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27 March 2024, 02:37:15 UTC
Revision 17d68b763f09a9ce824ae23eb62c9efc57b69271 authored by Gleb Natapov on 12 December 2013, 20:20:08 UTC, committed by Paolo Bonzini on 12 December 2013, 21:46:18 UTC 
KVM: x86: fix guest-initiated crash with x2apic (CVE-2013-6376)
 
A guest can cause a BUG_ON() leading to a host kernel crash.
When the guest writes to the ICR to request an IPI, while in x2apic
mode the following things happen, the destination is read from
ICR2, which is a register that the guest can control.

kvm_irq_delivery_to_apic_fast uses the high 16 bits of ICR2 as the
cluster id.  A BUG_ON is triggered, which is a protection against
accessing map->logical_map with an out-of-bounds access and manages
to avoid that anything really unsafe occurs.

The logic in the code is correct from real HW point of view. The problem
is that KVM supports only one cluster with ID 0 in clustered mode, but
the code that has the bug does not take this into account.

Reported-by: Lars Bull <larsbull@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1 parent fda4e2e
History
Tip revision: 17d68b763f09a9ce824ae23eb62c9efc57b69271 authored by Gleb Natapov on 12 December 2013, 20:20:08 UTC
KVM: x86: fix guest-initiated crash with x2apic (CVE-2013-6376)
Tip revision: 17d68b7
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security
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usr
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.gitignore -rw-r--r-- 1.1 KB
.mailmap -rw-r--r-- 4.4 KB
COPYING -rw-r--r-- 18.3 KB
CREDITS -rw-r--r-- 93.2 KB
Kbuild -rw-r--r-- 2.5 KB
Kconfig -rw-r--r-- 252 bytes
MAINTAINERS -rw-r--r-- 260.5 KB
Makefile -rw-r--r-- 48.2 KB
README -rw-r--r-- 18.3 KB
REPORTING-BUGS -rw-r--r-- 7.3 KB

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