SSH - Exija apenas o google-authenticator da rede local externa

3

Executando uma variante do Debian (osmc)

O que estou tentando fazer:

  • Desativar ssh através de senha, exigindo chave e google authenticator; Está tudo funcionando
  • Mas agora estou tentando apenas exigir a autenticação de 2 fatores da rede local externa (é mais fácil scripts de backup, mas se houver outra maneira melhor de fazer isso, por favor diga)

Atualmente usando putty & concurso de uma caixa do windows para testar, caso seja relevante

Estou usando a solução aqui - link

O que está acontecendo agora? Quando eu conecto de fora da rede, ele ainda requer a autenticação de 2 fatores conforme necessário De dentro da rede, parece que reconhece a chave, mas erros com "Mais autenticação necessária".

Muito obrigado antecipadamente por qualquer ajuda

sudo systemctl status ssh

Aug 25 19:51:36 mosmc sshd[10528]: error: PAM: Permission denied for osmc from beast
Aug 25 19:51:36 mosmc sshd[10528]: Failed keyboard-interactive/pam for osmc from 192.168.21.3 port 54330 ssh2
Aug 25 19:51:36 mosmc sshd[10528]: error: Received disconnect from 192.168.21.3: 14: No supported authentication methods available [preauth]

Gato de arquivos abaixo (onde ele menciona um script que acabei de criar o script da caixa de mídia, já que meu trabalho continua quebrando)

    osmc@mosmc:~$ cat /etc/ssh/sshd_config
# Package generated configuration file
# See the sshd_config(5) manpage for details

# What ports, IPs and protocols we listen for
Port XXXXXXX #changed by sshinstall
# Use these options to restrict which interfaces/protocols sshd will bind to
#ListenAddress ::
#ListenAddress 0.0.0.0
Protocol 2
# HostKeys for protocol version 2

# Inserted hostkeys by ssh-install script
HostKey /etc/ssh/ssh_host_ed25519_key
HostKey /etc/ssh/ssh_host_rsa_key
HostKey /etc/ssh/ssh_host_ecdsa_key
KexAlgorithms [email protected],ecdh-sha2-nistp521,ecdh-sha2-nistp384,ecdh-sha2-nistp256,diffie-hellman-group-exchange-sha256
Ciphers [email protected],[email protected],[email protected],aes256-ctr,aes192-ctr,aes128-ctr
MACs [email protected],[email protected],[email protected],hmac-sha2-512,hmac-sha2-256,[email protected]
#End of inserted code
#Privilege Separation is turned on for security
UsePrivilegeSeparation yes

# Lifetime and size of ephemeral version 1 server key
KeyRegenerationInterval 3600
ServerKeyBits 1024

# Logging
SyslogFacility AUTH
LogLevel VERBOSE #edited by script

# Inserted ftp by ssh-install script
# Log sftp level file access (read/write/etc.) that would not be easily logged otherwise.
Subsystem internal-sftp  /usr/lib/ssh/sftp-server -f AUTHPRIV -l INFO
#End of inserted code

# Authentication:
LoginGraceTime 120
PermitRootLogin no #edited by script
StrictModes yes

RSAAuthentication yes
PubkeyAuthentication yes
#AuthorizedKeysFile     %h/.ssh/authorized_keys

# Don't read the user's ~/.rhosts and ~/.shosts files
IgnoreRhosts yes
# For this to work you will also need host keys in /etc/ssh_known_hosts
RhostsRSAAuthentication no
# similar for protocol version 2
HostbasedAuthentication no
# Uncomment if you don't trust ~/.ssh/known_hosts for RhostsRSAAuthentication
#IgnoreUserKnownHosts yes

# To enable empty passwords, change to yes (NOT RECOMMENDED)
PermitEmptyPasswords no

# Change to yes to enable challenge-response passwords (beware issues with
# some PAM modules and threads)
ChallengeResponseAuthentication yes #edited by script

# Change to no to disable tunnelled clear text passwords
PasswordAuthentication no #edited by script

# Kerberos options
#KerberosAuthentication no
#KerberosGetAFSToken no
#KerberosOrLocalPasswd yes
#KerberosTicketCleanup yes

# GSSAPI options
#GSSAPIAuthentication no
#GSSAPICleanupCredentials yes

X11Forwarding yes
X11DisplayOffset 10
PrintMotd no
PrintLastLog yes
TCPKeepAlive yes
#UseLogin no

