_free+0xbe/0x340 mm/slub.c:2881 > >>>> [] kfree_skbmem+0xcf/0x100 net/core/skbuff.c:635 > >>>> [] __kfree_skb+0x1d/0x20 net/core/skbuff.c:676 > >>>> [] sk_wmem_free_skb include/net/sock.h:1447 [inline] > >>>> [] tcp_write_queue_purge include/net/tcp.h:1460 [inline] > >>>> [] tcp_connect_init net/ipv4/tcp_output.c:3122 [inline] > >>>> [] tcp_connect+0xb24/0x30c0 net/ipv4/tcp_output.c:3261 > >>>> [] tcp_v4_connect+0xf31/0x1890 net/ipv4/tcp_ipv4.c:246 > >>>> [] __inet_stream_connect+0x2a9/0xc30 net/ipv4/af_inet.c:615 > >>>> [] inet_stream_connect+0x55/0xa0 net/ipv4/af_inet.c:676 > >>>> [] SYSC_connect+0x1b8/0x300 net/socket.c:1557 > >>>> [] SyS_connect+0x24/0x30 net/socket.c:1538 > >>>> [] entry_SYSCALL_64_fastpath+0x22/0x9e > >>>> > >>>> Syzkaller reproducer(): > >>>> r0 = socket$packet(0x11, 0x3, 0x300) > >>>> r1 = socket$inet_tcp(0x2, 0x1, 0x0) > >>>> bind$inet(r1, &(0x7f0000000300)={0x2, 0x4e21, @multicast1}, 0x10) > >>>> connect$inet(r1, &(0x7f0000000140)={0x2, 0x1000004e21, @loopback}, 0x10) > >>>> recvmmsg(r1, &(0x7f0000001e40)=[{{0x0, 0x0, &(0x7f0000000100)=[{&(0x7f00000005c0)=""/88, 0x58}], 0x1}}], 0x1, 0x40000000, 0x0) > >>>> sendto$inet(r1, &(0x7f0000000000)="e2f7ad5b661c761edf", 0x9, 0x8080, 0x0, 0x0) > >>>> r2 = fcntl$dupfd(r1, 0x0, r0) > >>>> connect$unix(r2, &(0x7f00000001c0)=@file={0x0, './file0\x00'}, 0x6e) > >>>> > >>>> C repro link: https://syzkaller.appspot.com/text?tag=ReproC&x=14db474f800000 > >>>> > >>>> This is because when tcp_connect_init call tcp_write_queue_purge, it will > >>>> kfree all the skb in the write_queue, but the sk->sk_send_head forget to set NULL, > >>>> then tcp_write_xmit try to send skb, which has freed in tcp_write_queue_purge, UAF happens. > >>>> > >>>> Signed-off-by: Mao Wenan > >>>> --- > >>>> include/net/tcp.h | 1 + > >>>> 1 file changed, 1 insertion(+) > >>>> > >>>> diff --git a/include/net/tcp.h b/include/net/tcp.h > >>>> index bf8a0dae977a..8f8aace28cf8 100644 > >>>> --- a/include/net/tcp.h > >>>> +++ b/include/net/tcp.h > >>>> @@ -1457,6 +1457,7 @@ static inline void tcp_write_queue_purge(struct sock *sk) > >>>> > >>>> while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) > >>>> sk_wmem_free_skb(sk, skb); > >>>> + sk->sk_send_head = NULL; > >>>> sk_mem_reclaim(sk); > >>>> tcp_clear_all_retrans_hints(tcp_sk(sk)); > >>>> inet_csk(sk)->icsk_backoff = 0; > >>> > >>> Does this corrispond with a specific commit that is already in Linus's > >>> tree? If not, why, did we change/mess something up when doing > >>> backports, or is the code just that different? > >>> > >>> Also, is this needed in 4.9.y, 4.14.y, 4.19.y, and/or 5.2.y? Why just > >>> 4.4.y? > > > > Greg, > > > > I have tested latest stable tree > > 4.4.186 oops > > 4.9.151 oops > > 4.14.106 NO oops > > > > This patch can simple fix them. > > I have checked 4.14.y it has already existed the same fix as mine, this is the reason why 4.14.106 is NO oops. > commit dbbf2d1e4077bab0c65ece2765d3fc69cf7d610f > Author: Soheil Hassas Yeganeh > Date: Thu Mar 15 12:09:13 2018 -0400 > > tcp: reset sk_send_head in tcp_write_queue_purge > So if this patch is backported to 4.4.y and 4.9.y all will be fine? thanks, greg k-h