Bug 1324867 (CVE-2016-2085) - CVE-2016-2085 kernel: timing side channel vulnerability in the Linux Extended Verification Module
Summary: CVE-2016-2085 kernel: timing side channel vulnerability in the Linux Extended...
Keywords:
Status: CLOSED WONTFIX
Alias: CVE-2016-2085
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: 1332402
Blocks: 1324875
TreeView+ depends on / blocked
 
Reported: 2016-04-07 13:22 UTC by Andrej Nemec
Modified: 2019-09-29 13:46 UTC (History)
39 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2016-06-15 10:48:00 UTC


Attachments (Terms of Use)

Description Andrej Nemec 2016-04-07 13:22:29 UTC
A timing side channel vulnerability was discovered in the Linux Extended Verification Module (EVM). An attacker could use this to affect system integrity.

The problem exists because the vm_verify_hmac() function includes a use of memcmp(). This function is not safe to be used for comparing memory, allows timing side channel attacks; specifically a MAC forgery complexity drop from 2^128 to 2^12.  This patch changes the memcmp() to the cryptographically safe crypto_memneq().  


Upstream fix:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=613317bd212c585c20796c10afe5daaa95d4b0a1

Original bug report:

http://people.canonical.com/~ubuntu-security/cve/2016/CVE-2016-2085.html

Comment 1 Justin M. Forbes 2016-04-07 17:21:53 UTC
This does not impact Fedora as CONFIG_EVM is not enabled.

Comment 2 💾 Wade Mealing 💾 2016-04-29 14:34:33 UTC
Statement:

This issue does not affect the Linux kernels as shipped with Red Hat Enterprise Linux 4,5 and 6.

This issue affects the Linux kernels as shipped with Red Hat Enterprise Linux 7 and kernel-rt packages and does not plan to be addressed in a future update.


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