OS2-ized SSH up to channel management
This commit is contained in:
Tony Garnock-Jones
parent
72acd94def
commit
78a0721051
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@ -6,18 +6,31 @@
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(require "ssh-numbers.rkt")
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(require "ssh-transport.rkt")
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(require "ssh-session.rkt")
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(require "ssh-message-types.rkt")
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(require "ssh-exceptions.rkt")
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(require "os2-support.rkt")
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(define server-addr (tcp-listener 2322))
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(define (check-remote-identification! peer-identification-string)
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(define required-peer-identification-regex #rx"^SSH-2\\.0-.*")
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;; Each identification string is both a cleartext indicator that
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;; we've reached some notion of the right place and also input to
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;; the hash function used during D-H key exchange.
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(when (not (regexp-match required-peer-identification-regex
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peer-identification-string))
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(error 'ssh-session
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"Invalid peer identification string ~v"
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peer-identification-string)))
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(define (connection-handler local-addr remote-addr)
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(define local-identification #"SSH-2.0-RacketSSH_0.0")
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(nested-vm
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(list 'ssh-session-vm remote-addr)
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(lambda (nested-boot-pid)
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(transition 'running
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(spawn (timer-relay 'ssh-timer-relay) #:debug-name 'ssh-timer-relay)
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;; Issue identification string.
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(at-meta-level
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@ -39,6 +52,7 @@
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[(tcp-channel _ _ (? eof-object?))
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(transition state (kill))]
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[(tcp-channel _ _ (? bytes? remote-identification))
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(check-remote-identification! remote-identification)
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;; First, set the incoming mode to bytes. Then
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;; initialise the reader, switching to packet-reading
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;; mode. Finally, spawn the remaining processes and
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@ -49,9 +63,14 @@
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(spawn (ssh-writer local-addr remote-addr) #:debug-name 'ssh-writer)
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;; Wait for a cycle to let the reader and writer get
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;; started, then tell the reader we are ready for a
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;; single packet.
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;; single packet and spawn the session manager.
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(yield #:state state
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(transition state (send-message (inbound-credit 1)))))])))
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(transition state
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(send-message (inbound-credit 1))
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(spawn (ssh-session local-identification
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remote-identification
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'server)
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#:debug-name 'ssh-session))))])))
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#:debug-name 'ssh-reader)
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(role 'crash-listener
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@ -88,8 +88,13 @@
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([ (bs :: binary bytes n) (rest :: binary) ]
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(ks (bit-string->bytes bs) rest))
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(else (kf)))))
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((_ #f n) (lambda (bs)
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(bit-string (bs :: binary))))))
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((_ #t) (lambda (input ks kf)
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(bit-string-case input
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([ (rest :: binary) ]
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(ks (bit-string->bytes rest) #""))
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(else (kf)))))
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((_ #f n) (lambda (bs) (bit-string (bs :: binary))))
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((_ #f) (lambda (bs) (bit-string (bs :: binary))))))
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(define-syntax t:string
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(syntax-rules ()
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@ -137,7 +142,7 @@
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(string #'((t:string #:pack)))
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(mpint #'((t:mpint)))
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(name-list #'((t:name-list)))
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(extension #'(binary))))
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(extension #'((t:packed-bytes)))))
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(define-syntax compute-ssh-message-encoder
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(lambda (stx)
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643
ssh-session.rkt
643
ssh-session.rkt
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@ -15,12 +15,10 @@
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(require "ssh-exceptions.rkt")
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(require "ssh-transport.rkt")
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(provide required-peer-identification-regex
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client-preamble-lines
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client-identification-string
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rekey-interval
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rekey-volume
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(require "os2-support.rkt")
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(provide rekey-interval
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rekey-volume
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ssh-session)
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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@ -50,22 +48,19 @@
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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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;; A PacketHandler is a (Bytes DecodedPacket ConnectionState -> Transition).
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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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;; A ConnectionState is a (connection ... TODO fix this) representing
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;; the complete state of the SSH transport, authentication, and
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;; connection layers.
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(struct connection (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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authentication-state
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continuations
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channel-map
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is-server?
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local-id
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@ -92,8 +87,7 @@
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;; A ChannelState is a (ssh-channel ...) TODO
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;; Named ssh-channel to avoid conflicts with Racket's built-in
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;; synchronous channels.