#MaxStartups 10:30:60
#Banner /etc/issue.net

# Allow client to pass locale environment variables
AcceptEnv LANG LC_*


# 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'.

# Inserted google-auth settings by ssh-install script
AuthenticationMethods publickey,keyboard-interactive:pam
KbdInteractiveAuthentication yes
# Ensure /bin/login is not used so that it cannot bypass PAM settings for sshd.
UseLogin no
#End of inserted code
UsePAM yes

access-local.conf

osmc@mosmc:~$ cat /etc/security/access-local.conf
# only allow from local IP range
+ : ALL : 192.168.21.0/24
+ : ALL : LOCAL
- : ALL : ALL

pam.d

osmc@mosmc:~$ cat /etc/pam.d/sshd
# PAM configuration for the Secure Shell service

# Inserted PAM settings by ssh-install script
auth [success=1 default=ignore] pam_access.so accessfile=/etc/security/access-local.conf
auth required pam_google_authenticator.so
#End of inserted code

# Standard Un*x authentication.
#@include common-auth #commented out  by sshinstall

# Disallow non-root logins when /etc/nologin exists.
account    required     pam_nologin.so

# Uncomment and edit /etc/security/access.conf if you need to set complex
# access limits that are hard to express in sshd_config.
# account  required     pam_access.so

# Standard Un*x authorization.
@include common-account

# SELinux needs to be the first session rule.  This ensures that any
# lingering context has been cleared.  Without this it is possible that a
# module could execute code in the wrong domain.
session [success=ok ignore=ignore module_unknown=ignore default=bad]        pam_selinux.so close

# Set the loginuid process attribute.
session    required     pam_loginuid.so

# Create a new session keyring.
session    optional     pam_keyinit.so force revoke

# Standard Un*x session setup and teardown.
@include common-session

# Print the message of the day upon successful login.
# This includes a dynamically generated part from /run/motd.dynamic
# and a static (admin-editable) part from /etc/motd.
session    optional     pam_motd.so  motd=/run/motd.dynamic
session    optional     pam_motd.so noupdate

# Print the status of the user's mailbox upon successful login.
session    optional     pam_mail.so standard noenv # [1]

# Set up user limits from /etc/security/limits.conf.
session    required     pam_limits.so

# Read environment variables from /etc/environment and
# /etc/security/pam_env.conf.
session    required     pam_env.so # [1]
# In Debian 4.0 (etch), locale-related environment variables were moved to
# /etc/default/locale, so read that as well.
session    required     pam_env.so user_readenv=1 envfile=/etc/default/locale

# SELinux needs to intervene at login time to ensure that the process starts
# in the proper default security context.  Only sessions which are intended
# to run in the user's context should be run after this.
session [success=ok ignore=ignore module_unknown=ignore default=bad]        pam_selinux.so open

# Standard Un*x password updating.
@include common-password
    
por beardedfool 25.08.2017 / 20:58

2 respostas

2
auth [success=done default=ignore] pam_access.so accessfile=/etc/security/access-local.conf

Parece ser a resposta. Editando isso conforme eu aprendo mais.

De link

sucesso = concluído

done equivalent to ok with the side effect of terminating the module stack and PAM immediately returning to the application.

default = ignore

ignore when used with a stack of modules, the module's return status will not contribute to the return code the application obtains.

de - link

success = 1 pula uma linha.

Se alguém quiser escrever uma resposta melhor que explique o que está acontecendo - aceitarei com alegria isso.

Obrigado à Hostfission por me indicar a parte certa.

    
por 26.08.2017 / 19:36
0

@beaderdfool, obrigado pelo seu trabalho árduo. Estou ressurgindo para identificar que sua resposta funcionou, mas eu era capaz de autenticar com QUALQUER senha . Eu brinquei um pouco e encontrei a seguinte solução hacky:

auth [success=1 default=ignore] pam_access.so accessfile=/etc/security/access.conf
auth sufficient pam_google_authenticator.so
auth required pam_unix.so

a primeira linha usa as regras no access.conf. Se isso corresponder, success=1 pulará a próxima linha. Em outras palavras: uma correspondência na rede local pulará o google authenticator e tentará uma correspondência de required da senha de pam_unix.so

Por outro lado: se pam.access.so não corresponder, google_authenticator será executado e será sufficient se isso acontecer ... o que significa que ele não se importa com mais nada na pilha, ou seja, pam_unix.so e não exigirá uma senha adicional.

Minha configuração é assim:

  • A rede local exige apenas um nome de usuário e uma senha;
  • Todos os outros requerem uma chave privada (configurada em / etc / sshd_config) e o google authenticator

Eu teria deixado um comentário, mas sem credenciais suficientes.

    
por 14.05.2018 / 05:11