Bug 383371 (CVE-2006-7228)

Summary:	CVE-2006-7228 pcre integer overflow
Product:	[Other] Security Response	Reporter:	Josh Bressers <bressers>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	james.antill, karsten, kasal, kreilly, omoris, thoger
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2008-01-11 17:33:45 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:	380511, 380521, 380531, 380541, 381991, 382081, 392031, 392041, 392051, 392061, 411731, 413871, 414271, 430870, 445917
Bug Blocks:	373021

Description Josh Bressers 2007-11-14 20:53:56 UTC

CVE-2006-7224 initially described several integer overflows in pcre, all
described here:
http://scary.beasts.org/security/CESA-2007-006.html

This id should be used to describe issue #2         
in that advisory:

3) More possible integer overflow trouble.

pcre_compile:
---
    if (min == 0)
      {
      length++;
      if (max > 0) length += (max - 1) * (duplength + 3 + 2*LINK_SIZE);
      }
...
    else
      {
      length += (min - 1) * duplength;
      if (max > min)   /* Need this test as max=-1 means no limit */
        length += (max - min) * (duplength + 3 + 2*LINK_SIZE)
          - (2 + 2*LINK_SIZE);
      }
---

In both these cases, I see no reason why a malicious regexp pattern couldn't
cause an integer overflow by using large min / max / duplength values. This will
really mess up the critical "length" value.

Comment 2 Tomas Hoger 2007-11-15 10:58:34 UTC

Reference in PCRE changelog for version 6.7:

11. Subpatterns that are repeated with specific counts have to be replicated in
    the compiled pattern. The size of memory for this was computed from the
    length of the subpattern and the repeat count. The latter is limited to
    65535, but there was no limit on the former, meaning that integer overflow
    could in principle occur. The compiled length of a repeated subpattern is
    now limited to 30,000 bytes in order to prevent this.

Comment 11 James Antill 2007-11-20 15:37:52 UTC

 Looking at the RHEL-4 included pcre, the only thing I can see referencing
duplength is:

      if (minval == 0) length++;
        else if (minval > 1) length += (minval - 1) * duplength;
      if (maxval > minval) length += (maxval - minval) * (duplength + 1);

...which does look like a bug, but the code is different (the code is basically
the same for RHEL-2.1 and RHEL-3).
 It looks like that's the "only"[1] thing I need to fix, is that so?

 [1] I've also added the code to get out the loop and fail if any of the adds in
the loop cross the 65535 barrier or go negative.

Comment 12 James Antill 2007-11-20 15:38:34 UTC

My comment is in reference to python's pypcre (for anyone being confused about
now :).

Comment 13 Tomas Hoger 2007-11-21 09:28:48 UTC

Re comment 11:

James, I'm not quite sure I understand your question, hope I do... ;)

Yes, the code snippet is the place where the problem occurs.  I've checked your
patch.  Unlike upstream pcre, it does not add arbitrary hard-coded limit
(duplength <= 30000), but looks good to me.

Comment 22 Red Hat Product Security 2008-01-11 17:33:45 UTC

This issue was addressed in:

Red Hat Enterprise Linux:
  http://rhn.redhat.com/errata/RHSA-2007-1059.html
  http://rhn.redhat.com/errata/RHSA-2007-1063.html
  http://rhn.redhat.com/errata/RHSA-2007-1065.html
  http://rhn.redhat.com/errata/RHSA-2007-1068.html
  http://rhn.redhat.com/errata/RHSA-2007-1077.html
  http://rhn.redhat.com/errata/RHSA-2007-1076.html