Re: recursive ssh invocation
From: Andrei Alexandrescu (See Website for Email) (seewebsiteforemail_at_moderncppdesign.com)
Date: 05/29/05
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Date: Sat, 28 May 2005 19:39:55 -0700
> But that looks like he does NOT have publickey set up to be used between
> the computers. This makes it unlikely that this recursive procedure will work.
> (in fact it does not if there is no publickey valid method between machine1
> and machine2) It cannot ask for a password.
Thanks to all who've answered. Indeed, my net uses Kerberos with
OpenSSH on Linux. Public key authentication is not allowed (they say
"for security reasons"; the scenario they mention is that you start a
session, leave your computer, and someone comes and scp's your public
key to some other place thus gaining forever access to the net on your
behalf). However, with Kerberos you can ssh from one machine to the
next without having to type your password.
For reasons I don't get, however, the procedure fails on recursive
invocations.
Anyway. I paste below the results of a successful session, and then
the results of an unsuccessful recursive session. I crank debug info
to the max ("-v -v -v"). I replaced a bit of sensitive info.
machine% ssh machine1 -v -v -v
OpenSSH_3.9p1, OpenSSL 0.9.7a Feb 19 2003
debug1: Reading configuration data /etc/ssh/ssh_config
debug2: ssh_connect: needpriv 0
debug1: Connecting to machine1 [xxx.xxx.xxx.xxx] port 22.
debug1: Connection established.
debug3: Not a RSA1 key file /homes/username/.ssh/identity.
debug2: key_type_from_name: unknown key type '-----BEGIN'
debug3: key_read: missing keytype
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug2: key_type_from_name: unknown key type '-----END'
debug3: key_read: missing keytype
debug1: identity file /homes/username/.ssh/identity type 2
debug1: identity file /homes/username/.ssh/id_rsa type -1
debug1: identity file /homes/username/.ssh/id_dsa type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_3.9p1
debug1: match: OpenSSH_3.9p1 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_3.9p1
debug2: fd 3 setting O_NONBLOCK
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit:
diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit:
aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit:
aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit:
hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit:
hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: kex_parse_kexinit:
diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit:
aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit:
aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit:
hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit:
hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: mac_init: found hmac-md5
debug1: kex: server->client aes128-cbc hmac-md5 none
debug2: mac_init: found hmac-md5
debug1: kex: client->server aes128-cbc hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug2: dh_gen_key: priv key bits set: 126/256
debug2: bits set: 504/1024
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug3: check_host_in_hostfile: filename /homes/username/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 84
debug3: check_host_in_hostfile: filename /homes/username/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 84
debug1: Host 'machine1' is known and matches the RSA host key.
debug1: Found key in /homes/username/.ssh/known_hosts:84
debug2: bits set: 495/1024
debug1: ssh_rsa_verify: signature correct
debug2: kex_derive_keys
debug2: set_newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: /homes/username/.ssh/identity (0x8905d08)
debug2: key: /homes/username/.ssh/id_rsa ((nil))
debug2: key: /homes/username/.ssh/id_dsa ((nil))
debug1: Authentications that can continue:
gssapi-with-mic,password,keyboard-interactive
debug3: start over, passed a different list
gssapi-with-mic,password,keyboard-interactive
debug3: preferred gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup gssapi-with-mic
debug3: remaining preferred: publickey,keyboard-interactive,password
debug3: authmethod_is_enabled gssapi-with-mic
debug1: Next authentication method: gssapi-with-mic
debug2: we sent a gssapi-with-mic packet, wait for reply
debug1: Delegating credentials
debug1: Delegating credentials
debug1: Authentication succeeded (gssapi-with-mic).
debug2: fd 5 setting O_NONBLOCK
debug3: fd 6 is O_NONBLOCK
debug1: channel 0: new [client-session]
debug3: ssh_session2_open: channel_new: 0
debug2: channel 0: send open
debug1: Entering interactive session.
debug2: callback start
debug2: x11_get_proto: /usr/X11R6/bin/xauth list unix:11.0 . 2>/dev/null
debug1: Requesting X11 forwarding with authentication spoofing.
