Bug 512861 (CVE-2009-2406)

Summary: CVE-2009-2406 kernel: ecryptfs stack overflow in parse_tag_11_packet()
Product: [Other] Security Response Reporter: Eugene Teo (Security Response) <eteo>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: dhoward, esandeen, jpirko, jrusnack, jskrabal, lsmid, lwang, rcvalle, rwheeler, security-response-team, sgrubb
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: 2010-12-21 18:03:43 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: 512862, 512863    
Bug Blocks:    
Attachments:
Description Flags
[PATCH 1/2] eCryptfs: Check Tag 11 literal data buffer size none

Description Eugene Teo (Security Response) 2009-07-21 01:15:41 UTC 
Description of problem:
Ramon de Carvalho Valle was testing eCryptfs with fsfuzzer and ran across a stack overflow bug.  At the beginning of each eCryptfs file, metadata is stored containing things like encrypted file encryption key (EFEK), key signature of key used to decrypt the EFEK, etc.  This metadata is stored in "packets", as per RFC 2440 - OpenPGP Message Format.

The header of each packet contains a packet length field.  As the eCryptfs kernel module reads the packet contents, it uses that packet length field in a memcpy() to the destination buffer.  However, no checks existed to make sure the buffer was big enough to hold the entire packet contents.

A malicious user on the system that has permissions to perform an eCryptfs mount (root or setuid mount helper needed) can modify the metadata using hexedit and specify a bigger packet size than what the destination buffer can hold and also modify the packet contents, which would probably allow them to handcraft the data used to overwrite the stack.
Comment 1 Eugene Teo (Security Response) 2009-07-21 01:31:40 UTC 
Created attachment 354415 [details]
[PATCH 1/2] eCryptfs: Check Tag 11 literal data buffer size
Comment 9 Eugene Teo (Security Response) 2009-07-29 02:01:53 UTC 
Upstream commit:
http://git.kernel.org/linus/6352a29305373ae6196491e6d4669f301e26492e
Comment 10 Fedora Update System 2009-07-29 22:26:06 UTC 
kernel-2.6.29.6-217.2.3.fc11 has been submitted as an update for Fedora 11.
http://admin.fedoraproject.org/updates/kernel-2.6.29.6-217.2.3.fc11
Comment 11 Vincent Danen 2009-07-31 19:35:42 UTC 
Common Vulnerabilities and Exposures assigned an identifier CVE-2009-2406 to
the following vulnerability:

Name: CVE-2009-2406
URL: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-2406
Assigned: 20090709
Reference: BUGTRAQ:20090728 [RISE-2009002] Linux eCryptfs parse_tag_11_packet Literal Data Buffer Overflow Vulnerability
Reference: URL: http://www.securityfocus.com/archive/1/archive/1/505334/100/0/threaded
Reference: MISC: http://risesecurity.org/advisories/RISE-2009002.txt
Reference: CONFIRM: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=6352a29305373ae6196491e6d4669f301e26492e
Reference: CONFIRM: http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.30.4
Reference: DEBIAN:DSA-1844
Reference: URL: http://www.debian.org/security/2009/dsa-1844
Reference: DEBIAN:DSA-1845
Reference: URL: http://www.debian.org/security/2009/dsa-1845
Reference: UBUNTU:USN-807-1
Reference: URL: http://www.ubuntu.com/usn/usn-807-1
Reference: BID:35851
Reference: URL: http://www.securityfocus.com/bid/35851
Reference: SECUNIA:35985
Reference: URL: http://secunia.com/advisories/35985
Reference: SECUNIA:36045
Reference: URL: http://secunia.com/advisories/36045
Reference: SECUNIA:36051
Reference: URL: http://secunia.com/advisories/36051
Reference: SECUNIA:36054
Reference: URL: http://secunia.com/advisories/36054
Reference: VUPEN:ADV-2009-2041
Reference: URL: http://www.vupen.com/english/advisories/2009/2041

Stack-based buffer overflow in the parse_tag_11_packet function in
fs/ecryptfs/keystore.c in the eCryptfs subsystem in the Linux kernel
before 2.6.30.4 allows local users to cause a denial of service
(system crash) or possibly gain privileges via vectors involving a
crafted eCryptfs file, related to not ensuring that the key signature
length in a Tag 11 packet is compatible with the key signature buffer
size.
Comment 12 Fedora Update System 2009-08-03 16:58:59 UTC 
kernel-2.6.27.29-170.2.78.fc10 has been submitted as an update for Fedora 10.
http://admin.fedoraproject.org/updates/kernel-2.6.27.29-170.2.78.fc10
Comment 13 errata-xmlrpc 2009-08-04 13:15:38 UTC 
This issue has been addressed in following products:

  Red Hat Enterprise Linux 5

Via RHSA-2009:1193 https://rhn.redhat.com/errata/RHSA-2009-1193.html
Comment 14 Fedora Update System 2009-08-05 00:30:18 UTC 
kernel-2.6.27.29-170.2.78.fc10 has been pushed to the Fedora 10 stable repository.  If problems still persist, please make note of it in this bug report.
Comment 15 Fedora Update System 2009-08-05 00:35:43 UTC 
kernel-2.6.29.6-217.2.3.fc11 has been pushed to the Fedora 11 stable repository.  If problems still persist, please make note of it in this bug report.
Comment 19 Vincent Danen 2013-09-27 17:52:43 UTC 
Acknowledgements:

Red Hat would like to thank Ramon de C. Valle for reporting this issue.