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authorSeunghun Han <kkamagui@gmail.com>2017-07-18 20:03:51 +0900
committerIngo Molnar <mingo@kernel.org>2017-07-20 10:27:59 +0200
commitdad5ab0db8deac535d03e3fe3d8f2892173fa6a4 (patch)
tree059f12b39e9be8cf55fabb631d8e57df283f5ff5 /arch
parent4c07f9046e48c3126978911239e20a5622ad0ad6 (diff)
downloadlinux-dad5ab0db8deac535d03e3fe3d8f2892173fa6a4.tar.bz2
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>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/acpi/boot.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 6bb680671088..7491e73d9253 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -347,6 +347,14 @@ static void __init mp_override_legacy_irq(u8 bus_irq, u8 polarity, u8 trigger,
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'.
*/
ioapic = mp_find_ioapic(gsi);