A failure to decode the instruction can cause a NULL pointer access.
This is fixed simply by moving the "done" label as close as possible
to the return.
This fixes CVE-2014-8481.
Reported-by: Andy Lutomirski <l...@amacapital.net>
Cc: sta...@vger.kernel.org
Fixes: 41061cdb98a0bec464278b4db8e894a3121671f5
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
arch/x86/kvm/emulate.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 02c8ea804aaf..eb3b1c46f995 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4580,10 +4580,10 @@ done_prefixes:
/* Decode and fetch the destination operand: register or memory. */
rc = decode_operand(ctxt, &ctxt->dst, (ctxt->d >> DstShift) & OpMask);
-done:
if (ctxt->rip_relative)
ctxt->memopp->addr.mem.ea += ctxt->_eip;
+done:
return (rc != X86EMUL_CONTINUE) ? EMULATION_FAILED : EMULATION_OK;
}
--
1.8.3.1
--
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