Bug 1122472 (CVE-2014-5045) - CVE-2014-5045 kernel: vfs: refcount issues during unmount on symlink
Summary: CVE-2014-5045 kernel: vfs: refcount issues during unmount on symlink
Keywords:
Status: CLOSED ERRATA
Alias: CVE-2014-5045
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1121323 1122376 1122480 1122481 1122482 1135165
Blocks: 1122485
TreeView+ depends on / blocked
 
Reported: 2014-07-23 10:58 UTC by Petr Matousek
Modified: 2023-05-12 04:32 UTC (History)
30 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
A flaw was found in the way the Linux kernel's VFS subsystem handled reference counting when performing unmount operations on symbolic links. A local, unprivileged user could use this flaw to exhaust all available memory on the system or, potentially, trigger a use-after-free error, resulting in a system crash or privilege escalation.
Clone Of:
Environment:
Last Closed: 2016-09-26 03:32:23 UTC
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2014:1392 0 normal SHIPPED_LIVE Important: kernel security, bug fix, and enhancement update 2014-10-14 01:28:44 UTC
Red Hat Product Errata RHSA-2014:1971 0 normal SHIPPED_LIVE Important: kernel security and bug fix update 2014-12-10 01:33:29 UTC
Red Hat Product Errata RHSA-2015:0062 0 normal SHIPPED_LIVE Important: kernel security, bug fix, and enhancement update 2015-01-20 22:21:42 UTC

Description Petr Matousek 2014-07-23 10:58:51 UTC 
A flaw was found in the way reference counting was handled in the Linux kernel's
VFS subsystem when unmount on symlink was performed.

On Red Hat Enterprise Linux 6 an unprivileged local user could use this flaw to
cause OOM conditions leading to denial of service or, potentially, trigger
use-after-free error.

On Red Hat Enterprise Linux 7 a privileged local user with CAP_SYS_ADMIN
capability (also in a container) could use this flaw to cause OOM conditions
leading to denial of service or, potentially, trigger use-after-free error.

Acknowledgements:

Red Hat would like to thank Vasily Averin of Parallels for reporting this issue.
Comment 1 Petr Matousek 2014-07-23 11:12:15 UTC 
Statement:

This issue does not affect Linux kernel packages as shipped with Red Hat
Enterprise Linux 5 and Red Hat Enterprise MRG 2.

Future Linux kernel updates for Red Hat Enterprise Linux 6 and 7 may address
this issue.
Comment 2 Petr Matousek 2014-07-23 11:13:38 UTC 
Proposed upstream patch:

  https://lkml.org/lkml/2014/7/21/98
Comment 4 Petr Matousek 2014-07-23 11:21:09 UTC 
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1122482]
Comment 5 Vasily Averin 2014-07-24 05:57:45 UTC 
CVE-2014-5045 was assigned for this issue
Comment 6 Martin Prpič 2014-10-10 08:46:18 UTC 
IssueDescription:

A flaw was found in the way the Linux kernel's VFS subsystem handled reference counting when performing unmount operations on symbolic links. A local, unprivileged user could use this flaw to exhaust all available memory on the system or, potentially, trigger a use-after-free error, resulting in a system crash or privilege escalation.
Comment 7 errata-xmlrpc 2014-10-14 06:19:40 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 6

Via RHSA-2014:1392 https://rhn.redhat.com/errata/RHSA-2014-1392.html
Comment 9 errata-xmlrpc 2014-12-09 20:34:47 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2014:1971 https://rhn.redhat.com/errata/RHSA-2014-1971.html
Comment 10 errata-xmlrpc 2015-01-20 17:22:44 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 6.5 EUS - Server and Compute Node Only

Via RHSA-2015:0062 https://rhn.redhat.com/errata/RHSA-2015-0062.html
Note You need to log in before you can comment on or make changes to this bug.