Bug 527534 (CVE-2009-2908)

Summary: CVE-2009-2908 kernel ecryptfs NULL pointer dereference
Product: [Other] Security Response Reporter: Josh Bressers <bressers>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: cebbert, davej, dhoward, esandeen, jkacur, jlieskov, jpirko, jskrabal, kyle, lwang, rcvalle
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2010-12-21 19:15:08 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Bug Depends On: 527834, 527835, 537286    
Bug Blocks:    

Description Josh Bressers 2009-10-06 20:21:10 UTC
A flaw was found in ecryptfs which can result in a NULL pointer dereference. Quoting the commit message:

  When calling vfs_unlink() on the lower dentry, d_delete() turns the
  dentry into a negative dentry when the d_count is 1.  This eventually
  caused a NULL pointer deref when a read() or write() was done and the
  negative dentry's d_inode was dereferenced in
  ecryptfs_read_update_atime() or ecryptfs_getxattr().

The upstream commit is here:

There is a launchpad bug with more details here:

Comment 1 Josh Bressers 2009-10-06 20:22:15 UTC
I suspect this flaw could result in arbitrary code execution, but I'm not 100% honestly. The pointer in question does contain function pointers. It's possible it's not, but my limited knowledge tells me to treat is as such.

Comment 4 Jan Lieskovsky 2009-10-13 12:42:27 UTC
MITRE's CVE-2009-2908 entry:

The d_delete function in fs/ecryptfs/inode.c in eCryptfs in the Linux
kernel 2.6.31 allows local users to cause a denial of service (kernel
OOPS) and possibly execute arbitrary code via unspecified vectors that
cause a "negative dentry" and trigger a NULL pointer dereference, as
demonstrated via a Mutt temporary directory in an eCryptfs mount.


Comment 5 Fedora Update System 2009-10-15 00:21:15 UTC
kernel- has been submitted as an update for Fedora 10.

Comment 6 Fedora Update System 2009-10-15 22:37:01 UTC
kernel- has been pushed to the Fedora 10 stable repository.  If problems still persist, please make note of it in this bug report.

Comment 7 Fedora Update System 2009-10-18 01:57:29 UTC
kernel- has been submitted as an update for Fedora 11.

Comment 8 Fedora Update System 2009-10-27 06:47:37 UTC
kernel- has been pushed to the Fedora 11 stable repository.  If problems still persist, please make note of it in this bug report.

Comment 10 errata-xmlrpc 2009-11-03 19:33:44 UTC
This issue has been addressed in following products:

  Red Hat Enterprise Linux 5

Via RHSA-2009:1548 https://rhn.redhat.com/errata/RHSA-2009-1548.html