Commit 036d59f4 authored by Seunghun Han's avatar Seunghun Han Committed by Greg Kroah-Hartman

x86/acpi: Prevent out of bound access caused by broken ACPI tables

commit dad5ab0d upstream.

The bus_irq argument of mp_override_legacy_irq() is used as the index into
the isa_irq_to_gsi[] array. The bus_irq argument originates from
ACPI_MADT_TYPE_IO_APIC and ACPI_MADT_TYPE_INTERRUPT items in the ACPI
tables, but is nowhere sanity checked.

That allows broken or malicious ACPI tables to overwrite memory, which
might cause malfunction, panic or arbitrary code execution.

Add a sanity check and emit a warning when that triggers.

[ tglx: Added warning and rewrote changelog ]
Signed-off-by: default avatarSeunghun Han <kkamagui@gmail.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: security@kernel.org
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 456a9974
......@@ -337,6 +337,14 @@ static void __init mp_override_legacy_irq(u8 bus_irq, u8 polarity, u8 trigger,
int pin;
struct mpc_intsrc mp_irq;
/*
* Check bus_irq boundary.
*/
if (bus_irq >= NR_IRQS_LEGACY) {
pr_warn("Invalid bus_irq %u for legacy override\n", bus_irq);
return;
}
/*
* Convert 'gsi' to 'ioapic.pin'.
*/
......
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