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 8EC3DC28B21 for ; Thu, 9 Sep 2021 12:55:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6FD3A611C9 for ; Thu, 9 Sep 2021 12:55:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356479AbhIIMzP (ORCPT ); Thu, 9 Sep 2021 08:55:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:57486 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353016AbhIIMno (ORCPT ); Thu, 9 Sep 2021 08:43:44 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6E91E61BD3; Thu, 9 Sep 2021 11:55:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631188543; bh=PX2xQm/C4MK4PU4j7gsqvgYGjt7b7XdaBqs4CaQJ+Bo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U5L/qtym6hWewlp4oE475OrFl8AIu2k39gx+dCdmkEmScJnsAAS02bmw5Z2c1r08F kFSQCxbUlWS4yJP95uhAnL7D71lE/UEcAONvlHT6xvcMdlP+cKIE9x/ynI0SHzCkHX E+ksd/S2yXN60ElVrJIiO9QIDt1eIJruqsKXoBSNgN9BK82Mv/1qfKHtQojHErbgqg 7NwP/rAKYeMvgpN1Zsujo7KFa11Zhxj45YoAjIGzMSyfbBx53gGOp8TAcIBUxE3P1U z2vQm9Yq1DbKG8i5M4hZEdj4AfKv69rlRMoL+EZbuwfhbTrSkxa0Ps4ju/xz9z0HIp HM/r0iyKlz8kA== 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 5.4 028/109] video: fbdev: asiliantfb: Error out if 'pixclock' equals zero Date: Thu, 9 Sep 2021 07:53:45 -0400 Message-Id: <20210909115507.147917-28-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210909115507.147917-1-sashal@kernel.org> References: <20210909115507.147917-1-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-kernel@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 ea31054a28ca..c1d6e6336225 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