Identische SSHD-Konfiguration, unterschiedliches Serververhalten, warum?
Hallo Liste,
ich würde mich gerne auf zwei Debian-Stretch-Systemen per SSH einloggen
können - und zwar sowohl als normaler Benutzer "user", als auch als
root, aber letzteres nur mit einem SSH-Keyfile (während der normale User
vorerst auch per Passwort erreichbar bleibt).
Auf einem System gelingt mir das, auf einem anderen - was die gleiche
SSHD-Konfiguration hat - aber nicht; dort kann ich mich zwar als
Benutzer "user" per Keyfile einloggen, für root wird das Keyfile aber
abgelehnt. Ich werde dann nach dem root-Passwort gefragt, dieses wird
aber logischerweise auch nicht akzeptiert, da in der SSHD-Konfiguration
"PermitRootLogin prohibit-password" gesetzt ist (so will ich es ja auch).
Der Client ist in beiden Fällen ein Ubuntu Xenial, aber der Effekt tritt
genauso von anderen Client-Betriebssystemen aus auf.
Funktionierendes System:
root@stretch64vm:~# ls -lahd /home/user/.ssh/
drwx------ 2 user user 4,0K Jan 5 17:47 /home/user/.ssh/
root@stretch64vm:~# ls -lahd /home/user/.ssh/authorized_keys
-rw------- 1 user user 393 Jan 5 17:47 /home/user/.ssh/authorized_keys
root@stretch64vm:~# md5sum /home/user/.ssh/authorized_keys
de1021845a76ef36c285d2b10e58e522 /home/user/.ssh/authorized_keys
root@stretch64vm:~# ls -lahd /root/.ssh/
drwx------ 2 root root 4,0K Jan 5 17:46 /root/.ssh/
root@stretch64vm:~# ls -lahd /root/.ssh/authorized_keys
-rw------- 1 root root 393 Jan 5 17:46 /root/.ssh/authorized_keys
root@stretch64vm:~# md5sum /root/.ssh/authorized_keys
de1021845a76ef36c285d2b10e58e522 /root/.ssh/authorized_keys
# Keyfile-MD5 für beide gleich, Verzeichnis-Rechte und Ownerships auch
root@stretch64vm:~# md5sum /etc/ssh/sshd_config
65326545d54f82d7f93d843447283b04 /etc/ssh/sshd_config
Test:
user@client:~$ ssh -A user@stretch64vm 'echo $HOSTNAME'
stretch64vm
# klappt
user@client:~$ ssh -A root@stretch64vm 'echo $HOSTNAME'
stretch64vm
# klappt auch
Zickiges System:
root@stretch:~# ls -lahd /home/user/.ssh/
drwx------ 2 user user 4,0K Jan 5 17:47 /home/user/.ssh/
root@stretch:~# ls -lahd /home/user/.ssh/authorized_keys
-rw------- 1 user user 393 Jan 5 17:47 /home/user/.ssh/authorized_keys
root@stretch:~# md5sum /home/user/.ssh/authorized_keys
de1021845a76ef36c285d2b10e58e522 /home/user/.ssh/authorized_keys
root@stretch:~# ls -lahd /root/.ssh/
drw------- 2 root root 4,0K Jan 5 14:02 /root/.ssh/
root@stretch:~# ls -lahd /root/.ssh/authorized_keys
-rw------- 1 root root 393 Jan 5 17:48 /root/.ssh/authorized_keys
root@stretch:~# md5sum /root/.ssh/authorized_keys
de1021845a76ef36c285d2b10e58e522 /root/.ssh/authorized_keys
# Keyfile-MD5 für beide gleich, Verzeichnis-Rechte und Ownerships auch
root@stretch:~# md5sum /etc/ssh/sshd_config
65326545d54f82d7f93d843447283b04 /etc/ssh/sshd_config
Test:
user@client:~$ ssh -A user@stretch 'echo $HOSTNAME'
stretch
# klappt
user@client:~$ ssh -A root@stretch 'echo $HOSTNAME'
root@stretch's password:
# klappt nicht, also nochmal, mit etwas mehr Details ...
ssh -A -vvv root@stretch 'echo $HOSTNAME'
OpenSSH_7.2p2 Ubuntu-4ubuntu2.2, OpenSSL 1.0.2g 1 Mar 2016
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: resolving "stretch" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to stretch [192.168.0.123] port 22.
