Fix silent data corruptoin from strlen() on binary packet data - #560
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This is an import of OpenKermit/ckermit@b58e033 Original description follows: When a data packet arrives out of order and gets stashed for later, replaying it once the window catches up recalculated its size with strlen(). That breaks when a packet contains a NULL. Each truncated packet still carries a valid checksum for its own wrong length, so nothing flags an error. The transfer reports success with an incomplete or corrupted file. rpack() already computes the correct length when it first parses and validates a packet. The fix stores that in r_pkt[].pk_len (mirroring s_pkt[].pk_len on the send side) and uses it instead of recomputing from the data on replay. The underlying bug has been present since this code was introduced in C-Kermit 5A(188) in 1992, 34 years ago! Commit OpenKermit/ckermit@a213649
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This is an import of
OpenKermit/ckermit@b58e033
Original description follows:
When a data packet arrives out of order and gets stashed for later, replaying it once the window catches up recalculated its size with strlen(). That breaks when a packet contains a NULL.
Each truncated packet still carries a valid checksum for its own wrong length, so nothing flags an error. The transfer reports success with an incomplete or corrupted file.
rpack() already computes the correct length when it first parses and validates a packet. The fix stores that in r_pkt[].pk_len (mirroring s_pkt[].pk_len on the send side) and uses it instead of recomputing from the data on replay.
The underlying bug has been present since this code was introduced in C-Kermit 5A(188) in 1992, 34 years ago! Commit
OpenKermit/ckermit@a213649