Pumpkin-MC/Pumpkin · error · PacketError

Invalid length

Error message

Invalid length

What it means

PacketError guard for RCON packet framing: the length prefix of an RCON packet (used for both requests and responses) is invalid — negative, smaller than the minimum 10-byte body, or otherwise out of the plausible range. The offending input is the 4-byte little-endian length field of the RCON packet; a bad value means a malformed or hostile RCON client.

Solutions

1. Drop the malformed RCON packet
2. Check the length header covers the full received payload
3. Log the short packet at debug level

When it happens

Trigger: Thrown at crates/pumpkin-protocol/src/rcon.rs:52 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of Pumpkin-MC/Pumpkin@8d4639e25a (2026-09-09). Data as JSON: /api/errors/c8c7dadb882a34f3. Report an issue: GitHub.

Appendix: source

Thrown at crates/pumpkin-protocol/src/rcon.rs:52

impl ClientboundPacket {
    #[must_use]
    pub fn write_buf(self, id: i32, body: &str) -> BytesMut {
        let mut buf = BytesMut::new();
        // 10 is for 4 bytes ty, 4 bytes id, and 2 terminating nul bytes.
        buf.put_i32_le(10 + body.len() as i32);
        buf.put_i32_le(id);
        buf.put_i32_le(self as i32);
        let bytes = body.as_bytes();
        buf.put_slice(bytes);
        buf.put_u8(0);
        buf.put_u8(0);
        buf
    }
}

#[derive(Error, Debug)]
pub enum PacketError {
    #[error("Invalid length")]
    InvalidLength,
    #[error("Failed to send packet: {0}")]
    FailedSend(std::io::Error),
    #[error("Missing packet null terminator")]
    MissingNullTerminator,
    #[error("Invalid packet string body: {0}")]
    InvalidBody(std::str::Utf8Error),
    #[error("Unknown packet type: {0}")]
    UnknownPacketType(i32),
}

#[derive(Debug, PartialEq, Eq)]
/// Serverbound packet
pub struct Packet {
    id: i32,
    ptype: ServerboundPacket,
    body: Box<str>,
}

View on GitHub (pinned to 8d4639e25a)