Split session management and transport apart.
This commit is contained in:
Tony Garnock-Jones
parent
18fcb4cebd
commit
a27b56e538
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@ -0,0 +1,616 @@
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#lang racket/base
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(require (planet tonyg/bitsyntax))
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(require (planet vyzo/crypto:2:3))
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;; (require (planet vyzo/crypto/util)) ;; hex, unhex
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;; (require racket/port)
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(require racket/match)
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(require racket/class)
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;; (require rackunit)
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;; (require "aes-ctr.rkt")
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(require "safe-io.rkt")
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(require "oakley-groups.rkt")
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(require "host-key.rkt")
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(require "conversation.rkt")
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(require "standard-thread.rkt")
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(require "ssh-numbers.rkt")
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(require "ssh-message-types.rkt")
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(require "ssh-exceptions.rkt")
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(require "ssh-transport.rkt")
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Data definitions
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; A RekeyState is one of
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;; - a (rekey-wait Number Number), representing a time or
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;; transfer-amount by which rekeying should be started
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;; - a (rekey-local SshMsgKexinit), when we've sent our local
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;; algorithm list and are waiting for the other party to send theirs
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;; - a (rekey-in-progress KeyExchangeState), when both our local
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;; algorithm list has been sent and the remote one has arrived and the
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;; actual key exchange has begun
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(struct rekey-wait (deadline threshold-bytes) #:transparent)
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(struct rekey-local (local-algorithms) #:transparent)
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(struct rekey-in-progress (state) #:transparent)
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;; A PacketDispatcher is a Hashtable mapping Byte to PacketHandler.
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;; A PacketHandler is a (Bytes DecodedPacket ConnectionState -> ConnectionState).
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;; The raw received bytes of the packet are given because sometimes
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;; cryptographic operations on the received bytes are mandated by the
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;; protocol.
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;; A ConnectionState is a (connection StreamState StreamState
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;; PacketDispatcher ... TODO fix this) representing the complete state
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;; of the SSH transport, authentication, and connection layers.
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(struct connection (io-room-handle
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session-room-handle
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discard-next-packet?
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dispatch-table
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total-transferred
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rekey-state
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is-server?
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local-id
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remote-id
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session-id) ;; starts off #f until initial keying
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#:transparent)
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;; Generic inputs into the exchange-hash part of key
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;; exchange. Diffie-Hellman uses these fields along with the host key,
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;; the exchange values, and the shared secret to get the final hash.
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(struct exchange-hash-info (client-id
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server-id
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client-kexinit-bytes
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server-kexinit-bytes)
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#:transparent)
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Parameters
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(define identification-recogniser #rx"^SSH-")
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(define (identification-line? str)
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(regexp-match identification-recogniser str))
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(define required-peer-identification-regex (make-parameter #rx"^SSH-2\\.0-.*"))
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(define client-preamble-lines (make-parameter '()))
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(define client-identification-string (make-parameter "SSH-2.0-RacketSSH_0.0"))
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(define rekey-interval (make-parameter 5)) ;;3600))
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(define rekey-volume (make-parameter 1000000000))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Packet dispatch and handling
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Bytes -> Byte
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;; Retrieves the packet type byte from a packet.
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(define (encoded-packet-msg-type encoded-packet)
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(bytes-ref encoded-packet 0))
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;; PacketDispatcher [ Byte Maybe<PacketHandler> ]* -> PacketDispatcher
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;; Adds or removes handlers to or from the given PacketDispatcher.
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(define (extend-packet-dispatcher core-dispatcher . key-value-pairs)
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(let loop ((d core-dispatcher)
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(key-value-pairs key-value-pairs))
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(cond
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((null? key-value-pairs)
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d)
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((null? (cdr key-value-pairs))
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(error 'extend-packet-dispatcher
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"Must call extend-packet-dispatcher with matched key/value pairs"))
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(else
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(loop (let ((packet-type-number (car key-value-pairs))
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(packet-handler-or-false (cadr key-value-pairs)))
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(if packet-handler-or-false
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(hash-set d packet-type-number packet-handler-or-false)
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(hash-remove d packet-type-number)))
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(cddr key-value-pairs))))))
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;; ConnectionState [ Byte Maybe<PacketHandler> ]* -> ConnectionState
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;; Installs (or removes) PacketHandlers in the given connection state;
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;; see extend-packet-dispatcher.
