From: Radim Krčmář <rkrcmar@redhat.com>
Date: Thu, 18 May 2017 17:37:30 +0000 (+0200)
Subject: KVM: x86: zero base3 of unusable segments
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=f0367ee1d64d27fa08be2407df5c125442e885e3;p=openwrt%2Fstaging%2Fblogic.git

KVM: x86: zero base3 of unusable segments

Static checker noticed that base3 could be used uninitialized if the
segment was not present (useable).  Random stack values probably would
not pass VMCS entry checks.

Reported-by:  Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 1aa366163b8b ("KVM: x86 emulator: consolidate segment accessors")
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 519f3572e48e..02363e37d4a6 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5067,6 +5067,8 @@ static bool emulator_get_segment(struct x86_emulate_ctxt *ctxt, u16 *selector,
 
 	if (var.unusable) {
 		memset(desc, 0, sizeof(*desc));
+		if (base3)
+			*base3 = 0;
 		return false;
 	}