1.问题概要：
您好，最近，在我们的基础设施生产环境中，新用户无法通过 ssh 进入 Debian 跳转服务器。跳转服务器的 SSH 守护进程从 LDAP 服务器检索 SSH 公钥。我们验证了 sshd 本地配置、sshd 日志、LDAP 公钥是否存在，但我们无法完全理解是什么阻止了用户有效登录。
2.详细信息（配置文件）：
# Package generated configuration file
# See the sshd_config(5) manpage for details
# What ports, IPs and protocols we listen for
Port 22
# 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
HostKey /etc/ssh/ssh_host_rsa_key
HostKey /etc/ssh/ssh_host_dsa_key
HostKey /etc/ssh/ssh_host_ecdsa_key
HostKey /etc/ssh/ssh_host_ed25519_key
#Privilege Separation is turned on for security
UsePrivilegeSeparation yes
# Logging
SyslogFacility AUTH
LogLevel VERBOSE
# Authentication:
LoginGraceTime 120
PermitRootLogin no
StrictModes yes
PubkeyAuthentication yes
# Don't read the user's ~/.rhosts and ~/.shosts files
IgnoreRhosts yes
# 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 no
# Change to no to disable tunnelled clear text passwords
PasswordAuthentication no
# Kerberos options
#KerberosAuthentication no
#KerberosGetAFSToken no
#KerberosOrLocalPasswd yes
#KerberosTicketCleanup yes
# GSSAPI options
#GSSAPIAuthentication no
#GSSAPICleanupCredentials yes
X11Forwarding no
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_*
Subsystem sftp /usr/lib/openssh/sftp-server
# 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
UseDNS no
Match Address 172.20.1.*,10.*
PasswordAuthentication yes
Match Group ldap-user
AuthorizedKeysFile /dev/null
AuthorizedKeysCommand /opt/ourcompanyname/scripts/ldap_keys.sh
AuthorizedKeysCommandUser nobody
查询 LDAP 的脚本：
#!/bin/bash
if [ $(whoami) = nobody ]; then
/usr/local/bin/ldap_ssh_keys -f /tmp/ssh_keys.log -b dc=prod,dc=ourcompany -u ldaps://ldap.prod.ourcompanydomain -l DEBUG $1
else
echo "should be run as user nobody"
fi
3.我们尝试过的方法（日志）：
用户尝试连接服务器（客户端）
myusername@laptophostname currentfoldr % ssh -vvv [email protected]
OpenSSH_7.9p1, LibreSSL 2.7.3
debug1: Reading configuration data /Users/myusername/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 48: Applying options for *
debug2: resolving "jbox01.prod.ourcompanydomain" port 22
debug2: ssh_connect_direct
debug1: Connecting to jbox01.prod.ourcompanydomain [172.20.1.66] port 22.
debug1: Connection established.
debug1: identity file /Users/myusername/.ssh/id_rsa type 0
debug1: identity file /Users/myusername/.ssh/id_rsa-cert type -1
debug1: identity file /Users/myusername/.ssh/id_dsa type -1
debug1: identity file /Users/myusername/.ssh/id_dsa-cert type -1
debug1: identity file /Users/myusername/.ssh/id_ecdsa type -1
debug1: identity file /Users/myusername/.ssh/id_ecdsa-cert type -1
debug1: identity file /Users/myusername/.ssh/id_ed25519 type -1
debug1: identity file /Users/myusername/.ssh/id_ed25519-cert type -1
debug1: identity file /Users/myusername/.ssh/id_xmss type -1
debug1: identity file /Users/myusername/.ssh/id_xmss-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_7.9
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.4p1 Debian-10+deb9u6
debug1: match: OpenSSH_7.4p1 Debian-10+deb9u6 pat OpenSSH_7.0*,OpenSSH_7.1*,OpenSSH_7.2*,OpenSSH_7.3*,OpenSSH_7.4*,OpenSSH_7.5*,OpenSSH_7.6*,OpenSSH_7.7* compat 0x04000002
debug2: fd 5 setting O_NONBLOCK
debug1: Authenticating to jbox01.prod.ourcompanydomain:22 as 'myusername'
debug3: hostkeys_foreach: reading file "/Users/myusername/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /Users/myusername/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from jbox01.prod.ourcompanydomain
debug3: order_hostkeyalgs: prefer hostkeyalgs: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521
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,[email protected],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,ext-info-c
debug2: host key algorithms: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,[email protected],[email protected],[email protected],[email protected],ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected],zlib
debug2: compression stoc: none,[email protected],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,[email protected],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,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected]
debug2: compression stoc: none,[email protected]
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: [email protected] MAC: <implicit> compression: none
debug1: kex: client->server cipher: [email protected] 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: ecdsa-sha2-nistp256 SHA256:VKd849z2c6XlUO3p7GnZpwVIwtdhI6Gl+6EsTImYwLI
debug3: hostkeys_foreach: reading file "/Users/myusername/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /Users/myusername/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from jbox01.prod.ourcompanydomain
debug3: hostkeys_foreach: reading file "/Users/myusername/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /Users/myusername/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from 172.20.1.66
debug1: Host 'jbox01.prod.ourcompanydomain' is known and matches the ECDSA host key.
