System crash in case payload length too large

SNMP++/AGENT++
#1

The master agent can crash (on linux with signal 6 - SIGABRT) when the payload length of the subagent request is too large. This can happen if the master agent and sub agent run on a different target, have a different endianness and didn’t set the network byte order.

I didn’t find any specifications for max payload length, so I put it on 0xffff.

I modified “AgentX::receive_agentx”:

…
payloadLen = octets.decode_int(pos, netByteOrder);

// avoid SIGABRT
if (payloadLen > 0xffff)
{
return AGENTX_DISCONNECT;
}

u_char* pbuf = new u_char[payloadLen+1];
…

#2

I have fixed that for the next release, although I made the maximum payload length configurable per preprocessor definition. The default will be 0xFFFFFF (less than 16MByte).