The get_instantiation_keyring function in security/keys/keyctl.c in the KEYS subsystem in the Linux kernel before 2.6.32-rc5 does not properly maintain the reference count of a keyring, which allows local users to gain privileges or cause a denial of service (OOPS) via vectors involving calls to this function without specifying a keyring by ID, as demonstrated by a series of keyctl request2 and keyctl list commands.
git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=21279cfa107af07ef985539ac0de2152b9cba5f5
lists.opensuse.org/opensuse-security-announce/2010-01/msg00000.html
marc.info/?l=oss-security&m=125619420905341&w=2
marc.info/?l=oss-security&m=125624091417161&w=2
secunia.com/advisories/37086
secunia.com/advisories/38017
twitter.com/spendergrsec/statuses/4916661870
www.kernel.org/pub/linux/kernel/v2.6/testing/ChangeLog-2.6.32-rc5
www.ubuntu.com/usn/usn-864-1