405545 – (CVE-2012-0879) linux < 2.6.33(-rc1) kernel: block: CLONE_IO io_context refcounting issues (CVE-2012-0879)

Bug 405545 (CVE-2012-0879) - linux < 2.6.33(-rc1) kernel: block: CLONE_IO io_context refcounting issues (CVE-2012-0879)

Summary: linux < 2.6.33(-rc1) kernel: block: CLONE_IO io_context refcounting issues (C...

Status:	RESOLVED OBSOLETE

Alias:	CVE-2012-0879

Product:	Gentoo Security
Classification:	Unclassified
Component:	Kernel (show other bugs)
Hardware:	All Linux

Importance:	Normal minor (vote)
Assignee:	Gentoo Kernel Security

URL:	https://bugzilla.redhat.com/show_bug....
Whiteboard:	[linux < 2.6.33(-rc1)]
Keywords:	PATCH

Depends on:
Blocks:

Reported:	2012-02-24 10:09 UTC by Michael Harrison
Modified:	2018-04-04 18:08 UTC (History)
CC List:	1 user (show)

See Also:
Package list:
Runtime testing required:	---

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Description Michael Harrison 2012-02-24 10:09:59 UTC

With CLONE_IO, copy_io() increments both ioc->refcount and ioc->nr_tasks.
However exit_io_context() only decrements ioc->refcount if ioc->nr_tasks
reaches 0.

With CLONE_IO, parent's io_context->nr_tasks is incremented, but never
decremented whenever copy_process() fails afterwards, which prevents
xit_io_context() from calling IO schedulers exit functions.

An unprivileged local user could use these flaws cause denial of service.

Upstream fixes:
61cc74fbb87af6aa551a06a370590c9bc07e29d9
b69f2292063d2caf37ca9aec7d63ded203701bf3

References:
http://comments.gmane.org/gmane.linux.kernel/922519

Comment 1 Aaron Bauman (RETIRED) gentoo-dev

2018-04-04 18:08:38 UTC

There are no longer any 2.x kernels available in the repository with the exception of sys-kernel/xbox-sources which is unsupported by security.