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 3A92B1586FA; Wed, 3 Apr 2024 17:17:47 +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=1712164668; cv=none; b=uHmRLylpGIWjtQ0wOGA+kEb3vc5WnGL9TRuXVWbfb1KEzwUeHeZgNKQ1nEOQKYvT1L8cUklxob5ArmYrzFa/qx00+nWfWX5gGyc8V4JVqbJf/s4Hm8ziNFpzRTCgn/XlprOCxEugyvTFfA9lS1r3ahHMRjdwczXjRLO8M1L5pew= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712164668; c=relaxed/simple; bh=hpvSuFBNptZidQwfefjWF5ZfybfxvIK+yhTcUOeTRwo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nJQhvdIzgVUsdIe5hw3gBelIlOuD/KIYJqIhUZ3JAIxqK44Bl2Yqf6Ol8EpNkfB7WXrnnMPicjrAnvvgoNYE+fxHLjJQq9nFNtiXqLXSpjCHgD2YT47G/w4t9YmbM6ZRHGxT8i2QQtp/few9QaKNrAretiOtPCqER8ITyQA/kP8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lEqQeOgS; 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="lEqQeOgS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CA6BDC433A6; Wed, 3 Apr 2024 17:17:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1712164667; bh=hpvSuFBNptZidQwfefjWF5ZfybfxvIK+yhTcUOeTRwo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lEqQeOgSFPMiRgpBF1qKb+G38gRjx9007SNB23JnpyaMYOe9N5ENqWfzWqg0EHzyx VGmxPZ4RRxbhpSRvk8ANVQ/mq6PECAC/D0Ew8sUqE3Br1M/Vy9D6dqAP9FIaDjPAFf mMw37o0t9El6WKeZh87nUIkjMH8/Lw1J0SfsRi8TewAClRcyfpmOFTvhvWVEXf6gM9 +EqRPKjUPYQa1nbKkSu4KNEjKyD4TC7nejTQahVQ7U9Ztte0LQjmD/MUG/QqXuCfxn QZ6XztRI8ZLOcsJ80pZdChbvqll8ebksmx+La6vo4bcq6H6ssNx/Z931iQSvBKLi3i j6buQj4XnFq3A== 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 6.8 25/28] fbmon: prevent division by zero in fb_videomode_from_videomode() Date: Wed, 3 Apr 2024 13:16:27 -0400 Message-ID: <20240403171656.335224-25-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240403171656.335224-1-sashal@kernel.org> References: <20240403171656.335224-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.8.3 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 79e5bfbdd34c2..0a26399dbc899 100644 --- a/drivers/video/fbdev/core/fbmon.c +++ b/drivers/video/fbdev/core/fbmon.c @@ -1311,7 +1311,7 @@ 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; @@ -1344,8 +1344,9 @@ 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