From mboxrd@z Thu Jan 1 00:00:00 1970 From: syzbot Subject: KASAN: slab-out-of-bounds Read in bpf_csum_update Date: Sun, 03 Jun 2018 16:36:02 -0700 Message-ID: <000000000000b2a7ea056dc54779@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes To: ast@kernel.org, daniel@iogearbox.net, davem@davemloft.net, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.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=17eb2d7b800000 kernel config: https://syzkaller.appspot.com/x/.config?x=968b0b23c7854c0b dashboard link: https://syzkaller.appspot.com/bug?extid=efae31b384d5badbd620 compiler: gcc (GCC) 8.0.1 20180413 (experimental) syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=162c6def800000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14fe3db7800000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+efae31b384d5badbd620@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 ____bpf_csum_update net/core/filter.c:1679 [inline] BUG: KASAN: slab-out-of-bounds in bpf_csum_update+0xb4/0xc0 net/core/filter.c:1673 Read of size 1 at addr ffff8801d9235b50 by task syz-executor507/4513 CPU: 0 PID: 4513 Comm: syz-executor507 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_load1_noabort+0x14/0x20 mm/kasan/report.c:430 ____bpf_csum_update net/core/filter.c:1679 [inline] bpf_csum_update+0xb4/0xc0 net/core/filter.c:1673 Allocated by task 0: (stack is not available) Freed by task 0: (stack is not available) The buggy address belongs to the object at ffff8801d9235a40 which belongs to the cache skbuff_head_cache of size 232 The buggy address is located 40 bytes to the right of 232-byte region [ffff8801d9235a40, ffff8801d9235b28) The buggy address belongs to the page: page:ffffea0007648d40 count:1 mapcount:0 mapping:ffff8801d9235040 index:0x0 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffff8801d9235040 0000000000000000 000000010000000c raw: ffffea00074360a0 ffff8801d944d848 ffff8801d9bdd6c0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d9235a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801d9235a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff8801d9235b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8801d9235b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801d9235c00: 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