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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 BB334C433F5 for ; Thu, 9 Sep 2021 12:35:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A8CF3610FF for ; Thu, 9 Sep 2021 12:35:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236882AbhIIMgW (ORCPT ); Thu, 9 Sep 2021 08:36:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:34546 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353353AbhIIM2X (ORCPT ); Thu, 9 Sep 2021 08:28:23 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2777961B2D; Thu, 9 Sep 2021 11:52:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631188337; bh=CFxoJqTD6D2XgEUt9WJ2SR1eXohXAMMWRfLmxb/Gz8Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=STw6gSM66Qsnzkk4zWUs0e7w0JErqKfGkuYFd5D2NaYTBBW7chtIqltg/NN18expi tHu2bXgvq1ikKxPbdb4jqGFmRuqbkEaVurBn+kO7q3C23PHXt9x8Hh28l4EIWbRs5z /jQfkClplmuz4Gzj8564VG8oosFoJ/sBfhTfGYAPeiKeSDTnofmf/OelpeTT46r1dB qdMVpPa9GpbdfmESUrEDtMB5mvmxXhN09hTMCXCceuieB4hpcro+8aWymPhGqyYbU5 B+Byre5GuEbBbfwcNMi0E5xibcaeF6MQD5278aKjir1gkqpwqDwTozo+mkNWOejrDD sIwId4Yf8v7hw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Zheyu Ma , Sam Ravnborg , Sasha Levin , dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org Subject: [PATCH AUTOSEL 5.10 046/176] video: fbdev: asiliantfb: Error out if 'pixclock' equals zero Date: Thu, 9 Sep 2021 07:49:08 -0400 Message-Id: <20210909115118.146181-46-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210909115118.146181-1-sashal@kernel.org> References: <20210909115118.146181-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org From: Zheyu Ma [ Upstream commit b36b242d4b8ea178f7fd038965e3cac7f30c3f09 ] The userspace program could pass any values to the driver through ioctl() interface. If the driver doesn't check the value of 'pixclock', it may cause divide error. Fix this by checking whether 'pixclock' is zero first. The following log reveals it: [ 43.861711] divide error: 0000 [#1] PREEMPT SMP KASAN PTI [ 43.861737] CPU: 2 PID: 11764 Comm: i740 Not tainted 5.14.0-rc2-00513-gac532c9bbcfb-dirty #224 [ 43.861756] RIP: 0010:asiliantfb_check_var+0x4e/0x730 [ 43.861843] Call Trace: [ 43.861848] ? asiliantfb_remove+0x190/0x190 [ 43.861858] fb_set_var+0x2e4/0xeb0 [ 43.861866] ? fb_blank+0x1a0/0x1a0 [ 43.861873] ? lock_acquire+0x1ef/0x530 [ 43.861884] ? lock_release+0x810/0x810 [ 43.861892] ? lock_is_held_type+0x100/0x140 [ 43.861903] ? ___might_sleep+0x1ee/0x2d0 [ 43.861914] ? __mutex_lock+0x620/0x1190 [ 43.861921] ? do_fb_ioctl+0x313/0x700 [ 43.861929] ? mutex_lock_io_nested+0xfa0/0xfa0 [ 43.861936] ? __this_cpu_preempt_check+0x1d/0x30 [ 43.861944] ? _raw_spin_unlock_irqrestore+0x46/0x60 [ 43.861952] ? lockdep_hardirqs_on+0x59/0x100 [ 43.861959] ? _raw_spin_unlock_irqrestore+0x46/0x60 [ 43.861967] ? trace_hardirqs_on+0x6a/0x1c0 [ 43.861978] do_fb_ioctl+0x31e/0x700 Signed-off-by: Zheyu Ma Signed-off-by: Sam Ravnborg Link: https://patchwork.freedesktop.org/patch/msgid/1627293835-17441-2-git-send-email-zheyuma97@gmail.com Signed-off-by: Sasha Levin --- drivers/video/fbdev/asiliantfb.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/video/fbdev/asiliantfb.c b/drivers/video/fbdev/asiliantfb.c index 3e006da47752..84c56f525889 100644 --- a/drivers/video/fbdev/asiliantfb.c +++ b/drivers/video/fbdev/asiliantfb.c @@ -227,6 +227,9 @@ static int asiliantfb_check_var(struct fb_var_screeninfo *var, { unsigned long Ftarget, ratio, remainder; + if (!var->pixclock) + return -EINVAL; + ratio = 1000000 / var->pixclock; remainder = 1000000 % var->pixclock; Ftarget = 1000000 * ratio + (1000000 * remainder) / var->pixclock; -- 2.30.2