debug1: Connection established.
debug1: identity file /home/user/.ssh/id_rsa type 1
debug1: key_load_public: No such file or directory
debug1: identity file /home/user/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/user/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/user/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/user/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/user/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/user/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/user/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.2
debug1: Remote protocol version 2.0, remote software version
OpenSSH_7.4p1 Debian-10+deb9u2
debug1: match: OpenSSH_7.4p1 Debian-10+deb9u2 pat OpenSSH* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to stretch:22 as 'root'
debug3: hostkeys_foreach: reading file "/home/user/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file
/home/user/.ssh/known_hosts:60
debug3: load_hostkeys: loaded 1 keys from stretch
debug3: order_hostkeyalgs: prefer hostkeyalgs:
ssh-rsa-cert-v01@openssh.com,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms:
curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,ext-info-c
debug2: host key algorithms:
ssh-rsa-cert-v01@openssh.com,rsa-sha2-512,rsa-sha2-256,ssh-rsa,ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ssh-ed25519-cert-v01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519
debug2: ciphers ctos:
chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc
debug2: ciphers stoc:
chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc
debug2: MACs ctos:
umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc:
umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib@openssh.com,zlib
debug2: compression stoc: none,zlib@openssh.com,zlib
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug2: peer server KEXINIT proposal
debug2: KEX algorithms:
curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1
debug2: host key algorithms: ssh-rsa,rsa-sha2-512,rsa-sha2-256
debug2: ciphers ctos:
chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: ciphers stoc:
chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: MACs ctos:
umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc:
umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib@openssh.com
debug2: compression stoc: none,zlib@openssh.com
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug1: kex: algorithm: curve25519-sha256@libssh.org
debug1: kex: host key algorithm: rsa-sha2-512
debug1: kex: server->client cipher: chacha20-poly1305@openssh.com MAC:
<implicit> compression: none
debug1: kex: client->server cipher: chacha20-poly1305@openssh.com MAC:
<implicit> compression: none
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: Server host key: ssh-rsa
SHA256:yPCiUoD85xpI5lzrMrtU/0ABsqRr46oUZB0p8i1ylz8
debug3: hostkeys_foreach: reading file "/home/user/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file
/home/user/.ssh/known_hosts:60
debug3: load_hostkeys: loaded 1 keys from stretch
debug3: hostkeys_foreach: reading file "/home/user/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file
/home/user/.ssh/known_hosts:61
debug3: load_hostkeys: loaded 1 keys from 192.168.0.9
debug1: Host 'stretch' is known and matches the RSA host key.
debug1: Found key in /home/user/.ssh/known_hosts:60
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug2: set_newkeys: mode 0
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS received
debug2: key: /home/user/.ssh/id_rsa (0x55d27ba70cc0), agent
debug2: key: /home/user/.ssh/id_dsa ((nil))
debug2: key: /home/user/.ssh/id_ecdsa ((nil))
debug2: key: /home/user/.ssh/id_ed25519 ((nil))
debug3: send packet: type 5
debug3: receive packet: type 7
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info:
server-sig-algs=<ssh-ed25519,ssh-rsa,ssh-dss,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521>
debug3: receive packet: type 6
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey,password
debug3: start over, passed a different list publickey,password
debug3: preferred
gssapi-keyex,gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /home/user/.ssh/id_rsa
debug3: send_pubkey_test
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey,password
debug1: Trying private key: /home/user/.ssh/id_dsa
debug3: no such identity: /home/user/.ssh/id_dsa: No such file or directory
debug1: Trying private key: /home/user/.ssh/id_ecdsa
debug3: no such identity: /home/user/.ssh/id_ecdsa: No such file or
directory
debug1: Trying private key: /home/user/.ssh/id_ed25519
debug3: no such identity: /home/user/.ssh/id_ed25519: No such file or
directory
debug2: we did not send a packet, disable method
debug3: authmethod_lookup password
debug3: remaining preferred: ,password
debug3: authmethod_is_enabled password
debug1: Next authentication method: password
root@stretch's password:
# klappt wieder nicht
Die sshd_config hat auf beiden Systemen (nachprüfbar über die oben
angegebene MD5-Summe) diesen Inhalt:
