From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by sourceware.org (Postfix) with ESMTPS id C643C385F02A for ; Fri, 20 Mar 2020 21:04:06 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org C643C385F02A Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 02KL30B5116700; Fri, 20 Mar 2020 17:04:06 -0400 Received: from ppma04dal.us.ibm.com (7a.29.35a9.ip4.static.sl-reverse.com [169.53.41.122]) by mx0b-001b2d01.pphosted.com with ESMTP id 2yu98vyj6a-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 20 Mar 2020 17:04:06 -0400 Received: from pps.filterd (ppma04dal.us.ibm.com [127.0.0.1]) by ppma04dal.us.ibm.com (8.16.0.27/8.16.0.27) with SMTP id 02KKnfbo015044; Fri, 20 Mar 2020 21:04:05 GMT Received: from b01cxnp23034.gho.pok.ibm.com (b01cxnp23034.gho.pok.ibm.com [9.57.198.29]) by ppma04dal.us.ibm.com with ESMTP id 2yrpw7g2pr-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 20 Mar 2020 21:04:05 +0000 Received: from b01ledav006.gho.pok.ibm.com (b01ledav006.gho.pok.ibm.com [9.57.199.111]) by b01cxnp23034.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 02KL45NV49676688 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 20 Mar 2020 21:04:05 GMT Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 05CB1AC05F; Fri, 20 Mar 2020 21:04:05 +0000 (GMT) Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9C958AC05E; Fri, 20 Mar 2020 21:04:04 +0000 (GMT) Received: from linux.ibm.com (unknown [9.85.181.175]) by b01ledav006.gho.pok.ibm.com (Postfix) with ESMTP; Fri, 20 Mar 2020 21:04:04 +0000 (GMT) From: Tulio Magno Quites Machado Filho To: libc-stable@sourceware.org Cc: Andreas Schwab Subject: [2.28 COMMITTED] Fix use-after-free in glob when expanding ~user (bug 25414) Date: Fri, 20 Mar 2020 18:03:33 -0300 Message-Id: <20200320210333.202385-2-tuliom@linux.ibm.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200320210333.202385-1-tuliom@linux.ibm.com> References: <20200320210333.202385-1-tuliom@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 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 phishscore=0 clxscore=1015 adultscore=0 mlxlogscore=906 suspectscore=4 impostorscore=0 mlxscore=0 lowpriorityscore=0 malwarescore=0 bulkscore=0 priorityscore=1501 spamscore=0 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 21:04:08 -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) --- NEWS | 4 ++++ posix/glob.c | 25 +++++++++++++------------ 2 files changed, 17 insertions(+), 12 deletions(-) diff --git a/NEWS b/NEWS index 038541c83b..1d00542a5d 100644 --- a/NEWS +++ b/NEWS @@ -73,6 +73,7 @@ The following bugs are resolved with this release: [25204] Ignore LD_PREFER_MAP_32BIT_EXEC for SUID programs [25225] ld.so fails to link on x86 if GCC defaults to -fcf-protection [25232] No const correctness for strchr et al. for Clang++ + [25414] 'glob' use-after-free bug (CVE-2020-1752) [25423] Array overflow in backtrace on powerpc Security related changes: @@ -109,6 +110,9 @@ Security related changes: addresses for loaded libraries and thus bypass ASLR for a setuid program. Reported by Marcin Kościelnicki. + CVE-2020-1752: A use-after-free vulnerability in the glob function when + expanding ~user has been fixed. + Version 2.28 diff --git a/posix/glob.c b/posix/glob.c index 8444b2f79e..1b389d2da1 100644 --- a/posix/glob.c +++ b/posix/glob.c @@ -827,31 +827,32 @@ __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); - char *d; + char *d, *newp; + bool use_alloca = glob_use_alloca (alloca_used, + home_len + rest_len + 1); - if (__glibc_unlikely (malloc_dirname)) - free (dirname); - malloc_dirname = 0; - - 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) { scratch_buffer_free (&pwtmpbuf); retval = GLOB_NOSPACE; goto out; } - malloc_dirname = 1; } - d = mempcpy (dirname, p->pw_dir, home_len); + 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