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(define (set-handlers conn . key-value-pairs)
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(struct-copy connection conn
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[dispatch-table (apply extend-packet-dispatcher
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(connection-dispatch-table conn)
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key-value-pairs)]))
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;; ConnectionState Byte PacketHandler -> ConnectionState
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;; Installs a PacketHandler that removes the installed dispatch entry
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;; and then delegates to its argument.
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(define (oneshot-handler conn packet-type-number packet-handler)
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(set-handlers conn
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packet-type-number
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(lambda (packet message conn)
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(packet-handler packet
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message
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(set-handlers conn packet-type-number #f)))))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Handlers for core transport packet types
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; PacketHandler for handling SSH_MSG_DISCONNECT.
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(define (handle-msg-disconnect packet message conn)
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(disconnect-with-error* #t
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'()
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(ssh-msg-disconnect-reason-code message)
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"Received SSH_MSG_DISCONNECT with reason code ~a and message ~s"
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(ssh-msg-disconnect-reason-code message)
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(bytes->string/utf-8 (bit-string->bytes
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(ssh-msg-disconnect-description message)))))
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;; PacketHandler for handling SSH_MSG_IGNORE.
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(define (handle-msg-ignore packet message conn)
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conn)
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;; PacketHandler for handling SSH_MSG_UNIMPLEMENTED.
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(define (handle-msg-unimplemented packet message conn)
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(disconnect-with-error/local-info
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`((offending-sequence-number ,(ssh-msg-unimplemented-sequence-number message)))
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SSH_DISCONNECT_PROTOCOL_ERROR
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"Disconnecting because of received SSH_MSG_UNIMPLEMENTED."))
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;; PacketHandler for handling SSH_MSG_DEBUG.
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(define (handle-msg-debug packet message conn)
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;; TODO: use Racket log API.
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(log-debug (format "Received SSHv2 SSH_MSG_DEBUG packet ~v" message))
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conn)
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Key Exchange
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(define (rekey-in-seconds-or-bytes delta-seconds delta-bytes total-transferred)
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(rekey-wait (+ (current-seconds) delta-seconds)
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(+ total-transferred delta-bytes)))
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(define (time-to-rekey? rekey conn)
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(and (rekey-wait? rekey)
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(or (>= (current-seconds) (rekey-wait-deadline rekey))
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(>= (connection-total-transferred conn) (rekey-wait-threshold-bytes rekey)))))
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;; (SshMsgKexinit -> Symbol) SshMsgKexinit SshMsgKexinit -> Symbol
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;; Computes the name of the "best" algorithm choice at the given
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;; getter, using the rules from the RFC and the client and server
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;; algorithm precedence lists.
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(define (best-result getter client-algs server-algs)
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(define client-list0 (getter client-algs))
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(define server-list (getter server-algs))
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(let loop ((client-list client-list0))
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(cond
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((null? client-list) (disconnect-with-error/local-info
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`((client-list ,client-list0)
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(server-list ,server-list))
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SSH_DISCONNECT_KEY_EXCHANGE_FAILED
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"Could not agree on a suitable algorithm for ~v"
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getter))
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((memq (car client-list) server-list) (car client-list))
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(else (loop (cdr client-list))))))
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;; ExchangeHashInfo Bytes Natural Natural Natural -> Bytes
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;; Computes the session ID as defined by SSH's DH key exchange method.
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(define (dh-exchange-hash hash-info host-key e f k)
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(let ((block-to-hash
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(bit-string->bytes
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(bit-string ((string->bytes/utf-8 (exchange-hash-info-client-id hash-info)) :: (t:string))
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((string->bytes/utf-8 (exchange-hash-info-server-id hash-info)) :: (t:string))
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((exchange-hash-info-client-kexinit-bytes hash-info) :: (t:string))
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((exchange-hash-info-server-kexinit-bytes hash-info) :: (t:string))
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(host-key :: (t:string))
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(e :: (t:mpint))
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(f :: (t:mpint))
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(k :: (t:mpint))))))
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;;(pretty-print `((block-to-hash ,(hex block-to-hash))))
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(sha1 block-to-hash)))
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;; ExchangeHashInfo Symbol Symbol ConnectionState
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;; (Bytes Bytes Symbol ConnectionState -> ConnectionState)
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;; -> ConnectionState
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;; Performs the server's half of the Diffie-Hellman key exchange protocol.
