linux-toradex.git/virt/kvm/iommu.c, branch v3.2.70

kvm: fix excessive pages un-pinning in kvm_iommu_map error path.

2014-12-14T16:23:51+00:00

commit 3d32e4dbe71374a6780eaf51d719d76f9a9bf22f upstream.

The third parameter of kvm_unpin_pages() when called from
kvm_iommu_map_pages() is wrong, it should be the number of pages to un-pin
and not the page size.

This error was facilitated with an inconsistent API: kvm_pin_pages() takes
a size, but kvn_unpin_pages() takes a number of pages, so fix the problem
by matching the two.

This was introduced by commit 350b8bd ("kvm: iommu: fix the third parameter
of kvm_iommu_put_pages (CVE-2014-3601)"), which fixes the lack of
un-pinning for pages intended to be un-pinned (i.e. memory leak) but
unfortunately potentially aggravated the number of pages we un-pin that
should have stayed pinned. As far as I understand though, the same
practical mitigations apply.

This issue was found during review of Red Hat 6.6 patches to prepare
Ksplice rebootless updates.

Thanks to Vegard for his time on a late Friday evening to help me in
understanding this code.

Fixes: 350b8bd ("kvm: iommu: fix the third parameter of... (CVE-2014-3601)")
Cc: stable@vger.kernel.org
Signed-off-by: Quentin Casasnovas 
Signed-off-by: Vegard Nossum 
Signed-off-by: Jamie Iles 
Reviewed-by: Sasha Levin 
Signed-off-by: Paolo Bonzini 
[bwh: Backported to 3.2: kvm_pin_pages() also takes a struct kvm *kvm param]
Signed-off-by: Ben Hutchings

kvm: iommu: fix the third parameter of kvm_iommu_put_pages (CVE-2014-3601)

2014-09-13T22:41:45+00:00

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 
Signed-off-by: Michael S. Tsirkin 
Signed-off-by: Paolo Bonzini 
Signed-off-by: Ben Hutchings

KVM: IOMMU: hva align mapping page size

2014-01-03T04:33:17+00:00

commit 27ef63c7e97d1e5dddd85051c03f8d44cc887f34 upstream.

When determining the page size we could use to map with the IOMMU, the
page size should also be aligned with the hva, not just the gfn.  The
gfn may not reflect the real alignment within the hugetlbfs file.

Most of the time, this works fine.  However, if the hugetlbfs file is
backed by non-contiguous huge pages, a multi-huge page memslot starts at
an unaligned offset within the hugetlbfs file, and the gfn is aligned
with respect to the huge page size, kvm_host_page_size() will return the
huge page size and we will use that to map with the IOMMU.

When we later unpin that same memslot, the IOMMU returns the unmap size
as the huge page size, and we happily unpin that many pfns in
monotonically increasing order, not realizing we are spanning
non-contiguous huge pages and partially unpin the wrong huge page.

Ensure the IOMMU mapping page size is aligned with the hva corresponding
to the gfn, which does reflect the alignment within the hugetlbfs file.

Reviewed-by: Marcelo Tosatti 
Signed-off-by: Greg Edwards 
Signed-off-by: Gleb Natapov 
[bwh: Backported to 3.2: s/__gfn_to_hva_memslot/gfn_to_hva_memslot/]
Signed-off-by: Ben Hutchings

KVM: lock slots_lock around device assignment

2012-05-30T23:43:11+00:00

(cherry picked from commit 21a1416a1c945c5aeaeaf791b63c64926018eb77)

As pointed out by Jason Baron, when assigning a device to a guest
we first set the iommu domain pointer, which enables mapping
and unmapping of memory slots to the iommu.  This leaves a window
where this path is enabled, but we haven't synchronized the iommu
mappings to the existing memory slots.  Thus a slot being removed
at that point could send us down unexpected code paths removing
non-existent pinnings and iommu mappings.  Take the slots_lock
around creating the iommu domain and initial mappings as well as
around iommu teardown to avoid this race.

