Impact
LoginPacket uses BinaryStream->getLInt() to read the lengths of JSON payloads it wants to decode. Unfortunately, BinaryStream->getLInt() returns a signed integer, meaning that a malicious client can craft a packet with a large uint32 value for payload buffer size (which would be interpreted as a negative signed int32), causing BinaryStream->get() to throw an exception.
In the context of PocketMine-MP, this leads to a server crash when the vulnerability is exploited.
Patches
e3fce7632b94e83fd6a518a87dcaf6a11681c4ac
Workarounds
This can be worked around by registering a custom LoginPacket implementation into PacketPool which overrides this code to patch it.
For more information
References
Impact
LoginPacketusesBinaryStream->getLInt()to read the lengths of JSON payloads it wants to decode. Unfortunately,BinaryStream->getLInt()returns a signed integer, meaning that a malicious client can craft a packet with a large uint32 value for payload buffer size (which would be interpreted as a negative signed int32), causingBinaryStream->get()to throw an exception.In the context of PocketMine-MP, this leads to a server crash when the vulnerability is exploited.
Patches
e3fce7632b94e83fd6a518a87dcaf6a11681c4ac
Workarounds
This can be worked around by registering a custom
LoginPacketimplementation intoPacketPoolwhich overrides this code to patch it.For more information
References