Bug 481604 (CVE-2009-0269)

Summary:	CVE-2009-0269 kernel: ecryptfs readlink flaw
Product:	[Other] Security Response	Reporter:	Mark J. Cox <mjc>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	anton, bhu, cebbert, davej, dhoward, esandeen, jpirko, jtluka, kernel-maint, kernel-mgr, kseifried, lgoncalv, lwang, mhlavink, ovirt-maint, williams
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
URL:	http://nvd.nist.gov/nvd.cfm?cvename=CVE-2009-0269
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2011-09-30 22:00:53 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:	481605, 481606, 481607
Bug Blocks:

Description Mark J. Cox 2009-01-26 17:59:07 UTC

Common Vulnerabilities and Exposures assigned an identifier CVE-2009-0269 to the following vulnerability:

fs/ecryptfs/inode.c in the eCryptfs subsystem in the Linux kernel before 2.6.28.1 allows local users to cause a denial of service (fault or memory corruption), or possibly have unspecified other impact, via a readlink call that results in an error, leading to use of a -1 return value as an array index.

Hyperlink:https://lists.launchpad.net/ecryptfs-devel/msg00011.html  
Hyperlink:https://lists.launchpad.net/ecryptfs-devel/msg00010.html  
Hyperlink:http://git.kernel.org/?p=linux/kernel/git/stable/linux-2.6.27.y.git;a=commit;h=a17d5232de7b53d34229de79ec22f4bb04adb7e4

Comment 3 Mark J. Cox 2009-01-27 10:29:06 UTC

So based on a quick technical first pass on the affected code:

- it can only affect systems that are using and have mounted a ecryptfs directory, and allow such to be done by unprivileged users
- the local attacker would need to be able to make a readlink on a symlink fail, most likely permissions, or perhaps too many symlinks. 
- the outcome would be writing a single null byte one memory address before the kmalloc()ed buffer.

Some sites are writing up this issue as a privilege escalation flaw, but I believe that given the circumstances this is most unlikely.  Setting severity to moderate and requesting review from a kernel engineer.

Comment 4 Eric Sandeen 2009-02-04 16:02:27 UTC

Mark, I concur with your severity analysis.

Patch sent to rhkernel-list on 2/4/2009 (sorry for the delay...)

-Eric

Comment 7 errata-xmlrpc 2009-03-27 00:15:25 UTC

This issue has been addressed in following products:

  MRG for RHEL-5

Via RHSA-2009:0360 https://rhn.redhat.com/errata/RHSA-2009-0360.html

Comment 8 errata-xmlrpc 2009-04-01 08:32:24 UTC

This issue has been addressed in following products:

  Red Hat Enterprise Linux 5

Via RHSA-2009:0326 https://rhn.redhat.com/errata/RHSA-2009-0326.html

Comment 9 Jan Tluka 2009-07-20 15:46:40 UTC

Patch is in -158.el5. Adding SanityOnly.