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Commit 3d32e4db authored by Quentin Casasnovas's avatar Quentin Casasnovas Committed by Paolo Bonzini
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kvm: fix excessive pages un-pinning in kvm_iommu_map error path.



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 350b8bdd ("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: 350b8bdd ("kvm: iommu: fix the third parameter of... (CVE-2014-3601)")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarQuentin Casasnovas <quentin.casasnovas@oracle.com>
Signed-off-by: default avatarVegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: default avatarJamie Iles <jamie.iles@oracle.com>
Reviewed-by: default avatarSasha Levin <sasha.levin@oracle.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 3f6f1480
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