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=2.4 required=3.0 tests=CHARSET_FARAWAY_HEADER, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 BD29FC43603 for ; Wed, 18 Dec 2019 00:56:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9DE1C206D3 for ; Wed, 18 Dec 2019 00:56:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726708AbfLRA4s (ORCPT ); Tue, 17 Dec 2019 19:56:48 -0500 Received: from www262.sakura.ne.jp ([202.181.97.72]:61358 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726205AbfLRA4r (ORCPT ); Tue, 17 Dec 2019 19:56:47 -0500 Received: from fsav104.sakura.ne.jp (fsav104.sakura.ne.jp [27.133.134.231]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id xBI0txmv079214; Wed, 18 Dec 2019 09:55:59 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav104.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav104.sakura.ne.jp); Wed, 18 Dec 2019 09:55:59 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav104.sakura.ne.jp) Received: from www262.sakura.ne.jp (localhost [127.0.0.1]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id xBI0tx9E079208; Wed, 18 Dec 2019 09:55:59 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Received: (from i-love@localhost) by www262.sakura.ne.jp (8.15.2/8.15.2/Submit) id xBI0txro079201; Wed, 18 Dec 2019 09:55:59 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Message-Id: <201912180055.xBI0txro079201@www262.sakura.ne.jp> X-Authentication-Warning: www262.sakura.ne.jp: i-love set sender to penguin-kernel@i-love.sakura.ne.jp using -f Subject: Re: BUG: unable to handle kernel NULL pointer dereference in =?ISO-2022-JP?B?bWVtX3NlcmlhbF9vdXQ=?= From: Tetsuo Handa To: Dmitry Vyukov Cc: Greg KH , syzbot , Andy Shevchenko , asierra@xes-inc.com, ext-kimmo.rautkoski@vaisala.com, Jiri Slaby , kai heng feng , LKML , linux-serial , mika.westerberg@linux.intel.com, o.barta89@gmail.com, paulburton@kernel.org, sr@denx.de, syzkaller-bugs , yegorslists@googlemail.com MIME-Version: 1.0 Date: Wed, 18 Dec 2019 09:55:59 +0900 References: <20191213093357.GB2135612@kroah.com> In-Reply-To: Content-Type: text/plain; charset="ISO-2022-JP" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hmm, this is a surprising bug. syzbot provided a C reproducer, but the definition of "struct serial_struct" used in that reproducer is wrong. As a result, syzbot was reporting crash caused by passing wrong arguments. ;-) close_delay field used in the C reproducer is sizeof(unsigned int) bytes rather than sizeof(unsigned short) bytes, thus fields after close_delay field are incorrectly interpreted. ---------------------------------------- #include #include #include #include #include #include struct bad_serial_struct { int type; int line; unsigned int port; int irq; int flags; int xmit_fifo_size; int custom_divisor; int baud_base; unsigned int close_delay; /* Correct type is "unsigned short". */ char io_type; char reserved_char[1]; int hub6; unsigned short closing_wait; unsigned short closing_wait2; unsigned char *iomem_base; unsigned short iomem_reg_shift; unsigned int port_high; unsigned long iomap_base; }; int main(int argc, char *argv[]) { struct bad_serial_struct ss = { }; int fd = open("/dev/ttyS3", O_RDONLY); ss.type = 0xa; ss.line = 0x400000; ss.port = 0x100; ss.irq = 0; ss.flags = 0x400000; ss.xmit_fifo_size = 0; ss.custom_divisor = 0; ss.baud_base = 0x80000; ss.close_delay = 0x200ff; ss.io_type = 0; ss.reserved_char[0] = 0x41; ss.hub6 = 3; ss.closing_wait = 0; ss.closing_wait2 = 0x7c5; ss.iomem_base = NULL; ss.iomem_reg_shift = 0; ss.port_high = 0; ss.iomap_base = 0; ioctl(fd, TIOCSSERIAL, &ss); return 0; } ----------------------------------------