Commit message: KVM: perform an invalid memslot step for gpa base change

PPC must flush all translations before the new memory slot
is visible.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
CVE: CVE-2013-4592
CWE: CWE-399
Vulnerability description: Memory leak in the __kvm_set_memory_region function in virt/kvm/kvm_main.c in the Linux kernel before 3.9 allows local users to cause a denial of service (memory consumption) by leveraging certain device access to trigger movement of memory slots.

Project: linux
File: kvm_main.c

static void kvm_free_physmem_slot(struct kvm_memory_slot *free,
				  struct kvm_memory_slot *dont)
{
	if (!dont || free->dirty_bitmap != dont->dirty_bitmap)
		kvm_destroy_dirty_bitmap(free);

	kvm_arch_free_memslot(free, dont);

	free->npages = 0;
}

Project: linux
File: kvm_main.c

void kvm_kvfree(const void *addr)
{
	if (is_vmalloc_addr(addr))
		vfree(addr);
	else
		kfree(addr);
}

Project: linux
File: kvm_main.c

static int kvm_read_hva(void *data, void __user *hva, int len)
{
	return __copy_from_user(data, hva, len);
}

Project: linux
File: kvm_main.c

static int kvm_read_hva_atomic(void *data, void __user *hva, int len)
{
	return __copy_from_user_inatomic(data, hva, len);
}

Project: linux
File: kvm_main.c

bool kvm_vcpu_yield_to(struct kvm_vcpu *target)
{
	struct pid *pid;
	struct task_struct *task = NULL;

	rcu_read_lock();
	pid = rcu_dereference(target->pid);
	if (pid)
		task = get_pid_task(target->pid, PIDTYPE_PID);
	rcu_read_unlock();
	if (!task)
		return false;
	if (task->flags & PF_VCPU) {
		put_task_struct(task);
		return false;
	}
	if (yield_to(task, 1)) {
		put_task_struct(task);
		return true;
	}
	put_task_struct(task);
	return false;
}

Project: linux
File: kvm_main.c

static long kvm_vm_ioctl(struct file *filp,
			   unsigned int ioctl, unsigned long arg)
{
	struct kvm *kvm = filp->private_data;
	void __user *argp = (void __user *)arg;
	int r;

	if (kvm->mm != current->mm)
		return -EIO;
	switch (ioctl) {
	case KVM_CREATE_VCPU:
		r = kvm_vm_ioctl_create_vcpu(kvm, arg);
		if (r < 0)
			goto out;
		break;
	case KVM_SET_USER_MEMORY_REGION: {
		struct kvm_userspace_memory_region kvm_userspace_mem;

		r = -EFAULT;
		if (copy_from_user(&kvm_userspace_mem, argp,
						sizeof kvm_userspace_mem))
			goto out;

		r = kvm_vm_ioctl_set_memory_region(kvm, &kvm_userspace_mem, 1);
		if (r)
			goto out;
		break;
	}
	case KVM_GET_DIRTY_LOG: {
		struct kvm_dirty_log log;

		r = -EFAULT;
		if (copy_from_user(&log, argp, sizeof log))
			goto out;
		r = kvm_vm_ioctl_get_dirty_log(kvm, &log);
		if (r)
			goto out;
		break;
	}
#ifdef KVM_COALESCED_MMIO_PAGE_OFFSET
	case KVM_REGISTER_COALESCED_MMIO: {
		struct kvm_coalesced_mmio_zone zone;
		r = -EFAULT;
		if (copy_from_user(&zone, argp, sizeof zone))
			goto out;
		r = kvm_vm_ioctl_register_coalesced_mmio(kvm, &zone);
		if (r)
			goto out;
		r = 0;
		break;
	}
	case KVM_UNREGISTER_COALESCED_MMIO: {
		struct kvm_coalesced_mmio_zone zone;
		r = -EFAULT;
		if (copy_from_user(&zone, argp, sizeof zone))
			goto out;
		r = kvm_vm_ioctl_unregister_coalesced_mmio(kvm, &zone);
		if (r)
			goto out;
		r = 0;
		break;
	}
#endif
	case KVM_IRQFD: {
		struct kvm_irqfd data;

		r = -EFAULT;
		if (copy_from_user(&data, argp, sizeof data))
			goto out;
		r = kvm_irqfd(kvm, &data);
		break;
	}
	case KVM_IOEVENTFD: {
		struct kvm_ioeventfd data;

		r = -EFAULT;
		if (copy_from_user(&data, argp, sizeof data))
			goto out;
		r = kvm_ioeventfd(kvm, &data);
		break;
	}
#ifdef CONFIG_KVM_APIC_ARCHITECTURE
	case KVM_SET_BOOT_CPU_ID:
		r = 0;
		mutex_lock(&kvm->lock);
		if (atomic_read(&kvm->online_vcpus) != 0)
			r = -EBUSY;
		else
			kvm->bsp_vcpu_id = arg;
		mutex_unlock(&kvm->lock);
		break;
#endif
#ifdef CONFIG_HAVE_KVM_MSI
	case KVM_SIGNAL_MSI: {
		struct kvm_msi msi;

		r = -EFAULT;
		if (copy_from_user(&msi, argp, sizeof msi))
			goto out;
		r = kvm_send_userspace_msi(kvm, &msi);
		break;
	}
#endif
#ifdef __KVM_HAVE_IRQ_LINE
	case KVM_IRQ_LINE_STATUS:
	case KVM_IRQ_LINE: {
		struct kvm_irq_level irq_event;

		r = -EFAULT;
		if (copy_from_user(&irq_event, argp, sizeof irq_event))
			goto out;

		r = kvm_vm_ioctl_irq_line(kvm, &irq_event);
		if (r)
			goto out;

		r = -EFAULT;
		if (ioctl == KVM_IRQ_LINE_STATUS) {
			if (copy_to_user(argp, &irq_event, sizeof irq_event))
				goto out;
		}

		r = 0;
		break;
	}
#endif
	default:
		r = kvm_arch_vm_ioctl(filp, ioctl, arg);
		if (r == -ENOTTY)
			r = kvm_vm_ioctl_assigned_device(kvm, ioctl, arg);
	}
out:
	return r;
}