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 <segooon@xxxxxxxxx> --- Compile tesed only. arch/x86/kvm/x86.c | 6 ++++++ 1 files changed, 6 insertions(+), 0 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index b0818f6..463c65b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2560,6 +2560,7 @@ 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 = @@ -2573,12 +2574,14 @@ 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, @@ -2623,6 +2626,7 @@ 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, @@ -3106,6 +3110,7 @@ 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; } @@ -3486,6 +3491,7 @@ long kvm_arch_vm_ioctl(struct file *filp, user_ns.clock = kvm->arch.kvmclock_offset + now_ns; local_irq_enable(); 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))) -- Vasiliy -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
