Bug 1308452 (CVE-2016-2383)

Summary:	CVE-2016-2383 kernel: incorrect branch fixups for eBPG allow arbitrary read
Product:	[Other] Security Response	Reporter:	Andrej Nemec <anemec>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	agordeev, aquini, arm-mgr, bhu, carnil, dhoward, esammons, fhrbata, gansalmon, iboverma, itamar, jforbes, jkacur, joelsmith, jonathan, jross, jwboyer, kernel-maint, kernel-mgr, kstutsma, lgoncalv, lwang, madhu.chinakonda, matt, mchehab, mcressma, mguzik, nmurray, pholasek, plougher, rt-maint, rvrbovsk, slawomir, vdronov, williams
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:	2016-02-18 15:33:49 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:	1308453
Bug Blocks:	1308454

Description Andrej Nemec 2016-02-15 09:29:47 UTC

When ctx access is used, the kernel often needs to expand/rewrite
instructions, so after that patching, branch offsets have to be
adjusted for both forward and backward jumps in the new eBPF program,
but for backward jumps it fails to account the delta. Meaning, for
example, if the expansion happens exactly on the insn that sits at
the jump target, it doesn't fix up the back jump offset.

Upstream report and fix:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=a1b14d27ed0965838350f1377ff97c93ee383492

External reference:

http://seclists.org/oss-sec/2016/q1/330

CVE assignment:

http://seclists.org/oss-sec/2016/q1/333

Comment 1 Andrej Nemec 2016-02-15 09:30:28 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1308453]

Comment 3 Vladis Dronov 2016-02-18 15:33:49 UTC

Statement:

This issue does not affect the Linux kernel packages as shipped with Red Hat Enterprise Linux 5, 6, 7 and MRG-2, as the code with the flaw is not present in the products listed.

Comment 4 Fedora Update System 2016-02-28 08:20:10 UTC

kernel-4.3.6-201.fc22 has been pushed to the Fedora 22 stable repository. If problems still persist, please make note of it in this bug report.

Comment 5 Fedora Update System 2016-02-28 12:21:31 UTC

kernel-4.4.2-301.fc23 has been pushed to the Fedora 23 stable repository. If problems still persist, please make note of it in this bug report.

Comment 6 Fedora Update System 2016-03-05 01:19:12 UTC

kernel-4.4.3-201.fc22 has been pushed to the Fedora 22 stable repository. If problems still persist, please make note of it in this bug report.