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 193F11DB13A for ; Sat, 28 Jun 2025 20:09:09 +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=1751141357; cv=none; b=LWPTqN9zNdrd0PHfjvBI/Hp1i25Q23rvKm+q7qMk93EXrFZI3wlaSPQUOP2lCEJ0sAkoQixrRr3jB9yuWptNuqTnrO2aZeKnLRv++blNmVyg1Ge9LfQyCvtGaRTvael1Xq/cyQfCKwDcVOfnFWsc6hSxqU5YWgXqbxhRjAlqlfc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751141357; c=relaxed/simple; bh=5hWkkrj0Kz+tzvW51IeBJYR498i4gZqIZsFEkkRwr+A=; h=Message-ID:Date:MIME-Version:Subject:From:To:References: In-Reply-To:Content-Type; b=p+oimJi1QsjmL75pCfIE1guhSvEtrf7VqjGZmcjIOvfCeN/Jbi5zwb6ZEF+E/tHTsuk4euxHfUebESaAxFiCA/l6yMWPm95sBeyPOcOQWLdwJ6UuhaT5TTjI9ngnAJJy0MQ4/PphfdgOFymPMwJoF/ujoEBOAlisDcZE912Pv/g= 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 [192.168.2.102] (213.87.128.215) 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; Sat, 28 Jun 2025 23:08:59 +0300 Message-ID: Date: Sat, 28 Jun 2025 23:08:58 +0300 Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] NFSv4: prevent integer overflow while calling nfs4_set_lease_period() From: Sergey Shtylyov To: Anna Schumaker , , Trond Myklebust , Anna Schumaker References: <4904f32e-a392-803b-9766-4aa2d5cee12b@omp.ru> <7206ed18-0e5b-4306-b451-e7eecde71d9f@oracle.com> Content-Language: en-US Organization: Open Mobile Platform In-Reply-To: Content-Type: text/plain; charset="UTF-8" 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: 6.1.1, Database issued on: 06/28/2025 19:52:16 X-KSE-AntiSpam-Status: KAS_STATUS_NOT_DETECTED X-KSE-AntiSpam-Method: none X-KSE-AntiSpam-Rate: 19 X-KSE-AntiSpam-Info: Lua profiles 194405 [Jun 28 2025] X-KSE-AntiSpam-Info: Version: 6.1.1.11 X-KSE-AntiSpam-Info: Envelope from: s.shtylyov@omp.ru X-KSE-AntiSpam-Info: LuaCore: 62 0.3.62 e2af3448995f5f8a7fe71abf21bb23519d0f38c3 X-KSE-AntiSpam-Info: {rep_avail} X-KSE-AntiSpam-Info: {Tracking_uf_ne_domains} X-KSE-AntiSpam-Info: {Tracking_from_domain_doesnt_match_to} X-KSE-AntiSpam-Info: {SMTP from is not routable} X-KSE-AntiSpam-Info: {Found in DNSBL: 213.87.128.215 in (user) b.barracudacentral.org} X-KSE-AntiSpam-Info: {Found in DNSBL: 213.87.128.215 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: {Tracking_ip_hunter} X-KSE-AntiSpam-Info: FromAlignment: s X-KSE-AntiSpam-Info: ApMailHostAddress: 213.87.128.215 X-KSE-AntiSpam-Info: {DNS response errors} X-KSE-AntiSpam-Info: Rate: 19 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: 06/28/2025 19:54:00 X-KSE-Antivirus-Interceptor-Info: scan successful X-KSE-Antivirus-Info: Clean, bases: 6/28/2025 6:40:00 PM X-KSE-Attachment-Filter-Triggered-Rules: Clean X-KSE-Attachment-Filter-Triggered-Filters: Clean X-KSE-BulkMessagesFiltering-Scan-Result: InTheLimit On 9/18/24 11:52 PM, Sergey Shtylyov wrote: [...] >>> The nfs_client::cl_lease_time field (as well as the jiffies variable it's >>> used with) is declared as *unsigned long*, which is 32-bit type on 32-bit >>> arches and 64-bit type on 64-bit arches. When nfs4_set_lease_period() that >>> sets nfs_client::cl_lease_time is called, 32-bit nfs_fsinfo::lease_time >>> field is multiplied by HZ -- that might overflow *unsigned long* on 32-bit >>> arches. Actually, there's no need to multiply by HZ at all the call sites >>> of nfs4_set_lease_period() -- it makes more sense to do that once, inside >>> that function (using mul_u32_u32(), as it produces a better code on 32-bit >>> x86 arch), also checking for an overflow there and returning -ERANGE if it >>> does happen (we're also making that function *int* instead of *void* and >>> adding the result checks to its callers)... >>> >>> Found by Linux Verification Center (linuxtesting.org) with the Svace static >>> analysis tool. >>> >>> Signed-off-by: Sergey Shtylyov >>> Cc: stable@vger.kernel.org > [...] > >>> Index: linux-nfs/fs/nfs/nfs4renewd.c >>> =================================================================== >>> --- linux-nfs.orig/fs/nfs/nfs4renewd.c >>> +++ linux-nfs/fs/nfs/nfs4renewd.c >>> @@ -137,15 +137,22 @@ nfs4_kill_renewd(struct nfs_client *clp) [...] >>> + unsigned long lease = result; >>> + >>> + /* First see if period * HZ actually fits into unsigned long... */ >>> + if (result > ULONG_MAX) >>> + return -ERANGE; >> >> However, I'm not sold that this should be an error condition. I wonder if it would be better to change the clp->cl_lease_time field to a u64 so it has the same size on 32bit and 64bit architectures? > > That would be much more invasive change. And pretty fruitless, I think, because nfs_client::cl_lease_time is only involved in the jiffies math, > and since jiffies is *unsigned long* (i.e. 32-bit on a 32-bit arch), the > results of our u64 math would get truncated to 32 bits anyway in the end... > Looking at time_{after|before}(), I even suspected they could complain > at compile time -- however I wasn't able to trigger that so far... Alternatively, we could set the lease variable on overflow to MAX_JIFFY_OFFSET which seems to be a max timeout in jiffies... [...] MBR, Sergey