command= in openssh 3.4p1 failed with PermitRootLogin forced-commands-only

From: Doug Munsinger (dmunsinger@attbi.nospam.com)
Date: 08/19/02 

From: Doug Munsinger <dmunsinger@attbi.nospam.com>
Date: Mon, 19 Aug 2002 16:45:09 GMT

I am trying to enable root to execute forced commands placed in
~/.ssh/authorized_keys while still setting "PermitRootLogin
forced-commands-only" in sshd_config.

So far this fails completely unless "PermitRootLogin yes" is set,
despite continuing references to being able to restrict root and still
execute commands

 From running debug commands, it LOOKS like the authentication simply
will not succeed - I've tried restricting the protocol to 1 and using
rsa1 key instead, same with restricting to protocol 2 and using an rsa
key only. Also tried with a dsa key and with simpler options (JUST
command="")

Without setting "PermitRootLogin yes", the command fails.

The keys are encrypted and loaded into ssh-agent - "qssh" is an alias
that sources the agent-info file, grabbing the keys in memory before
excuting ssh.

Using an unexcrypted test key produced the same results.

Any suggestions for getting this to work would be greatly appreciated...
Or just commiseration if this really is a bug and doesn't work period.

Much Thanks in advance.
--dmunsinger

Here's the testing I've done and the results:

in authorized_keys on server mass:
from="172.26.2.22",command="echo
yes",no-pty,no-port-forwarding,no-X11-forwarding,no-agent-forwarding
ssh-rsa <key> root.rsync.rsa

and the result of
ssh -v -v -v mass from 172.26.2.22 when PermitRootLogin
forced-commands-only is set:

--------------------------------------------------------------------
qssh is an alias sourcing an ssh-agent info file...

[root@ford /root]# qssh -v -v -v mass
OpenSSH_3.4p1, SSH protocols 1.5/2.0, OpenSSL 0x0090605f
debug1: Reading configuration data /usr/local/etc/ssh_config
debug1: Rhosts Authentication disabled, originating port will not be
trusted.
debug1: ssh_connect: needpriv 0
debug1: Connecting to mass [172.26.2.24] port 22.
debug1: Connection established.
debug1: identity file /root/.ssh/identity type 0
debug3: Not a RSA1 key file /root/.ssh/id_rsa.
debug2: key_type_from_name: unknown key type '-----BEGIN'
debug3: key_read: no key found
debug2: key_type_from_name: unknown key type 'Proc-Type:'
debug3: key_read: no key found
debug2: key_type_from_name: unknown key type 'DEK-Info:'
debug3: key_read: no key found
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug2: key_type_from_name: unknown key type '-----END'
debug3: key_read: no key found
debug1: identity file /root/.ssh/id_rsa type 1
debug1: identity file /root/.ssh/id_dsa type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_3.4p1
debug1: match: OpenSSH_3.4p1 pat OpenSSH*
Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_3.4p1
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit:
diffie-hellman-group-exchange-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
debug2: kex_parse_kexinit:
aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se
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
debug2: kex_parse_kexinit: none
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-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
debug2: kex_parse_kexinit:
aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se
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 sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: dh_gen_key: priv key bits set: 125/256
debug1: bits set: 1625/3191
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug3: check_host_in_hostfile: filename /root/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 70
debug3: check_host_in_hostfile: filename /root/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 70
debug1: Host 'mass' is known and matches the RSA host key.
debug1: Found key in /root/.ssh/known_hosts:70
debug1: bits set: 1617/3191
debug1: ssh_rsa_verify: signature correct
debug1: kex_derive_keys
debug1: newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: waiting for SSH2_MSG_NEWKEYS
debug1: newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: done: ssh_kex2.
debug1: send SSH2_MSG_SERVICE_REQUEST
debug1: service_accept: ssh-userauth
debug1: got SSH2_MSG_SERVICE_ACCEPT
debug1: authentications that can continue:
publickey,password,keyboard-interactive
debug3: start over, passed a different list
publickey,password,keyboard-interactive
debug3: preferred publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: next auth method to try is publickey
debug1: userauth_pubkey_agent: testing agent key /root/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Remote: Forced command: echo yes
debug1: Remote: Pty allocation disabled.
debug1: Remote: Port forwarding disabled.
debug1: Remote: X11 forwarding disabled.
debug1: Remote: Agent forwarding disabled.
debug1: input_userauth_pk_ok: pkalg ssh-rsa blen 149 lastkey 0x810b270
hint -1
debug2: input_userauth_pk_ok: fp
< fingerprint for key >
debug3: sign_and_send_pubkey
debug3: clear_auth_state: key_free 0x810b270
debug1: Remote: Forced command: echo yes
debug1: Remote: Pty allocation disabled.
debug1: Remote: Port forwarding disabled.
debug1: Remote: X11 forwarding disabled.
debug1: Remote: Agent forwarding disabled.
debug1: authentications that can continue:
publickey,password,keyboard-interactive
debug2: userauth_pubkey_agent: no more keys
debug2: userauth_pubkey_agent: no message sent
debug1: try pubkey: /root/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
Connection closed by 172.26.2.24
debug1: Calling cleanup 0x8061978(0x0)
[root@ford /root]#