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(struct ssh-channel (room-handle ;; RoomHandle
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my-ref ;; Uint32
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(struct ssh-channel (my-ref ;; Uint32
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your-ref ;; Maybe<Uint32>
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type ;; String
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continuations ;; TransactionManager (see ordered-rpc.rkt)
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@ -118,15 +112,6 @@
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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 3600))
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(define rekey-volume (make-parameter 1000000000))
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@ -158,20 +143,22 @@
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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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;; Transition [ 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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(define (set-handlers t . key-value-pairs)
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(extend-transition* t
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(lambda (conn)
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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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;; Transition 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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(define (oneshot-handler t packet-type-number packet-handler)
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(set-handlers t
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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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@ -198,8 +185,8 @@
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#f)))
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(if handler
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(handler packet message conn)
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(begin (write-message!/flush (ssh-msg-unimplemented seq) conn)
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conn)))))
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(transition conn
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(send-message (outbound-packet (ssh-msg-unimplemented seq))))))))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Handlers for core transport packet types
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@ -236,6 +223,10 @@
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(define (rekey-in-seconds-or-bytes delta-seconds delta-bytes total-transferred)
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;; (transition conn
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;; (send-message (set-timer 'rekey-timer
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;; (* (rekey-wait-deadline rekey) 1000)
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;; 'absolute)))]
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(rekey-wait (+ (current-seconds) delta-seconds)
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(+ total-transferred delta-bytes)))
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@ -267,8 +258,8 @@
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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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(bit-string ((exchange-hash-info-client-id hash-info) :: (t:string))
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((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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@ -279,11 +270,11 @@
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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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;; -> Transition
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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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[(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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@ -310,51 +301,52 @@
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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!/flush (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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(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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(prefix-transition (finish shared-secret exchange-hash hash-alg conn)
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(send-message (outbound-packet
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(ssh-msg-kexdh-reply (bit-string->bytes host-key-bytes)
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public-key-as-integer
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(bit-string->bytes h-signature)))))))]
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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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;; -> Transition
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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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[(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!/flush (ssh-msg-kexdh-init public-key-as-integer) 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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(prefix-transition
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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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(send-message (outbound-packet (ssh-msg-kexdh-init public-key-as-integer))))]
