From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751684AbeFCXgG (ORCPT ); Sun, 3 Jun 2018 19:36:06 -0400 Received: from mail-it0-f71.google.com ([209.85.214.71]:36217 "EHLO mail-it0-f71.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751354AbeFCXgD (ORCPT ); Sun, 3 Jun 2018 19:36:03 -0400 X-Google-Smtp-Source: ADUXVKJFXZs69llGFi5a8Y9ZdrH2hgLTuhpOzUSfRUP/GKirh/fSGSoYaAh60ZGXWSPEq2Mk2KF2CS1HeMOrOJOKXRCM9rE2kRf/ MIME-Version: 1.0 Date: Sun, 03 Jun 2018 16:36:02 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000b7be6e056dc547e8@google.com> Subject: KASAN: slab-out-of-bounds Read in skb_ensure_writable From: syzbot To: ast@kernel.org, daniel@iogearbox.net, davem@davemloft.net, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, syzbot found the following crash on: HEAD commit: 0512e0134582 Merge tag 'xfs-4.17-fixes-3' of git://git.ker.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=14956af7800000 kernel config: https://syzkaller.appspot.com/x/.config?x=968b0b23c7854c0b dashboard link: https://syzkaller.appspot.com/bug?extid=e5190cb881d8660fb1a3 compiler: gcc (GCC) 8.0.1 20180413 (experimental) syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=123d9d7b800000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=100329d7800000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+e5190cb881d8660fb1a3@syzkaller.appspotmail.com random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) ================================================================== BUG: KASAN: slab-out-of-bounds in pskb_may_pull include/linux/skbuff.h:2104 [inline] BUG: KASAN: slab-out-of-bounds in skb_ensure_writable+0x554/0x620 net/core/skbuff.c:5101 Read of size 4 at addr ffff8801aefc1780 by task syz-executor159/4509 CPU: 0 PID: 4509 Comm: syz-executor159 Not tainted 4.17.0-rc7+ #78 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1b9/0x294 lib/dump_stack.c:113 print_address_description+0x6c/0x20b mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432 pskb_may_pull include/linux/skbuff.h:2104 [inline] skb_ensure_writable+0x554/0x620 net/core/skbuff.c:5101 __bpf_try_make_writable net/core/filter.c:1419 [inline] bpf_try_make_writable net/core/filter.c:1425 [inline] ____bpf_l3_csum_replace net/core/filter.c:1546 [inline] bpf_l3_csum_replace+0x8c/0x4d0 net/core/filter.c:1537 Allocated by task 0: (stack is not available) Freed by task 0: (stack is not available) The buggy address belongs to the object at ffff8801aefc1680 which belongs to the cache skbuff_head_cache of size 232 The buggy address is located 24 bytes to the right of 232-byte region [ffff8801aefc1680, ffff8801aefc1768) The buggy address belongs to the page: page:ffffea0006bbf040 count:1 mapcount:0 mapping:ffff8801aefc1040 index:0x0 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffff8801aefc1040 0000000000000000 000000010000000c raw: ffffea0006b61060 ffffea0006bd69e0 ffff8801d9bdd6c0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801aefc1680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801aefc1700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff8801aefc1780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8801aefc1800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801aefc1880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with syzbot. syzbot can test patches for this bug, for details see: https://goo.gl/tpsmEJ#testing-patches