Bug 1163792 (CVE-2014-7822)

Summary:	CVE-2014-7822 kernel: splice: lack of generic write checks
Product:	[Other] Security Response	Reporter:	Petr Matousek <pmatouse>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	aquini, bhu, carnil, crempel, dhoward, fhrbata, iboverma, jkacur, jross, kernel-mgr, lgoncalv, matt, mcressma, myamazak, nmurray, plougher, redhat-bz, rvrbovsk, security-response-team, williams, xifeng
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:	A flaw was found in the way the Linux kernel's splice() system call validated its parameters. On certain file systems, a local, unprivileged user could use this flaw to write past the maximum file size, and thus crash the system.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2019-06-08 02:36:06 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:	1155900, 1155907, 1155908, 1163798, 1163799, 1163800
Bug Blocks:	1163802

Description Petr Matousek 2014-11-13 13:42:22 UTC

It was found that there are no size checks in the splice IO path, so it's
possible to send a write past s_maxbytes to a filesystem.  For ext4, at
least, this ends badly, with a BUG_ON.

A local unprivileged user could use this flaw to crash the system.

Acknowledgements:

Red Hat would like to thank Akira Fujita of NEC for reporting this issue.

Upstream patches:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=8d0207652cbe27d1f962050737848e5ad4671958

(this patch rearranges splice with a side effect of invoking
generic_write_checks() along the way)

Comment 3 Petr Matousek 2014-11-13 13:49:34 UTC

Statement:

This issue does affect the Linux kernel packages as shipped with Red Hat Enterprise Linux 5, 6, 7 and Red Hat Enterprise MRG 2. Future kernel updates for the respective releases may address this flaw.

Comment 5 errata-xmlrpc 2015-01-28 19:11:03 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2015:0102 https://rhn.redhat.com/errata/RHSA-2015-0102.html

Comment 6 errata-xmlrpc 2015-02-10 21:52:02 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 5

Via RHSA-2015:0164 https://rhn.redhat.com/errata/RHSA-2015-0164.html

Comment 11 errata-xmlrpc 2015-03-11 15:28:09 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 6

Via RHSA-2015:0674 https://rhn.redhat.com/errata/RHSA-2015-0674.html

Comment 12 errata-xmlrpc 2015-03-17 14:41:03 UTC

This issue has been addressed in the following products:

  MRG for RHEL-6 v.2

Via RHSA-2015:0694 https://rhn.redhat.com/errata/RHSA-2015-0694.html