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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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@ -369,9 +361,6 @@
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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!/flush local-algs 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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@ -454,24 +443,31 @@
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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!/flush (ssh-msg-newkeys) 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
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c2s-enc s2c-enc
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c2s-mac s2c-mac
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c2s-zip s2c-zip))
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(set-handlers (struct-copy connection conn
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[rekey-state
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(rekey-in-seconds-or-bytes
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(rekey-interval)
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(rekey-volume)
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(connection-total-transferred conn))])
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SSH_MSG_SERVICE_REQUEST handle-msg-service-request))))
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(transition
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(set-handlers (struct-copy connection conn
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[rekey-state
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(rekey-in-seconds-or-bytes
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(rekey-interval)
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(rekey-volume)
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(connection-total-transferred conn))])
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SSH_MSG_SERVICE_REQUEST handle-msg-service-request)
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(send-message (outbound-packet (ssh-msg-newkeys)))
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(send-message
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(new-keys (connection-is-server? conn)
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derive-key
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c2s-enc s2c-enc
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c2s-mac s2c-mac
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c2s-zip s2c-zip))))))
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(if should-discard-first-kex-packet
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(struct-copy connection (continue-after-discard conn) [discard-next-packet? #t])
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(continue-after-discard conn)))
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(let ((t (if should-discard-first-kex-packet
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(struct-copy connection (continue-after-discard conn) [discard-next-packet? #t])
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(continue-after-discard conn))))
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(prefix-transition* t
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(lambda (conn)
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(if (rekey-wait? (connection-rekey-state conn))
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(transition (struct-copy connection conn [rekey-state (rekey-local local-algs)])
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(send-message (outbound-packet local-algs)))
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conn)))))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Service request manager
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@ -480,19 +476,18 @@
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(define (handle-msg-service-request packet message conn)
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(define service (bit-string->bytes (ssh-msg-service-request-service-name message)))
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(match service
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(#"ssh-userauth"
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[#"ssh-userauth"
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(if (connection-authentication-state conn)
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(disconnect-with-error SSH_DISCONNECT_SERVICE_NOT_AVAILABLE
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"Repeated authentication is not permitted")
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(begin
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(write-message!/flush (ssh-msg-service-accept service) conn)
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(oneshot-handler conn
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SSH_MSG_USERAUTH_REQUEST
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handle-msg-userauth-request))))
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(else
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(prefix-transition (oneshot-handler conn
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SSH_MSG_USERAUTH_REQUEST
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handle-msg-userauth-request)
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(send-message (outbound-packet (ssh-msg-service-accept service)))))]
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[else
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(disconnect-with-error SSH_DISCONNECT_SERVICE_NOT_AVAILABLE
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"Service ~v not supported"
