android_kernel_samsung_msm8976/virt/kvm
Michael S. Tsirkin 6e0db2f1e5 kvm: iommu: fix the third parameter of kvm_iommu_put_pages (CVE-2014-3601)
commit 350b8bdd689cd2ab2c67c8a86a0be86cfa0751a7 upstream.

The third parameter of kvm_iommu_put_pages is wrong,
It should be 'gfn - slot->base_gfn'.

By making gfn very large, malicious guest or userspace can cause kvm to
go to this error path, and subsequently to pass a huge value as size.
Alternatively if gfn is small, then pages would be pinned but never
unpinned, causing host memory leak and local DOS.

Passing a reasonable but large value could be the most dangerous case,
because it would unpin a page that should have stayed pinned, and thus
allow the device to DMA into arbitrary memory.  However, this cannot
happen because of the condition that can trigger the error:

- out of memory (where you can't allocate even a single page)
  should not be possible for the attacker to trigger

- when exceeding the iommu's address space, guest pages after gfn
  will also exceed the iommu's address space, and inside
  kvm_iommu_put_pages() the iommu_iova_to_phys() will fail.  The
  page thus would not be unpinned at all.

Reported-by: Jack Morgenstein <jackm@mellanox.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-05 16:28:36 -07:00
..
assigned-dev.c KVM: Move irq routing to generic code 2013-04-26 20:27:17 +02:00
async_pf.c
async_pf.h
coalesced_mmio.c KVM: return an error code in kvm_vm_ioctl_register_coalesced_mmio() 2014-02-22 12:41:29 -08:00
coalesced_mmio.h
eventfd.c KVM: Introduce CONFIG_HAVE_KVM_IRQ_ROUTING 2013-04-26 20:27:14 +02:00
ioapic.c KVM: x86: always exit on EOIs for interrupts listed in the IOAPIC redir table 2014-09-05 16:28:35 -07:00
ioapic.h KVM: Set TMR when programming ioapic entry 2013-04-16 16:32:40 -03:00
iodev.h
iommu.c kvm: iommu: fix the third parameter of kvm_iommu_put_pages (CVE-2014-3601) 2014-09-05 16:28:36 -07:00
irq_comm.c KVM: Move irq routing setup to irqchip.c 2013-04-26 20:27:18 +02:00
irqchip.c KVM: Move irq routing setup to irqchip.c 2013-04-26 20:27:18 +02:00
Kconfig KVM: Introduce CONFIG_HAVE_KVM_IRQ_ROUTING 2013-04-26 20:27:14 +02:00
kvm_main.c mm: close PageTail race 2014-04-03 12:01:05 -07:00