Merge tag 'acpi-6.15-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull ACPI fix from Rafael Wysocki:
 "Fix ACPI PPTT parsing code to address a regression introduced recently
  and add more sanity checking of data supplied by the platform firmware
  to avoid using invalid data (Jeremy Linton)"

* tag 'acpi-6.15-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: PPTT: Fix processor subtable walk

Author: torvalds

drivers/acpi/pptt.c

@@ -231,16 +231,18 @@ static int acpi_pptt_leaf_node(struct acpi_table_header *table_hdr,
 			     sizeof(struct acpi_table_pptt));
 	proc_sz = sizeof(struct acpi_pptt_processor);
 
-	while ((unsigned long)entry + proc_sz < table_end) {
+	/* ignore subtable types that are smaller than a processor node */
+	while ((unsigned long)entry + proc_sz <= table_end) {
 		cpu_node = (struct acpi_pptt_processor *)entry;
+
 		if (entry->type == ACPI_PPTT_TYPE_PROCESSOR &&
 		    cpu_node->parent == node_entry)
 			return 0;
 		if (entry->length == 0)
 			return 0;
+
 		entry = ACPI_ADD_PTR(struct acpi_subtable_header, entry,
 				     entry->length);
-
 	}
 	return 1;
 }
@@ -273,15 +275,18 @@ static struct acpi_pptt_processor *acpi_find_processor_node(struct acpi_table_he
 	proc_sz = sizeof(struct acpi_pptt_processor);
 
 	/* find the processor structure associated with this cpuid */
-	while ((unsigned long)entry + proc_sz < table_end) {
+	while ((unsigned long)entry + proc_sz <= table_end) {
 		cpu_node = (struct acpi_pptt_processor *)entry;
 
 		if (entry->length == 0) {
 			pr_warn("Invalid zero length subtable\n");
 			break;
 		}
+		/* entry->length may not equal proc_sz, revalidate the processor structure length */
 		if (entry->type == ACPI_PPTT_TYPE_PROCESSOR &&
 		    acpi_cpu_id == cpu_node->acpi_processor_id &&
+		    (unsigned long)entry + entry->length <= table_end &&
+		    entry->length == proc_sz + cpu_node->number_of_priv_resources * sizeof(u32) &&
 		     acpi_pptt_leaf_node(table_hdr, cpu_node)) {
 			return (struct acpi_pptt_processor *)entry;
 		}