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=-5.7 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, 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 E5A98C282C0 for ; Wed, 23 Jan 2019 20:45:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AAE7521872 for ; Wed, 23 Jan 2019 20:45:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726322AbfAWUpF (ORCPT ); Wed, 23 Jan 2019 15:45:05 -0500 Received: from mail-it1-f197.google.com ([209.85.166.197]:59542 "EHLO mail-it1-f197.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id 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MIME-Version: 1.0 X-Received: by 2002:a24:4e4b:: with SMTP id r72mr3274597ita.18.1548276303930; Wed, 23 Jan 2019 12:45:03 -0800 (PST) Date: Wed, 23 Jan 2019 12:45:03 -0800 In-Reply-To: <000000000000d78798057e773261@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000001c337b0580262b5d@google.com> Subject: Re: KASAN: use-after-free Read in refcount_inc_not_zero_checked From: syzbot To: davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org syzbot has found a reproducer for the following crash on: HEAD commit: 333478a7eb21 Merge branch 'for-rc' of git://git.kernel.org.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=14ec4628c00000 kernel config: https://syzkaller.appspot.com/x/.config?x=505743eba4e4f68 dashboard link: https://syzkaller.appspot.com/bug?extid=defa700d16f1bd1b9a05 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=142f7590c00000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+defa700d16f1bd1b9a05@syzkaller.appspotmail.com IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready 8021q: adding VLAN 0 to HW filter on device batadv0 IPVS: ftp: loaded support on port[0] = 21 chnl_net:caif_netlink_parms(): no params data found ================================================================== BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:21 [inline] BUG: KASAN: use-after-free in refcount_inc_not_zero_checked+0x91/0x2e0 lib/refcount.c:120 Read of size 4 at addr ffff888089bba440 by task syz-executor5/11381 CPU: 1 PID: 11381 Comm: syz-executor5 Not tainted 5.0.0-rc3+ #40 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+0x1db/0x2d0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 check_memory_region_inline mm/kasan/generic.c:185 [inline] check_memory_region+0x123/0x190 mm/kasan/generic.c:191 kasan_check_read+0x11/0x20 mm/kasan/common.c:100 atomic_read include/asm-generic/atomic-instrumented.h:21 [inline] refcount_inc_not_zero_checked+0x91/0x2e0 lib/refcount.c:120 refcount_inc_checked+0x17/0x70 lib/refcount.c:153 sock_hold include/net/sock.h:647 [inline] nr_release+0x62/0x3c0 net/netrom/af_netrom.c:523 __sock_release+0xd3/0x250 net/socket.c:579 sock_close+0x1b/0x30 net/socket.c:1141 __fput+0x3c5/0xb10 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x1f4/0x2b0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xad7/0x26e0 kernel/exit.c:867 do_group_exit+0x177/0x430 kernel/exit.c:971 get_signal+0x8b4/0x19b0 kernel/signal.c:2517 do_signal+0x91/0x1ea0 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x2f7/0x3b0 arch/x86/entry/common.c:162 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x696/0x800 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x458099 Code: 6d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f7c8a6a7cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000073c228 RCX: 0000000000458099 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000073c228 RBP: 000000000073c220 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000073c22c R13: 00007ffc1cd8e9ef R14: 00007f7c8a6a89c0 R15: 0000000000000005 Allocated by task 11350: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_kmalloc mm/kasan/common.c:496 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:469 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:504 __do_kmalloc mm/slab.c:3711 [inline] __kmalloc+0x15c/0x740 mm/slab.c:3720 kmalloc include/linux/slab.h:550 [inline] sk_prot_alloc+0x19c/0x2e0 net/core/sock.c:1477 sk_alloc+0xd7/0x1690 net/core/sock.c:1531 nr_create+0xb9/0x5e0 net/netrom/af_netrom.c:436 __sock_create+0x532/0x930 net/socket.c:1277 sock_create net/socket.c:1317 [inline] __sys_socket+0x106/0x260 net/socket.c:1347 __do_sys_socket net/socket.c:1356 [inline] __se_sys_socket net/socket.c:1354 [inline] __x64_sys_socket+0x73/0xb0 net/socket.c:1354 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 11170: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:458 kasan_slab_free+0xe/0x10 mm/kasan/common.c:466 __cache_free mm/slab.c:3487 [inline] kfree+0xcf/0x230 mm/slab.c:3806 sk_prot_free net/core/sock.c:1514 [inline] __sk_destruct+0x76d/0xa60 net/core/sock.c:1596 sk_destruct+0x7b/0x90 net/core/sock.c:1604 __sk_free+0xce/0x300 net/core/sock.c:1615 sk_free+0x42/0x50 net/core/sock.c:1626 sock_put include/net/sock.h:1707 [inline] nr_heartbeat_expiry+0x489/0x520 net/netrom/nr_timer.c:130 call_timer_fn+0x254/0x900 kernel/time/timer.c:1325 expire_timers kernel/time/timer.c:1362 [inline] __run_timers+0x6fc/0xd50 kernel/time/timer.c:1681 run_timer_softirq+0x52/0xb0 kernel/time/timer.c:1694 __do_softirq+0x30b/0xb11 kernel/softirq.c:292 The buggy address belongs to the object at ffff888089bba3c0 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 128 bytes inside of 2048-byte region [ffff888089bba3c0, ffff888089bbabc0) The buggy address belongs to the page: page:ffffea000226ee80 count:1 mapcount:0 mapping:ffff88812c3f0c40 index:0xffff888089bbb4c0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea0002608f08 ffffea0002501688 ffff88812c3f0c40 raw: ffff888089bbb4c0 ffff888089bba3c0 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888089bba300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888089bba380: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb > ffff888089bba400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888089bba480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888089bba500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================