debug1: Found key in /Users/myusername/.ssh/known_hosts:1
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
debug1: SSH2_MSG_NEWKEYS received
debug2: set_newkeys: mode 0
debug1: rekey after 134217728 blocks
debug1: Will attempt key: /Users/myusername/.ssh/id_rsa RSA SHA256:6pLYo9k0m0LK2E4Og69uAmu24SyTOX8FUX91/HDx1gk
debug1: Will attempt key: /Users/myusername/.ssh/id_dsa
debug1: Will attempt key: /Users/myusername/.ssh/id_ecdsa
debug1: Will attempt key: /Users/myusername/.ssh/id_ed25519
debug1: Will attempt key: /Users/myusername/.ssh/id_xmss
debug2: pubkey_prepare: done
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
debug3: start over, passed a different list publickey
debug3: preferred 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 public key: /Users/myusername/.ssh/id_rsa RSA SHA256:6pLYo9k0m0LK2E4Og69uAmu24SyTOX8FUX91/HDx1gk
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
debug1: Trying private key: /Users/myusername/.ssh/id_dsa
debug3: no such identity: /Users/myusername/.ssh/id_dsa: No such file or directory
debug1: Trying private key: /Users/myusername/.ssh/id_ecdsa
debug3: no such identity: /Users/myusername/.ssh/id_ecdsa: No such file or directory
debug1: Trying private key: /Users/myusername/.ssh/id_ed25519
debug3: no such identity: /Users/myusername/.ssh/id_ed25519: No such file or directory
debug1: Trying private key: /Users/myusername/.ssh/id_xmss
debug3: no such identity: /Users/myusername/.ssh/id_xmss: No such file or directory
debug2: we did not send a packet, disable method
debug1: No more authentication methods to try.
[email protected]: Permission denied (publickey).
myusername@mylaptopname:currentfoldername % ssh -vv [email protected]
OpenSSH_7.9p1, LibreSSL 2.7.3
debug1: Reading configuration data /Users/myusername/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 48: Applying options for *
debug2: resolving "jbox01.prod.ourcompanydomain" port 22
debug2: ssh_connect_direct
debug1: Connecting to jbox01.prod.ourcompanydomain [172.20.1.66] port 22.
debug1: Connection established.
