From mboxrd@z Thu Jan 1 00:00:00 1970 From: marc.zyngier@arm.com (Marc Zyngier) Date: Sat, 18 Oct 2014 12:56:54 +0100 Subject: [PATCH 04/12] arm/arm64: KVM: fix potential NULL dereference in user_mem_abort() In-Reply-To: <1413633422-14907-1-git-send-email-marc.zyngier@arm.com> References: <1413633422-14907-1-git-send-email-marc.zyngier@arm.com> Message-ID: <1413633422-14907-5-git-send-email-marc.zyngier@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Ard Biesheuvel Handle the potential NULL return value of find_vma_intersection() before dereferencing it. Acked-by: Marc Zyngier Signed-off-by: Ard Biesheuvel Signed-off-by: Christoffer Dall --- arch/arm/kvm/mmu.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index 8f0c7a4..bb2e110 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -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(¤t->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(¤t->mm->mmap_sem); + return -EFAULT; + } + if (is_vm_hugetlb_page(vma)) { hugetlb = true; gfn = (fault_ipa & PMD_MASK) >> PAGE_SHIFT; -- 2.1.1