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

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: Seunghun Han <kkamagui@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: security@kernel.org
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: stable@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
CVE-2017-11473

Change-Id: I06eeb72e3207d795a87279ecfdd362e361f505f7
This commit is contained in:
Seunghun Han 2017-07-18 20:03:51 +09:00 committed by syphyr
parent 18e9cbeb9d
commit 94bee3919a
1 changed files with 8 additions and 0 deletions

View File

@ -967,6 +967,14 @@ void __init mp_override_legacy_irq(u8 bus_irq, u8 polarity, u8 trigger, u32 gsi)
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'.
*/