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service))))
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service)]))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; User authentication
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@ -502,218 +497,30 @@
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(define user-name (bit-string->bytes (ssh-msg-userauth-request-user-name message)))
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(define service-name (bit-string->bytes (ssh-msg-userauth-request-service-name message)))
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(cond
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((and (positive? (bytes-length user-name))
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[(and (positive? (bytes-length user-name))
|
||||
(equal? service-name #"ssh-connection"))
|
||||
;; TODO: Actually implement client authentication
|
||||
(write-message!/flush (ssh-msg-userauth-success) conn)
|
||||
(start-connection-service
|
||||
(set-handlers (struct-copy connection conn
|
||||
[authentication-state (authenticated user-name service-name)])
|
||||
SSH_MSG_USERAUTH_REQUEST
|
||||
(lambda (packet message conn)
|
||||
;; RFC4252 section 5.1 page 6
|
||||
conn))))
|
||||
(else
|
||||
(write-message!/flush (ssh-msg-userauth-failure '(none) #f) conn)
|
||||
conn)))
|
||||
|
||||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||||
;; Channel management
|
||||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||||
|
||||
(define (allocate-channel conn room type your-ref outbound-window outbound-packet-size)
|
||||
(define my-ref (hash-count (connection-channel-map conn)))
|
||||
(define ch (ssh-channel (join-room room 'session)
|
||||
my-ref
|
||||
your-ref
|
||||
type
|
||||
(make-transaction-manager)
|
||||
outbound-window
|
||||
outbound-packet-size
|
||||
1048576 ;; TODO: parameterize? Make configurable by app?
|
||||
'neither
|
||||
'neither
|
||||
))
|
||||
(values ch
|
||||
(struct-copy connection (send-initial-credit conn ch)
|
||||
[channel-map (hash-set (connection-channel-map conn) my-ref ch)])))
|
||||
|
||||
(define (send-initial-credit conn ch)
|
||||
(define remaining-window (ssh-channel-outbound-window ch))
|
||||
(if (and remaining-window
|
||||
(positive? remaining-window))
|
||||
(channel-notify conn ch (credit 'app remaining-window))
|
||||
conn))
|
||||
|
||||
(define (get-channel conn my-ref)
|
||||
(hash-ref (connection-channel-map conn) my-ref))
|
||||
|
||||
(define (update-channel conn ch)
|
||||
(struct-copy connection conn
|
||||
[channel-map (hash-set (connection-channel-map conn) (ssh-channel-my-ref ch) ch)]))
|
||||
|
||||
(define (discard-channel ch conn)
|
||||
(struct-copy connection conn
|
||||
[channel-map (hash-remove (connection-channel-map conn) (ssh-channel-my-ref ch))]))
|
||||
|
||||
;; CloseState Either<'local,'remote> -> CloseState
|
||||
(define (update-close-state old-state action)
|
||||
(define local? (case action ((local) #t) ((remote) #f)))
|
||||
(case old-state
|
||||
((neither) (if local? 'local 'remote))
|
||||
((local) (if local? 'local 'both))
|
||||
((remote) (if local? 'both 'remote))
|
||||
((both) 'both)))
|
||||
|
||||
(define (maybe-close-channel ch conn action)
|
||||
(define new-close-state (update-close-state (ssh-channel-close-state ch) action))
|
||||
(case action
|
||||
((local) (write-message!/flush (ssh-msg-channel-close (ssh-channel-your-ref ch))
|
||||
conn))
|
||||
((remote) (send (ssh-channel-room-handle ch) depart 'remote-closed)))
|
||||
(if (eq? new-close-state 'both)
|
||||
(discard-channel ch conn)
|
||||
(update-channel conn (struct-copy ssh-channel ch
|
||||
[close-state new-close-state]))))
|
||||
|
||||
(define (channel-notify conn ch message)
|
||||
(send (ssh-channel-room-handle ch) say message)
|
||||
conn)
|
||||
|
||||
(define (channel-request conn ch message k)
|
||||
(update-channel conn
|
||||
(struct-copy ssh-channel ch
|
||||
[continuations (room-rpc (ssh-channel-room-handle ch)
|
||||
(ssh-channel-continuations ch)
|
||||
message
|
||||
k)])))
|
||||
|
||||
(define (finish-channel-request ch conn txn message)
|
||||
(define-values (worklist new-continuations)
|
||||
(room-rpc-finish (ssh-channel-continuations ch) txn message))
|
||||
(let loop ((worklist worklist)
|
||||
(ch (struct-copy ssh-channel ch [continuations new-continuations]))
|
||||
(conn conn))
|
||||
(if (null? worklist)
|
||||
(update-channel conn ch)
|
||||
(let ((item (car worklist)))
|
||||
(define-values (new-ch new-conn) (item ch conn))
|
||||
(loop (cdr worklist) new-ch new-conn)))))
|
||||
|
||||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||||
;; Connection service
|
||||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||||
(prefix-transition
|
||||
(start-connection-service
|
||||
(set-handlers (struct-copy connection conn
|
||||
[authentication-state (authenticated user-name service-name)])
|
||||
SSH_MSG_USERAUTH_REQUEST
|
||||
(lambda (packet message conn)
|
||||
;; RFC4252 section 5.1 page 6
|
||||
conn)))
|
||||
(send-message (outbound-packet (ssh-msg-userauth-success))))]
|
||||
[else
|
||||
(transition conn
|
||||
(send-message (outbound-packet (ssh-msg-userauth-failure '(none) #f))))]))
|
||||
|
||||
;; SKETCH-O
|
||||
(define (start-connection-service conn)
|
||||
(set-handlers conn
|
||||
;; TODO: SSH_MSG_GLOBAL_REQUEST handle-msg-global-request
|
||||
SSH_MSG_CHANNEL_OPEN handle-msg-channel-open
|
||||
SSH_MSG_CHANNEL_WINDOW_ADJUST handle-msg-window-adjust
|
||||
SSH_MSG_CHANNEL_DATA handle-msg-channel-data
|
||||
SSH_MSG_CHANNEL_EXTENDED_DATA handle-msg-channel-extended-data
|
||||
SSH_MSG_CHANNEL_EOF handle-msg-channel-eof
|
||||
SSH_MSG_CHANNEL_CLOSE handle-msg-channel-close
|
||||
SSH_MSG_CHANNEL_REQUEST handle-msg-channel-request))
|
||||
|
||||
