KVM: x86: Handle errors when RIP is set during far jumps

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Far jmp/call/ret may fault while loading a new RIP.  Currently KVM does not
handle this case, and may result in failed vm-entry once the assignment is
done.  The tricky part of doing so is that loading the new CS affects the
VMCS/VMCB state, so if we fail during loading the new RIP, we are left in
unconsistent state.  Therefore, this patch saves on 64-bit the old CS
descriptor and restores it if loading RIP failed.

This fixes CVE-2014-3647.

Cc: stable@vger.kernel.org
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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Nadav Amit 2014-09-18 22:39:39 +03:00 • committed by Paolo Bonzini

parent 234f3ce485

commit d1442d85cc

1 changed files with 88 additions and 30 deletions

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arch/x86/kvm/emulate.c

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