[PATCH 4.14 023/115] KVM: fix spectrev1 gadgets

Greg Kroah-Hartman
2019-05-15T11:58:19Z

[ Upstream commit 1d487e9bf8ba66a7174c56a0029c54b1eca8f99c ]

These were found with smatch, and then generalized when applicable.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/kvm/lapic.c | 4 +++-
include/linux/kvm_host.h | 10 ++++++----
virt/kvm/irqchip.c | 5 +++--
virt/kvm/kvm_main.c | 6 ++++--
4 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index f7c34184342a5..053e4937af0cb 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -133,6 +133,7 @@ static inline bool kvm_apic_map_get_logical_dest(struct kvm_apic_map *map,
if (offset <= max_apic_id) {
u8 cluster_size = min(max_apic_id - offset + 1, 16U);

+ offset = array_index_nospec(offset, map->max_apic_id + 1);
*cluster = &map->phys_map[offset];
*mask = dest_id & (0xffff >> (16 - cluster_size));
} else {
@@ -829,7 +830,8 @@ static inline bool kvm_apic_map_get_dest_lapic(struct kvm *kvm,
if (irq->dest_id > map->max_apic_id) {
*bitmap = 0;
} else {
- *dst = &map->phys_map[irq->dest_id];
+ u32 dest_id = array_index_nospec(irq->dest_id, map->max_apic_id + 1);
+ *dst = &map->phys_map[dest_id];
*bitmap = 1;
}
return true;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 753c16633bac5..026615e242d8e 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -27,6 +27,7 @@
#include <linux/irqbypass.h>
#include <linux/swait.h>
#include <linux/refcount.h>
+#include <linux/nospec.h>
#include <asm/signal.h>

#include <linux/kvm.h>
@@ -483,10 +484,10 @@ static inline struct kvm_io_bus *kvm_get_bus(struct kvm *kvm, enum kvm_bus idx)

static inline struct kvm_vcpu *kvm_get_vcpu(struct kvm *kvm, int i)
{
- /* Pairs with smp_wmb() in kvm_vm_ioctl_create_vcpu, in case
- * the caller has read kvm->online_vcpus before (as is the case
- * for kvm_for_each_vcpu, for example).
- */
+ int num_vcpus = atomic_read(&kvm->online_vcpus);
+ i = array_index_nospec(i, num_vcpus);
+
+ /* Pairs with smp_wmb() in kvm_vm_ioctl_create_vcpu. */
smp_rmb();
return kvm->vcpus[i];
}
@@ -570,6 +571,7 @@ void kvm_put_kvm(struct kvm *kvm);

static inline struct kvm_memslots *__kvm_memslots(struct kvm *kvm, int as_id)
{
+ as_id = array_index_nospec(as_id, KVM_ADDRESS_SPACE_NUM);
return srcu_dereference_check(kvm->memslots[as_id], &kvm->srcu,
lockdep_is_held(&kvm->slots_lock) ||
!refcount_read(&kvm->users_count));
diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c
index b1286c4e07122..0bd0683640bdf 100644
--- a/virt/kvm/irqchip.c
+++ b/virt/kvm/irqchip.c
@@ -144,18 +144,19 @@ static int setup_routing_entry(struct kvm *kvm,
{
struct kvm_kernel_irq_routing_entry *ei;
int r;
+ u32 gsi = array_index_nospec(ue->gsi, KVM_MAX_IRQ_ROUTES);

/*
* Do not allow GSI to be mapped to the same irqchip more than once.
* Allow only one to one mapping between GSI and non-irqchip routing.
*/
- hlist_for_each_entry(ei, &rt->map[ue->gsi], link)
+ hlist_for_each_entry(ei, &rt->map[gsi], link)
if (ei->type != KVM_IRQ_ROUTING_IRQCHIP ||
ue->type != KVM_IRQ_ROUTING_IRQCHIP ||
ue->u.irqchip.irqchip == ei->irqchip.irqchip)
return -EINVAL;

- e->gsi = ue->gsi;
+ e->gsi = gsi;
e->type = ue->type;
r = kvm_set_routing_entry(kvm, e, ue);
if (r)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index a373c60ef1c06..b91716b1b428e 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2886,12 +2886,14 @@ static int kvm_ioctl_create_device(struct kvm *kvm,
struct kvm_device_ops *ops = NULL;
struct kvm_device *dev;
bool test = cd->flags & KVM_CREATE_DEVICE_TEST;
+ int type;
int ret;

if (cd->type >= ARRAY_SIZE(kvm_device_ops_table))
return -ENODEV;

- ops = kvm_device_ops_table[cd->type];
+ type = array_index_nospec(cd->type, ARRAY_SIZE(kvm_device_ops_table));
+ ops = kvm_device_ops_table[type];
if (ops == NULL)
return -ENODEV;

@@ -2906,7 +2908,7 @@ static int kvm_ioctl_create_device(struct kvm *kvm,
dev->kvm = kvm;

mutex_lock(&kvm->lock);
- ret = ops->create(dev, cd->type);
+ ret = ops->create(dev, type);
if (ret < 0) {
mutex_unlock(&kvm->lock);
kfree(dev);
--
2.20.1