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(define (perform-server-key-exchange hash-info kex-alg host-key-alg conn finish)
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(case kex-alg
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((diffie-hellman-group14-sha1 diffie-hellman-group1-sha1)
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(define group (if (eq? kex-alg 'diffie-hellman-group14-sha1)
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dh:oakley-group-14
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dh:oakley-group-2)) ;; yes, SSH's group1 == Oakley/RFC2409 group 2
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(define-values (private-key public-key) (generate-key group))
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(define public-key-as-integer (bit-string->integer public-key #t #f))
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(oneshot-handler conn
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SSH_MSG_KEXDH_INIT
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(lambda (packet message conn)
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(define e (ssh-msg-kexdh-init-e message))
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(define e-width (mpint-width e))
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(define e-as-bytes (integer->bit-string e (* 8 e-width) #t))
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(define shared-secret (compute-key private-key e-as-bytes))
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(define hash-alg sha1)
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(define-values (host-key-private host-key-public)
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(host-key-algorithm->keys host-key-alg))
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(define host-key-bytes
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(pieces->ssh-host-key (public-key->pieces host-key-public)))
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(define exchange-hash
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(dh-exchange-hash hash-info
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host-key-bytes
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e
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public-key-as-integer
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(bit-string->integer shared-secret #t #f)))
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(define h-signature (host-key-signature host-key-private
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host-key-alg
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exchange-hash))
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(write-message! (ssh-msg-kexdh-reply host-key-bytes
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public-key-as-integer
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h-signature)
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conn)
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(flush-outbound-messages! conn)
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(finish shared-secret exchange-hash hash-alg conn))))
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(else (disconnect-with-error SSH_DISCONNECT_KEY_EXCHANGE_FAILED
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"Bad key-exchange algorithm ~v" kex-alg))))
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;; ExchangeHashInfo Symbol Symbol ConnectionState
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;; (Bytes Bytes Symbol ConnectionState -> ConnectionState)
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;; -> ConnectionState
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;; Performs the client's half of the Diffie-Hellman key exchange protocol.
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(define (perform-client-key-exchange hash-info kex-alg host-key-alg conn finish)
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(case kex-alg
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((diffie-hellman-group14-sha1 diffie-hellman-group1-sha1)
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(define group (if (eq? kex-alg 'diffie-hellman-group14-sha1)
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dh:oakley-group-14
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dh:oakley-group-2)) ;; yes, SSH's group1 == Oakley/RFC2409 group 2
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(define-values (private-key public-key) (generate-key group))
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(define public-key-as-integer (bit-string->integer public-key #t #f))
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(write-message! (ssh-msg-kexdh-init public-key-as-integer) conn)
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(flush-outbound-messages! conn)
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(oneshot-handler conn
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SSH_MSG_KEXDH_REPLY
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(lambda (packet message conn)
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(define f (ssh-msg-kexdh-reply-f message))
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(define f-width (mpint-width f))
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(define f-as-bytes (integer->bit-string f (* 8 f-width) #t))
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(define shared-secret (compute-key private-key f-as-bytes))
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(define hash-alg sha1)
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(define host-key-bytes (ssh-msg-kexdh-reply-host-key message))
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(define host-public-key
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(pieces->public-key (ssh-host-key->pieces host-key-bytes)))
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(define exchange-hash
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(dh-exchange-hash hash-info
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host-key-bytes
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public-key-as-integer
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f
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(bit-string->integer shared-secret #t #f)))
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(verify-host-key-signature! host-public-key
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host-key-alg
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exchange-hash
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(ssh-msg-kexdh-reply-h-signature message))
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(finish shared-secret exchange-hash hash-alg conn))))
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(else (disconnect-with-error SSH_DISCONNECT_KEY_EXCHANGE_FAILED
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"Bad key-exchange algorithm ~v" kex-alg))))
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;; PacketHandler for handling SSH_MSG_KEXINIT.
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(define (handle-msg-kexinit packet message conn)
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(define rekey (connection-rekey-state conn))
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(when (rekey-in-progress? rekey)
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(disconnect-with-error SSH_DISCONNECT_PROTOCOL_ERROR
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"Received SSH_MSG_KEXINIT during ongoing key exchange"))
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(define local-algs (if (rekey-local? rekey)
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(rekey-local-local-algorithms rekey)
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((local-algorithm-list))))
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(define encoded-local-algs (ssh-message-encode local-algs))
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(define remote-algs message)
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(define encoded-remote-algs packet)
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(when (rekey-wait? rekey)
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(write-message! local-algs conn)
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(flush-outbound-messages! conn))
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(define is-server? (connection-is-server? conn))
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(define c (if is-server? remote-algs local-algs))
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(define s (if is-server? local-algs remote-algs))
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(define kex-alg (best-result ssh-msg-kexinit-kex_algorithms c s))
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(define host-key-alg (best-result ssh-msg-kexinit-server_host_key_algorithms c s))
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(define c2s-enc (best-result ssh-msg-kexinit-encryption_algorithms_client_to_server c s))
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(define s2c-enc (best-result ssh-msg-kexinit-encryption_algorithms_server_to_client c s))
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(define c2s-mac (best-result ssh-msg-kexinit-mac_algorithms_client_to_server c s))
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(define s2c-mac (best-result ssh-msg-kexinit-mac_algorithms_server_to_client c s))
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(define c2s-zip (best-result ssh-msg-kexinit-compression_algorithms_client_to_server c s))
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(define s2c-zip (best-result ssh-msg-kexinit-compression_algorithms_server_to_client c s))
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;; Ignore languages.
