diff options
| -rw-r--r-- | guix/ssh.scm | 39 |
1 files changed, 27 insertions, 12 deletions
diff --git a/guix/ssh.scm b/guix/ssh.scm index 519c723155..291ce20b61 100644 --- a/guix/ssh.scm +++ b/guix/ssh.scm @@ -98,14 +98,20 @@ actual key does not match." key type)))))))) (define* (open-ssh-session host #:key user port identity + host-key (compression %compression) (timeout 3600)) "Open an SSH session for HOST and return it. IDENTITY specifies the file name of a private key to use for authenticating with the host. When USER, PORT, or IDENTITY are #f, use default values or whatever '~/.ssh/config' -specifies; otherwise use them. Install TIMEOUT as the maximum time in seconds -after which a read or write operation on a channel of the returned session is -considered as failing. +specifies; otherwise use them. + +When HOST-KEY is true, it must be a string like \"ssh-ed25519 AAAAC3Nz… +root@example.org\"; the server is authenticated and an error is raised if its +host key is different from HOST-KEY. + +Install TIMEOUT as the maximum time in seconds after which a read or write +operation on a channel of the returned session is considered as failing. Throw an error on failure." (let ((session (make-session #:user user @@ -115,6 +121,11 @@ Throw an error on failure." #:timeout 10 ;seconds ;; #:log-verbosity 'protocol + ;; Prevent libssh from reading + ;; ~/.ssh/known_hosts when the caller provides + ;; a HOST-KEY to match against. + #:knownhosts (and host-key "/dev/null") + ;; We need lightweight compression when ;; exchanging full archives. #:compression compression @@ -125,16 +136,20 @@ Throw an error on failure." (match (connect! session) ('ok - ;; Authenticate against ~/.ssh/known_hosts. - (match (authenticate-server session) - ('ok #f) - (reason - (raise (condition - (&message - (message (format #f (G_ "failed to authenticate \ + (if host-key + ;; Make sure the server's key is what we expect. + (authenticate-server* session host-key) + + ;; Authenticate against ~/.ssh/known_hosts. + (match (authenticate-server session) + ('ok #f) + (reason + (raise (condition + (&message + (message (format #f (G_ "failed to authenticate \ server at '~a': ~a") - (session-get session 'host) - reason))))))) + (session-get session 'host) + reason)))))))) ;; Use public key authentication, via the SSH agent if it's available. (match (userauth-public-key/auto! session) |