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racket-ssh-2012
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Use signature-verification code; correct exchange-hash-info block construction for servers.

This commit is contained in:
Tony Garnock-Jones 2011-10-20 14:19:50 -04:00
parent 8676d74702
commit 09eb765b65
1 changed files with 24 additions and 20 deletions
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44
ssh-transport.rkt
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@ -574,11 +574,6 @@
((memq (car client-list) server-list) (car client-list))
(else (loop (cdr client-list))))))
(define (check-host-key! host-key)
;; TODO: If we are *re*keying, worth checking here that the key hasn't *changed* either.
(write `(TODO check-host-key! ,(hex (bit-string->bytes host-key)))) (newline) (flush-output)
(void))
;; ExchangeHashInfo Bytes Natural Natural Natural -> Bytes
;; Computes the session ID as defined by SSH's DH key exchange method.
(define (dh-exchange-hash hash-info host-key e f k)
@ -657,17 +652,19 @@
(define f-as-bytes (integer->bit-string f (* 8 f-width) #t))
(define shared-secret (compute-key private-key f-as-bytes))
(define hash-alg sha1)
(define host-key-bytes (ssh-msg-kexdh-reply-host-key message))
(define host-public-key
(pieces->public-key (ssh-host-key->pieces host-key-bytes)))
(define exchange-hash
(dh-exchange-hash hash-info
(ssh-msg-kexdh-reply-host-key message)
host-key-bytes
public-key-as-integer
f
(bit-string->integer shared-secret #t #f)))
;; (pretty-print `((public-key ,(hex public-key))
;; (f-as-bytes ,(hex f-as-bytes))
;; (shared-secret ,(hex shared-secret))
;; (exchange-hash ,(hex exchange-hash))))
(check-host-key! (ssh-msg-kexdh-reply-host-key message))
(verify-host-key-signature! host-public-key
host-key-alg
exchange-hash
(ssh-msg-kexdh-reply-h-signature message))
(finish shared-secret exchange-hash hash-alg conn))))
(else (disconnect-with-error SSH_DISCONNECT_KEY_EXCHANGE_FAILED
"Bad key-exchange algorithm ~v" kex-alg))))
@ -709,7 +706,7 @@
(define hmac ((supported-hmac-factory hmac-description)
(derive-key (if c2s #"E" #"F") (supported-hmac-key-length hmac-description))))
(pretty-print `(,is-server? ,(if c2s 'c2s 's2c) ,enc ,mac))
;;(pretty-print `(,is-server? ,(if c2s 'c2s 's2c) ,enc ,mac))
(struct-copy stream-state state
[cipher cipher]
[cipher-description cipher-description]
@ -770,12 +767,18 @@
(guess-matches? s2c-zip ssh-msg-kexinit-compression_algorithms_server_to_client)))))
(define (continue-after-discard conn)
(define hash-info (exchange-hash-info (connection-local-id conn)
(connection-remote-id conn)
encoded-local-algs
encoded-remote-algs))
((if is-server? perform-server-key-exchange perform-client-key-exchange)
hash-info
((if is-server?
perform-server-key-exchange
perform-client-key-exchange)
(if is-server?
(exchange-hash-info (connection-remote-id conn)
(connection-local-id conn)
encoded-remote-algs
encoded-local-algs)
(exchange-hash-info (connection-local-id conn)
(connection-remote-id conn)
encoded-local-algs
encoded-remote-algs))
kex-alg
host-key-alg
conn
@ -1004,5 +1007,6 @@
(let-values (((i o) (tcp-accept s)))
(ssh-session 'server i o))))
;;(t-client)
(t-server)
(if (getenv "servermode")
(t-server)
(t-client))