From c829f3431b6fe186c37bad3a5e1dbb8084de0581 Mon Sep 17 00:00:00 2001 From: Vasiliy Kulikov Date: Sat, 30 Oct 2010 22:54:47 +0400 Subject: [PATCH] KVM: x86: fix information leak to userland commit 97e69aa62f8b5d338d6cff49be09e37cc1262838 upstream. Structures kvm_vcpu_events, kvm_debugregs, kvm_pit_state2 and kvm_clock_data are copied to userland with some padding and reserved fields unitialized. It leads to leaking of contents of kernel stack memory. We have to initialize them to zero. In patch v1 Jan Kiszka suggested to fill reserved fields with zeros instead of memset'ting the whole struct. It makes sense as these fields are explicitly marked as padding. No more fields need zeroing. Signed-off-by: Vasiliy Kulikov Signed-off-by: Marcelo Tosatti Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/x86.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index acc64063c89d..3f2d2b3b4d85 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2305,6 +2305,7 @@ static void kvm_vcpu_ioctl_x86_get_vcpu_events(struct kvm_vcpu *vcpu, !kvm_exception_is_soft(vcpu->arch.exception.nr); events->exception.nr = vcpu->arch.exception.nr; events->exception.has_error_code = vcpu->arch.exception.has_error_code; + events->exception.pad = 0; events->exception.error_code = vcpu->arch.exception.error_code; events->interrupt.injected = @@ -2318,12 +2319,14 @@ static void kvm_vcpu_ioctl_x86_get_vcpu_events(struct kvm_vcpu *vcpu, events->nmi.injected = vcpu->arch.nmi_injected; events->nmi.pending = vcpu->arch.nmi_pending; events->nmi.masked = kvm_x86_ops->get_nmi_mask(vcpu); + events->nmi.pad = 0; events->sipi_vector = vcpu->arch.sipi_vector; events->flags = (KVM_VCPUEVENT_VALID_NMI_PENDING | KVM_VCPUEVENT_VALID_SIPI_VECTOR | KVM_VCPUEVENT_VALID_SHADOW); + memset(&events->reserved, 0, sizeof(events->reserved)); } static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu, @@ -2366,6 +2369,7 @@ static void kvm_vcpu_ioctl_x86_get_debugregs(struct kvm_vcpu *vcpu, dbgregs->dr6 = vcpu->arch.dr6; 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, @@ -2849,6 +2853,7 @@ static int kvm_vm_ioctl_get_pit2(struct kvm *kvm, struct kvm_pit_state2 *ps) sizeof(ps->channels)); ps->flags = kvm->arch.vpit->pit_state.flags; mutex_unlock(&kvm->arch.vpit->pit_state.lock); + memset(&ps->reserved, 0, sizeof(ps->reserved)); return r; } @@ -3229,6 +3234,7 @@ long kvm_arch_vm_ioctl(struct file *filp, now_ns = timespec_to_ns(&now); user_ns.clock = kvm->arch.kvmclock_offset + now_ns; user_ns.flags = 0; + memset(&user_ns.pad, 0, sizeof(user_ns.pad)); r = -EFAULT; if (copy_to_user(argp, &user_ns, sizeof(user_ns))) -- 2.34.1