Bug 1355654 (CVE-2016-6198)

Summary: CVE-2016-6198 kernel: vfs: missing detection of hardlinks in vfs_rename() on overlayfs
Product: [Other] Security Response Reporter: Martin Prpič <mprpic>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: aquini, bhu, carnil, dhoward, fhrbata, gansalmon, iboverma, itamar, jforbes, jkacur, joelsmith, jonathan, jross, jwboyer, kernel-maint, kernel-mgr, kstutsma, lgoncalv, madhu.chinakonda, mchehab, mcressma, nmurray, rt-maint, rvrbovsk, slawomir, williams, wmealing
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: If docs needed, set a value
Doc Text:
A flaw was found that the vfs_rename() function did not detect hard links on overlayfs. A local, unprivileged user could use the rename syscall on overlayfs on top of xfs to crash the system.
Story Points: ---
Clone Of: Environment:
Last Closed: 2021-10-21 00:54:18 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: 1258556, 1341795, 1355655    
Bug Blocks: 1355693    

Description Martin Prpič 2016-07-12 07:30:51 UTC
It was found that the vfs_rename() function did not detect hard links on overlayfs. A local, unprivileged user could use the rename syscall on overlayfs on top of xfs to crash the system.

Upstream patches:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=54d5ca871e72f2bb172ec9323497f01cd5091ec7
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=9409e22acdfc9153f88d9b1ed2bd2a5b34d2d3ca

CVE assignment:

http://seclists.org/oss-sec/2016/q3/42

Comment 1 Martin Prpič 2016-07-12 07:31:30 UTC
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1355655]

Comment 2 Martin Prpič 2016-07-12 14:01:30 UTC
Acknowledgments:

Name: CAI Qian (Red Hat)

Comment 3 Wade Mealing 2016-07-22 07:14:27 UTC
Statement: 

This issue is not present in the Linux kernel packages as shipped with Red Hat Enterprise Linux versions 5 and 6.

This issue affects the Linux kernel packages as shipped with Red Hat Enterprise Linux 7 and MRG-2. Future Linux kernel updates for the respective releases may address this issue.

Comment 8 errata-xmlrpc 2016-11-03 17:07:34 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2016:2574 https://rhn.redhat.com/errata/RHSA-2016-2574.html

Comment 9 errata-xmlrpc 2016-11-03 19:55:17 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2016:2584 https://rhn.redhat.com/errata/RHSA-2016-2584.html

Comment 10 errata-xmlrpc 2016-11-03 21:37:11 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2016:2574 https://rhn.redhat.com/errata/RHSA-2016-2574.html

Comment 11 errata-xmlrpc 2016-11-03 21:44:49 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2016:2584 https://rhn.redhat.com/errata/RHSA-2016-2584.html