[CVE-2011-2022] agp: fix arbitrary kernel memory writes

[Andy Whitcroft]

CVE-2011-2022

	The agp_generic_remove_memory function in
	drivers/char/agp/generic.c in the Linux kernel before 2.6.38.5 does
	not validate a certain start parameter, which allows local users
	to gain privileges or cause a denial of service (system crash)
	via a crafted AGPIOC_UNBIND agp_ioctl ioctl call, a different
	vulnerability than CVE-2011-1745.

This is already fixed and released in Oneiric, Natty, and Lucid arriving
via mainline and stable.  Following this email is a patch applicable to
both Maverick and Hardy.

Proposing for Maverick and Hardy.

-apw