From mboxrd@z Thu Jan 1 00:00:00 1970 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 552EB143742 for ; Mon, 10 Jun 2024 17:50:46 +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=1718041849; cv=none; b=XF8crI6qlxpJxBVgd0DP8rjXGhjXZ01+QS4kUhhBuJMGBlNTo0Qj7JvyVESu81DLqqjtWijFdgmXnjTsxlb3XANeI/4vi4OB7bcxhs3MiLw3nMEQjcT1V9LKerUGc1ogi5Hwm5S26zst1HuaaV0VazbjlDZ3x4bGEdX4Nyk+Ps0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718041849; c=relaxed/simple; bh=ruWNEcf0BDSZHErPpwcsr9VitpsVDWtnotTNfWKkD1U=; h=Subject:To:CC:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=OUvX7ta4F7ARdUIDF30/1vQ2v1uEoQvKjLlnw1/wh4XgekTSFE0PoFoiHtBOVIC0B1QPzSi8bjmSzsRMWtQm6ELljvMOUvFlqstSEYGhxN3hSGXpi/TsN1a0qEvrjnRfsC2yFyBGGms1va86H6+pPCUfgLXPy/VdKc+iAS4bUiM= 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 [192.168.1.105] (178.176.78.79) 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; Mon, 10 Jun 2024 20:50:36 +0300 Subject: Re: [PATCH] udf: balloc: prevent integer overflow in udf_bitmap_free_blocks() To: Roman Smirnov , Jan Kara , CC: References: <20240610072523.12002-1-r.smirnov@omp.ru> From: Sergey Shtylyov Organization: Open Mobile Platform Message-ID: <4ca63af4-df02-32e6-3531-1e5df154c13e@omp.ru> Date: Mon, 10 Jun 2024 20:50:35 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20240610072523.12002-1-r.smirnov@omp.ru> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit 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: 06/10/2024 17:37:56 X-KSE-AntiSpam-Status: KAS_STATUS_NOT_DETECTED X-KSE-AntiSpam-Method: none X-KSE-AntiSpam-Rate: 59 X-KSE-AntiSpam-Info: Lua profiles 185843 [Jun 10 2024] X-KSE-AntiSpam-Info: Version: 6.1.0.4 X-KSE-AntiSpam-Info: Envelope from: s.shtylyov@omp.ru X-KSE-AntiSpam-Info: LuaCore: 20 0.3.20 743589a8af6ec90b529f2124c2bbfc3ce1d2f20f X-KSE-AntiSpam-Info: {rep_avail} X-KSE-AntiSpam-Info: {Tracking_phishing_log_reg_60_70} 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: 178.176.78.79 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: FromAlignment: s X-KSE-AntiSpam-Info: {rdns complete} X-KSE-AntiSpam-Info: {fromrtbl complete} X-KSE-AntiSpam-Info: ApMailHostAddress: 178.176.78.79 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=none header.from=omp.ru;spf=none 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: 06/10/2024 17:41:00 X-KSE-Antivirus-Interceptor-Info: scan successful X-KSE-Antivirus-Info: Clean, bases: 6/10/2024 2:11:00 PM X-KSE-Attachment-Filter-Triggered-Rules: Clean X-KSE-Attachment-Filter-Triggered-Filters: Clean X-KSE-BulkMessagesFiltering-Scan-Result: InTheLimit On 6/10/24 10:25 AM, Roman Smirnov wrote: > An overflow may occur if the function is called with the last > block and an offset greater than zero. It is necessary to add > a check to avoid this. > > Found by Linux Verification Center (linuxtesting.org) with Svace. > > Signed-off-by: Roman Smirnov > --- > fs/udf/balloc.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/fs/udf/balloc.c b/fs/udf/balloc.c > index ab3ffc355949..cd83bbc7d890 100644 > --- a/fs/udf/balloc.c > +++ b/fs/udf/balloc.c > @@ -151,6 +151,13 @@ static void udf_bitmap_free_blocks(struct super_block *sb, > block = bloc->logicalBlockNum + offset + > (sizeof(struct spaceBitmapDesc) << 3); Hm, I can't say I understand this code well... Is the block variable here counted in blocks or bytes? > As I've already said, we hardly need an empty line here -- just don't add an empty line after your *if*... > + if (block < offset + (sizeof(struct spaceBitmapDesc) << 3)) { Thinking about this again, this addition may overflow 32 bits as well, so it's better to compare block with bloc->logicalBlockNum... [...] MBR, Sergey