48 lines
1.8 KiB
Diff
48 lines
1.8 KiB
Diff
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References: CVE-2012-5513 XSA-29 bnc#789951
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xen: add missing guest address range checks to XENMEM_exchange handlers
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Ever since its existence (3.0.3 iirc) the handler for this has been
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using non address range checking guest memory accessors (i.e.
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the ones prefixed with two underscores) without first range
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checking the accessed space (via guest_handle_okay()), allowing
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a guest to access and overwrite hypervisor memory.
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This is XSA-29 / CVE-2012-5513.
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Signed-off-by: Jan Beulich <jbeulich@suse.com>
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Acked-by: Ian Campbell <ian.campbell@citrix.com>
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Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
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--- a/xen/common/compat/memory.c
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+++ b/xen/common/compat/memory.c
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@@ -115,6 +115,12 @@ int compat_memory_op(unsigned int cmd, X
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(cmp.xchg.out.nr_extents << cmp.xchg.out.extent_order)) )
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return -EINVAL;
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+ if ( !compat_handle_okay(cmp.xchg.in.extent_start,
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+ cmp.xchg.in.nr_extents) ||
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+ !compat_handle_okay(cmp.xchg.out.extent_start,
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+ cmp.xchg.out.nr_extents) )
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+ return -EFAULT;
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+
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start_extent = cmp.xchg.nr_exchanged;
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end_extent = (COMPAT_ARG_XLAT_SIZE - sizeof(*nat.xchg)) /
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(((1U << ABS(order_delta)) + 1) *
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--- a/xen/common/memory.c
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+++ b/xen/common/memory.c
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@@ -308,6 +308,13 @@ static long memory_exchange(XEN_GUEST_HA
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goto fail_early;
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}
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+ if ( !guest_handle_okay(exch.in.extent_start, exch.in.nr_extents) ||
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+ !guest_handle_okay(exch.out.extent_start, exch.out.nr_extents) )
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+ {
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+ rc = -EFAULT;
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+ goto fail_early;
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+ }
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+
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/* Only privileged guests can allocate multi-page contiguous extents. */
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if ( !multipage_allocation_permitted(current->domain,
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exch.in.extent_order) ||
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