--------------------------------------------------------------------

and then the same command using sshd_config with
PermitRootLogin yes

--------------------------------------------------------------------
[root@ford /root]# qssh -v -v -v mass
OpenSSH_3.4p1, SSH protocols 1.5/2.0, OpenSSL 0x0090605f
debug1: Reading configuration data /usr/local/etc/ssh_config
debug1: Rhosts Authentication disabled, originating port will not be
trusted.
debug1: ssh_connect: needpriv 0
debug1: Connecting to mass [172.26.2.24] port 22.
debug1: Connection established.
debug1: identity file /root/.ssh/identity type 0
debug3: Not a RSA1 key file /root/.ssh/id_rsa.
debug2: key_type_from_name: unknown key type '-----BEGIN'
debug3: key_read: no key found
debug2: key_type_from_name: unknown key type 'Proc-Type:'
debug3: key_read: no key found
debug2: key_type_from_name: unknown key type 'DEK-Info:'
debug3: key_read: no key found
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug3: key_read: no space
debug2: key_type_from_name: unknown key type '-----END'
debug3: key_read: no key found
debug1: identity file /root/.ssh/id_rsa type 1
debug1: identity file /root/.ssh/id_dsa type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_3.4p1
debug1: match: OpenSSH_3.4p1 pat OpenSSH*
Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_3.4p1
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit:
diffie-hellman-group-exchange-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
debug2: kex_parse_kexinit:
aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se
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
debug2: kex_parse_kexinit: none
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-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
debug2: kex_parse_kexinit:
aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se
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 sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: dh_gen_key: priv key bits set: 125/256
debug1: bits set: 1613/3191
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug3: check_host_in_hostfile: filename /root/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 70
debug3: check_host_in_hostfile: filename /root/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 70
debug1: Host 'mass' is known and matches the RSA host key.
debug1: Found key in /root/.ssh/known_hosts:70
debug1: bits set: 1646/3191
debug1: ssh_rsa_verify: signature correct
debug1: kex_derive_keys
debug1: newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: waiting for SSH2_MSG_NEWKEYS
debug1: newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: done: ssh_kex2.
debug1: send SSH2_MSG_SERVICE_REQUEST
debug1: service_accept: ssh-userauth
debug1: got SSH2_MSG_SERVICE_ACCEPT
debug1: authentications that can continue:
publickey,password,keyboard-interactive
debug3: start over, passed a different list
publickey,password,keyboard-interactive
debug3: preferred publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: next auth method to try is publickey
debug1: userauth_pubkey_agent: testing agent key /root/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Remote: Forced command: echo yes
debug1: Remote: Pty allocation disabled.
debug1: Remote: Port forwarding disabled.
debug1: Remote: X11 forwarding disabled.
debug1: Remote: Agent forwarding disabled.
debug1: input_userauth_pk_ok: pkalg ssh-rsa blen 149 lastkey 0x810b270
hint -1
debug2: input_userauth_pk_ok: fp
< fingerprint for key >
debug3: sign_and_send_pubkey
debug3: clear_auth_state: key_free 0x810b270
debug1: Remote: Forced command: echo yes
debug1: Remote: Pty allocation disabled.
debug1: Remote: Port forwarding disabled.
debug1: Remote: X11 forwarding disabled.
debug1: Remote: Agent forwarding disabled.
debug1: ssh-userauth2 successful: method publickey
debug1: channel 0: new [client-session]
debug3: ssh_session2_open: channel_new: 0
debug1: send channel open 0
debug1: Entering interactive session.
debug2: callback start
debug1: ssh_session2_setup: id 0
debug1: channel request 0: pty-req
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: 3 127
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 1
debug3: tty_make_modes: 55 1
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 1
debug3: tty_make_modes: 61 1
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
debug1: channel request 0: shell
debug1: fd 3 setting TCP_NODELAY
debug2: callback done
debug1: channel 0: open confirm rwindow 0 rmax 32768
debug2: channel 0: rcvd adjust 131072
yes
    debug1: client_input_channel_req: channel 0 rtype exit-status reply 0
debug1: channel 0: rcvd eof
debug1: channel 0: output open -> drain
debug1: channel 0: obuf empty
debug1: channel 0: close_write
debug1: channel 0: output drain -> closed
debug1: channel 0: rcvd close
debug1: channel 0: close_read
debug1: channel 0: input open -> closed
debug3: channel 0: will not send data after close
debug1: channel 0: almost dead
debug1: channel 0: gc: notify user
debug1: channel 0: gc: user detached
debug1: channel 0: send close
debug1: channel 0: is dead
debug1: channel 0: garbage collecting
debug1: channel_free: channel 0: client-session, nchannels 1
debug3: channel_free: status: The following connections are open:
   #0 client-session (t4 r0 i3/0 o3/0 fd -1/-1)

debug3: channel_close_fds: channel 0: r -1 w -1 e 6
Connection to mass closed.
debug1: Transferred: stdin 0, stdout 0, stderr 28 bytes in 0.0 seconds
debug1: Bytes per second: stdin 0.0, stdout 0.0, stderr 689.5
debug1: Exit status 0
[root@ford /root]#

--------------------------------------------------------------------

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