ACPICA: Update parameter validation for data_table_region and load_table

ACPICA commit 51ab555e60b4a3de3cc4a846e86d0de255be441a

Add additional validation for the table signature and
the OEM strings. Eliminates buffer read overrun in data_table_region.
ACPICA BZ 1184.

Link: https://bugs.acpica.org/show_bug.cgi?id=1184
Link: https://github.com/acpica/acpica/commit/51ab555e
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/actables.h

@@ -164,4 +164,6 @@ acpi_tb_install_fixed_table(acpi_physical_address address,
 
 acpi_status acpi_tb_parse_root_table(acpi_physical_address rsdp_address);
 
+u8 acpi_is_valid_signature(char *signature);
+
 #endif				/* __ACTABLES_H__ */

drivers/acpi/acpica/dsopcode.c

@@ -480,8 +480,8 @@ acpi_ds_eval_table_region_operands(struct acpi_walk_state *walk_state,
 	union acpi_operand_object **operand;
 	struct acpi_namespace_node *node;
 	union acpi_parse_object *next_op;
-	u32 table_index;
 	struct acpi_table_header *table;
+	u32 table_index;
 
 	ACPI_FUNCTION_TRACE_PTR(ds_eval_table_region_operands, op);
 
@@ -504,39 +504,43 @@ acpi_ds_eval_table_region_operands(struct acpi_walk_state *walk_state,
 		return_ACPI_STATUS(status);
 	}
 
+	operand = &walk_state->operands[0];
+
 	/*
 	 * Resolve the Signature string, oem_id string,
 	 * and oem_table_id string operands
 	 */
 	status = acpi_ex_resolve_operands(op->common.aml_opcode,
 					  ACPI_WALK_OPERANDS, walk_state);
 	if (ACPI_FAILURE(status)) {
-		return_ACPI_STATUS(status);
+		goto cleanup;
 	}
 
-	operand = &walk_state->operands[0];
-
 	/* Find the ACPI table */
 
 	status = acpi_tb_find_table(operand[0]->string.pointer,
 				    operand[1]->string.pointer,
 				    operand[2]->string.pointer, &table_index);
 	if (ACPI_FAILURE(status)) {
-		return_ACPI_STATUS(status);
+		if (status == AE_NOT_FOUND) {
+			ACPI_ERROR((AE_INFO,
+				    "ACPI Table [%4.4s] OEM:(%s, %s) not found in RSDT/XSDT",
+				    operand[0]->string.pointer,
+				    operand[1]->string.pointer,
+				    operand[2]->string.pointer));
+		}
+		goto cleanup;
 	}
 
-	acpi_ut_remove_reference(operand[0]);
-	acpi_ut_remove_reference(operand[1]);
-	acpi_ut_remove_reference(operand[2]);
-
 	status = acpi_get_table_by_index(table_index, &table);
 	if (ACPI_FAILURE(status)) {
-		return_ACPI_STATUS(status);
+		goto cleanup;
 	}
 
 	obj_desc = acpi_ns_get_attached_object(node);
 	if (!obj_desc) {
-		return_ACPI_STATUS(AE_NOT_EXIST);
+		status = AE_NOT_EXIST;
+		goto cleanup;
 	}
 
 	obj_desc->region.address = ACPI_PTR_TO_PHYSADDR(table);
@@ -551,6 +555,11 @@ acpi_ds_eval_table_region_operands(struct acpi_walk_state *walk_state,
 
 	obj_desc->region.flags |= AOPOBJ_DATA_VALID;
 
+cleanup:
+	acpi_ut_remove_reference(operand[0]);
+	acpi_ut_remove_reference(operand[1]);
+	acpi_ut_remove_reference(operand[2]);
+
 	return_ACPI_STATUS(status);
 }
 

drivers/acpi/acpica/exconfig.c

@@ -162,14 +162,6 @@ acpi_ex_load_table_op(struct acpi_walk_state *walk_state,
 
 	ACPI_FUNCTION_TRACE(ex_load_table_op);
 
-	/* Validate lengths for the Signature, oem_id, and oem_table_id strings */
-
-	if ((operand[0]->string.length > ACPI_NAME_SIZE) ||
-	    (operand[1]->string.length > ACPI_OEM_ID_SIZE) ||
-	    (operand[2]->string.length > ACPI_OEM_TABLE_ID_SIZE)) {
-		return_ACPI_STATUS(AE_AML_STRING_LIMIT);
-	}
-
 	/* Find the ACPI table in the RSDT/XSDT */
 
 	status = acpi_tb_find_table(operand[0]->string.pointer,

drivers/acpi/acpica/tbfind.c

@@ -68,12 +68,25 @@ acpi_status
 acpi_tb_find_table(char *signature,
 		   char *oem_id, char *oem_table_id, u32 *table_index)
 {
-	u32 i;
 	acpi_status status;
 	struct acpi_table_header header;
+	u32 i;
 
 	ACPI_FUNCTION_TRACE(tb_find_table);
 
+	/* Validate the input table signature */
+
+	if (!acpi_is_valid_signature(signature)) {
+		return_ACPI_STATUS(AE_BAD_SIGNATURE);
+	}
+
+	/* Don't allow the OEM strings to be too long */
+
+	if ((strlen(oem_id) > ACPI_OEM_ID_SIZE) ||
+	    (strlen(oem_table_id) > ACPI_OEM_TABLE_ID_SIZE)) {
+		return_ACPI_STATUS(AE_AML_STRING_LIMIT);
+	}
+
 	/* Normalize the input strings */
 
 	memset(&header, 0, sizeof(struct acpi_table_header));

drivers/acpi/acpica/tbutils.c

@@ -412,3 +412,36 @@ acpi_status __init acpi_tb_parse_root_table(acpi_physical_address rsdp_address)
 
 	return_ACPI_STATUS(AE_OK);
 }
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_is_valid_signature
+ *
+ * PARAMETERS:  signature           - Sig string to be validated
+ *
+ * RETURN:      TRUE if signature is correct length and has valid characters
+ *
+ * DESCRIPTION: Validate an ACPI table signature.
+ *
+ ******************************************************************************/
+
+u8 acpi_is_valid_signature(char *signature)
+{
+	u32 i;
+
+	/* Validate the signature length */
+
+	if (strlen(signature) != ACPI_NAME_SIZE) {
+		return (FALSE);
+	}
+
+	/* Validate each character in the signature */
+
+	for (i = 0; i < ACPI_NAME_SIZE; i++) {
+		if (!acpi_ut_valid_acpi_char(signature[i], i)) {
+			return (FALSE);
+		}
+	}
+
+	return (TRUE);
+}