diff options
| author | Andy Honig <ahonig@google.com> | 2013-02-20 14:49:16 -0800 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2013-04-25 20:25:50 +0100 |
| commit | 6d29de40486edf7d5a61d40f4b18431e2c644ad0 (patch) | |
| tree | 79b8bca014162a42c335fc082cc6294aec35247d | |
| parent | 767d3d43c0a02485a8574c0efe39524f246d698b (diff) | |
KVM: Fix bounds checking in ioapic indirect register reads (CVE-2013-1798)
commit a2c118bfab8bc6b8bb213abfc35201e441693d55 upstream.
If the guest specifies a IOAPIC_REG_SELECT with an invalid value and follows
that with a read of the IOAPIC_REG_WINDOW KVM does not properly validate
that request. ioapic_read_indirect contains an
ASSERT(redir_index < IOAPIC_NUM_PINS), but the ASSERT has no effect in
non-debug builds. In recent kernels this allows a guest to cause a kernel
oops by reading invalid memory. In older kernels (pre-3.3) this allows a
guest to read from large ranges of host memory.
Tested: tested against apic unit tests.
Signed-off-by: Andrew Honig <ahonig@google.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | virt/kvm/ioapic.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c index 3eed61eb486..79647cde86f 100644 --- a/virt/kvm/ioapic.c +++ b/virt/kvm/ioapic.c @@ -73,9 +73,12 @@ static unsigned long ioapic_read_indirect(struct kvm_ioapic *ioapic, u32 redir_index = (ioapic->ioregsel - 0x10) >> 1; u64 redir_content; - ASSERT(redir_index < IOAPIC_NUM_PINS); + if (redir_index < IOAPIC_NUM_PINS) + redir_content = + ioapic->redirtbl[redir_index].bits; + else + redir_content = ~0ULL; - redir_content = ioapic->redirtbl[redir_index].bits; result = (ioapic->ioregsel & 0x1) ? (redir_content >> 32) & 0xffffffff : redir_content & 0xffffffff; |