fix(rss): remove null-terminator from RSS metadata

Remove the null-terminator of the string-like data items
from the RSS measurement's metadata. The 'version' and
'sw_type' items have an associated length value which
should not include a null-terminator when storing the
measurement.

Change-Id: Ia91ace2fff8b6f75686dd2e1862475268300bbdb
Signed-off-by: David Vincze <david.vincze@arm.com>

include/lib/psa/measured_boot.h

@@ -34,14 +34,14 @@
  *
  * index			Slot number in which measurement is to be stored
  * signer_id			Pointer to signer_id buffer.
- * signer_id_size		Size of the signer_id buffer in bytes.
+ * signer_id_size		Size of the signer_id in bytes.
  * version			Pointer to version buffer.
- * version_size			Size of the version buffer in bytes.
+ * version_size			Size of the version string in bytes (with \0).
  * measurement_algo		Algorithm identifier used for measurement.
  * sw_type			Pointer to sw_type buffer.
- * sw_type_size			Size of the sw_type buffer in bytes.
+ * sw_type_size			Size of the sw_type string in bytes (with \0).
  * measurement_value		Pointer to measurement_value buffer.
- * measurement_value_size	Size of the measurement_value buffer in bytes.
+ * measurement_value_size	Size of the measurement_value in bytes.
  * lock_measurement		Boolean flag requesting whether the measurement
  *				is to be locked.
  *

lib/psa/measured_boot.c

@@ -80,22 +80,24 @@ rss_measured_boot_extend_measurement(uint8_t index,
 		.lock_measurement = lock_measurement,
 		.measurement_algo = measurement_algo,
 		.sw_type = {0},
-		.sw_type_size = sw_type_size,
+		/* Removing \0 */
+		.sw_type_size = (sw_type_size > 0) ? (sw_type_size - 1) : 0,
 	};
 
 	psa_invec in_vec[] = {
 		{.base = &extend_iov,
 			.len = sizeof(struct measured_boot_extend_iovec_t)},
 		{.base = signer_id, .len = signer_id_size},
-		{.base = version, .len = version_size},
+		{.base = version,
+			.len = (version_size > 0) ? (version_size - 1) : 0},
 		{.base = measurement_value, .len = measurement_value_size}
 	};
 
 	if (sw_type != NULL) {
-		if (sw_type_size > SW_TYPE_MAX_SIZE) {
+		if (extend_iov.sw_type_size > SW_TYPE_MAX_SIZE) {
 			return PSA_ERROR_INVALID_ARGUMENT;
 		}
-		memcpy(extend_iov.sw_type, sw_type, sw_type_size);
+		memcpy(extend_iov.sw_type, sw_type, extend_iov.sw_type_size);
 	}
 
 	log_measurement(index, signer_id, signer_id_size,