linux-stable.git/virt, branch linux-3.4.y

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

2015-02-02T09:04:59+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)")
Signed-off-by: Quentin Casasnovas 
Signed-off-by: Vegard Nossum 
Signed-off-by: Jamie Iles 
Reviewed-by: Sasha Levin 
Signed-off-by: Paolo Bonzini 
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li

kvm: don't take vcpu mutex for obviously invalid vcpu ioctls

2015-02-02T09:04:42+00:00

commit 2ea75be3219571d0ec009ce20d9971e54af96e09 upstream.

vcpu ioctls can hang the calling thread if issued while a vcpu is running.
However, invalid ioctls can happen when userspace tries to probe the kind
of file descriptors (e.g. isatty() calls ioctl(TCGETS)); in that case,
we know the ioctl is going to be rejected as invalid anyway and we can
fail before trying to take the vcpu mutex.

This patch does not change functionality, it just makes invalid ioctls
fail faster.

Signed-off-by: David Matlack 
Signed-off-by: Paolo Bonzini 
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li

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

2014-09-25T03:49:10+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: Zefan Li

KVM: IOMMU: hva align mapping page size

2014-03-11T23:10:03+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 
Cc: Qiang Huang 
Signed-off-by: Greg Kroah-Hartman

KVM: return an error code in kvm_vm_ioctl_register_coalesced_mmio()

2014-02-22T18:32:46+00:00

commit aac5c4226e7136c331ed384c25d5560204da10a0 upstream.

If kvm_io_bus_register_dev() fails then it returns success but it should
return an error code.

I also did a little cleanup like removing an impossible NULL test.

Fixes: 2b3c246a682c ('KVM: Make coalesced mmio use a device per zone')
Signed-off-by: Dan Carpenter 
Signed-off-by: Paolo Bonzini 
Signed-off-by: Greg Kroah-Hartman

KVM: Fix buffer overflow in kvm_set_irq()

2014-02-20T18:45:33+00:00

commit f2ebd422f71cda9c791f76f85d2ca102ae34a1ed upstream.

kvm_set_irq() has an internal buffer of three irq routing entries, allowing
connecting a GSI to three IRQ chips or on MSI.  However setup_routing_entry()
does not properly enforce this, allowing three irqchip routes followed by
an MSI route to overflow the buffer.

Fix by ensuring that an MSI entry is added to an empty list.

Signed-off-by: Avi Kivity 
Signed-off-by: Ben Hutchings 
Cc: Li Zefan 
Signed-off-by: Greg Kroah-Hartman

KVM: Improve create VCPU parameter (CVE-2013-4587)

2013-12-20T15:34:19+00:00

commit 338c7dbadd2671189cec7faf64c84d01071b3f96 upstream.

In multiple functions the vcpu_id is used as an offset into a bitfield.  Ag
malicious user could specify a vcpu_id greater than 255 in order to set or
clear bits in kernel memory.  This could be used to elevate priveges in the
kernel.  This patch verifies that the vcpu_id provided is less than 255.
The api documentation already specifies that the vcpu_id must be less than
max_vcpus, but this is currently not checked.

Reported-by: Andrew Honig 
Signed-off-by: Andrew Honig 
Signed-off-by: Paolo Bonzini 
Signed-off-by: Greg Kroah-Hartman

KVM: Fix iommu map/unmap to handle memory slot moves

2013-12-04T18:50:34+00:00

commit e40f193f5bb022e927a57a4f5d5194e4f12ddb74 upstream.

The iommu integration into memory slots expects memory slots to be
added or removed and doesn't handle the move case.  We can unmap
slots from the iommu after we mark them invalid and map them before
installing the final memslot array.  Also re-order the kmemdup vs
map so we don't leave iommu mappings if we get ENOMEM.

Reviewed-by: Gleb Natapov 
Signed-off-by: Alex Williamson 
Signed-off-by: Marcelo Tosatti 
Cc: Luis Henriques 
Signed-off-by: Greg Kroah-Hartman

KVM: perform an invalid memslot step for gpa base change

2013-12-04T18:50:34+00:00

commit 12d6e7538e2d418c08f082b1b44ffa5fb7270ed8 upstream.

PPC must flush all translations before the new memory slot
is visible.

Signed-off-by: Marcelo Tosatti 
Signed-off-by: Avi Kivity 
Cc: Luis Henriques 
Signed-off-by: Greg Kroah-Hartman

KVM: Allow cross page reads and writes from cached translations.

2013-04-26T04:19:55+00:00

commit 8f964525a121f2ff2df948dac908dcc65be21b5b upstream.

This patch adds support for kvm_gfn_to_hva_cache_init functions for
reads and writes that will cross a page.  If the range falls within
the same memslot, then this will be a fast operation.  If the range
is split between two memslots, then the slower kvm_read_guest and
kvm_write_guest are used.

Tested: Test against kvm_clock unit tests.

Signed-off-by: Andrew Honig 
Signed-off-by: Gleb Natapov 
Cc: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman