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=-0.4 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 7FF45C43334 for ; Thu, 6 Sep 2018 03:17:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4054820659 for ; Thu, 6 Sep 2018 03:17:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4054820659 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by 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X-Gm-Message-State: APzg51A4kc50JgirS3xUhvyCEerTBC3T2yEp6/MHdS0tWhwIs1wAaWjv vepY2V8nOwH/jdw4sdm5Y7ZAHfCzT1FhIIT5eb38idXfLJxe X-Google-Smtp-Source: ANB0VdYpIhnTRZ4iJ2zEuFAjivdH69GLlCa4Ut0AJS1rymSsm/TCr4wKSDmagihIezAt9kkMD7tvHpVak3/FXSZmWLZThXhm97fo MIME-Version: 1.0 X-Received: by 2002:a6b:bf47:: with SMTP id p68-v6mr490014iof.82.1536203822981; Wed, 05 Sep 2018 20:17:02 -0700 (PDT) Date: Wed, 05 Sep 2018 20:17:02 -0700 In-Reply-To: <0000000000003658b00574dc08cc@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000002bef6405752b530b@google.com> Subject: Re: KASAN: slab-out-of-bounds Read in _decode_session6 From: syzbot To: ast@kernel.org, daniel@iogearbox.net, davem@davemloft.net, dvyukov@google.com, herbert@gondor.apana.org.au, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, steffen.klassert@secunet.com, syzkaller-bugs@googlegroups.com, yoshfuji@linux-ipv6.org Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org syzbot has found a reproducer for the following crash on: HEAD commit: b36fdc6853a3 Merge tag 'gpio-v4.19-2' of git://git.kernel... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=164938d1400000 kernel config: https://syzkaller.appspot.com/x/.config?x=4c7e83258d6e0156 dashboard link: https://syzkaller.appspot.com/bug?extid=acffccec848dc13fe459 compiler: gcc (GCC) 8.0.1 20180413 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=115f172e400000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16399be1400000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+acffccec848dc13fe459@syzkaller.appspotmail.com IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready 8021q: adding VLAN 0 to HW filter on device team0 ================================================================== BUG: KASAN: slab-out-of-bounds in _decode_session6+0x1331/0x14e0 net/ipv6/xfrm6_policy.c:161 Read of size 1 at addr ffff8801d4a67f07 by task syz-executor092/4673 CPU: 1 PID: 4673 Comm: syz-executor092 Not tainted 4.19.0-rc2+ #223 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+0x1c9/0x2b4 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+0x242/0x30d mm/kasan/report.c:412 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430 _decode_session6+0x1331/0x14e0 net/ipv6/xfrm6_policy.c:161 __xfrm_decode_session+0x71/0x140 net/xfrm/xfrm_policy.c:2299 xfrm_decode_session include/net/xfrm.h:1232 [inline] vti6_tnl_xmit+0x3fc/0x1bb1 net/ipv6/ip6_vti.c:542 __netdev_start_xmit include/linux/netdevice.h:4287 [inline] netdev_start_xmit include/linux/netdevice.h:4296 [inline] xmit_one net/core/dev.c:3216 [inline] dev_hard_start_xmit+0x272/0xc10 net/core/dev.c:3232 __dev_queue_xmit+0x2ab2/0x3870 net/core/dev.c:3802 dev_queue_xmit+0x17/0x20 net/core/dev.c:3835 __bpf_tx_skb net/core/filter.c:2012 [inline] __bpf_redirect_common net/core/filter.c:2050 [inline] __bpf_redirect+0x5b7/0xae0 net/core/filter.c:2057 ____bpf_clone_redirect net/core/filter.c:2090 [inline] bpf_clone_redirect+0x2f6/0x490 net/core/filter.c:2062 bpf_prog_c39d1ba309a769f7+0xe9e/0x1000 Allocated by task 4673: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553 __do_kmalloc_node mm/slab.c:3682 [inline] __kmalloc_node_track_caller+0x47/0x70 mm/slab.c:3696 __kmalloc_reserve.isra.41+0x3a/0xe0 net/core/skbuff.c:137 pskb_expand_head+0x230/0x10e0 net/core/skbuff.c:1463 skb_ensure_writable+0x3dd/0x640 net/core/skbuff.c:5129 __bpf_try_make_writable net/core/filter.c:1633 [inline] bpf_try_make_writable net/core/filter.c:1639 [inline] bpf_try_make_head_writable net/core/filter.c:1647 [inline] ____bpf_clone_redirect net/core/filter.c:2084 [inline] bpf_clone_redirect+0x14a/0x490 net/core/filter.c:2062 bpf_prog_c39d1ba309a769f7+0xe9e/0x1000 Freed by task 3286: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kfree+0xd9/0x210 mm/slab.c:3813 load_elf_binary+0x2569/0x5610 fs/binfmt_elf.c:1118 search_binary_handler+0x17d/0x570 fs/exec.c:1653 exec_binprm fs/exec.c:1695 [inline] __do_execve_file.isra.35+0x15ff/0x2460 fs/exec.c:1819 do_execveat_common fs/exec.c:1866 [inline] do_execve fs/exec.c:1883 [inline] __do_sys_execve fs/exec.c:1964 [inline] __se_sys_execve fs/exec.c:1959 [inline] __x64_sys_execve+0x8f/0xc0 fs/exec.c:1959 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8801d4a67d00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 7 bytes to the right of 512-byte region [ffff8801d4a67d00, ffff8801d4a67f00) The buggy address belongs to the page: page:ffffea00075299c0 count:1 mapcount:0 mapping:ffff8801dac00940 index:0x0 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffffea0007529988 ffffea0007529a48 ffff8801dac00940 raw: 0000000000000000 ffff8801d4a67080 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d4a67e00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8801d4a67e80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ffff8801d4a67f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8801d4a67f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801d4a68000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================