From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELs2qV6dBXug59WvOKjEw3L4Hs7XgcmBpvmYleXPKAx/d6pofhF3i1LP/+dbTomQ0EGuHgXc ARC-Seal: i=1; a=rsa-sha256; t=1520536847; cv=none; d=google.com; s=arc-20160816; b=jKwHRENkB9ywAWFz7/IYPwdR7lpNfP2xQpoYUekGWB0ckcsUK+PVxE6ytrq7JRZ40x 1xNPaEEthnQb742gKvjvIViCdQtm7oGchHRX4mN2pOfWcMqDWz+nWLId0aeT6+Tg+031 RJKuYQvBqhVwgck6QTgAppTw17jbcjruYNZ4a6Ny4gmrFSpLjYWG7YPP1gPutGAN1InT pwWm7RNNVlwkkVRWlVfukD0M3hkjs3GoDvHP2MrB6hP9UBTsrQ2LSWCW2IGdrv3M9zQg GxBD/oBOvyZo0GEAzc7cfmMY7gLMO1nnCmpE17FEIq/Tzw0bgaLuO7M0LRHAn5JL8T8+ Hp1g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=message-id:content-transfer-encoding:mime-version:references :in-reply-to:date:cc:to:from:subject:delivered-to:list-id :list-subscribe:list-unsubscribe:list-help:list-post:precedence :mailing-list:arc-authentication-results; bh=Gr0ZDg7fk7B4fk2I5TNzHbQ37FYgt/SS399K0RcN0oA=; b=FWdkgDfq1ZBQdMG9jB9z9u3kx4IM9w5TJjdgJBdoMlfyhQlSfB25aRs2kgypIYpC3H K7gjYBVNST47n/uLg9SD6NHwFSOGcL2flREnv4/DDEokUS/zOOSCtkdJbZ1hxid8Re65 q/kSd+N4rMFoLsHhEiUWx69hfnjlKjLfE85/P5Nsw4HGTo8y0kAmCGZPIuXl5cCZbVMM OMbNzTOyJL/zTp2XKAslIFUvhIhnYNHxD94Ux6RkzzxZBj09i+Ex7PGVuOHPFWTC6gcT 823BRxaYT+fwTluqU3GGQu6NC1TEhpX6xXua9y+zvRhHrDisKx+kvRYE83lVBaVn5lfE 0/GA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of kernel-hardening-return-12252-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-12252-gregkh=linuxfoundation.org@lists.openwall.com; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=ibm.com Authentication-Results: mx.google.com; spf=pass (google.com: domain of kernel-hardening-return-12252-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-12252-gregkh=linuxfoundation.org@lists.openwall.com; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=ibm.com Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm List-Post: List-Help: List-Unsubscribe: List-Subscribe: Subject: Re: [PATCH] ima: drop vla in ima_audit_measurement() From: Mimi Zohar To: Tycho Andersen Cc: Andy Shevchenko , Dmitry Kasatkin , linux-integrity@vger.kernel.org, Linux Kernel Mailing List , kernel-hardening@lists.openwall.com, Richard Guy Briggs Date: Thu, 08 Mar 2018 14:20:17 -0500 In-Reply-To: <20180308190431.5fstqsjmbpquzqii@smitten> References: <20180308171456.2597-1-tycho@tycho.ws> <20180308183721.mnsrmhekyfo2dbso@smitten> <1520535030.3605.64.camel@linux.vnet.ibm.com> <20180308190431.5fstqsjmbpquzqii@smitten> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.20.5 (3.20.5-1.fc24) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 18030819-0040-0000-0000-0000043C8794 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18030819-0041-0000-0000-000020DFA8CF Message-Id: <1520536817.3605.74.camel@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-03-08_11:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1803080214 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1594389722092015419?= X-GMAIL-MSGID: =?utf-8?q?1594398444814811232?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Thu, 2018-03-08 at 12:04 -0700, Tycho Andersen wrote: > On Thu, Mar 08, 2018 at 01:50:30PM -0500, Mimi Zohar wrote: > > On Thu, 2018-03-08 at 11:37 -0700, Tycho Andersen wrote: > > > On Thu, Mar 08, 2018 at 07:47:37PM +0200, Andy Shevchenko wrote: > > > > On Thu, Mar 8, 2018 at 7:14 PM, Tycho Andersen wrote: > > > > > In keeping with the directive to get rid of VLAs [1], let's drop the VLA > > > > > from ima_audit_measurement(). We need to adjust the return type of > > > > > ima_audit_measurement, because now this function can fail if an allocation > > > > > fails. > > > > > > > > > > > > > > > > > + algo_hash_len = hash_len + strlen(algo_name) + 2; > > > > > + algo_hash = kzalloc(algo_hash_len, GFP_KERNEL); > > > > > > > > > - snprintf(algo_hash, sizeof(algo_hash), "%s:%s", algo_name, hash); > > > > > + snprintf(algo_hash, algo_hash_len, "%s:%s", algo_name, hash); > > > > > > > > kasprintf() ? > > > > > > Sure, in fact I think we could just do: > > > > > > - snprintf(algo_hash, algo_hash_len, "%s:%s", algo_name, hash); > > > - audit_log_untrustedstring(ab, algo_hash); > > > + audit_log_untrustedstring(ab, algo_name); > > > + audit_log_format(ab, ":"); > > > + audit_log_untrustedstring(ab, hash); > > > > > > and get rid of the allocation entirely. I'll test and make sure it > > > works and then re-send. > > > > The hash algorithm name is an enumeration that comes from the kernel. > >  It's defined in crypto/hash_info.c: hash_algo_name.  Why do we need > > to use audit_log_untrustedstring()? > > Yes, I suppose we don't need it for the hash either, since we're > generating that and we know it's just hex digits and not any audit > control characters or "s or anything. > > It looks like we could get rid of the other allocation too by just > using audit_log_n_hex, but that uses hex_byte_pack_upper, vs. the > hex_byte_pack that's currently in use in this function. Is that too > much of a breakage? Based on the discussion with Richard Briggs, we need to differentiate between the ima_audit_measurement() and the ima_parse_rule() usage of AUDIT_INTEGRITY_RULE.  The ima_parse_rule() will continue to use AUDIT_INTEGRITY_RULE.  ima_audit_measurement() will need to define and use a new number.  Auidt name suggestions would be appreciated. When we make that sort of change, any other changes are insignificant. How different are the two formats? Mimi