json utils: Remove dependency on C99 I/O formatting specifiers for 8/…

…16-bit sscanf items
espressif · Mar 7, 2017 · 7132505 · 7132505
1 parent 26e4132
commit 7132505
Showing 1 changed file with 21 additions and 3 deletions.
diff --git a/src/aws_iot_json_utils.c b/src/aws_iot_json_utils.c
@@ -87,10 +87,16 @@ IoT_Error_t parseUnsignedInteger8Value(uint8_t *i, const char *jsonString, jsmnt
 		return JSON_PARSE_ERROR;
 	}
 
-	if(('-' == (char) (jsonString[token->start])) || (1 != sscanf(jsonString + token->start, "%" SCNu8, i))) {
+	uint32_t i_word;
+	if(('-' == (char) (jsonString[token->start])) || (1 != sscanf(jsonString + token->start, "%" SCNu32, &i_word))) {
 		IOT_WARN("Token was not an unsigned integer.");
 		return JSON_PARSE_ERROR;
 	}
+	if (i_word > UINT8_MAX) {
+		IOT_WARN("Token value %u exceeds 8 bits", i_word);
+		return JSON_PARSE_ERROR;
+	}
+	*i = i_word;
 
 	return SUCCESS;
 }
@@ -115,10 +121,16 @@ IoT_Error_t parseInteger16Value(int16_t *i, const char *jsonString, jsmntok_t *t
 		return JSON_PARSE_ERROR;
 	}
 
-	if(1 != sscanf(jsonString + token->start, "%" SCNi16, i)) {
+	int32_t i_word;
+	if(1 != sscanf(jsonString + token->start, "%" SCNi32, &i_word)) {
 		IOT_WARN("Token was not an integer.");
 		return JSON_PARSE_ERROR;
 	}
+	if(i_word < INT16_MIN || i_word > INT16_MAX) {
+		IOT_WARN("Token value %d out of range for 16-bit int", i_word);
+		return JSON_PARSE_ERROR;
+	}
+	*i = i_word;
 
 	return SUCCESS;
 }
@@ -129,10 +141,16 @@ IoT_Error_t parseInteger8Value(int8_t *i, const char *jsonString, jsmntok_t *tok
 		return JSON_PARSE_ERROR;
 	}
 
-	if(1 != sscanf(jsonString + token->start, "%" SCNi8, i)) {
+	int32_t i_word;
+	if(1 != sscanf(jsonString + token->start, "%" SCNi32, &i_word)) {
 		IOT_WARN("Token was not an integer.");
 		return JSON_PARSE_ERROR;
 	}
+	if(i_word < INT8_MIN || i_word > INT8_MAX) {
+		IOT_WARN("Token value %d out of range for 8-bit int", i_word);
+		return JSON_PARSE_ERROR;
+	}
+	*i = i_word;
 
 	return SUCCESS;
 }