From: Vasiliy Kulikov Date: Sat, 30 Oct 2010 18:54:47 +0000 (+0400) Subject: KVM: x86: fix information leak to userland X-Git-Tag: v2.6.34.9~154 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=eba62cf05ef4fc1780a582ce37a04900e0d40e00;p=thirdparty%2Fkernel%2Fstable.git 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. [PG: 34 doesn't have the dbgregs section to be memset, so drop that bit] KVM-Stable-Tag. Signed-off-by: Vasiliy Kulikov Signed-off-by: Marcelo Tosatti Signed-off-by: Paul Gortmaker --- diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 7ea288846aecb..8ced130d8c0d8 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2115,6 +2115,7 @@ static void kvm_vcpu_ioctl_x86_get_vcpu_events(struct kvm_vcpu *vcpu, events->exception.injected = vcpu->arch.exception.pending; 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 = vcpu->arch.interrupt.pending; @@ -2124,11 +2125,13 @@ 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); + memset(&events->reserved, 0, sizeof(events->reserved)); vcpu_put(vcpu); } @@ -2589,6 +2592,7 @@ 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; } @@ -2983,6 +2987,7 @@ 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)))