KVM: x86: zero base3 of unusable segments
authorRadim Krčmář <rkrcmar@redhat.com>
Thu, 18 May 2017 17:37:30 +0000 (19:37 +0200)
committerWilly Tarreau <w@1wt.eu>
Thu, 2 Nov 2017 06:16:29 +0000 (07:16 +0100)
commit f0367ee1d64d27fa08be2407df5c125442e885e3 upstream.

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>
Signed-off-by: Willy Tarreau <w@1wt.eu>
arch/x86/kvm/x86.c

index b70b67bde90dd1ba03a8dbb648a1c206fc326a65..3d316cafff91637d60275595fe8a7c214100e681 100644 (file)
@@ -4596,6 +4596,8 @@ 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;
        }