Bug 801648 (CVE-2012-1148)

Summary: CVE-2012-1148 expat: Memory leak in poolGrow
Product: [Other] Security Response Reporter: Kurt Seifried <kseifried>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: acathrow, alee, apevec, bbaranow, bmaxwell, bmcclain, bsettle, ccoleman, cdewolf, cfergeau, cfu, chazlett, cpelland, csutherl, dandread, darran.lofthouse, dblechte, dmcphers, dosoudil, dpal, erik-fedora, gzaronik, idith, jason.greene, jawilson, jboss-set, jclere, jdoyle, jgalipea, jialiu, jmagne, jorton, lgao, lmeyer, lsurette, mbabacek, mburns, mharmsen, michal.skrivanek, mizdebsk, mmcgrath, mnewsome, mturk, myarboro, pgier, psakar, pslavice, rh-spice-bugs, rjones, rmeggins, rnetuka, rsvoboda, seceng-idm-qe-list, slong, srevivo, twalsh, uril, vtunka, weli, ykaul
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
See Also: https://issues.redhat.com/browse/JBCS-50
https://issues.redhat.com/browse/JWS-221
Whiteboard:
Fixed In Version: expat 2.1.0 Doc Type: Bug Fix
Doc Text:
A memory leak flaw was found in Expat. If an XML file processed by an application linked against Expat triggered a memory re-allocation failure, Expat failed to free the previously allocated memory. This could cause the application to exit unexpectedly or crash when all available memory is exhausted.
Story Points: ---
Clone Of: Environment:
Last Closed: 2019-06-10 10:58:21 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 811830, 811831, 811832, 811833, 811834, 811835, 811836, 811837, 982563, 982566, 1200324, 1200326, 1238182, 1351488    
Bug Blocks: 801654, 1286624, 1395463    

Description Kurt Seifried 2012-03-09 04:54:47 UTC
Tim Boddy reported a memory leak in poolGrow [1]

This bug applies at least to 1.95.8, 2.0.0 and 2.0.1

poolGrow in xml.parse.cpp has the following block of code:
 
  if (pool->blocks && pool->start == pool->blocks->s) {
    int blockSize = (int)(pool->end - pool->start)*2;
    pool->blocks = (BLOCK *)
      pool->mem->realloc_fcn(pool->blocks,
                             (offsetof(BLOCK, s)
                              + blockSize * sizeof(XML_Char)));
    if (pool->blocks == NULL)
      return XML_FALSE;
    pool->blocks->size = blockSize;
    pool->ptr = pool->blocks->s + (pool->ptr - pool->start);
    pool->start = pool->blocks->s;
    pool->end = pool->start + blockSize;
  }
It looks like this will cause a memory leak if realloc_fcn returns NULL because pool->blocks will be overwritten but the old memory area to which it pointed won't be freed.
 
The other places where reallocation is done in this file (via the REALLOC macro) don't have this bug because they correctly store the result in a temporary variable.
 
This bug allows a serious DOS attack on a server that accepts XML-based requests if a request is seen of the following form:

<!DOCTYPE foo [
<!ENTITY a "1234567890" >
<!ENTITY b "&a;&a;&a;&a;&a;&a;&a;&a;" >
<!ENTITY c "&b;&b;&b;&b;&b;&b;&b;&b;" >
<!ENTITY d "&c;&c;&c;&c;&c;&c;&c;&c;" >
<!ENTITY e "&d;&d;&d;&d;&d;&d;&d;&d;" >
<!ENTITY f "&e;&e;&e;&e;&e;&e;&e;&e;" >
<!ENTITY g "&f;&f;&f;&f;&f;&f;&f;&f;" >
<!ENTITY h "&g;&g;&g;&g;&g;&g;&g;&g;" >
<!ENTITY i "&h;&h;&h;&h;&h;&h;&h;&h;" >
<!ENTITY j "&i;&i;&i;&i;&i;&i;&i;&i;" >
<!ENTITY k "&j;&j;&j;&j;&j;&j;&j;&j;" >
<!ENTITY l "&k;&k;&k;&k;&k;&k;&k;&k;" >
<!ENTITY m "&l;&l;&l;&l;&l;&l;&l;&l;" >
<!ENTITY n "&m;&m;&m;&m;&m;&m;&m;&m;" >
]>
<foo bar="&n;"/>

When the attribute is expanded, the realloc (assuming that it bounds the size of the request) will fail, leaking the buffer from before the realloc.

[1]
http://mail.python.org/pipermail/expat-bugs/2010-February/002870.html
http://sourceforge.net/tracker/?func=detail&atid=110127&aid=2958794&group_id=10127

Comment 7 errata-xmlrpc 2012-06-13 14:01:15 UTC
This issue has been addressed in following products:

  Red Hat Enterprise Linux 6
  Red Hat Enterprise Linux 5

Via RHSA-2012:0731 https://rhn.redhat.com/errata/RHSA-2012-0731.html

Comment 8 Jan Lieskovsky 2013-07-09 10:08:22 UTC
Created compat-expat1 tracking bugs for this issue:

Affects: fedora-all [bug 982563]

Comment 16 errata-xmlrpc 2016-01-21 15:55:30 UTC
This issue has been addressed in the following products:

  JBoss Web Server 2.1.0

Via RHSA-2016:0062 https://rhn.redhat.com/errata/RHSA-2016-0062.html

Comment 17 errata-xmlrpc 2016-12-15 22:13:03 UTC
This issue has been addressed in the following products:



Via RHSA-2016:2957 https://rhn.redhat.com/errata/RHSA-2016-2957.html