ACPICA: Resources: Not a valid resource if buffer length too long

ACPICA commit 9f76de2d249b18804e35fb55d14b1c2604d627a1
ACPICA commit b2e89d72ef1e9deefd63c3fd1dee90f893575b3a
ACPICA commit 23b5bbe6d78afd3c5abf3adb91a1b098a3000b2e

The declared buffer length must be the same as the length of the
byte initializer list, otherwise not a valid resource descriptor.

Link: https://github.com/acpica/acpica/commit/9f76de2d
Link: https://github.com/acpica/acpica/commit/b2e89d72
Link: https://github.com/acpica/acpica/commit/23b5bbe6
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/acpica/utresrc.c

@@ -421,8 +421,10 @@ acpi_ut_walk_aml_resources(struct acpi_walk_state *walk_state,
 
 	ACPI_FUNCTION_TRACE(ut_walk_aml_resources);
 
-	/* The absolute minimum resource template is one end_tag descriptor */
-
+	/*
+	 * The absolute minimum resource template is one end_tag descriptor.
+	 * However, we will treat a lone end_tag as just a simple buffer.
+	 */
 	if (aml_length < sizeof(struct aml_resource_end_tag)) {
 		return_ACPI_STATUS(AE_AML_NO_RESOURCE_END_TAG);
 	}
@@ -454,9 +456,8 @@ acpi_ut_walk_aml_resources(struct acpi_walk_state *walk_state,
 		/* Invoke the user function */
 
 		if (user_function) {
-			status =
-			    user_function(aml, length, offset, resource_index,
-					  context);
+			status = user_function(aml, length, offset,
+					       resource_index, context);
 			if (ACPI_FAILURE(status)) {
 				return_ACPI_STATUS(status);
 			}
@@ -480,6 +481,12 @@ acpi_ut_walk_aml_resources(struct acpi_walk_state *walk_state,
 				*context = aml;
 			}
 
+			/* Check if buffer is defined to be longer than the resource length */
+
+			if (aml_length > (offset + length)) {
+				return_ACPI_STATUS(AE_AML_NO_RESOURCE_END_TAG);
+			}
+
 			/* Normal exit */
 
 			return_ACPI_STATUS(AE_OK);