decoder/opus: limit tag size to 64 kB

NEWS

 ver 0.19.14 (not yet released)
+* decoder
+  - opus: limit tag size to 64 kB
 * fix build failures on non-glibc builds due to constexpr Mutex
 
 ver 0.19.13 (2016/02/23)

src/decoder/plugins/OpusReader.hxx

@@ -85,7 +85,7 @@ public:
 
 	char *ReadString() {
 		uint32_t length;
-		if (!ReadWord(length))
+		if (!ReadWord(length) || length >= 65536)
 			return nullptr;
 
 		const char *src = (const char *)Read(length);