Re: REPL Server: Guard against HTTP inter-protocol exploitation attacks.

[Ludovic Courtès]

Alex Kost <address@hidden> skribis:

> Hello, I've noticed an insignificant typo in commit
> 08c021916dbd3a235a9f9cc33df4c418c0724e03 (in the fancy warning message).
>
> [...]
>> +               ;; Print a report to STDERR (POSIX file descriptor 2).
>> +               ;; XXX Can we do better here?
>> +               (call-with-port (dup->port 2 "w")
>> +                 (cut format <> "
>> +@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
>> +@@ POSSIBLE BREAK-IN ATTEMPT ON THE REPL SERVER                @@
>> +@@ BY AN HTTP INTER-PROTOCOL EXPLOITATION ATTACK.  See:        @@
>> +@@ <https://en.wikipedia.org/wiki/Inter-protocol_exploitation> @@
>> +@@ Possible HTTP request received: ~S
>                                                                   ^^
> Missing trailing "@@" in the above line.

As discussed on IRC, I think this is intended: we don’t know the length
of the string being printed by ~S.

Ludo’.