[PATCH 1/3][V2] acpi: lib: add two helper functions

[Alex Hung]

Includes:
  fwts_acpi_structure_length_zero_check
  fwts_acpi_structure_range_check

Signed-off-by: Alex Hung <alex.hung at canonical.com>
---
 src/lib/include/fwts_acpi_tables.h |  2 ++
 src/lib/src/fwts_acpi_tables.c     | 46 ++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/src/lib/include/fwts_acpi_tables.h b/src/lib/include/fwts_acpi_tables.h
index 56414730..54b5a254 100644
--- a/src/lib/include/fwts_acpi_tables.h
+++ b/src/lib/include/fwts_acpi_tables.h
@@ -76,6 +76,8 @@ void fwts_acpi_reserved_bits_check_(fwts_framework *fw, const char *table, const
 void fwts_acpi_reserved_type_check(fwts_framework *fw, const char *table, uint8_t value, uint8_t min, uint8_t reserved, bool *passed);
 bool fwts_acpi_table_length_check(fwts_framework *fw, const char *table, uint32_t length, uint32_t size);
 bool fwts_acpi_structure_length_check(fwts_framework *fw, const char *table, uint8_t subtable_type, uint32_t subtable_length, uint32_t size);
+bool fwts_acpi_structure_length_zero_check(fwts_framework *fw, const char *table, uint16_t length, uint32_t offset);
+bool fwts_acpi_structure_range_check(fwts_framework *fw, const char *table, uint32_t table_length, uint32_t offset);
 void fwts_acpi_fixed_value_check(fwts_framework *fw, fwts_log_level level, const char *table, const char *field, uint8_t actual, uint8_t must_be, bool *passed);
 void fwts_acpi_space_id_check(fwts_framework *fw, const char *table, const char *field, bool *passed, uint8_t actual, uint8_t num_type, ...);
 
diff --git a/src/lib/src/fwts_acpi_tables.c b/src/lib/src/fwts_acpi_tables.c
index dc42a8bd..4a6c578d 100644
--- a/src/lib/src/fwts_acpi_tables.c
+++ b/src/lib/src/fwts_acpi_tables.c
@@ -1738,6 +1738,52 @@ bool fwts_acpi_structure_length_check(
 	return true;
 }
 
+/*
+ *  fwts_acpi_structure_length_zero_check()
+ *  verify whether sub structure length is zero
+ */
+bool fwts_acpi_structure_length_zero_check(
+	fwts_framework *fw,
+	const char *table,
+	const uint16_t length,
+	const uint32_t offset)
+{
+	if (length == 0) {
+		char label[30];
+
+		strncpy(label, table, 4);	/* ACPI name is 4 char long */
+		strncpy(label + 4, "StructLengthZero", sizeof(label) - 4);
+		fwts_failed(fw, LOG_LEVEL_CRITICAL, label,
+			"%4.4s structure (offset 0x%4.4" PRIx32 ") "
+			"length cannot be 0", table, offset);
+		return true;
+	}
+	return false;
+}
+
+/*
+ *  fwts_acpi_structure_range_check()
+ *  verify whether sub structure is out of table range
+ */
+bool fwts_acpi_structure_range_check(
+	fwts_framework *fw,
+	const char *table,
+	const uint32_t table_length,
+	const uint32_t offset)
+{
+	if (offset > table_length) {
+		char label[30];
+
+		strncpy(label, table, 4);	/* ACPI name is 4 char long */
+		strncpy(label + 4, "BadTableLength", sizeof(label) - 4);
+		fwts_failed(fw, LOG_LEVEL_CRITICAL, label,
+			"%4.4s has more subtypes than its size can handle", table);
+
+		return true;
+	}
+	return false;
+}
+
 static uint32_t acpi_version;
 /*
  *  fwts_get_acpi_version()
-- 
2.31.1