(define (handle-msg-global-request packet message conn)
|
||||
(log-error "TODO: Unimplemented: handle-msg-global-request")
|
||||
conn)
|
||||
|
||||
(define (handle-msg-channel-open packet message conn)
|
||||
(match-define (ssh-msg-channel-open channel-type*
|
||||
sender-channel
|
||||
initial-window-size
|
||||
maximum-packet-size
|
||||
extra-request-data*)
|
||||
message)
|
||||
(define channel-type (bit-string->bytes channel-type*))
|
||||
(define extra-request-data (bit-string->bytes extra-request-data*))
|
||||
(app-request conn
|
||||
`(open-channel ,(connection-username conn) ,channel-type ,extra-request-data)
|
||||
(lambda (reply conn)
|
||||
(match reply
|
||||
(`(ok ,(? room? room) ,(? bytes? extra-reply-data))
|
||||
(let-values (((ch conn) (allocate-channel conn
|
||||
room
|
||||
channel-type
|
||||
sender-channel
|
||||
initial-window-size
|
||||
maximum-packet-size)))
|
||||
(write-message!/flush (ssh-msg-channel-open-confirmation
|
||||
sender-channel
|
||||
(ssh-channel-my-ref ch)
|
||||
(ssh-channel-inbound-window ch)
|
||||
(default-packet-limit) ;; TODO get from reader
|
||||
extra-reply-data)
|
||||
conn)
|
||||
conn))
|
||||
(`(error ,reason-code ,description)
|
||||
(write-message!/flush (ssh-msg-channel-open-failure
|
||||
sender-channel
|
||||
reason-code
|
||||
(string->bytes/utf-8 description)
|
||||
#"")
|
||||
conn)
|
||||
conn)))))
|
||||
|
||||
(define (handle-msg-window-adjust packet message conn)
|
||||
(match-define (ssh-msg-channel-window-adjust recipient-channel count) message)
|
||||
(define ch (get-channel conn recipient-channel))
|
||||
(channel-notify conn ch (credit 'app count)))
|
||||
|
||||
(define (handle-msg-channel-data packet message conn)
|
||||
(match-define (ssh-msg-channel-data recipient-channel data*) message)
|
||||
(define data (bit-string->bytes data*))
|
||||
(define ch (get-channel conn recipient-channel))
|
||||
(channel-notify conn ch `(data ,data)))
|
||||
|
||||
(define (handle-msg-channel-extended-data packet message conn)
|
||||
(match-define (ssh-msg-channel-extended-data recipient-channel type-code data*) message)
|
||||
(define data (bit-string->bytes data*))
|
||||
(define ch (get-channel conn recipient-channel))
|
||||
(channel-notify conn ch `(extended-data ,type-code ,data)))
|
||||
|
||||
(define (handle-msg-channel-eof packet message conn)
|
||||
(define ch (get-channel conn (ssh-msg-channel-eof-recipient-channel message)))
|
||||
(update-channel (channel-notify conn ch `(eof))
|
||||
(struct-copy ssh-channel ch
|
||||
[eof-state (update-close-state (ssh-channel-eof-state ch)
|
||||
'remote)])))
|
||||
|
||||
(define (handle-msg-channel-close packet message conn)
|
||||
(define ch (get-channel conn (ssh-msg-channel-close-recipient-channel message)))
|
||||
(maybe-close-channel ch conn 'remote))
|
||||
|
||||
(define (handle-msg-channel-request packet message conn)
|
||||
(match-define (ssh-msg-channel-request recipient-channel type* want-reply? data*) message)
|
||||
(define type (bit-string->bytes type*))
|
||||
(define data (bit-string->bytes data*))
|
||||
(define ch (get-channel conn recipient-channel))
|
||||
(if (not want-reply?)
|
||||
(channel-notify conn ch `(notify ,type ,data))
|
||||
(channel-request conn ch `(,type ,data)
|
||||
(lambda (reply ch conn)
|
||||
(define your-ref (ssh-channel-your-ref ch))
|
||||
(write-message!/flush (match reply
|
||||
('ok (ssh-msg-channel-success your-ref))
|
||||
('error (ssh-msg-channel-failure your-ref)))
|
||||
conn)
|
||||
(values ch conn)))))
|
||||
|
||||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||||
;; Session main loop
|
||||
;; Session main process
|
||||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||||
|
||||
(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 (write-message!/flush message conn)
|
||||
(write-message! message conn)
|
||||
(flush-outbound-messages! conn))
|
||||
|
||||
(define (connection-username conn)
|
||||
(match (connection-authentication-state conn)
|
||||
((authenticated username servicename)
|
||||
|
|
@ -721,76 +528,11 @@
|
|||
(else (disconnect-with-error SSH_DISCONNECT_PROTOCOL_ERROR
|
||||
"Not authenticated"))))
|
||||
|
||||
(define (app-notify conn message)
|
||||
(send (connection-session-room-handle conn) say message)
|
||||
conn)
|
||||
|
||||
(define (app-request conn message k)
|
||||
(struct-copy connection conn
|
||||
[continuations (room-rpc (connection-session-room-handle conn)
|
||||
(connection-continuations conn)
|
||||
message
|
||||
k)]))
|
||||
|
||||
(define (finish-app-request conn txn message)
|
||||
(define-values (worklist new-continuations)
|
||||
(room-rpc-finish (connection-continuations conn) txn message))
|
||||
(foldl (lambda (item conn) (item conn))
|
||||
(struct-copy connection conn [continuations new-continuations])
|
||||
worklist))
|
||||
|
||||
(define (maybe-send-disconnect-message! e conn)
|
||||
(when (not (exn:fail:contract:protocol-originated-at-peer? e))
|
||||
(write-message!/flush (ssh-msg-disconnect (exn:fail:contract:protocol-reason-code e)
|
||||
(string->bytes/utf-8 (exn-message e))
|
||||
#"")
|
||||
conn)))
|
||||
|
||||
(define (bump-total amount conn)
|
||||
(struct-copy connection conn [total-transferred (+ (connection-total-transferred conn) amount)]))
|
||||
|
||||
(define io-room-message-handler
|
||||
(lambda (message)
|
||||
(define (bump-total t amount)
|
||||
(extend-transition* t
|
||||
(lambda (conn)
|
||||
(match message
|
||||
((arrived 'read-thread)
|
||||
(send (connection-io-room-handle conn) say (credit 'read-thread 1))
|
||||
conn)
|
||||
((arrived _)
|
||||
conn)
|
||||
((and departure (departed who why))
|
||||
(if (zero? (hash-count (connection-channel-map conn)))
|
||||
;; No open or half-open channels. No point in complaining; just leave.
