added js string boundaries checks for string parser, fixes issue #31; added tests to cover it; fixed makefile to use custom cflags/ldflags

Makefile

@@ -13,15 +13,15 @@ test: jsmn_test
 	./jsmn_test
 
 jsmn_test: jsmn_test.o
-	$(CC) -L. -ljsmn $< -o $@
+	$(CC) $(LDFLAGS) -L. -ljsmn $< -o $@
 
 jsmn_test.o: jsmn_test.c libjsmn.a
 
 simple_example: example/simple.o libjsmn.a
-	$(CC) $^ -o $@
+	$(CC) $(LDFLAGS) $^ -o $@
 
 jsondump: example/jsondump.o libjsmn.a
-	$(CC) $^ -o $@
+	$(CC) $(LDFLAGS) $^ -o $@
 
 clean:
 	rm -f jsmn.o jsmn_test.o example/simple.o

jsmn.c

@@ -113,8 +113,8 @@ static jsmnerr_t jsmn_parse_string(jsmn_parser *parser, const char *js,
 		}
 
 		/* Backslash: Quoted symbol expected */
-		if (c == '\\') {
+		if (c == '\\' && parser->pos + 1 < len) {
-			int i = 0;
+			int i;
 			parser->pos++;
 			switch (js[parser->pos]) {
 				/* Allowed escaped symbols */
@@ -124,7 +124,7 @@ static jsmnerr_t jsmn_parse_string(jsmn_parser *parser, const char *js,
 				/* Allows escaped symbol \uXXXX */
 				case 'u':
 					parser->pos++;
-					for(; i < 4 && js[parser->pos] != '\0'; i++) {
+					for(i = 0; i < 4 && parser->pos < len && js[parser->pos] != '\0'; i++) {
 						/* If it isn't a hex character we have an error */
 						if(!((js[parser->pos] >= 48 && js[parser->pos] <= 57) || /* 0-9 */
 									(js[parser->pos] >= 65 && js[parser->pos] <= 70) || /* A-F */

jsmn_test.c

@@ -206,6 +206,16 @@ int test_partial_string() {
 	check(TOKEN_STRING(js, tok[0], "x"));
 	check(p.toknext == 1);
 
+	jsmn_init(&p);
+	char js_slash[9] = "\"x\": \"va\\";
+	r = jsmn_parse(&p, js_slash, sizeof(js_slash), tok, 10);
+	check(r == JSMN_ERROR_PART);
+
+	jsmn_init(&p);
+	char js_unicode[10] = "\"x\": \"va\\u";
+	r = jsmn_parse(&p, js_unicode, sizeof(js_unicode), tok, 10);
+	check(r == JSMN_ERROR_PART);
+
 	js = "\"x\": \"valu";
 	r = jsmn_parse(&p, js, strlen(js), tok, 10);
 	check(r == JSMN_ERROR_PART && tok[0].type == JSMN_STRING);