3.2.44-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Andy Honig <ahonig@xxxxxxxxxx> 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@xxxxxxxxxx> Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx> Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> --- virt/kvm/ioapic.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/virt/kvm/ioapic.c +++ b/virt/kvm/ioapic.c @@ -73,9 +73,12 @@ static unsigned long ioapic_read_indirec 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; -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html