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 B054C17837A; Thu, 12 Sep 2024 17:36:24 +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=1726162590; cv=none; b=gqTUE9ExYd899IppjxGDQou5fQFGLtaYB7ehERELKYoUkL0cDYQjwWG9AAfxKLBZ6+OyIMxCiWcpySosMm2dd29NB9sOCsEko3a1kFDSh7A3HhnDs0ZeI+2OEZRMx1s2Lu0cCZggCEBjgT/ukG9h/H4x6Rw51R67y3xHA1PhduQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726162590; c=relaxed/simple; bh=+FlbC/3U714LtmseffHdvybFIBJGuTjQcO+84rTczl0=; h=Subject:To:CC:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=WBISU5GQ8+RMMfI4fFrfdJnPbBCDYq2qosbkg3nm4LqzOIAI20lRY4k3a3vWhTDQl/uavzQocwI2D9JSRAafACBzSnYodqk4qTereKltjPJAzGtq1XFJlf9e72KzkuGlS0kLVZ4bGesnPXBuGVLvOf25YEQm3MtNop/K+eN2fso= 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] (178.176.74.114) 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 20:36:10 +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> <8774f6a2-9bec-b699-6b68-63a26019c5b3@omp.ru> From: Sergey Shtylyov Organization: Open Mobile Platform Message-ID: Date: Thu, 12 Sep 2024 20:36:08 +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-crypto@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 17:17:50 X-KSE-AntiSpam-Status: KAS_STATUS_NOT_DETECTED X-KSE-AntiSpam-Method: none X-KSE-AntiSpam-Rate: 59 X-KSE-AntiSpam-Info: Lua profiles 187714 [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: 178.176.74.114 in (user) b.barracudacentral.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: ApMailHostAddress: 178.176.74.114 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 17:20:00 X-KSE-Antivirus-Interceptor-Info: scan successful X-KSE-Antivirus-Info: Clean, bases: 9/12/2024 1:09:00 PM X-KSE-Attachment-Filter-Triggered-Rules: Clean X-KSE-Attachment-Filter-Triggered-Filters: Clean X-KSE-BulkMessagesFiltering-Scan-Result: InTheLimit On 9/12/24 5:27 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... :-) > > Right (lazy validation, first null ignores rest) No, contrariwise: since we use && and !, first non-NULL would ignore the rest. > BR, Jarkko MBR, Sergey