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 8E7BF1A0BD4; Thu, 12 Sep 2024 13:51:43 +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=1726149110; cv=none; b=i5g2GSqvNnLlOGboZKUfGZq3v5ib9eGKcjxlIJ8+CnLCzZEBofmfqGzlAqqqBSIbSjRXthtWBSGZHakxOf9qhp28fnuvKZVo1KPsSvObSZd+xBJG7n7sGuVEZkIMVg3+62V68NZplQjs3da7JdzXDU14Sym4KLDPxyXUqCtaBi8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726149110; c=relaxed/simple; bh=qzHvcMNowk6NzrnJnzjlLOM0xR+661lK3QZTiFzxQc0=; h=Subject:To:CC:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=cezc3LNYIg3pXDIYllHma2ukaGt5Kg04lAHGO8XYu6+Awpxs6UwOG/7J0ukJ2a2JTB1CSZaZ9D/ZCOSWzsFsgU19OsbvkKfTNO174h7R5uOcmg6Lw5ATjS1oFqTV1W0Fhy7QvFNwa9nJGTzFYC0D35KvDMaggsd9yUTGd6dCp14= 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 [192.168.1.106] (31.173.87.196) 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; Thu, 12 Sep 2024 16:51:35 +0300 Subject: Re: [PATCH v2] KEYS: prevent NULL pointer dereference in find_asymmetric_key() To: Jarkko Sakkinen , Roman Smirnov , David Howells , Herbert Xu , "David S. Miller" , Andrew Zaborowski CC: , , , References: <20240910111806.65945-1-r.smirnov@omp.ru> <84d6b0fa-4948-fe58-c766-17f87c2a2dba@omp.ru> From: Sergey Shtylyov Organization: Open Mobile Platform Message-ID: <8774f6a2-9bec-b699-6b68-63a26019c5b3@omp.ru> Date: Thu, 12 Sep 2024 16:51:34 +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: 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: 6.1.1, Database issued on: 09/12/2024 13:36:58 X-KSE-AntiSpam-Status: KAS_STATUS_NOT_DETECTED X-KSE-AntiSpam-Method: none X-KSE-AntiSpam-Rate: 59 X-KSE-AntiSpam-Info: Lua profiles 187710 [Sep 12 2024] X-KSE-AntiSpam-Info: Version: 6.1.1.5 X-KSE-AntiSpam-Info: Envelope from: s.shtylyov@omp.ru X-KSE-AntiSpam-Info: LuaCore: 34 0.3.34 8a1fac695d5606478feba790382a59668a4f0039 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: 31.173.87.196 in (user) b.barracudacentral.org} X-KSE-AntiSpam-Info: {Found in DNSBL: 31.173.87.196 in (user) dbl.spamhaus.org} X-KSE-AntiSpam-Info: d41d8cd98f00b204e9800998ecf8427e.com:7.1.1;127.0.0.199:7.1.2;31.173.87.196:7.1.2;omp.ru:7.1.1 X-KSE-AntiSpam-Info: FromAlignment: s X-KSE-AntiSpam-Info: ApMailHostAddress: 31.173.87.196 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: 09/12/2024 13:41:00 X-KSE-Antivirus-Interceptor-Info: scan successful X-KSE-Antivirus-Info: Clean, bases: 9/12/2024 10:54:00 AM X-KSE-Attachment-Filter-Triggered-Rules: Clean X-KSE-Attachment-Filter-Triggered-Filters: Clean X-KSE-BulkMessagesFiltering-Scan-Result: InTheLimit On 9/11/24 4:18 PM, Jarkko Sakkinen wrote: [...] >>>> In find_asymmetric_key(), if all NULLs are passed in id_{0,1,2} parameters >>>> the kernel will first emit WARN and then have an oops because id_2 gets >>>> dereferenced anyway. >>>> >>>> Found by Linux Verification Center (linuxtesting.org) with Svace static >>>> analysis tool. >>> >>> Weird, I recall that I've either sent a patch to address the same site >>> OR have commented a patch with similar reasoning. Well, it does not >>> matter, I think it this makes sense to me. >>> >>> You could further add to the motivation that given the panic_on_warn >>> kernel command-line parameter, it is for the best limit the scope and >>> use of the WARN-macro. >> >> I don't understand what you mean -- this version of the patch keeps >> the WARN_ON() call, it just moves that call, so that the duplicate id_{0,1,2} >> checks are avoided... > > I overlooked the code change (my bad sorry). Here's a better version of > the first paragraph: > > "find_asymmetric_keys() has nullity checks of id_0 and id_1 but ignores > validation for id_2. Check nullity also for id_2." Hm, what about WARN_ON(!id_0 && !id_1 && !id_2) -- it used to check all the pointers, right? I think our variant was closer to reality... :-) [...] > BR, Jarkko MBR, Sergey