[PATCH 2/2] ACPI: riscv: validate interrupt controller MADT entries

[Jiale Yao]

The PLIC and APLIC MADT callbacks cast generic subtable headers to
fixed-size records before checking that the complete records are
present. Truncated firmware entries can therefore cause out-of-bounds
field reads.

Reject entries that do not contain the complete controller-specific
structure before registering an interrupt controller.

Signed-off-by: Jiale Yao <yaojiale02 at 163.com>
---
 drivers/acpi/riscv/irq.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/acpi/riscv/irq.c b/drivers/acpi/riscv/irq.c
index da2c42e0ebfd..1f6fee5c5746 100644
--- a/drivers/acpi/riscv/irq.c
+++ b/drivers/acpi/riscv/irq.c
@@ -220,6 +220,9 @@ static int __init riscv_acpi_aplic_parse_madt(union acpi_subtable_headers *heade
 {
 	struct acpi_madt_aplic *aplic = (struct acpi_madt_aplic *)header;
 
+	if (BAD_MADT_ENTRY(aplic, end))
+		return -EINVAL;
+
 	return riscv_acpi_register_ext_intc(aplic->gsi_base, aplic->num_sources, aplic->num_idcs,
 					    aplic->id, ACPI_RISCV_IRQCHIP_APLIC);
 }
@@ -229,6 +232,9 @@ static int __init riscv_acpi_plic_parse_madt(union acpi_subtable_headers *header
 {
 	struct acpi_madt_plic *plic = (struct acpi_madt_plic *)header;
 
+	if (BAD_MADT_ENTRY(plic, end))
+		return -EINVAL;
+
 	return riscv_acpi_register_ext_intc(plic->gsi_base, plic->num_irqs, 0,
 					    plic->id, ACPI_RISCV_IRQCHIP_PLIC);
 }
-- 
2.34.1