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=-0.6 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 6D450C04EB8 for ; Mon, 10 Dec 2018 18:49:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2E54F2081F for ; Mon, 10 Dec 2018 18:49:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2E54F2081F 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: AA+aEWYVJxczcdonCcQdBnP4pihft0vU6R6/OmpOaYAjavFiKTkolfsv zNq7Cf1FCFQlvgbDZw8DYuXP2YJAIQEqbIPF2nXp+eeQ98bt X-Google-Smtp-Source: AFSGD/VKBRtyHB+cBO5JuPfTODkvuU342pLkoJA29+2pXlQeirYYIpu+IZyuvWpRKSmXfFsZsh4+ufN64s3oefFrLtbTCl4IJL8M MIME-Version: 1.0 X-Received: by 2002:a24:2289:: with SMTP id o131mr11148063ito.7.1544467743551; Mon, 10 Dec 2018 10:49:03 -0800 (PST) Date: Mon, 10 Dec 2018 10:49:03 -0800 In-Reply-To: <000000000000a1adb3057ca63d3b@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <00000000000038b88e057caf6bd9@google.com> Subject: Re: KASAN: use-after-free Read in ___neigh_create From: syzbot To: christian@brauner.io, davem@davemloft.net, dsahern@gmail.com, edumazet@google.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, roopa@cumulusnetworks.com, syzkaller-bugs@googlegroups.com, w.bumiller@proxmox.com 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: 14cf8c1d5b90 Add linux-next specific files for 20181210 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=1666c56d400000 kernel config: https://syzkaller.appspot.com/x/.config?x=c9133d0a4284c012 dashboard link: https://syzkaller.appspot.com/bug?extid=e4d42eb35f6a27b0a628 compiler: gcc (GCC) 8.0.1 20180413 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12438215400000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11399125400000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+e4d42eb35f6a27b0a628@syzkaller.appspotmail.com ================================================================== BUG: KASAN: use-after-free in neigh_forced_gc net/core/neighbour.c:208 [inline] BUG: KASAN: use-after-free in neigh_alloc net/core/neighbour.c:365 [inline] BUG: KASAN: use-after-free in ___neigh_create+0x21fd/0x2600 net/core/neighbour.c:553 Read of size 8 at addr ffff8881b3566b70 by task syz-executor075/6593 CPU: 1 PID: 6593 Comm: syz-executor075 Not tainted 4.20.0-rc6-next-20181210+ #164 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+0x244/0x39d lib/dump_stack.c:113 print_address_description.cold.4+0x9/0x1ff mm/kasan/report.c:187 kasan_report.cold.5+0x1b/0x39 mm/kasan/report.c:317 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135 neigh_forced_gc net/core/neighbour.c:208 [inline] neigh_alloc net/core/neighbour.c:365 [inline] ___neigh_create+0x21fd/0x2600 net/core/neighbour.c:553 __neigh_create+0x30/0x40 net/core/neighbour.c:640 neigh_create include/net/neighbour.h:319 [inline] __neigh_lookup_errno include/net/neighbour.h:529 [inline] arp_req_set+0x59d/0xaa0 net/ipv4/arp.c:1066 arp_ioctl+0x48b/0xae0 net/ipv4/arp.c:1230 inet_ioctl+0x237/0x360 net/ipv4/af_inet.c:932 sock_do_ioctl+0xeb/0x420 net/socket.c:951 sock_ioctl+0x313/0x690 net/socket.c:1075 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x440e39 Code: e8 cc ab 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 bb 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffea8160338 EFLAGS: 00000213 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440e39 RDX: 0000000020000000 RSI: 0000000000008955 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00000000004002c8 R09: 00000000004002c8 R10: 0000000001fe3880 R11: 0000000000000213 R12: 000000000000d704 R13: 0000000000401e10 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 6083: save_stack+0x43/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] kasan_kmalloc+0xcb/0xd0 mm/kasan/common.c:482 __do_kmalloc mm/slab.c:3709 [inline] __kmalloc+0x15d/0x760 mm/slab.c:3718 kmalloc include/linux/slab.h:550 [inline] kzalloc include/linux/slab.h:740 [inline] neigh_alloc net/core/neighbour.c:375 [inline] ___neigh_create+0x13fc/0x2600 net/core/neighbour.c:553 __neigh_create+0x30/0x40 net/core/neighbour.c:640 neigh_create include/net/neighbour.h:319 [inline] __neigh_lookup_errno include/net/neighbour.h:529 [inline] arp_req_set+0x59d/0xaa0 net/ipv4/arp.c:1066 arp_ioctl+0x48b/0xae0 net/ipv4/arp.c:1230 inet_ioctl+0x237/0x360 net/ipv4/af_inet.c:932 sock_do_ioctl+0xeb/0x420 net/socket.c:951 sock_ioctl+0x313/0x690 net/socket.c:1075 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 0: save_stack+0x43/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:444 kasan_slab_free+0xe/0x10 mm/kasan/common.c:452 __cache_free mm/slab.c:3485 [inline] kfree+0xcf/0x230 mm/slab.c:3804 __rcu_reclaim kernel/rcu/rcu.h:233 [inline] rcu_do_batch kernel/rcu/tree.c:2452 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2773 [inline] rcu_process_callbacks+0xd91/0x15f0 kernel/rcu/tree.c:2754 __do_softirq+0x308/0xb7e kernel/softirq.c:292 The buggy address belongs to the object at ffff8881b3566900 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 624 bytes inside of 1024-byte region [ffff8881b3566900, ffff8881b3566d00) The buggy address belongs to the page: page:ffffea0006cd5980 count:1 mapcount:0 mapping:ffff8881da800ac0 index:0x0 compound_mapcount: 0 flags: 0x2fffc0000010200(slab|head) raw: 02fffc0000010200 ffffea0007354b88 ffffea000704b308 ffff8881da800ac0 raw: 0000000000000000 ffff8881b3566000 0000000100000007 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881b3566a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881b3566a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8881b3566b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881b3566b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881b3566c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================