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 38E58221F31 for ; Fri, 27 Jun 2025 20:23:38 +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=1751055823; cv=none; b=P3h8wmpXwj2Afrcrgm+m7b1L46WHhGG+vclRxVwl9ScW1VlvxmalnXSQjlc+OvdvRisGD3yvJ2iIgmVBR1C9zKtKapUEUP6TFrxIPJp4YEJra7ZTmINusZD0rK7/qXkHle5fjS1eOrbOo+RmL/10Ay7TWxdwNvK7WUZeUd8wU+g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751055823; c=relaxed/simple; bh=ieCYx06r3guWCSz2kV6ZQqbtoJFgArp/xJbXkaOvFWs=; h=Message-ID:Date:MIME-Version:Subject:From:To:References: In-Reply-To:Content-Type; b=Qt6351MsuitxS93hNNxOyHi/f1sgz5p9T1FKSrYrx/u3zHKOoyb1IQ1V/e0UcBEXwc4ntQcHRS64KG6U1funcUs77BlH0wBl27RadX2zydQOywmTxKwEHTY5zjxTCaSGLcCUVmlwOGGijT4GMyo2Hu+lxO5fKFtY7vtqjaEq6pw= 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] (213.87.153.12) 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; Fri, 27 Jun 2025 23:23:21 +0300 Message-ID: Date: Fri, 27 Jun 2025 23:23:20 +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: , Trond Myklebust , Anna Schumaker References: <4904f32e-a392-803b-9766-4aa2d5cee12b@omp.ru> Content-Language: en-US Organization: Open Mobile Platform In-Reply-To: <4904f32e-a392-803b-9766-4aa2d5cee12b@omp.ru> 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: 06/27/2025 20:08:19 X-KSE-AntiSpam-Status: KAS_STATUS_NOT_DETECTED X-KSE-AntiSpam-Method: none X-KSE-AntiSpam-Rate: 19 X-KSE-AntiSpam-Info: Lua profiles 194401 [Jun 27 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: 213.87.153.12 in (user) b.barracudacentral.org} X-KSE-AntiSpam-Info: 127.0.0.199:7.1.2;d41d8cd98f00b204e9800998ecf8427e.com:7.1.1;omp.ru:7.1.1 X-KSE-AntiSpam-Info: {Tracking_ip_hunter} X-KSE-AntiSpam-Info: FromAlignment: s X-KSE-AntiSpam-Info: ApMailHostAddress: 213.87.153.12 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: 06/27/2025 20:10:00 X-KSE-Antivirus-Interceptor-Info: scan successful X-KSE-Antivirus-Info: Clean, bases: 6/27/2025 7:10:00 PM X-KSE-Attachment-Filter-Triggered-Rules: Clean X-KSE-Attachment-Filter-Triggered-Filters: Clean X-KSE-BulkMessagesFiltering-Scan-Result: InTheLimit On 8/23/24 11:32 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 As the multiplication by HZ is performed on 32-bit field, the overflow will occur regardless of 32/64-bitness... > 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) > * nfs4_set_lease_period - Sets the lease period on a nfs_client > * > * @clp: pointer to nfs_client > - * @lease: new value for lease period > + * @period: new value for lease period (in seconds) > */ > -void nfs4_set_lease_period(struct nfs_client *clp, > - unsigned long lease) > +int nfs4_set_lease_period(struct nfs_client *clp, u32 period) > { > + u64 result = mul_u32_u32(period, HZ); > + unsigned long lease = result; > + > + /* First see if period * HZ actually fits into unsigned long... */ > + if (result > ULONG_MAX) > + return -ERANGE; > + Now that I have discovered check_mul_overflow(), I think I'll have to rewrite this code using it instead... [...] MBR, Sergey