Bug 1243465 (CVE-2015-3290) - CVE-2015-3290 kernel: x86: nested NMI handler and espfix64 interaction privilege escalation
Summary: CVE-2015-3290 kernel: x86: nested NMI handler and espfix64 interaction privil...
Status: CLOSED NOTABUG
Alias: CVE-2015-3290
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard: impact=important,public=20150722,repo...
Keywords: Security
Depends On: 1245936
Blocks: 1243467
TreeView+ depends on / blocked
 
Reported: 2015-07-15 13:42 UTC by Martin Prpič
Modified: 2019-06-08 20:39 UTC (History)
24 users (show)

(edit)
A flaw was found in the way the Linux kernel's nested NMI handler and espfix64 functionalities interacted during NMI processing. A local, unprivileged user could use this flaw to crash the system or, potentially, escalate their privileges on the system.
Clone Of:
(edit)
Last Closed: 2015-07-23 07:35:53 UTC


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Description Martin Prpič 2015-07-15 13:42:15 UTC
A flaw was found in the way Linux kernel's nested NMI handler and espfix64 functionalities interacted during NMI processing.

A local, unprivileged user could use this flaw to crash the system or, potentially, escalate their privileges on the system.

Upstream fix:
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=9b6e6a8334d56354853f9c255d1395c2ba570e0a

Acknowledgements:

Red Hat would like to thank Andy Lutomirski for reporting this issue.

Comment 2 Petr Matousek 2015-07-23 07:23:42 UTC
In order to exploit this issue non-root (non-privileged) user needs to make the Linux kernel's NMI handler perform an iret instruction, which re-enables NMIs and thus the nested NMI code path in the NMI handler is exercised.

To our knowledge, an unprivileged local user can do that since upstream commit https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=e00b12e64be9a34ef071de7b6052ca9ea29dd460.

Comment 3 Petr Matousek 2015-07-23 07:35:53 UTC
Statement:

This issue does not affect the Linux kernel packages as shipped with Red Hat Enterprise Linux 5 and 6 since they did not backport the nested NMI handler and espfix64 functionalities.

This issue does not affect the Linux kernel packages as shipped with Red Hat Enterprise Linux 7 and Red Hat Enterprise MRG 2 since they did not backport the espfix64 functionality and also did not backport upstream commit e00b12e64be9a3 that allowed an unprivileged local user to re-enable NMIs from the NMI handler.

Comment 4 Petr Matousek 2015-07-23 07:37:57 UTC
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1245936]


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