From patchwork Tue Mar 5 13:51:50 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roman Smirnov X-Patchwork-Id: 778664 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 55BD985642; Tue, 5 Mar 2024 13:52:56 +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=1709646781; cv=none; b=SkjhR40/3fmfNdNjwy1QOAeRrHOZtVDzQFXiCkQekA1BRDF/Wh/TCby1UN0Vg6ySxPzuc53BS4zJ8frF4ABhhgs01yYNr73Fvp56gHXNHatf+ln4vdv1ZeTLK61h0m9FJnUhIeyWPo9fMGFdAhHw3HNyLqiiPhBZkTIUoABG3hg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709646781; c=relaxed/simple; bh=L3FX6+fcZtzC0muuqsZRNP8m7eFA9OdDLL1jdvq6ldM=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=GJozrvTNfdG9IIHmCr/BoMGFVGDQzfG7dekC+sLKV2gH1GC2losMKmf/RVq/k10x43QuuEb+h8//M+ALlJ1/kl8Z6WGtWDqJK76gz57qV6pt1nANnYKoMakQS3Si8rBsLp6CD/7bmi73cR2o+UMYnFlW/VsLCQq3UWlbOfeZ1Ww= 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 (78.37.41.175) 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, 5 Mar 2024 16:52:48 +0300 From: Roman Smirnov To: Daniel Vetter , Helge Deller CC: Roman Smirnov , Thomas Zimmermann , Sergey Shtylyov , Karina Yankevich , , , , Subject: [PATCH v2] fbmon: prevent division by zero in fb_videomode_from_videomode() Date: Tue, 5 Mar 2024 16:51:50 +0300 Message-ID: <20240305135150.23240-1-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: 03/05/2024 13:15:25 X-KSE-AntiSpam-Status: KAS_STATUS_NOT_DETECTED X-KSE-AntiSpam-Method: none X-KSE-AntiSpam-Rate: 59 X-KSE-AntiSpam-Info: Lua profiles 183964 [Mar 05 2024] X-KSE-AntiSpam-Info: Version: 6.1.0.3 X-KSE-AntiSpam-Info: Envelope from: r.smirnov@omp.ru X-KSE-AntiSpam-Info: LuaCore: 8 0.3.8 4a99897b35b48c45ee5c877607d26a2d9f419920 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: 78.37.41.175 in (user) dbl.spamhaus.org} X-KSE-AntiSpam-Info: omp.ru:7.1.1; d41d8cd98f00b204e9800998ecf8427e.com:7.1.1; 127.0.0.199:7.1.2 X-KSE-AntiSpam-Info: ApMailHostAddress: 78.37.41.175 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: 03/05/2024 13:20:00 X-KSE-Antivirus-Interceptor-Info: scan successful X-KSE-Antivirus-Info: Clean, bases: 3/5/2024 11:10:00 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. 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..b137590386da 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 && (vm->pixelclock / htotal >= vtotal)) { fbmode->refresh = vm->pixelclock / (htotal * vtotal); /* a mode must have htotal and vtotal != 0 or it is invalid */ } else {