Date: Tue, 8 Dec 2015 20:32:03 -0500 (EST) From: Wade Mealing <wmealing@...hat.com> To: oss-security@...ts.openwall.com Cc: cve-assign@...re.org Subject: CVE request - Linux kernel - Fix handling of stored error in a negatively instantiated user key Gday, A bug was found by Dmitry Vyukov (of Google engineering) in the Linux kernel key management code. A malicious user with a local account may be able to escalate privileges and take control of local system by abusing the user key subsystem. >From the patch: -- If a user key gets negatively instantiated, an error code is cached in the payload area. A negatively instantiated key may be then be positively instantiated by updating it with valid data. However, the ->update key type method must be aware that the error code may be there. -- The paging address is predictable and mappable as userspace memory and can be used by abused by an attacker to escalate privileges. This is not the same issue as CVE-2015-7872, this issue persists after the fix is applied. I have only seen this affected on the 4.4 release candidates. Thanks, Wade Mealing Upstream fix ------------ - https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=096fe9eaea40a17e125569f9e657e34cdb6d73bd Red Hat Bugzilla: - https://bugzilla.redhat.com/show_bug.cgi?id=1284450
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