Bug 1391908 (CVE-2016-9178)

Summary: CVE-2016-9178 kernel: Information leak in get_user_ex function
Product: [Other] Security Response Reporter: Andrej Nemec <anemec>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED WONTFIX QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: agordeev, aquini, arm-mgr, bhu, carnil, dhoward, esammons, fhrbata, gansalmon, iboverma, ichavero, itamar, jforbes, jkacur, joelsmith, jonathan, jross, jwboyer, kernel-maint, kernel-mgr, labbott, lgoncalv, lwang, madhu.chinakonda, matt, mchehab, mcressma, mguzik, nmurray, pholasek, plougher, rt-maint, rvrbovsk, slawomir, vdronov, williams
Target Milestone: ---Keywords: Reopened, Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard: impact=low,public=20160915,reported=20161103,source=oss-security,cvss2=1.9/AV:L/AC:M/Au:N/C:P/I:N/A:N,cvss3=3.3/CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N,cwe=CWE-200,rhel-5/kernel=notaffected,rhel-6/kernel=wontfix,rhel-7/kernel=wontfix,rhel-7/kernel-rt=wontfix,mrg-2/realtime-kernel=wontfix,rhelsa-7/arm-kernel=wontfix,fedora-all/kernel=affected
Fixed In Version: Doc Type: Bug Fix
Doc Text:
The __get_user_asm_ex macro in arch/x86/include/asm/uaccess.h in the Linux kernel before 4.7.5 does not initialize a certain integer variable, which allows local users to obtain sensitive information from kernel stack memory by triggering failure of a get_user_ex call.
Story Points: ---
Clone Of: Environment:
Last Closed: 2017-01-20 10:34:20 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---
Bug Depends On: 1391910    
Bug Blocks: 1391915    

Description Andrej Nemec 2016-11-04 11:12:05 UTC
An information leak was found in the Linux kernel. The __get_user_asm_ex macro in arch/x86/include/asm/uaccess.h in the Linux kernel before 4.7.5 does not initialize a certain integer variable, which allows local users to obtain sensitive information from kernel stack memory by triggering failure of a get_user_ex call.

References:

http://seclists.org/oss-sec/2016/q4/320

Upstream patch:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=1c109fabbd51863475cd12ac206bdd249aee35af

Comment 1 Andrej Nemec 2016-11-04 11:13:03 UTC
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1391910]

Comment 2 Justin M. Forbes 2016-11-04 16:24:42 UTC
This issue was fixed in 4.7.5 stable updates across all Fedora releases.

Comment 5 Vladis Dronov 2017-01-20 10:34:20 UTC
Statement:

This issue does not affect the Linux kernel packages as shipped with Red Hat Enterprise Linux 5 as the code which can trigger the flaw is not present in the products listed.

This issue affects the Linux kernel packages as shipped with Red Hat Enterprise Linux 6, 7 and MRG-2. This has been rated as having Low security impact and is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.