Dennis Boone d6d01cd05c Workaround for locked up AMLC lines ...

As it was in the real world, especially with dialup ports, it is possible
for an emulator AMLC line to get blocked by stray flow control characters.
The blocked port may appear dead to the next user to connect, if they are
not "serial savvy" enough to try sending an XON character.

A large number of vulnerability scanners have found and have been hitting
the public emulators, injecting HTTP transactions or worse into the AMLC
ports and often locking all of them daily.

This workaround injects an XON (DC1, 0221) and a line kill character as
extracted from the DEFKIL field in FIGCOM, into the AMLC line when a new
connection is received.

There is a -dolineclear command line switch to enable the behavior.

2021-02-07 00:37:15 -05:00

283 KiB

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