From patchwork Tue Mar 19 08:13:44 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roman Smirnov X-Patchwork-Id: 13596347 Received: from mx01.omp.ru (mx01.omp.ru [90.154.21.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 25E2C537E6; Tue, 19 Mar 2024 08:15:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.154.21.10 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710836111; cv=none; b=OrKTaxn6YU52YFL9bOFBaK3kf7Mm0X5u/2GxHhWIIyY2ftDJLyaczp2vTp8EpARHjWJNaH602Dh9SyF97LTyBPwAKP2JrWlFmNMLQbGAjxYIAZkQgzX9DRet14QJh2l4GTv/MUNLaEu71liY4wjbh1GtLs30jL7+6/YUtnPS/XE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710836111; c=relaxed/simple; bh=Xpl1PNiijVb96eyxuYzuhaSzH0o8grAW99xMC3OtEq8=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=G3mpXbbx6BJgHxLZYsIqzvzzihmUuy57e+kt68zBBg/kykkKRkOjHLga8BekubJyRmOTsUqbAvWMno5YZ8FiFu7kNnLKloKaxB72SdJjE6GEaEqaxc65BUMHtSbAKGWaehxz/oKLjtJjO519KuT6cqQ6IvdHQsbW6dOph50Esc4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=omp.ru; spf=pass smtp.mailfrom=omp.ru; arc=none smtp.client-ip=90.154.21.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=omp.ru Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=omp.ru Received: from localhost.localdomain (78.37.41.5) by msexch01.omp.ru (10.188.4.12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.2.1258.12; Tue, 19 Mar 2024 11:15:00 +0300 From: Roman Smirnov To: Daniel Vetter , Helge Deller CC: Roman Smirnov , Thomas Zimmermann , Sergey Shtylyov , Karina Yankevich , , , , Subject: [PATCH v3] fbmon: prevent division by zero in fb_videomode_from_videomode() Date: Tue, 19 Mar 2024 11:13:44 +0300 Message-ID: <20240319081344.7223-1-r.smirnov@omp.ru> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-fbdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: msexch01.omp.ru (10.188.4.12) To msexch01.omp.ru (10.188.4.12) X-KSE-ServerInfo: msexch01.omp.ru, 9 X-KSE-AntiSpam-Interceptor-Info: scan successful X-KSE-AntiSpam-Version: 6.1.0, Database issued on: 03/19/2024 07:53:33 X-KSE-AntiSpam-Status: KAS_STATUS_NOT_DETECTED X-KSE-AntiSpam-Method: none X-KSE-AntiSpam-Rate: 59 X-KSE-AntiSpam-Info: Lua profiles 184251 [Mar 19 2024] X-KSE-AntiSpam-Info: Version: 6.1.0.4 X-KSE-AntiSpam-Info: Envelope from: r.smirnov@omp.ru X-KSE-AntiSpam-Info: LuaCore: 10 0.3.10 53c821b925e16276b831986eabc71d60ab82ee60 X-KSE-AntiSpam-Info: {rep_avail} X-KSE-AntiSpam-Info: {Tracking_from_domain_doesnt_match_to} X-KSE-AntiSpam-Info: {relay has no DNS name} X-KSE-AntiSpam-Info: {SMTP from is not routable} X-KSE-AntiSpam-Info: {Found in DNSBL: 78.37.41.5 in (user) b.barracudacentral.org} X-KSE-AntiSpam-Info: {Found in DNSBL: 78.37.41.5 in (user) dbl.spamhaus.org} X-KSE-AntiSpam-Info: 127.0.0.199:7.1.2;omp.ru:7.1.1;d41d8cd98f00b204e9800998ecf8427e.com:7.1.1 X-KSE-AntiSpam-Info: ApMailHostAddress: 78.37.41.5 X-KSE-AntiSpam-Info: {DNS response errors} X-KSE-AntiSpam-Info: Rate: 59 X-KSE-AntiSpam-Info: Status: not_detected X-KSE-AntiSpam-Info: Method: none X-KSE-AntiSpam-Info: Auth:dmarc=temperror header.from=omp.ru;spf=temperror smtp.mailfrom=omp.ru;dkim=none X-KSE-Antiphishing-Info: Clean X-KSE-Antiphishing-ScanningType: Heuristic X-KSE-Antiphishing-Method: None X-KSE-Antiphishing-Bases: 03/19/2024 07:57:00 X-KSE-Antivirus-Interceptor-Info: scan successful X-KSE-Antivirus-Info: Clean, bases: 3/19/2024 6:00:00 AM X-KSE-Attachment-Filter-Triggered-Rules: Clean X-KSE-Attachment-Filter-Triggered-Filters: Clean X-KSE-BulkMessagesFiltering-Scan-Result: InTheLimit 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 --- V1 -> V2: Replaced the code of the first version with a check. V2 -> V3: Replaced the code of the second version with a zero check drivers/video/fbdev/core/fbmon.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/video/fbdev/core/fbmon.c b/drivers/video/fbdev/core/fbmon.c index 79e5bfbdd34c..ca946919d962 100644 --- a/drivers/video/fbdev/core/fbmon.c +++ b/drivers/video/fbdev/core/fbmon.c @@ -1344,7 +1344,7 @@ 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) { + if (htotal && vtotal && (htotal * vtotal)) { fbmode->refresh = vm->pixelclock / (htotal * vtotal); /* a mode must have htotal and vtotal != 0 or it is invalid */ } else {