From: Nadav Amit <namit@cs.technion.ac.il>
Date: Mon, 27 Oct 2014 22:03:43 +0000 (+0200)
Subject: KVM: x86: Fix far-jump to non-canonical check
X-Git-Tag: v3.2.64~2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=77e4d28c8f46abfe542ac3ade2c877fd7b13c150;p=pandora-kernel.git

KVM: x86: Fix far-jump to non-canonical check

commit 7e46dddd6f6cd5dbf3c7bd04a7e75d19475ac9f2 upstream.

Commit d1442d85cc30 ("KVM: x86: Handle errors when RIP is set during far
jumps") introduced a bug that caused the fix to be incomplete.  Due to
incorrect evaluation, far jump to segment with L bit cleared (i.e., 32-bit
segment) and RIP with any of the high bits set (i.e, RIP[63:32] != 0) set may
not trigger #GP.  As we know, this imposes a security problem.

In addition, the condition for two warnings was incorrect.

Fixes: d1442d85cc30ea75f7d399474ca738e0bc96f715
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
[Add #ifdef CONFIG_X86_64 to avoid complaints of undefined behavior. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

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