arm/arm64: KVM: fix potential NULL dereference in user_mem_abort()
authorArd Biesheuvel <ard.biesheuvel@linaro.org>
Wed, 17 Sep 2014 21:56:17 +0000 (14:56 -0700)
committerChristoffer Dall <christoffer.dall@linaro.org>
Fri, 10 Oct 2014 11:07:37 +0000 (13:07 +0200)
Handle the potential NULL return value of find_vma_intersection()
before dereferencing it.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
arch/arm/kvm/mmu.c

index 8f0c7a4c49fc88299b2a15068d836a76493c9104..bb2e110e77c07e58239b3d2b1faedf07e699157a 100644 (file)
@@ -776,6 +776,12 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
        /* Let's check if we will get back a huge page backed by hugetlbfs */
        down_read(&current->mm->mmap_sem);
        vma = find_vma_intersection(current->mm, hva, hva + 1);
+       if (unlikely(!vma)) {
+               kvm_err("Failed to find VMA for hva 0x%lx\n", hva);
+               up_read(&current->mm->mmap_sem);
+               return -EFAULT;
+       }
+
        if (is_vm_hugetlb_page(vma)) {
                hugetlb = true;
                gfn = (fault_ipa & PMD_MASK) >> PAGE_SHIFT;