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;; Don't check the reserved field here, either. TODO: should we?
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(define (guess-matches? chosen-value getter)
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(let ((remote-choices (getter remote-algs)))
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(and (pair? remote-choices) ;; not strictly necessary because of
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;; the error behaviour of
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;; best-result.
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(eq? (car remote-choices) ;; the remote peer's guess for this parameter
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chosen-value))))
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(define should-discard-first-kex-packet
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(and (ssh-msg-kexinit-first_kex_packet_follows remote-algs)
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;; They've already transmitted their guess. Does their guess match
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;; what we've actually selected?
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(not (and
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(guess-matches? kex-alg ssh-msg-kexinit-kex_algorithms)
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(guess-matches? host-key-alg ssh-msg-kexinit-server_host_key_algorithms)
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(guess-matches? c2s-enc ssh-msg-kexinit-encryption_algorithms_client_to_server)
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(guess-matches? s2c-enc ssh-msg-kexinit-encryption_algorithms_server_to_client)
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(guess-matches? c2s-mac ssh-msg-kexinit-mac_algorithms_client_to_server)
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(guess-matches? s2c-mac ssh-msg-kexinit-mac_algorithms_server_to_client)
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(guess-matches? c2s-zip ssh-msg-kexinit-compression_algorithms_client_to_server)
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(guess-matches? s2c-zip ssh-msg-kexinit-compression_algorithms_server_to_client)))))
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(define (continue-after-discard conn)
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((if is-server?
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perform-server-key-exchange
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perform-client-key-exchange)
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(if is-server?
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(exchange-hash-info (connection-remote-id conn)
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(connection-local-id conn)
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encoded-remote-algs
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encoded-local-algs)
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(exchange-hash-info (connection-local-id conn)
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(connection-remote-id conn)
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encoded-local-algs
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encoded-remote-algs))
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kex-alg
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host-key-alg
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conn
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continue-after-key-exchange))
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(define (continue-after-key-exchange shared-secret exchange-hash hash-alg conn)
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(define session-id (if (connection-session-id conn)
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(connection-session-id conn) ;; don't overwrite existing ID
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exchange-hash))
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(define k-h-prefix (bit-string ((bit-string->integer shared-secret #t #f) :: (t:mpint))
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(exchange-hash :: binary)))
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(define (derive-key kind needed-bytes-or-false)
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(let extend ((key (hash-alg (bit-string->bytes
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(bit-string (k-h-prefix :: binary)
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(kind :: binary)
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(session-id :: binary))))))
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(cond
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((eq? #f needed-bytes-or-false)
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key)
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((>= (bytes-length key) needed-bytes-or-false)
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(subbytes key 0 needed-bytes-or-false))
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(else
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(extend (bytes-append key (hash-alg (bit-string->bytes
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(bit-string (k-h-prefix :: binary)
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(key :: binary))))))))))
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(oneshot-handler (struct-copy connection conn
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[session-id session-id]) ;; just in case it changed
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SSH_MSG_NEWKEYS
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(lambda (newkeys-packet newkeys-message conn)
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;; First, send our SSH_MSG_NEWKEYS,
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;; incrementing the various counters, and then
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;; apply the new algorithms.
