[3.16.y-ckt stable] Patch "arm/arm64: KVM: fix potential NULL dereference in user_mem_abort()" has been added to staging queue
Luis Henriques
luis.henriques at canonical.com
Wed May 20 12:30:25 UTC 2015
This is a note to let you know that I have just added a patch titled
arm/arm64: KVM: fix potential NULL dereference in user_mem_abort()
to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue
This patch is scheduled to be released in version 3.16.7-ckt12.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Luis
------
>From a3e0331251072077a86b2e4102fc78e3c9314880 Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ard.biesheuvel at linaro.org>
Date: Wed, 17 Sep 2014 14:56:17 -0700
Subject: arm/arm64: KVM: fix potential NULL dereference in user_mem_abort()
commit 37b544087ef3f65ca68465ba39291a07195dac26 upstream.
Handle the potential NULL return value of find_vma_intersection()
before dereferencing it.
Acked-by: Marc Zyngier <marc.zyngier at arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall at linaro.org>
Signed-off-by: Shannon Zhao <shannon.zhao at linaro.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
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 40e52eeaf12f..0258b22bf9d1 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -778,6 +778,12 @@ 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;
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