NationalSecurityAgency/ghidra · error · TraceRmiError

Cannot receive TraceRmi message with excessive message lengt

Error message

Cannot receive TraceRmi message with excessive message length

What it means

Intended to be raised as TraceRmiError by recv_delimited() when the length-prefix advertises a message size greater than MAX_MSG_LENGTH (1<<16 = 64 KiB), a sanity check against malicious/corrupt framing. IMPORTANT BUG: util.py raises 'TraceRmiError' but never imports or defines it, so if this line executes it throws NameError: name 'TraceRmiError' is not defined rather than the intended error.

Source

Thrown at Ghidra/Debug/Debugger-rmi-trace/src/main/py/src/ghidratrace/util.py:60

        part = s.recv(size - len(buf))
        if len(part) == 0:
            return buf
        buf += part
    return buf
    # return s.recv(size, socket.MSG_WAITALL)


def recv_length(s: socket.socket) -> int:
    buf = recv_all(s, 4)
    if len(buf) < 4:
        raise Exception("Socket closed")
    return int.from_bytes(buf, 'big')


def recv_delimited(s: socket.socket, msg: M, dbg_seq: int) -> M:
    size = recv_length(s)
    if size > MAX_MSG_LENGTH:
        raise TraceRmiError("Cannot receive TraceRmi message with excessive message length")
    buf = recv_all(s, size)
    if len(buf) < size:
        raise Exception("Socket closed")
    msg.ParseFromString(buf)
    return msg

View on GitHub (pinned to d5f144c24d)

Solutions

1. Confirm both ends speak the same TraceRmi protocol/version.
2. Ensure you are connecting to a TraceRmi endpoint and not an unrelated service.
3. If developing, fix the latent bug by importing/defining TraceRmiError so this guard is actually usable.

Example fix

// not a runtime fix per se — verify endpoint and version
# before: client pointed at wrong port/service
# after: connect to the Ghidra TraceRmi listening port and matching version

from ghidratrace.util import MAX_MSG_LENGTH
if size > MAX_MSG_LENGTH:
    raise ValueError(f'announced size {size} exceeds {MAX_MSG_LENGTH}; framing/endpoint mismatch')

try:
    msg = recv_delimited(s, proto, seq)
except (ValueError, NameError):
    # wrong endpoint or corrupt framing; reset connection
    raise

When it happens

Trigger: A corrupted/garbled length prefix decodes to a huge value; a peer using a different framing convention; memory corruption on the socket buffer; rarely a genuinely oversized message that bypassed the send-side guard due to the bug in 395.

Common situations: Protocol/version mismatch producing mis-framed bytes; noisy/unreliable link; debugging against a non-TraceRmi endpoint on the same port.

Related errors

• Cannot send TraceRmi message with excessive length
• Cannot send TraceRmi message with excessive length
• Cannot receive TraceRmi message with excessive message lengt
• Could not receive negotiation request
• Could not respond during negotiation

AI-assisted analysis of NationalSecurityAgency/ghidra@d5f144c24d (2026-08-14). Data as JSON: /api/errors/9dba8ebb4a58a813. Report an issue: GitHub.