Signed-off-by: Alex Williamson 
Signed-off-by: Marcelo Tosatti 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Ben Hutchings

KVM: unmap pages from the iommu when slots are removed

2012-05-11T12:14:07+00:00

commit 32f6daad4651a748a58a3ab6da0611862175722f upstream.

We've been adding new mappings, but not destroying old mappings.
This can lead to a page leak as pages are pinned using
get_user_pages, but only unpinned with put_page if they still
exist in the memslots list on vm shutdown.  A memslot that is
destroyed while an iommu domain is enabled for the guest will
therefore result in an elevated page reference count that is
never cleared.

Additionally, without this fix, the iommu is only programmed
with the first translation for a gpa.  This can result in
peer-to-peer errors if a mapping is destroyed and replaced by a
new mapping at the same gpa as the iommu will still be pointing
to the original, pinned memory address.

Signed-off-by: Alex Williamson 
Signed-off-by: Marcelo Tosatti 
Signed-off-by: Jonathan Nieder 
Signed-off-by: Ben Hutchings

kvm: iommu.c file requires the full module.h present.

2011-10-31T23:32:13+00:00

This file has things like module_param_named() and MODULE_PARM_DESC()
so it needs the full module.h header present.  Without it, you'll get:

  CC      arch/x86/kvm/../../../virt/kvm/iommu.o
virt/kvm/iommu.c:37: error: expected ‘)’ before ‘bool’
virt/kvm/iommu.c:39: error: expected ‘)’ before string constant
make[3]: *** [arch/x86/kvm/../../../virt/kvm/iommu.o] Error 1
make[2]: *** [arch/x86/kvm] Error 2

Signed-off-by: Paul Gortmaker

kvm: fix implicit use of stat.h header file

2011-10-31T23:32:12+00:00

This was coming in via an implicit module.h (and its sub-includes)
before, but we'll be cleaning that up shortly.  Call out the stat.h
include requirement in advance.

Signed-off-by: Paul Gortmaker

Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu

2011-10-30T22:46:19+00:00

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: (33 commits)
  iommu/core: Remove global iommu_ops and register_iommu
  iommu/msm: Use bus_set_iommu instead of register_iommu
  iommu/omap: Use bus_set_iommu instead of register_iommu
  iommu/vt-d: Use bus_set_iommu instead of register_iommu
  iommu/amd: Use bus_set_iommu instead of register_iommu
  iommu/core: Use bus->iommu_ops in the iommu-api
  iommu/core: Convert iommu_found to iommu_present
  iommu/core: Add bus_type parameter to iommu_domain_alloc
  Driver core: Add iommu_ops to bus_type
  iommu/core: Define iommu_ops and register_iommu only with CONFIG_IOMMU_API
  iommu/amd: Fix wrong shift direction
  iommu/omap: always provide iommu debug code
  iommu/core: let drivers know if an iommu fault handler isn't installed
  iommu/core: export iommu_set_fault_handler()
  iommu/omap: Fix build error with !IOMMU_SUPPORT
  iommu/omap: Migrate to the generic fault report mechanism
  iommu/core: Add fault reporting mechanism
  iommu/core: Use PAGE_SIZE instead of hard-coded value
  iommu/core: use the existing IS_ALIGNED macro
  iommu/msm: ->unmap() should return order of unmapped page
  ...

Fixup trivial conflicts in drivers/iommu/Makefile: "move omap iommu to
dedicated iommu folder" vs "Rename the DMAR and INTR_REMAP config
options" just happened to touch lines next to each other.

iommu/core: Convert iommu_found to iommu_present

2011-10-21T12:37:20+00:00

With per-bus iommu_ops the iommu_found function needs to
work on a bus_type too. This patch adds a bus_type parameter
to that function and converts all call-places.
The function is also renamed to iommu_present because the
function now checks if an iommu is present for a given bus
and does not check for a global iommu anymore.

Signed-off-by: Joerg Roedel

iommu/core: Add bus_type parameter to iommu_domain_alloc

2011-10-21T12:37:19+00:00

This is necessary to store a pointer to the bus-specific
iommu_ops in the iommu-domain structure. It will be used
later to call into bus-specific iommu-ops.

Signed-off-by: Joerg Roedel