From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by sourceware.org (Postfix) with ESMTPS id 0022D3AABC81 for ; Fri, 20 Mar 2020 21:24:10 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 0022D3AABC81 Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 02KL6tHc121503; Fri, 20 Mar 2020 17:24:10 -0400 Received: from ppma02dal.us.ibm.com (a.bd.3ea9.ip4.static.sl-reverse.com [169.62.189.10]) by mx0a-001b2d01.pphosted.com with ESMTP id 2yu71cpqg6-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 20 Mar 2020 17:24:10 -0400 Received: from pps.filterd (ppma02dal.us.ibm.com [127.0.0.1]) by ppma02dal.us.ibm.com (8.16.0.27/8.16.0.27) with SMTP id 02KLKwD1009508; Fri, 20 Mar 2020 21:24:09 GMT Received: from b03cxnp08025.gho.boulder.ibm.com (b03cxnp08025.gho.boulder.ibm.com [9.17.130.17]) by ppma02dal.us.ibm.com with ESMTP id 2yrpw7g16q-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 20 Mar 2020 21:24:09 +0000 Received: from b03ledav005.gho.boulder.ibm.com (b03ledav005.gho.boulder.ibm.com [9.17.130.236]) by b03cxnp08025.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 02KLO7vI55312678 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 20 Mar 2020 21:24:08 GMT Received: from b03ledav005.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E2152BE04F; Fri, 20 Mar 2020 21:24:07 +0000 (GMT) Received: from b03ledav005.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6282FBE051; Fri, 20 Mar 2020 21:24:07 +0000 (GMT) Received: from linux.ibm.com (unknown [9.85.181.175]) by b03ledav005.gho.boulder.ibm.com (Postfix) with ESMTP; Fri, 20 Mar 2020 21:24:07 +0000 (GMT) From: Tulio Magno Quites Machado Filho To: libc-stable@sourceware.org Cc: Andreas Schwab Subject: [2.26 COMMITTED] Fix use-after-free in glob when expanding ~user (bug 25414) Date: Fri, 20 Mar 2020 18:23:20 -0300 Message-Id: <20200320212320.203179-2-tuliom@linux.ibm.com> X-Mailer: git-send-email 2.24.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138, 18.0.645 definitions=2020-03-20_07:2020-03-20, 2020-03-20 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 lowpriorityscore=0 malwarescore=0 impostorscore=0 mlxscore=0 phishscore=0 priorityscore=1501 adultscore=0 clxscore=1015 bulkscore=0 mlxlogscore=785 suspectscore=3 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2003200081 X-Spam-Status: No, score=-27.6 required=5.0 tests=BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_DMARC_STATUS, RCVD_IN_DNSWL_LOW, SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-stable@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-stable mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 20 Mar 2020 21:24:12 -0000 From: Andreas Schwab The value of `end_name' points into the value of `dirname', thus don't deallocate the latter before the last use of the former. (cherry picked from commit ddc650e9b3dc916eab417ce9f79e67337b05035c with changes from commit d711a00f93fa964f41a53839228598fbf1a6b482) --- NEWS | 4 ++++ posix/glob.c | 28 +++++++++++++++++----------- 2 files changed, 21 insertions(+), 11 deletions(-) diff --git a/NEWS b/NEWS index cb62587dbb..b18a0f3d29 100644 --- a/NEWS +++ b/NEWS @@ -394,6 +394,9 @@ Security related changes: * A use-after-free vulnerability in clntudp_call in the Sun RPC system has been fixed (CVE-2017-12133). +* A use-after-free vulnerability in the glob function when expanding ~user has + been fixed (CVE-2020-1752). + The following bugs are resolved with this release: [984] network: Respond to changed resolv.conf in gethostbyname @@ -621,6 +624,7 @@ The following bugs are resolved with this release: [21839] localedata: Fix LC_MONETARY for ta_LK [21844] localedata: Fix Latin characters and Months Sequence. [21848] localedata: Fix mai_NP Title Name + [25414] 'glob' use-after-free bug (CVE-2020-1752) Version 2.25 diff --git a/posix/glob.c b/posix/glob.c index b2273ea7bc..0c6eeb3637 100644 --- a/posix/glob.c +++ b/posix/glob.c @@ -947,26 +947,32 @@ glob (const char *pattern, int flags, int (*errfunc) (const char *, int), size_t home_len = strlen (p->pw_dir); size_t rest_len = end_name == NULL ? 0 : strlen (end_name); - if (__glibc_unlikely (malloc_dirname)) - free (dirname); - malloc_dirname = 0; + char *d, *newp; + bool use_alloca = glob_use_alloca (alloca_used, + home_len + rest_len + 1); - if (glob_use_alloca (alloca_used, home_len + rest_len + 1)) - dirname = alloca_account (home_len + rest_len + 1, - alloca_used); + if (use_alloca) + newp = alloca_account (home_len + rest_len + 1, alloca_used); else { - dirname = malloc (home_len + rest_len + 1); - if (dirname == NULL) + newp = malloc (home_len + rest_len + 1); + if (newp == NULL) { free (malloc_pwtmpbuf); retval = GLOB_NOSPACE; goto out; } - malloc_dirname = 1; } - *((char *) mempcpy (mempcpy (dirname, p->pw_dir, home_len), - end_name, rest_len)) = '\0'; + + d = mempcpy (newp, p->pw_dir, home_len); + if (end_name != NULL) + d = mempcpy (d, end_name, rest_len); + *d = '\0'; + + if (__glibc_unlikely (malloc_dirname)) + free (dirname); + dirname = newp; + malloc_dirname = !use_alloca; dirlen = home_len + rest_len; dirname_modified = 1; -- 2.24.1