Fixed UTF-8 passwords for DeviceCommunicationControl to hold up to 20 UTF-8 characters (#767)

src/bacnet/bacstr.c

@@ -587,6 +587,29 @@ bool characterstring_ansi_same(
     return same_status;
 }
 
+/**
+ * Returns number of UTF8 code points in a character string.
+ *
+ * @param dest  Pointer to the string to count the UTF8 code points.
+ *
+ * @return Length of the character string in utf8 codepoints
+ */
+size_t characterstring_utf8_length(const BACNET_CHARACTER_STRING *str)
+{
+    size_t count = 0;
+    int i = 0;
+
+    while ((i < MAX_CHARACTER_STRING_BYTES) && (str->value[i] != '\0')) {
+        if ((str->value[i] & 0xc0) != 0x80) {
+            count++;
+        }
+
+        i++;
+    }
+
+    return count;
+}
+
 /**
  * Append some characters to the end of the characterstring
  *

src/bacnet/bacstr.h

@@ -118,6 +118,8 @@ const char *characterstring_value(const BACNET_CHARACTER_STRING *char_string);
 BACNET_STACK_EXPORT
 size_t characterstring_length(const BACNET_CHARACTER_STRING *char_string);
 BACNET_STACK_EXPORT
+size_t characterstring_utf8_length(const BACNET_CHARACTER_STRING *str);
+BACNET_STACK_EXPORT
 uint8_t characterstring_encoding(const BACNET_CHARACTER_STRING *char_string);
 BACNET_STACK_EXPORT
 size_t characterstring_capacity(const BACNET_CHARACTER_STRING *char_string);

src/bacnet/basic/object/device.c

@@ -667,7 +667,7 @@ bool Device_Reinitialize(BACNET_REINITIALIZE_DEVICE_DATA *rd_data)
         is absent or if the password is incorrect. For those devices that
         do not require a password, this parameter shall be ignored.*/
     if (Reinit_Password && strlen(Reinit_Password) > 0) {
-        if (characterstring_length(&rd_data->password) > 20) {
+        if (characterstring_utf8_length(&rd_data->password) > 20) {
             rd_data->error_class = ERROR_CLASS_SERVICES;
             rd_data->error_code = ERROR_CODE_PARAMETER_OUT_OF_RANGE;
         } else if (characterstring_ansi_same(

src/bacnet/basic/service/h_dcc.c

@@ -24,7 +24,13 @@
 #include "bacnet/basic/services.h"
 #include "bacnet/datalink/datalink.h"
 
-static char My_Password[32] = "filister";
+/* The byte length of a UTF-8 character can vary.
+ * In UTF-8, the number of bytes used to represent a character can range from 1
+ * to 4 bytes. Commonly used characters in the ASCII set are represented by 1
+ * byte,xi while other Unicode characters may require 2, 3, or 4 bytes. Let's
+ * add space for the null '\0' termination byte.
+ * */
+static char My_Password[20 * 4 + 1] = "filister";
 
 /** Sets (non-volatile hold) the password to be used for DCC requests.
  * @param new_password [in] The new DCC password, of up to 31 characters.

src/bacnet/dcc.c

@@ -8,9 +8,11 @@
 #include <stdint.h>
 /* BACnet Stack defines - first */
 #include "bacnet/bacdef.h"
+#include "bacnet/bacstr.h"
 /* BACnet Stack API */
 #include "bacnet/bacdcode.h"
 #include "bacnet/dcc.h"
+/** @file dcc.c  Enable/Disable Device Communication Control (DCC) */
 
 /* note: the disable and time are not expected to survive
    over a power cycle or reinitialization. */
@@ -267,7 +269,6 @@ int dcc_decode_service_request(
     uint32_t len_value_type = 0;
     BACNET_UNSIGNED_INTEGER decoded_unsigned = 0;
     uint32_t decoded_enum = 0;
-    uint32_t password_length = 0;
 
     if (apdu && apdu_len_max) {
         /* Tag 0: timeDuration, in minutes --optional-- */
@@ -321,7 +322,9 @@ int dcc_decode_service_request(
                         &apdu[apdu_len], apdu_len_max - apdu_len,
                         len_value_type, password);
                     if (len > 0) {
-                        password_length = len_value_type - 1;
+                        size_t password_length =
+                            characterstring_utf8_length(password);
+                        /* UTF-8 code points can be up to 4 bytes long */
                         if ((password_length >= 1) && (password_length <= 20)) {
                             apdu_len += len;
                         } else {

src/bacnet/rd.c

@@ -51,7 +51,8 @@ int reinitialize_device_encode(
     }
     /* password [1] CharacterString (SIZE (1..20)) OPTIONAL */
     if (password) {
-        if ((password->length >= 1) && (password->length <= 20)) {
+        if ((password->length >= 1) &&
+            (characterstring_utf8_length(password) <= 20)) {
             len = encode_context_character_string(apdu, 1, password);
             apdu_len += len;
         }