Bug 1451685 (CVE-2017-1000363)

Summary:	CVE-2017-1000363 kernel: Out-of-bounds write in lp_setup in drivers/char/lp.c
Product:	[Other] Security Response	Reporter:	Adam Mariš <amaris>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	agordeev, aquini, bhu, dhoward, dominik.mierzejewski, dvlasenk, esammons, fhrbata, iboverma, jforbes, jkacur, jross, lgoncalv, lwang, matt, mcressma, mguzik, nmurray, pholasek, plougher, rvrbovsk, security-response-team, vdronov, williams
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:	A vulnerability was found in the Linux kernel's lp_setup() function where it doesn't apply any bounds checking when passing "lp=none". This can result into overflow of the parport_nr[] array. An attacker with control over kernel command line can overwrite kernel code and data with fixed (0xff) values.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2017-07-25 12:18:08 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:	1456454, 1456493, 1456495, 1456496, 1456497, 1456499
Bug Blocks:	1451686

Description Adam Mariš 2017-05-17 09:54:18 UTC

lp_setup() functions doesn't apply any bounds checking when passing "lp=none" which can result into overflow of parport_nr[] array. Adversary having partial control over secure boot kernel command line can insert malicious code directly into kernel.

References:

https://alephsecurity.com/vulns/aleph-2017023

http://seclists.org/oss-sec/2017/q2/335

Upstream patch:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3e21f4af170bebf47c187c1ff8bf155583c9f3b1

Comment 1 Adam Mariš 2017-05-17 09:54:32 UTC

Acknowledgments:

Name: Roee Hay (HCL Technologies)

Comment 2 Vladis Dronov 2017-05-29 12:33:41 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1456454]

Comment 4 Vladis Dronov 2017-05-29 13:27:25 UTC

Statement:

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

Comment 9 Denys Vlasenko 2017-06-28 14:59:11 UTC

Our kernels have CONFIG_PRINTER=m, this bug shouldn't be affecting us: the function we patch sits inside "#ifndef MODULE" block.

Comment 10 Denys Vlasenko 2017-06-29 16:23:12 UTC

This bug can only be triggered if someone recompiles the kernel with CONFIG_PRINTER=y, and then boots with "lp=none,none,none,none,none,none,none,none,none" (i.e. with more than 8 "none" parameters for lp=) on the kernel command line.
I don't think this scenario is important for us.

I propose WONTFIXing this.

Comment 11 Justin M. Forbes 2018-01-29 17:05:50 UTC

This was fixed for fedora with 4.12 rebases.