From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A31C516FF29; Wed, 3 Apr 2024 17:20:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712164849; cv=none; b=OHcsuFihWV3PaVUn3ppSwIu35KdR9e0MnljP5bSR3q5Ci62nO2TJ4cKbTHFk1bCpzZuD6zztqJHA7iHzdBH2V/CtNLblB6m7uBPpaxU0wah2AqciUShqpMO71i7hd4YFybOMLB7DWDdL7NxJJOyzYSMP/c9JSuKL0hmvffj6ab4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712164849; c=relaxed/simple; bh=OVKcgb9zjiNlhCzNE3c8lkJ7toq0usAeeT9Ux2Oi8ew=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Yz4aFGfCv/Ll5+mDJo1+/iCq4au1QA7dIcbXv7LdKY006b9egcv/VqCEmKMvm56LvmRzYk15zFfRpp0U+WvqyQ79O/b/aGUA6tpPC87vP/MwbXOFktvoB+f3YnCv4Mabqm4Mzkq0Y6QtZdQ4lJyvu2zCrNU5/0ozpK0wqh8ZV0g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=f1bLCtQF; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="f1bLCtQF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4B155C433F1; Wed, 3 Apr 2024 17:20:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1712164849; bh=OVKcgb9zjiNlhCzNE3c8lkJ7toq0usAeeT9Ux2Oi8ew=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=f1bLCtQFl0XnQ/G+RX+NcXYdgVjh18yKaP58T3rMHYaAzuiB/r9xErQJiHI3GOHlq JsNMOlq7ymrXUvWT6UJCrwabuxrlcFHpjrA+68GuCfPeK2cFGjRMFTAk/S9kCQiNTp GryBhu239XRuzXTSAkBn0lYUmiSz2bvM279kJJ9BecvN76qwGV0VYLfNyqnaYmAUlN 539MM/kFWpDGW7M1lAe8CHlSL0NgUavUVZqkMRa6j6Vs1YB5iM/Pqb8W4il7FKbQnt FZE3b7+XRrjlzpUyMBJKCVWsp5XR20dU5dhgrzaJjj17Rach70OpnGXA9NFxrPg4Bc /wVJB3txzKuew== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Roman Smirnov , Sergey Shtylyov , Helge Deller , Sasha Levin , daniel@ffwll.ch, linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: [PATCH AUTOSEL 4.19 5/5] fbmon: prevent division by zero in fb_videomode_from_videomode() Date: Wed, 3 Apr 2024 13:20:38 -0400 Message-ID: <20240403172041.354877-5-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240403172041.354877-1-sashal@kernel.org> References: <20240403172041.354877-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-fbdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 4.19.311 Content-Transfer-Encoding: 8bit From: Roman Smirnov [ Upstream commit c2d953276b8b27459baed1277a4fdd5dd9bd4126 ] The expression htotal * vtotal can have a zero value on overflow. It is necessary to prevent division by zero like in fb_var_to_videomode(). Found by Linux Verification Center (linuxtesting.org) with Svace. Signed-off-by: Roman Smirnov Reviewed-by: Sergey Shtylyov Signed-off-by: Helge Deller Signed-off-by: Sasha Levin --- drivers/video/fbdev/core/fbmon.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/video/fbdev/core/fbmon.c b/drivers/video/fbdev/core/fbmon.c index 8607439d69328..e4040fb860bbc 100644 --- a/drivers/video/fbdev/core/fbmon.c +++ b/drivers/video/fbdev/core/fbmon.c @@ -1309,7 +1309,7 @@ int fb_get_mode(int flags, u32 val, struct fb_var_screeninfo *var, struct fb_inf int fb_videomode_from_videomode(const struct videomode *vm, struct fb_videomode *fbmode) { - unsigned int htotal, vtotal; + unsigned int htotal, vtotal, total; fbmode->xres = vm->hactive; fbmode->left_margin = vm->hback_porch; @@ -1342,8 +1342,9 @@ int fb_videomode_from_videomode(const struct videomode *vm, vtotal = vm->vactive + vm->vfront_porch + vm->vback_porch + vm->vsync_len; /* prevent division by zero */ - if (htotal && vtotal) { - fbmode->refresh = vm->pixelclock / (htotal * vtotal); + total = htotal * vtotal; + if (total) { + fbmode->refresh = vm->pixelclock / total; /* a mode must have htotal and vtotal != 0 or it is invalid */ } else { fbmode->refresh = 0; -- 2.43.0