From: Greg Kroah-Hartman gregkh@linuxfoundation.org
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@google.com Cc: Paolo Bonzini pbonzini@redhat.com Cc: Thomas Gleixner tglx@linutronix.de Cc: Ingo Molnar mingo@redhat.com Cc: Borislav Petkov bp@alien8.de Cc: Dave Hansen dave.hansen@linux.intel.com Cc: x86@kernel.org Cc: "H. Peter Anvin" hpa@zytor.com Cc: stable stable@kernel.org Reported-by: Xingyuan Mo hdthky0@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Message-Id: 20230214103304.3689213-1-gregkh@linuxfoundation.org Tested-by: Xingyuan Mo hdthky0@gmail.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 @@ -3637,12 +3637,11 @@ 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,