debug2: channel 0: request x11-req confirm 0
debug2: client_session2_setup: id 0
debug2: channel 0: request pty-req confirm 0
debug3: tty_make_modes: ospeed 38400
debug3: tty_make_modes: ispeed 38400
debug3: tty_make_modes: 1 3
debug3: tty_make_modes: 2 28
debug3: tty_make_modes: 3 8
debug3: tty_make_modes: 4 21
debug3: tty_make_modes: 5 4
debug3: tty_make_modes: 6 0
debug3: tty_make_modes: 7 0
debug3: tty_make_modes: 8 17
debug3: tty_make_modes: 9 19
debug3: tty_make_modes: 10 26
debug3: tty_make_modes: 12 18
debug3: tty_make_modes: 13 23
debug3: tty_make_modes: 14 22
debug3: tty_make_modes: 18 15
debug3: tty_make_modes: 30 0
debug3: tty_make_modes: 31 0
debug3: tty_make_modes: 32 0
debug3: tty_make_modes: 33 0
debug3: tty_make_modes: 34 0
debug3: tty_make_modes: 35 0
debug3: tty_make_modes: 36 1
debug3: tty_make_modes: 37 0
debug3: tty_make_modes: 38 1
debug3: tty_make_modes: 39 0
debug3: tty_make_modes: 40 0
debug3: tty_make_modes: 41 0
debug3: tty_make_modes: 50 1
debug3: tty_make_modes: 51 1
debug3: tty_make_modes: 52 0
debug3: tty_make_modes: 53 1
debug3: tty_make_modes: 54 0
debug3: tty_make_modes: 55 0
debug3: tty_make_modes: 56 0
debug3: tty_make_modes: 57 0
debug3: tty_make_modes: 58 0
debug3: tty_make_modes: 59 1
debug3: tty_make_modes: 60 0
debug3: tty_make_modes: 61 0
debug3: tty_make_modes: 62 0
debug3: tty_make_modes: 70 1
debug3: tty_make_modes: 71 0
debug3: tty_make_modes: 72 1
debug3: tty_make_modes: 73 0
debug3: tty_make_modes: 74 0
debug3: tty_make_modes: 75 0
debug3: tty_make_modes: 90 1
debug3: tty_make_modes: 91 1
debug3: tty_make_modes: 92 0
debug3: tty_make_modes: 93 0
debug2: channel 0: request shell confirm 0
debug2: fd 3 setting TCP_NODELAY
debug2: callback done
debug2: channel 0: open confirm rwindow 0 rmax 32768
debug2: channel 0: rcvd adjust 131072
Last login: Sat May 28 19:22:09 2005 from machine
machine1 [996] exit
logout
debug1: client_input_channel_req: channel 0 rtype exit-status reply 0
debug2: channel 0: rcvd eof
debug2: channel 0: output open -> drain
debug2: channel 0: obuf empty
debug2: channel 0: close_write
debug2: channel 0: output drain -> closed
debug2: channel 0: rcvd close
debug2: channel 0: close_read
debug2: channel 0: input open -> closed
debug3: channel 0: will not send data after close
debug2: channel 0: almost dead
debug2: channel 0: gc: notify user
debug2: channel 0: gc: user detached
debug2: channel 0: send close
debug2: channel 0: is dead
debug2: channel 0: garbage collecting
debug1: channel 0: free: client-session, nchannels 1
debug3: channel 0: status: The following connections are open:
#0 client-session (t4 r0 i3/0 o3/0 fd -1/-1 cfd -1)
debug3: channel 0: close_fds r -1 w -1 e 6 c -1
debug1: fd 1 clearing O_NONBLOCK
debug3: fd 2 is not O_NONBLOCK
Connection to machine1 closed.
debug1: Transferred: stdin 0, stdout 0, stderr 30 bytes in 6.7 seconds
debug1: Bytes per second: stdin 0.0, stdout 0.0, stderr 4.5
debug1: Exit status 0
Now follows the unsuccessful session:
machine% ssh machine1 "ssh -v -v -v machine2 echo hello"
OpenSSH_3.9p1, OpenSSL 0.9.7a Feb 19 2003
debug1: Reading configuration data /etc/ssh/ssh_config
debug2: ssh_connect: needpriv 0
debug1: Connecting to machine2 [xxx.xxx.xxx.xxx] port 22.
debug1: Connection established.
debug3: Not a RSA1 key file /homes/username/.ssh/identity.
