From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5481BC433FF for ; Thu, 8 Aug 2019 00:43:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2EB5D2186A for ; Thu, 8 Aug 2019 00:43:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730149AbfHHAna (ORCPT ); Wed, 7 Aug 2019 20:43:30 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:9592 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729624AbfHHAna (ORCPT ); Wed, 7 Aug 2019 20:43:30 -0400 Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x780fXOR164358; Wed, 7 Aug 2019 20:43:25 -0400 Received: from ppma03wdc.us.ibm.com (ba.79.3fa9.ip4.static.sl-reverse.com [169.63.121.186]) by mx0b-001b2d01.pphosted.com with ESMTP id 2u88ke9py8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 07 Aug 2019 20:43:25 -0400 Received: from pps.filterd (ppma03wdc.us.ibm.com [127.0.0.1]) by ppma03wdc.us.ibm.com (8.16.0.27/8.16.0.27) with SMTP id x780Q2h5013670; Thu, 8 Aug 2019 00:43:25 GMT Received: from b03cxnp08027.gho.boulder.ibm.com (b03cxnp08027.gho.boulder.ibm.com [9.17.130.19]) by ppma03wdc.us.ibm.com with ESMTP id 2u51w645ev-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 08 Aug 2019 00:43:25 +0000 Received: from b03ledav004.gho.boulder.ibm.com (b03ledav004.gho.boulder.ibm.com [9.17.130.235]) by b03cxnp08027.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x780hOWG60358964 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 8 Aug 2019 00:43:24 GMT Received: from b03ledav004.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 378587805F; Thu, 8 Aug 2019 00:43:24 +0000 (GMT) Received: from b03ledav004.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D8C777805E; Thu, 8 Aug 2019 00:43:22 +0000 (GMT) Received: from morokweng.localdomain (unknown [9.85.230.139]) by b03ledav004.gho.boulder.ibm.com (Postfix) with ESMTPS; Thu, 8 Aug 2019 00:43:22 +0000 (GMT) References: <201908072140.Qep3jWIW%lkp@intel.com> <2ee96e49ade2e30a44fa14840610b432@lip6.fr> User-agent: mu4e 1.2.0; emacs 26.2 From: Thiago Jung Bauermann To: Julia Lawall Cc: Mimi Zohar , linux-integrity@vger.kernel.org, kbuild-all@01.org Subject: [PATCH] ima: Fix use after free in ima_read_modsig() In-reply-to: <2ee96e49ade2e30a44fa14840610b432@lip6.fr> Date: Wed, 07 Aug 2019 21:43:18 -0300 Message-ID: <8736ico5ax.fsf@morokweng.localdomain> MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-08-07_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=2 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908080002 Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Julia Lawall writes: > This looks risky. See lines 80 and 81. That is indeed a bug. Thanks for spotting it! Here's the fix: >From 445e9ab15f61dc3b1fa1a30495d233bd2d2ecdaa Mon Sep 17 00:00:00 2001 From: Thiago Jung Bauermann Date: Wed, 7 Aug 2019 21:29:53 -0300 Subject: [PATCH] ima: Fix use after free in ima_read_modsig() If we can't parse the PKCS7 in the appended modsig, we will free the modsig structure and then access one of its members to determine the error value. Fixes: 39b07096364a ("ima: Implement support for module-style appended signatures") Reported-by: kbuild test robot Reported-by: Julia Lawall Signed-off-by: Thiago Jung Bauermann --- security/integrity/ima/ima_modsig.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/security/integrity/ima/ima_modsig.c b/security/integrity/ima/ima_modsig.c index c412e31d1714..d106885cc495 100644 --- a/security/integrity/ima/ima_modsig.c +++ b/security/integrity/ima/ima_modsig.c @@ -91,8 +91,9 @@ int ima_read_modsig(enum ima_hooks func, const void *buf, loff_t buf_len, hdr->pkcs7_msg = pkcs7_parse_message(buf + buf_len, sig_len); if (IS_ERR(hdr->pkcs7_msg)) { + rc = PTR_ERR(hdr->pkcs7_msg); kfree(hdr); - return PTR_ERR(hdr->pkcs7_msg); + return rc; } memcpy(hdr->raw_pkcs7, buf + buf_len, sig_len);