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(write-message! (ssh-msg-newkeys) conn)
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(flush-outbound-messages! conn)
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(send (connection-io-room-handle conn) say
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(new-keys (connection-is-server? conn)
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||||
derive-key
|
||||
c2s-enc s2c-enc
|
||||
c2s-mac s2c-mac
|
||||
c2s-zip s2c-zip))
|
||||
(struct-copy connection conn
|
||||
[rekey-state
|
||||
(rekey-in-seconds-or-bytes
|
||||
(rekey-interval)
|
||||
(rekey-volume)
|
||||
(connection-total-transferred conn))]))))
|
||||
|
||||
|
||||
(if should-discard-first-kex-packet
|
||||
(struct-copy connection (continue-after-discard conn) [discard-next-packet? #t])
|
||||
(continue-after-discard conn)))
|
||||
|
||||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||||
;; Session main loop
|
||||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||||
|
||||
(define (write-message! message conn)
|
||||
(send (connection-io-room-handle conn) say message))
|
||||
|
||||
(define (flush-outbound-messages! conn)
|
||||
(send (connection-io-room-handle conn) say 'flush))
|
||||
|
||||
(define (maybe-send-disconnect-message! e conn)
|
||||
(when (not (exn:fail:contract:protocol-originated-at-peer? e))
|
||||
(write-message! (ssh-msg-disconnect (exn:fail:contract:protocol-reason-code e)
|
||||
(string->bytes/utf-8 (exn-message e))
|
||||
#"")
|
||||
conn)
|
||||
(flush-outbound-messages! conn)))
|
||||
|
||||
(define (bump-total amount conn)
|
||||
(struct-copy connection conn [total-transferred (+ (connection-total-transferred conn) amount)]))
|
||||
|
||||
(define (run-ssh-session conn)
|
||||
(with-handlers
|
||||
((exn:fail:contract:protocol? (lambda (e)
|
||||
(maybe-send-disconnect-message! e conn)
|
||||
(raise e))))
|
||||
(let loop ((conn conn))
|
||||
(define rekey (connection-rekey-state conn))
|
||||
(if (time-to-rekey? rekey conn)
|
||||
(let ((algs ((local-algorithm-list))))
|
||||
(write-message! algs conn)
|
||||
(flush-outbound-messages! conn)
|
||||
(loop (struct-copy connection conn [rekey-state (rekey-local algs)])))
|
||||
(sync (if (rekey-wait? rekey)
|
||||
(handle-evt (alarm-evt (+ (current-inexact-milliseconds)
|
||||
(* (rekey-wait-deadline rekey) 1000)))
|
||||
(lambda (dummy) (loop conn)))
|
||||
never-evt)
|
||||
(handle-evt (send (connection-io-room-handle conn) listen-evt)
|
||||
(match-lambda
|
||||
((arrived 'read-thread)
|
||||
(send (connection-io-room-handle conn) say (credit 'read-thread 1))
|
||||
(loop conn))
|
||||
((arrived _)
|
||||
(loop conn))
|
||||
((and departure (departed who why))
|
||||
(disconnect-with-error/local-info
|
||||
departure
|
||||
SSH_DISCONNECT_CONNECTION_LOST
|
||||
"I/O error"))
|
||||
((says _ amount 'output-byte-count)
|
||||
;; writer reporting bytes transferred
|
||||
(loop (bump-total amount conn)))
|
||||
((says _ (received-packet seq packet message transferred-count) _)
|
||||
(send (connection-io-room-handle conn) say (credit 'read-thread 1))
|
||||
(loop
|
||||
(bump-total
|
||||
transferred-count
|
||||
(if (connection-discard-next-packet? conn)
|
||||
(struct-copy connection conn [discard-next-packet? #f])
|
||||
(let* ((packet-type-number (encoded-packet-msg-type packet))
|
||||
(packet-handler (hash-ref
|
||||
(connection-dispatch-table conn)
|
||||
packet-type-number
|
||||
#f)))
|
||||
(if packet-handler
|
||||
(packet-handler packet message conn)
|
||||
(begin
|
||||
(write-message! (ssh-msg-unimplemented seq) conn)
|
||||
conn)))))))))
|
||||
(handle-evt (send (connection-session-room-handle conn) listen-evt)
|
||||
(match-lambda
|
||||
((arrived _)
|
||||
(loop conn))
|
||||
((and departure (departed who why))
|
||||
(disconnect-with-error/local-info
|
||||
departure
|
||||
SSH_DISCONNECT_BY_APPLICATION
|
||||
"Application disconnected")))))))))
|
||||
|
||||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||||
;; Session choreography
|
||||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||||
|
||||
(define (send-preamble-and-identification! out)
|
||||
(let ((my-id (client-identification-string)))
|
||||
(for-each (lambda (line)
|
||||
(when (identification-line? line)
|
||||
(error 'ssh-session
|
||||
"Client preamble includes forbidden line ~v"
|
||||
line))
|
||||
(display line out)
|
||||
(display "\r\n" out))
|
||||
(client-preamble-lines))
|
||||
(display my-id out)
|
||||
(display "\r\n" out)
|
||||
(flush-output out)
|
||||
my-id))
|
||||
|
||||
;; Port -> String
|
||||
(define (read-preamble-and-identification! in)
|
||||
(let ((line (read-line-limited in 253))) ;; 255 incl CRLF
|
||||
(when (eof-object? line)
|
||||
(error 'ssh-session "EOF while reading connection preamble"))
|
||||
(if (identification-line? line)
|
||||
line
|
||||
(read-preamble-and-identification! in))))
|
||||
|
||||
;; PacketDispatcher. Handles the core transport message types.