debug1: identity file /Users/myusername/.ssh/id_rsa type 0
debug1: identity file /Users/myusername/.ssh/id_rsa-cert type -1
debug1: identity file /Users/myusername/.ssh/id_dsa type -1
debug1: identity file /Users/myusername/.ssh/id_dsa-cert type -1
debug1: identity file /Users/myusername/.ssh/id_ecdsa type -1
debug1: identity file /Users/myusername/.ssh/id_ecdsa-cert type -1
debug1: identity file /Users/myusername/.ssh/id_ed25519 type -1
debug1: identity file /Users/myusername/.ssh/id_ed25519-cert type -1
debug1: identity file /Users/myusername/.ssh/id_xmss type -1
debug1: identity file /Users/myusername/.ssh/id_xmss-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_7.9
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.4p1 Debian-10+deb9u6
debug1: match: OpenSSH_7.4p1 Debian-10+deb9u6 pat OpenSSH_7.0*,OpenSSH_7.1*,OpenSSH_7.2*,OpenSSH_7.3*,OpenSSH_7.4*,OpenSSH_7.5*,OpenSSH_7.6*,OpenSSH_7.7* compat 0x04000002
debug2: fd 5 setting O_NONBLOCK
debug1: Authenticating to jbox01.prod.ourcompanydomain:22 as 'myusername'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,[email protected],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,ext-info-c
debug2: host key algorithms: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,[email protected],[email protected],[email protected],[email protected],ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected],zlib
debug2: compression stoc: none,[email protected],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,[email protected],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,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected]
debug2: compression stoc: none,[email protected]
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: [email protected] MAC: <implicit> compression: none
debug1: kex: client->server cipher: [email protected] MAC: <implicit> compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:VKd849z2c6XlUO3p7GnZpwVIwtdhI6Gl+6EsTImYwLI
debug1: Host 'jbox01.prod.ourcompanydomain' is known and matches the ECDSA host key.
debug1: Found key in /Users/myusername/.ssh/known_hosts:1
debug2: set_newkeys: mode 1
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug2: set_newkeys: mode 0
debug1: rekey after 134217728 blocks
debug1: Will attempt key: /Users/myusername/.ssh/id_rsa RSA SHA256:6pLYo9k0m0LK2E4Og69uAmu24SyTOX8FUX91/HDx1gk
debug1: Will attempt key: /Users/myusername/.ssh/id_dsa
debug1: Will attempt key: /Users/myusername/.ssh/id_ecdsa
debug1: Will attempt key: /Users/myusername/.ssh/id_ed25519
debug1: Will attempt key: /Users/myusername/.ssh/id_xmss
debug2: pubkey_prepare: done
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>
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
**debug1: Offering public key: /Users/myusername/.ssh/id_rsa RSA SHA256:6pLYo9k0m0LK2E4Og69uAmu24SyTOX8FUX91/HDx1gk
debug2: we sent a publickey packet, wait for reply**
debug1: Authentications that can continue: publickey
debug1: Trying private key: /Users/myusername/.ssh/id_dsa
debug1: Trying private key: /Users/myusername/.ssh/id_ecdsa
debug1: Trying private key: /Users/myusername/.ssh/id_ed25519
debug1: Trying private key: /Users/myusername/.ssh/id_xmss
**debug2: we did not send a packet, disable method
debug1: No more authentication methods to try.
[email protected]: Permission denied (publickey).**
用户尝试连接服务器（服务器端）：
Mar 16 12:49:55 jbox01 sshd[26063]: Connection from 172.20.101.6 port 63442 on 172.20.1.66 port 22
Mar 16 12:49:56 jbox01 sshd[26063]: Failed publickey for myusername from 172.20.101.6 port 63442 ssh2: RSA SHA256:6pLYo9k0m0LK2E4Og69uAmu24SyTOX8FUX91/HDx1gk
我们还将 LDAP 中包含的密钥的 SHA256 与用户提供给服务器的密钥进行了比较，发现它们匹配。对此有什么建议吗？
答案1
我将首先测试自定义脚本是否返回预期的 SSH 密钥。
尝试这样的操作：
runuser -u nobody /opt/ourcompanyname/scripts/ldap_keys.sh myusername
还要检查我的用户名是该群组的成员ldap 用户：
id myusername
如果用户不是组成员ldap 用户指令内的 sshd_config 指令Match Group ldap-user不适用。而是使用全局设置或默认值。
答案2
实际上是通过以下方式解决的：
- 添加缺失值ldap 用户部分用户的 LDAP 门户中的组成员身份
- 重启jbox 节点让 PAM 系统刷新其缓存。通过 getent 团体现在可以看到ldap 用户团体
感谢 Michael 的支持