From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
commit 2c10b61421a28e95a46ab489fd56c0f442ff6952 upstream.
When calling the KVM_GET_DEBUGREGS ioctl, on some configurations, there
might be some unitialized portions of the kvm_debugregs structure that
could be copied to userspace. Prevent this as is done in the other kvm
ioctls, by setting the whole structure to 0 before copying anything into
it.
Bonus is that this reduces the lines of code as the explicit flag
setting and reserved space zeroing out can be removed.
Cc: Sean Christopherson <seanjc@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: <x86@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: stable <stable@xxxxxxxxxx>
Reported-by: Xingyuan Mo <hdthky0@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Message-Id: <20230214103304.3689213-1-gregkh@xxxxxxxxxxxxxxxxxxx>
Tested-by: Xingyuan Mo <hdthky0@xxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/x86.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3948,12 +3948,11 @@ static void kvm_vcpu_ioctl_x86_get_debug
{
unsigned long val;
+ memset(dbgregs, 0, sizeof(*dbgregs));
memcpy(dbgregs->db, vcpu->arch.db, sizeof(vcpu->arch.db));
kvm_get_dr(vcpu, 6, &val);
dbgregs->dr6 = val;
dbgregs->dr7 = vcpu->arch.dr7;
- dbgregs->flags = 0;
- memset(&dbgregs->reserved, 0, sizeof(dbgregs->reserved));
}
static int kvm_vcpu_ioctl_x86_set_debugregs(struct kvm_vcpu *vcpu,