|
||||
(define base-packet-dispatcher
|
||||
(hasheq SSH_MSG_DISCONNECT handle-msg-disconnect
|
||||
SSH_MSG_IGNORE handle-msg-ignore
|
||||
SSH_MSG_UNIMPLEMENTED handle-msg-unimplemented
|
||||
SSH_MSG_DEBUG handle-msg-debug
|
||||
SSH_MSG_KEXINIT handle-msg-kexinit))
|
||||
|
||||
(define (spy-on room)
|
||||
(define handle (join-room room (gensym 'spy)))
|
||||
(define (loop)
|
||||
(write (list (room-name room) (send handle listen)))
|
||||
(newline)
|
||||
(flush-output)
|
||||
(loop))
|
||||
(thread loop))
|
||||
|
||||
(define (ssh-session role in out)
|
||||
(define io-room (make-room (gensym 'ssh-session-io-room)))
|
||||
(spy-on io-room)
|
||||
(define session-room (make-room (gensym 'ssh-session-room)))
|
||||
(spy-on session-room)
|
||||
|
||||
(define local-identification-string (send-preamble-and-identification! out))
|
||||
(define peer-identification-string (read-preamble-and-identification! in))
|
||||
|
||||
;; Each identification string is both a cleartext indicator that
|
||||
;; we've reached some notion of the right place and also input to
|
||||
;; the hash function used during D-H key exchange.
|
||||
(when (not (regexp-match (required-peer-identification-regex)
|
||||
peer-identification-string))
|
||||
(display "Invalid identification\r\n" out)
|
||||
(flush-output out)
|
||||
(error 'ssh-session
|
||||
"Invalid peer identification string ~v"
|
||||
peer-identification-string))
|
||||
|
||||
(standard-thread (lambda () (ssh-reader in io-room)))
|
||||
(standard-thread (lambda () (ssh-writer out io-room)))
|
||||
(standard-thread
|
||||
(lambda ()
|
||||
(run-ssh-session (connection (join-room io-room 'session)
|
||||
(join-room session-room 'session)
|
||||
#f
|
||||
base-packet-dispatcher
|
||||
0
|
||||
(rekey-in-seconds-or-bytes -1 -1 0)
|
||||
(case role ((client) #f) ((server) #t))
|
||||
local-identification-string
|
||||
peer-identification-string
|
||||
#f))))
|
||||
|
||||
(make-object ssh-session% session-room))
|
||||
|
||||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||||
;; Session API
|
||||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||||
|
||||
(define ssh-session%
|
||||
(class* object% ()
|
||||
(init room-init)
|
||||
|
||||
(super-new)))
|
||||
|
||||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||||
;; Test driver code
|
||||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||||
|
||||
(require racket/tcp)
|
||||
(require racket/pretty)
|
||||
|
||||
(define (t-client)
|
||||
(let-values (((i o) (tcp-connect "localhost"
|
||||
2323
|
||||
;;22
|
||||
)))
|
||||
(let ((api (ssh-session 'client i o)))
|
||||
(printf "Got API ~v\n" api)
|
||||
(semaphore-wait (make-semaphore 0)))))
|
||||
|
||||
(define (t-server)
|
||||
(define s (tcp-listen 2322 4 #t "localhost"))
|
||||
(printf "Accepting...\n")
|
||||
(let loop ()
|
||||
(let-values (((i o) (tcp-accept s)))
|
||||
(standard-thread
|
||||
(lambda ()
|
||||
(let ((api (ssh-session 'server i o)))
|
||||
(printf "Got API ~v\n" api)
|
||||
(semaphore-wait (make-semaphore 0)))))
|
||||
(loop))))
|
||||
|
||||
(if (getenv "servermode")
|
||||
(t-server)
|
||||
(t-client))
|
||||
File diff suppressed because it is too large
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Reference in New Issue