From: Thomas Hellstrom <thellstrom@vmware.com>
Date: Tue, 24 Jan 2012 17:54:21 +0000 (+0100)
Subject: drm: Fix authentication kernel crash
X-Git-Tag: v3.3-rc2~30^2~3
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=598781d71119827b454fd75d46f84755bca6f0c6;p=pandora-kernel.git

drm: Fix authentication kernel crash

If the master tries to authenticate a client using drm_authmagic and
that client has already closed its drm file descriptor,
either wilfully or because it was terminated, the
call to drm_authmagic will dereference a stale pointer into kmalloc'ed memory
and corrupt it.

Typically this results in a hard system hang.

This patch fixes that problem by removing any authentication tokens
(struct drm_magic_entry) open for a file descriptor when that file
descriptor is closed.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
---

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