|
||||
#f
|
||||
;; At least one channel. Make more of a noise.
|
||||
(disconnect-with-error/local-info departure
|
||||
SSH_DISCONNECT_CONNECTION_LOST
|
||||
"I/O error")))
|
||||
((says _ amount 'output-byte-count)
|
||||
;; writer reporting bytes transferred
|
||||
(bump-total amount conn))
|
||||
((says _ (received-packet seq packet message transferred-count) _)
|
||||
(send (connection-io-room-handle conn) say (credit 'read-thread 1))
|
||||
(bump-total
|
||||
transferred-count
|
||||
(if (connection-discard-next-packet? conn)
|
||||
(struct-copy connection conn [discard-next-packet? #f])
|
||||
(dispatch-packet seq packet message conn))))))))
|
||||
|
||||
(define session-room-message-handler
|
||||
(lambda (message)
|
||||
(lambda (conn)
|
||||
(match message
|
||||
((arrived _)
|
||||
conn)
|
||||
((and departure (departed _ _))
|
||||
(disconnect-with-error/local-info
|
||||
departure
|
||||
SSH_DISCONNECT_BY_APPLICATION
|
||||
"Application disconnected"))
|
||||
((says _ (rpc-reply transaction message) _)
|
||||
;; TODO: not cap-secure. Introduce sealers, or indirect.
|
||||
(finish-app-request conn transaction message))))))
|
||||
(struct-copy connection conn
|
||||
[total-transferred (+ (connection-total-transferred conn) amount)]))))
|
||||
|
||||
;; (K V A -> A) A Hash<K,V> -> A
|
||||
(define (hash-fold fn seed hash)
|
||||
|
|
@ -798,91 +540,15 @@
|
|||
(seed seed (fn (hash-iterate-key hash pos) (hash-iterate-value hash pos) seed)))
|
||||
((not pos) seed)))
|
||||
|
||||
(define (channel-events conn)
|
||||
(hash-fold (lambda (my-ref ch evt)
|
||||
(choice-evt evt
|
||||
(handle-evt (send (ssh-channel-room-handle ch) listen-evt)
|
||||
(channel-room-message-handler my-ref))))
|
||||
never-evt
|
||||
(connection-channel-map conn)))
|
||||
|
||||
(define (channel-room-message-handler my-ref)
|
||||
(lambda (message)
|
||||
(define (rekey-wrap t)
|
||||
(extend-transition* t
|
||||
(lambda (conn)
|
||||
(define ch (get-channel conn my-ref))
|
||||
(define your-ref (ssh-channel-your-ref ch))
|
||||
(match message
|
||||
((arrived _)
|
||||
conn)
|
||||
((departed _ _)
|
||||
(maybe-close-channel ch conn 'local))
|
||||
((says _ (credit _ amount) _)
|
||||
(write-message!/flush (ssh-msg-channel-window-adjust your-ref amount) conn)
|
||||
conn)
|
||||
((says _ `(data ,bits) _)
|
||||
(write-message!/flush (ssh-msg-channel-data your-ref bits) conn)
|
||||
conn)
|
||||
((says _ `(eof) _)
|
||||
(write-message!/flush (ssh-msg-channel-eof your-ref) conn)
|
||||
conn)
|
||||
((says _ (rpc-reply id m) _)
|
||||
(finish-channel-request ch conn id m))))))
|
||||
|
||||
(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!/flush algs conn)
|
||||
(loop (struct-copy connection conn [rekey-state (rekey-local algs)])))
|
||||
(let ((handler (sync (if (rekey-wait? rekey)
|
||||
(handle-evt (alarm-evt (* (rekey-wait-deadline rekey) 1000))
|
||||
(lambda (dummy)
|
||||
(lambda (conn)
|
||||
conn)))
|
||||
never-evt)
|
||||
(handle-evt (send (connection-io-room-handle conn) listen-evt)
|
||||
io-room-message-handler)
|
||||
(handle-evt (send (connection-session-room-handle conn) listen-evt)
|
||||
session-room-message-handler)
|
||||
(channel-events conn))))
|
||||
(define new-conn (handler conn))
|
||||
;; The handler is permitted to return #f to indicate that the session is to be
|
||||
;; gracefully shut down.
