Use connected socket to filter out packets from wrong host - #198
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Use connected socket to filter out packets from wrong host#198fixthething wants to merge 1 commit into
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With the previous code, an obscure error could happen, where packets from an entirely different host than the intended connected server would be received by self._sock.recvfrom(), because the unconnected socket would accept a packet from any source address that matched the correct port. This could happen maliciously, but could also happen if the ephemeral source port were reused from a previously closed socket by an entirely different app but a response arrived late.
In a real-world example, I observed an IPMI request error out because the received packet was actually a stray DHCP response, which obviously did not match the expected format for an RMCP response packet.
When using a connected socket (see the added
self._sock.connect()), the OS will filter out packets coming from an incorrect source address or port and only receive a response from the server we are attempting to communicate with.I also updated examples/interface_rmcp.py with connection parameters compatible with ipmi_sim so anybody could run it repeatably without a live server at the 10.x.x.x hardcoded address.