SessionKey handshake for V1-initial S7-1200 PLCs#761
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Adds the full session_auth package (HarpoS7 port) for V1-initial S7-1200 PLCs that require a SessionKey handshake before data operations: - s7/session_auth/: Public-key-based session authentication (Family 0 key derivation, fingerprint matching, SecurityKeyEncryptedKey blob generation, legitimation challenge solver, HMAC key derivation) - V3 HMAC framing for post-auth data operations - TIA-style CreateObject attributes (required by V1-initial firmware) - PAOM string stripping in ServerSessionVersion echo - Post-auth legitimation flow (challenge read + solved blob write) - Connection.connect(password=) parameter for auth flow Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This was referenced Jul 11, 2026
Three places checked `self._server_session_version` against itself (same variable on both sides of `or`/`and`). Simplify to single checks. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
S7CommPlus responses use a 10-byte header (no SessionId field), not 14. The 14-byte header is only for requests. This fix corrects the CreateObject response parsing that crashed with "Unexpected end of VLQ data" on V1 PLCs (e.g. S7-1200 FW v4.2) because the 4-byte offset error caused the VLQ decoder to misparse object ID count as 161. Also fixes the test server to match real PLC behavior (10-byte response header with session ID in the body as ObjectIds[0], not in the header). Fixes #710 (comment by xBiggs on d5e8aaf). Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
…sionKey PLCs V1-initial S7-1200 PLCs with SessionKey auth reject GET_MULTI_VARIABLES (0x054C) with a TCP RST. They require GET_VAR_SUBSTREAMED (0x0586) and SET_VAR_SUBSTREAMED (0x057C) for all data operations — the same function codes that the legitimation handshake already uses successfully. When connection.requires_substreamed is True (session_key is set), db_read, db_write, db_read_multi, read_area, and write_area now route through substreamed function codes with ItemAddress fields encoded in the substreamed payload format. Addresses #710 (xBiggs: db_read RST after successful SessionKey auth). Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
# Conflicts: # s7/_s7commplus_server.py # s7/connection.py # s7/protocol.py
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Replaces #724 (GitHub's PR ref got stuck after force-push conflict resolution).
Summary
Adds the full
session_authpackage for V1-initial S7-1200 PLCs that require a SessionKey handshake before data operations:s7/session_auth/: Public-key-based session authentication (Family 0 key derivation, fingerprint matching, SecurityKeyEncryptedKey blob generation, legitimation challenge solver, HMAC key derivation)Connection.connect(password=)parameter for auth flowTest plan
Known limitations
01:prefix) public keys are includedsend_requestneeds V3 HMAC framing wired in for data operations