|
||||
(when new-conn
|
||||
(loop new-conn)))))))
|
||||
|
||||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||||
;; 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))))
|
||||
(transition (struct-copy connection conn [rekey-state (rekey-local algs)])
|
||||
(send-message (outbound-packet algs))))
|
||||
conn))))
|
||||
|
||||
;; PacketDispatcher. Handles the core transport message types.
|
||||
(define base-packet-dispatcher
|
||||
|
|
@ -892,43 +558,36 @@
|
|||
SSH_MSG_DEBUG handle-msg-debug
|
||||
SSH_MSG_KEXINIT handle-msg-kexinit))
|
||||
|
||||
(define (ssh-session role in out)
|
||||
(define io-room (make-room (gensym 'ssh-io-room)))
|
||||
;;(spy-on io-room)
|
||||
(define session-room (make-room (gensym 'ssh-session-room)))
|
||||
;;(spy-on session-room)
|
||||
(define (ssh-session local-identification-string
|
||||
peer-identification-string
|
||||
session-role)
|
||||
(lambda (self-pid)
|
||||
(transition (connection #f
|
||||
base-packet-dispatcher
|
||||
0
|
||||
(rekey-in-seconds-or-bytes -1 -1 0)
|
||||
#f
|
||||
(hash)
|
||||
(case session-role ((client) #f) ((server) #t))
|
||||
local-identification-string
|
||||
peer-identification-string
|
||||
#f)
|
||||
(role 'rekey-waiter (topic-subscriber (timer-expired 'rekey-timer (wild)))
|
||||
#:state conn
|
||||
[(timer-expired 'rekey-timer now)
|
||||
(rekey-wrap conn)])
|
||||
|
||||
(define local-identification-string (send-preamble-and-identification! out))
|
||||
(define peer-identification-string (read-preamble-and-identification! in))
|
||||
(role 'credit-listener (topic-subscriber (outbound-byte-credit (wild)))
|
||||
#:state conn
|
||||
[(outbound-byte-credit amount)
|
||||
(rekey-wrap (bump-total conn amount))])
|
||||
|
||||
;; 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)))
|
||||
(wait-for-members io-room '(read-thread write-thread))
|
||||
(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)
|
||||
#f
|
||||
(make-transaction-manager)
|
||||
(hash)
|
||||
(case role ((client) #f) ((server) #t))
|
||||
local-identification-string
|
||||
peer-identification-string
|
||||
#f))))
|
||||
|
||||
(join-room session-room 'app))
|
||||
(role 'packet-listener (topic-subscriber (inbound-packet (wild) (wild) (wild) (wild)))
|
||||
#:state conn
|
||||
[(inbound-packet sequence-number payload message transfer-size)
|
||||
(let* ((t (if (connection-discard-next-packet? conn)
|
||||
(struct-copy connection conn [discard-next-packet? #f])
|
||||
(dispatch-packet sequence-number payload message conn)))
|
||||
(t (bump-total t transfer-size))
|
||||
(t (extend-transition t (send-message (inbound-credit 1)))))
|
||||
(rekey-wrap t))]))))
|
||||
|
|
|
|||
Loading…
Reference in New Issue