From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755114AbdJIS1E (ORCPT ); Mon, 9 Oct 2017 14:27:04 -0400 Received: from mail-qt0-f195.google.com ([209.85.216.195]:34260 "EHLO mail-qt0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752311AbdJIS1B (ORCPT ); Mon, 9 Oct 2017 14:27:01 -0400 X-Google-Smtp-Source: AOwi7QB6Xxye+xFdvceD7vyDWhqxBgm6dM2QjNJb14Qoj/Aa/ws1K/8HO5nGGFNJN9KJSzlL3IWSsQ== Subject: Re: usb/media/imon: null-ptr-deref in imon_probe To: Andrey Konovalov , Mauro Carvalho Chehab , Sean Young , Hans Verkuil , Andi Shyti , Sakari Ailus , Daniel Wagner , Arnd Bergmann , linux-media@vger.kernel.org, LKML References: Cc: Dmitry Vyukov , Kostya Serebryany , syzkaller From: arvindY Message-ID: <59DBBF6C.3040506@gmail.com> Date: Mon, 9 Oct 2017 23:56:52 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Andrey, I have added NULL check for usb_ifnum_to_if() and send a patch. Please re-test it. ~arvind On Monday 09 October 2017 11:20 PM, Andrey Konovalov wrote: > Hi! > > I've got the following report while fuzzing the kernel with syzkaller. > > On commit 8a5776a5f49812d29fe4b2d0a2d71675c3facf3f (4.14-rc4). > > It seems that the return value of usb_ifnum_to_if() can be NULL and > needs to be checked. > > kasan: CONFIG_KASAN_INLINE enabled > kasan: GPF could be caused by NULL-ptr deref or user memory access > general protection fault: 0000 [#1] PREEMPT SMP KASAN > Modules linked in: > CPU: 1 PID: 1497 Comm: kworker/1:1 Not tainted > 4.14.0-rc4-43418-g43a3f84d2109-dirty #380 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > Workqueue: usb_hub_wq hub_event > task: ffff88006a5618c0 task.stack: ffff880068bc8000 > RIP: 0010:imon_probe+0x231/0x3f10 drivers/media/rc/imon.c:2519 > RSP: 0018:ffff880068bce2d8 EFLAGS: 00010206 > RAX: 0000000000000000 RBX: ffff8800627dd500 RCX: 0000000000000027 > RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000138 > RBP: ffff880068bce5e8 R08: ffff88006a5618c0 R09: ffffffff84b380fc > R10: ffff880068bce2c8 R11: 1ffff1000d4ac5b3 R12: ffff880061830000 > R13: ffff880061830008 R14: ffffffff883fa200 R15: ffffffff883fa080 > FS: 0000000000000000(0000) GS:ffff88006c500000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00000000206cbffc CR3: 0000000061085000 CR4: 00000000000006e0 > Call Trace: > usb_probe_interface+0x35d/0x8e0 drivers/usb/core/driver.c:361 > really_probe drivers/base/dd.c:413 > driver_probe_device+0x610/0xa00 drivers/base/dd.c:557 > __device_attach_driver+0x230/0x290 drivers/base/dd.c:653 > bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463 > __device_attach+0x26e/0x3d0 drivers/base/dd.c:710 > device_initial_probe+0x1f/0x30 drivers/base/dd.c:757 > bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523 > device_add+0xd0b/0x1660 drivers/base/core.c:1835 > usb_set_configuration+0x104e/0x1870 drivers/usb/core/message.c:1932 > generic_probe+0x73/0xe0 drivers/usb/core/generic.c:174 > usb_probe_device+0xaf/0xe0 drivers/usb/core/driver.c:266 > really_probe drivers/base/dd.c:413 > driver_probe_device+0x610/0xa00 drivers/base/dd.c:557 > __device_attach_driver+0x230/0x290 drivers/base/dd.c:653 > bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463 > __device_attach+0x26e/0x3d0 drivers/base/dd.c:710 > device_initial_probe+0x1f/0x30 drivers/base/dd.c:757 > bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523 > device_add+0xd0b/0x1660 drivers/base/core.c:1835 > usb_new_device+0x7b8/0x1020 drivers/usb/core/hub.c:2457 > hub_port_connect drivers/usb/core/hub.c:4903 > hub_port_connect_change drivers/usb/core/hub.c:5009 > port_event drivers/usb/core/hub.c:5115 > hub_event+0x194d/0x3740 drivers/usb/core/hub.c:5195 > process_one_work+0xc7f/0x1db0 kernel/workqueue.c:2119 > worker_thread+0x221/0x1850 kernel/workqueue.c:2253 > kthread+0x3a1/0x470 kernel/kthread.c:231 > ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 > Code: ff e8 a4 81 cb 01 31 f6 48 89 df e8 2a cc 65 ff 0f ae f0 48 8d > b8 38 01 00 00 48 ba 00 00 00 00 00 fc ff df 48 89 f9 48 c1 e9 03 <80> > 3c 11 00 0f 85 e8 31 00 00 48 8b 98 38 01 00 00 0f ae f0 44 > RIP: imon_probe+0x231/0x3f10 RSP: ffff880068bce2d8 > ---[ end trace 07febd2eebe02f84 ]---