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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 8B8D9C433F4 for ; Wed, 15 Jul 2020 07:00:27 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6C3B2205CB for ; Wed, 15 Jul 2020 07:00:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6C3B2205CB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=i-love.sakura.ne.jp Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E813B6E451; Wed, 15 Jul 2020 06:59:58 +0000 (UTC) Received: from www262.sakura.ne.jp (www262.sakura.ne.jp [202.181.97.72]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0D6CD6E0B7 for ; Wed, 15 Jul 2020 00:24:17 +0000 (UTC) Received: from fsav401.sakura.ne.jp (fsav401.sakura.ne.jp [133.242.250.100]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 06F0O9m6009533; Wed, 15 Jul 2020 09:24:09 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav401.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav401.sakura.ne.jp); Wed, 15 Jul 2020 09:24:09 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav401.sakura.ne.jp) Received: from [192.168.1.9] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 06F0O80A009529 (version=TLSv1.2 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 15 Jul 2020 09:24:09 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Subject: Re: [PATCH] fbdev: Detect integer underflow at "struct fbcon_ops"->clear_margins. To: George Kennedy , Bartlomiej Zolnierkiewicz References: <189fc902-db7c-9886-cc31-c0348435303a@i-love.sakura.ne.jp> <20200712111013.11881-1-penguin-kernel@I-love.SAKURA.ne.jp> <20200712111013.11881-2-penguin-kernel@I-love.SAKURA.ne.jp> From: Tetsuo Handa Message-ID: Date: Wed, 15 Jul 2020 09:24:06 +0900 User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Mailman-Approved-At: Wed, 15 Jul 2020 06:59:56 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-fbdev@vger.kernel.org, Greg Kroah-Hartman , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Dan Carpenter , Jiri Slaby , Dmitry Vyukov Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 2020/07/15 2:15, George Kennedy wrote: > Can you try the a.out built from the original Syzkaller modified repro C program? It walks 0-7 through xres and yres of the fb_var_screeninfo struct. I'm not familiar with exploit code. What do you want to explain via this program? > struct fb_var_screeninfo *varp = (struct fb_var_screeninfo *)0x200001c0; > struct fb_var_screeninfo *starting_varp = malloc(sizeof(struct fb_var_screeninfo *)); > memcpy(starting_varp, varp, sizeof(struct fb_var_screeninfo)); > memcpy(varp, starting_varp, sizeof(struct fb_var_screeninfo)); At least, I suspect there is a memory corruption bug in this program because of malloc()ing only sizeof(struct fb_var_screeninfo *) bytes. _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel