ACPI: bounds check IRQ to prevent memory corruption
acpi_penalize_isa_irq() should validate irq before using it to
index the acpi_irq_penalty[] table.
Here's the path I'm concerned about:
pnpacpi_parse_allocated_irqresource()
{
...
irq = acpi_register_gsi(gsi, triggering, polarity);
if (irq >= 0)
pcibios_penalize_isa_irq(irq, 1);
There's no guarantee that acpi_register_gsi() will return an IRQ
within the bounds of acpi_irq_penalty[].
I have not seen a failure I can attribute to this. However,
ACPI_MAX_IRQS is only 256, and I'm pretty sure ia64 can have
IRQs larger than that.
I think this should go in 2.6.27.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
index 89f3b2a..cf47805 100644
--- a/drivers/acpi/pci_link.c
+++ b/drivers/acpi/pci_link.c
@@ -849,7 +849,7 @@
if (irq < 0)
continue;
- if (irq >= ACPI_MAX_IRQS)
+ if (irq >= ARRAY_SIZE(acpi_irq_penalty))
continue;
if (used)
@@ -872,10 +872,12 @@
*/
void acpi_penalize_isa_irq(int irq, int active)
{
- if (active)
- acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
- else
- acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
+ if (irq >= 0 && irq < ARRAY_SIZE(acpi_irq_penalty)) {
+ if (active)
+ acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
+ else
+ acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
+ }
}
/*