debug2: key_type_from_name: unknown key type '-----BEGIN'
debug3: key_read: missing keytype
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug2: key_type_from_name: unknown key type '-----END'
debug3: key_read: missing keytype
debug1: identity file /homes/username/.ssh/identity type 2
debug1: identity file /homes/username/.ssh/id_rsa type -1
debug1: identity file /homes/username/.ssh/id_dsa type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_3.9p1
debug1: match: OpenSSH_3.9p1 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_3.9p1
debug2: fd 3 setting O_NONBLOCK
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit:
diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit:
aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit:
aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit:
hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit:
hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: kex_parse_kexinit:
diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit:
aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit:
aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit:
hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit:
hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: mac_init: found hmac-md5
debug1: kex: server->client aes128-cbc hmac-md5 none
debug2: mac_init: found hmac-md5
debug1: kex: client->server aes128-cbc hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug2: dh_gen_key: priv key bits set: 134/256
debug2: bits set: 474/1024
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug3: check_host_in_hostfile: filename /homes/username/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 85
debug3: check_host_in_hostfile: filename /homes/username/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 85
debug1: Host 'machine2' is known and matches the RSA host key.
debug1: Found key in /homes/username/.ssh/known_hosts:85
debug2: bits set: 550/1024
debug1: ssh_rsa_verify: signature correct
debug2: kex_derive_keys
debug2: set_newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: /homes/username/.ssh/identity (0x83ebd08)
debug2: key: /homes/username/.ssh/id_rsa ((nil))
debug2: key: /homes/username/.ssh/id_dsa ((nil))
debug1: Authentications that can continue:
gssapi-with-mic,password,keyboard-interactive
debug3: start over, passed a different list
gssapi-with-mic,password,keyboard-interactive
debug3: preferred gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup gssapi-with-mic
debug3: remaining preferred: publickey,keyboard-interactive,password
debug3: authmethod_is_enabled gssapi-with-mic
debug1: Next authentication method: gssapi-with-mic
debug2: we sent a gssapi-with-mic packet, wait for reply
debug1: Delegating credentials
debug1: Miscellaneous failure
No credentials cache found
debug1: Trying to start again
debug2: we sent a gssapi-with-mic packet, wait for reply
debug1: Authentications that can continue:
gssapi-with-mic,password,keyboard-interactive
debug2: we sent a gssapi-with-mic packet, wait for reply
debug1: Authentications that can continue:
gssapi-with-mic,password,keyboard-interactive
debug2: we did not send a packet, disable method
debug3: authmethod_lookup keyboard-interactive
debug3: remaining preferred: password
debug3: authmethod_is_enabled keyboard-interactive
debug1: Next authentication method: keyboard-interactive
debug2: userauth_kbdint
debug2: we sent a keyboard-interactive packet, wait for reply
debug1: Authentications that can continue:
gssapi-with-mic,password,keyboard-interactive
debug3: userauth_kbdint: disable: no info_req_seen
debug2: we did not send a packet, disable method
debug3: authmethod_lookup password
debug3: remaining preferred:
debug3: authmethod_is_enabled password
debug1: Next authentication method: password
ssh_askpass: exec(/usr/libexec/openssh/ssh-askpass): No such file or
directory
debug3: packet_send2: adding 64 (len 53 padlen 11 extra_pad 64)
debug2: we sent a password packet, wait for reply
debug1: Authentications that can continue:
gssapi-with-mic,password,keyboard-interactive
Permission denied, please try again.
ssh_askpass: exec(/usr/libexec/openssh/ssh-askpass): No such file or
directory
debug3: packet_send2: adding 64 (len 53 padlen 11 extra_pad 64)
debug2: we sent a password packet, wait for reply
debug1: Authentications that can continue:
gssapi-with-mic,password,keyboard-interactive
Permission denied, please try again.
ssh_askpass: exec(/usr/libexec/openssh/ssh-askpass): No such file or
directory
debug3: packet_send2: adding 64 (len 53 padlen 11 extra_pad 64)
debug2: we sent a password packet, wait for reply
debug1: Authentications that can continue:
gssapi-with-mic,password,keyboard-interactive
debug2: we did not send a packet, disable method
debug1: No more authentication methods to try.
Permission denied (gssapi-with-mic,password,keyboard-interactive).
Thanks in advance,
Andrei
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