Index: src/OFString+JSONValue.h
==================================================================
--- src/OFString+JSONValue.h
+++ src/OFString+JSONValue.h
@@ -41,6 +41,28 @@
  *          instead check the returned object using @ref isKindOfClass:.
  *
  * @return An object
  */
 - (id)JSONValue;
+
+/*!
+ * @brief Creates an object from the JSON value of the string.
+ *
+ * @note This also allows parsing JSON5, an extension of JSON. See
+ *	 http://json5.org/ for more details.
+ *
+ * @warning Although not specified by the JSON specification, this can also
+ *          return primitives like strings and numbers. The rationale behind
+ *          this is that most JSON parsers allow JSON data just consisting of a
+ *          single primitive, leading to realworld JSON files sometimes only
+ *          consisting of a single primitive. Therefore, you should not make any
+ *          assumptions about the object returned by this method if you don't
+ *          want your program to terminate due to a message not understood, but
+ *          instead check the returned object using @ref isKindOfClass:.
+ *
+ * @brief depthLimit The maximum depth the parser should accept (defaults to 32
+ *		     if not specified, 0 means no limit (insecure!))
+ *
+ * @return An object
+ */
+- (id)JSONValueWithDepthLimit: (size_t)depthLimit;
 @end

Index: src/OFString+JSONValue.m
==================================================================
--- src/OFString+JSONValue.m
+++ src/OFString+JSONValue.m
@@ -32,11 +32,11 @@
 #import "macros.h"
 
 int _OFString_JSONValue_reference;
 
 static id nextObject(const char *restrict *, const char*,
-    size_t *restrict line);
+    size_t *restrict line, size_t depth, size_t depthLimit);
 
 static void
 skipWhitespaces(const char *restrict *pointer, const char *stop,
     size_t *restrict line)
 {
@@ -390,16 +390,19 @@
 	return nil;
 }
 
 static inline OFMutableArray*
 parseArray(const char *restrict *pointer, const char *stop,
-    size_t *restrict line)
+    size_t *restrict line, size_t depth, size_t depthLimit)
 {
 	OFMutableArray *array = [OFMutableArray array];
 
 	if (++(*pointer) >= stop)
 		return nil;
+
+	if (++depth > depthLimit)
+		return nil;
 
 	while (**pointer != ']') {
 		id object;
 
 		skipWhitespacesAndComments(pointer, stop, line);
@@ -417,11 +420,12 @@
 				return nil;
 
 			break;
 		}
 
-		if ((object = nextObject(pointer, stop, line)) == nil)
+		object = nextObject(pointer, stop, line, depth, depthLimit);
+		if (object == nil)
 			return nil;
 
 		[array addObject: object];
 
 		skipWhitespacesAndComments(pointer, stop, line);
@@ -443,16 +447,19 @@
 	return array;
 }
 
 static inline OFMutableDictionary*
 parseDictionary(const char *restrict *pointer, const char *stop,
-    size_t *restrict line)
+    size_t *restrict line, size_t depth, size_t depthLimit)
 {
 	OFMutableDictionary *dictionary = [OFMutableDictionary dictionary];
 
 	if (++(*pointer) >= stop)
 		return nil;
+
+	if (++depth > depthLimit)
+		return nil;
 
 	while (**pointer != '}') {
 		id key, object;
 
 		skipWhitespacesAndComments(pointer, stop, line);
@@ -479,11 +486,12 @@
 		if ((**pointer >= 'a' && **pointer <= 'z') ||
 		    (**pointer >= 'A' && **pointer <= 'Z') ||
 		    **pointer == '_' || **pointer == '$' || **pointer == '\\')
 			key = parseIdentifier(pointer, stop);
 		else
-			key = nextObject(pointer, stop, line);
+			key = nextObject(pointer, stop, line,
+			    depth, depthLimit);
 
 		if (key == nil)
 			return nil;
 
 		skipWhitespacesAndComments(pointer, stop, line);
@@ -490,11 +498,12 @@
 		if (*pointer + 1 >= stop || **pointer != ':')
 			return nil;
 
 		(*pointer)++;
 
-		if ((object = nextObject(pointer, stop, line)) == nil)
+		object = nextObject(pointer, stop, line, depth, depthLimit);
+		if (object == nil)
 			return nil;
 
 		[dictionary setObject: object
 			       forKey: key];
 
@@ -563,11 +572,11 @@
 	return number;
 }
 
 static id
 nextObject(const char *restrict *pointer, const char *stop,
-    size_t *restrict line)
+    size_t *restrict line, size_t depth, size_t depthLimit)
 {
 	skipWhitespacesAndComments(pointer, stop, line);
 
 	if (*pointer >= stop)
 		return nil;
@@ -575,13 +584,13 @@
 	switch (**pointer) {
 	case '"':
 	case '\'':
 		return parseString(pointer, stop, line);
 	case '[':
-		return parseArray(pointer, stop, line);
+		return parseArray(pointer, stop, line, depth, depthLimit);
 	case '{':
-		return parseDictionary(pointer, stop, line);
+		return parseDictionary(pointer, stop, line, depth, depthLimit);
 	case 't':
 		if (*pointer + 3 >= stop)
 			return nil;
 
 		if (memcmp(*pointer, "true", 4))
@@ -629,20 +638,25 @@
 }
 
 @implementation OFString (JSONValue)
 - (id)JSONValue
 {
+	return [self JSONValueWithDepthLimit: 32];
+}
+
+- (id)JSONValueWithDepthLimit: (size_t)depthLimit
+{
 	const char *pointer = [self UTF8String];
 	const char *stop = pointer + [self UTF8StringLength];
 	id object;
 	size_t line = 1;
 
-	object = nextObject(&pointer, stop, &line);
+	object = nextObject(&pointer, stop, &line, 0, depthLimit);
 	skipWhitespacesAndComments(&pointer, stop, &line);
 
 	if (pointer < stop || object == nil)
 		@throw [OFInvalidJSONException exceptionWithClass: [self class]
 							     line: line];
 
 	return object;
 }
 @end