# $OpenBSD: sshd_config,v 1.100 2016/08/15 12:32:04 naddy Exp $
# This is the sshd server system-wide configuration file. See
# sshd_config(5) for more information.
# This sshd was compiled with PATH=/usr/bin:/bin:/usr/sbin:/sbin
# The strategy used for options in the default sshd_config shipped with
# OpenSSH is to specify options with their default value where
# possible, but leave them commented. Uncommented options override the
# default value.
#Port 22
#AddressFamily any
#ListenAddress 0.0.0.0
#ListenAddress ::
#HostKey /etc/ssh/ssh_host_rsa_key
#HostKey /etc/ssh/ssh_host_ecdsa_key
#HostKey /etc/ssh/ssh_host_ed25519_key
# Ciphers and keying
#RekeyLimit default none
# Logging
#SyslogFacility AUTH
#LogLevel INFO
# Authentication:
#LoginGraceTime 2m
PermitRootLogin prohibit-password
#StrictModes yes
#MaxAuthTries 6
#MaxSessions 10
#PubkeyAuthentication yes
# Expect .ssh/authorized_keys2 to be disregarded by default in future.
#AuthorizedKeysFile .ssh/authorized_keys .ssh/authorized_keys2
#AuthorizedPrincipalsFile none
#AuthorizedKeysCommand none
#AuthorizedKeysCommandUser nobody
# For this to work you will also need host keys in /etc/ssh/ssh_known_hosts
#HostbasedAuthentication no
# Change to yes if you don't trust ~/.ssh/known_hosts for
# HostbasedAuthentication
#IgnoreUserKnownHosts no
# Don't read the user's ~/.rhosts and ~/.shosts files
#IgnoreRhosts yes
# To disable tunneled clear text passwords, change to no here!
#PasswordAuthentication yes
#PermitEmptyPasswords no
# Change to yes to enable challenge-response passwords (beware issues with
# some PAM modules and threads)
ChallengeResponseAuthentication no
# Kerberos options
#KerberosAuthentication no
#KerberosOrLocalPasswd yes
#KerberosTicketCleanup yes
#KerberosGetAFSToken no
# GSSAPI options
#GSSAPIAuthentication no
#GSSAPICleanupCredentials yes
#GSSAPIStrictAcceptorCheck yes
#GSSAPIKeyExchange no
# Set this to 'yes' to enable PAM authentication, account processing,
# and session processing. If this is enabled, PAM authentication will
# be allowed through the ChallengeResponseAuthentication and
# PasswordAuthentication. Depending on your PAM configuration,
# PAM authentication via ChallengeResponseAuthentication may bypass
# the setting of "PermitRootLogin without-password".
# If you just want the PAM account and session checks to run without
# PAM authentication, then enable this but set PasswordAuthentication
# and ChallengeResponseAuthentication to 'no'.
UsePAM yes
#AllowAgentForwarding yes
#AllowTcpForwarding yes
#GatewayPorts no
X11Forwarding yes
#X11DisplayOffset 10
#X11UseLocalhost yes
#PermitTTY yes
PrintMotd no
#PrintLastLog yes
#TCPKeepAlive yes
#UseLogin no
#UsePrivilegeSeparation sandbox
#PermitUserEnvironment no
#Compression delayed
#ClientAliveInterval 0
#ClientAliveCountMax 3
#UseDNS no
#PidFile /var/run/sshd.pid
#MaxStartups 10:30:100
#PermitTunnel no
#ChrootDirectory none
#VersionAddendum none
# no default banner path
#Banner none
# Allow client to pass locale environment variables
AcceptEnv LANG LC_*
# override default of no subsystems
Subsystem sftp /usr/lib/openssh/sftp-server
# Example of overriding settings on a per-user basis
#Match User anoncvs
# X11Forwarding no
# AllowTcpForwarding no
# PermitTTY no
# ForceCommand cvs server
Ich habe sshd schon neu gestartet, gestoppt und gestartet, und den
ganzen Server durchgestartet. Nichts davon hilft. Was geht da schief?
Wer nimmt mir die Tomaten von den Augen?
Gruß
Stefan
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