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=unavailable 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 4ED17C43387 for ; Fri, 4 Jan 2019 09:27:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1E6B421872 for ; Fri, 4 Jan 2019 09:27:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726847AbfADJ1D (ORCPT ); Fri, 4 Jan 2019 04:27:03 -0500 Received: from mail-io1-f70.google.com ([209.85.166.70]:50563 "EHLO mail-io1-f70.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:a6b:e519:: with SMTP id y25mr27940927ioc.36.1546594022271; Fri, 04 Jan 2019 01:27:02 -0800 (PST) Date: Fri, 04 Jan 2019 01:27:02 -0800 In-Reply-To: <0000000000003692760578e651dd@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000004f34dd057e9e7b2a@google.com> Subject: Re: KASAN: use-after-free Write in hci_sock_release From: syzbot To: davem@davemloft.net, johan.hedberg@gmail.com, linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org, marcel@holtmann.org, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-bluetooth-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org syzbot has found a reproducer for the following crash on: HEAD commit: 645ff1e8e704 Merge branch 'for-linus' of git://git.kernel... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1303e2bb400000 kernel config: https://syzkaller.appspot.com/x/.config?x=7308e68273924137 dashboard link: https://syzkaller.appspot.com/bug?extid=b364ed862aa07c74bc62 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=152532bb400000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13f73320c00000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+b364ed862aa07c74bc62@syzkaller.appspotmail.com ================================================================== BUG: KASAN: use-after-free in atomic_dec include/asm-generic/atomic-instrumented.h:127 [inline] BUG: KASAN: use-after-free in hci_sock_release+0x154/0x3c0 net/bluetooth/hci_sock.c:873 Write of size 4 at addr ffff888098651620 by task syz-executor472/8899 CPU: 1 PID: 8899 Comm: syz-executor472 Not tainted 4.20.0+ #8 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_write+0x14/0x20 mm/kasan/common.c:106 atomic_dec include/asm-generic/atomic-instrumented.h:127 [inline] hci_sock_release+0x154/0x3c0 net/bluetooth/hci_sock.c:873 __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 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x32a/0x3b0 arch/x86/entry/common.c:166 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: 0033:0x446419 Code: e8 0c e8 ff ff 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 7b 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ff91cfd4da8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 00000000006dbc28 RCX: 0000000000446419 RDX: 0000000000446419 RSI: 0000000000446419 RDI: 0000000000000004 RBP: 00000000006dbc20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc2c R13: 6368762f7665642f R14: 00007ff91cfd59c0 R15: 00000000006dbd2c Allocated by task 8889: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] kasan_kmalloc mm/kasan/common.c:482 [inline] kasan_kmalloc+0xcf/0xe0 mm/kasan/common.c:455 kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3607 kmalloc include/linux/slab.h:545 [inline] kzalloc include/linux/slab.h:740 [inline] hci_alloc_dev+0x148/0x21a0 net/bluetooth/hci_core.c:3116 __vhci_create_device+0x101/0x5a0 drivers/bluetooth/hci_vhci.c:114 vhci_create_device drivers/bluetooth/hci_vhci.c:163 [inline] vhci_get_user drivers/bluetooth/hci_vhci.c:219 [inline] vhci_write+0x2d0/0x470 drivers/bluetooth/hci_vhci.c:299 call_write_iter include/linux/fs.h:1862 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x764/0xb40 fs/read_write.c:487 vfs_write+0x20c/0x580 fs/read_write.c:549 ksys_write+0x105/0x260 fs/read_write.c:598 __do_sys_write fs/read_write.c:610 [inline] __se_sys_write fs/read_write.c:607 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:607 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 8888: save_stack+0x45/0xd0 mm/kasan/common.c:73 kobject: 'rfkill320' (00000000e0cb8fff): fill_kobj_path: path = '/devices/virtual/bluetooth/hci4/rfkill320' 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 bt_host_release+0x19/0x30 net/bluetooth/hci_sysfs.c:86 device_release+0x7d/0x210 drivers/base/core.c:919 kobject_cleanup lib/kobject.c:662 [inline] kobject_release lib/kobject.c:691 [inline] kref_put include/linux/kref.h:67 [inline] kobject_put.cold+0x28f/0x2ec lib/kobject.c:708 put_device+0x20/0x30 drivers/base/core.c:2060 hci_free_dev+0x19/0x20 net/bluetooth/hci_core.c:3208 vhci_release+0x7e/0xf0 drivers/bluetooth/hci_vhci.c:355 kobject: 'rfkill313' (00000000d3ffb8c5): kobject_uevent_env __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 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x32a/0x3b0 arch/x86/entry/common.c:166 kobject: 'rfkill313' (00000000d3ffb8c5): fill_kobj_path: path = '/devices/virtual/bluetooth/hci2/rfkill313' 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 The buggy address belongs to the object at ffff8880986505c0 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 4192 bytes inside of 8192-byte region [ffff8880986505c0, ffff8880986525c0) The buggy address belongs to the page: kobject: 'rfkill313' (00000000d3ffb8c5): kobject_cleanup, parent (null) page:ffffea0002619400 count:1 mapcount:0 mapping:ffff88812c3f2080 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea0002616508 ffffea0002302f08 ffff88812c3f2080 raw: 0000000000000000 ffff8880986505c0 0000000100000001 0000000000000000 kobject: 'rfkill313' (00000000d3ffb8c5): calling ktype release page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888098651500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888098651580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb kobject: 'rfkill313': free name > ffff888098651600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888098651680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888098651700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================