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某个用户的 SSH 访问被拒绝

tag-icon • tag-icon ssh rsa
某个用户的 SSH 访问被拒绝

对于一个用户，我在尝试通过 SSH 连接到服务器时遇到错误。此用户的主目录位于 /opt，具有 .ssh 目录（权限：700）和包含公钥的 authorized_keys 文件。它与其他用户一起使用，这些用户的主目录位于 /home，使用我可以作为其他用户连接的相同 rsa 密钥。在 /var/log/secure 中我得到：

Apr  8 14:48:22 myserver sshd[338949]: pam_sss(sshd:account): Access denied for user myuser: 6 (Permission denied)
Apr  8 14:48:22 myserver sshd[338949]: fatal: Access denied for user myuser by PAM account configuration [preauth]

使用 ssh -vvv 最后几行是：

debug1: Server accepts key: pkalg rsa-sha2-512 blen 535
debug2: input_userauth_pk_ok: fp SHA256:XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
debug3: sign_and_send_pubkey: RSA SHA256:XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
debug3: send packet: type 50
Authentication failed.

如果我使用相同的密钥以另一个用户身份连接到此服务器，则可以看到唯一的区别是主目录位于 /opt 而不是 /home。并且此用户的登录名中有一个下划线。您遇到过这种情况吗？

[编辑] 附加信息：

SELinux 已禁用

[root@myserver ~]# getenforce
Disabled

[myuser@myserver ~]$ ls -la /opt/myuser/
drwx------ 2 myuser myuser    80 Apr  8 14:46 .ssh

[myuser@myserver ~]# ls -l /opt/myuser/.ssh/authorized_keys
-rw------- 1 myuser myuser  1131 Apr  8 14:46 /opt/myuser/.ssh/authorized_keys

[root@myserver ~]# namei -l /opt/myuser/.ssh/authorized_keys
f: /opt/myuser/.ssh/authorized_keys
dr-xr-xr-x root         root         /
drwxr-xr-x root         root         opt
drwx------ myuser       myuser       myuser
drwx------ myuser       myuser       .ssh
-rw------- myuser       myuser       authorized_keys

[root@myserver ~]# grep -v ^# /etc/ssh/sshd_config
HostKey /etc/ssh/ssh_host_rsa_key
HostKey /etc/ssh/ssh_host_ecdsa_key
HostKey /etc/ssh/ssh_host_ed25519_key

SyslogFacility AUTHPRIV

PermitRootLogin no

AuthorizedKeysFile      .ssh/authorized_keys

PasswordAuthentication yes

ChallengeResponseAuthentication no

GSSAPIAuthentication yes
GSSAPICleanupCredentials no

UsePAM yes

X11Forwarding yes

AcceptEnv LANG LC_CTYPE LC_NUMERIC LC_TIME LC_COLLATE LC_MONETARY LC_MESSAGES
AcceptEnv LC_PAPER LC_NAME LC_ADDRESS LC_TELEPHONE LC_MEASUREMENT
AcceptEnv LC_IDENTIFICATION LC_ALL LANGUAGE
AcceptEnv XMODIFIERS

Subsystem       sftp    /usr/libexec/openssh/sftp-server

[root@myserver ~]# cat /etc/pam.d/sshd
#%PAM-1.0
auth       required     pam_sepermit.so
auth       substack     password-auth
auth       include      postlogin
# Used with polkit to reauthorize users in remote sessions
-auth      optional     pam_reauthorize.so prepare
account    required     pam_nologin.so
account    include      password-auth
password   include      password-auth
# pam_selinux.so close should be the first session rule
session    required     pam_selinux.so close
session    required     pam_loginuid.so
# pam_selinux.so open should only be followed by sessions to be executed in the user context
session    required     pam_selinux.so open env_params
session    required     pam_namespace.so
session    optional     pam_keyinit.so force revoke
session    include      password-auth
session    include      postlogin
# Used with polkit to reauthorize users in remote sessions
-session   optional     pam_reauthorize.so prepare

LDAP 身份验证也已通过 sssd 启用。

答案1

假设已启用 LDAP 身份验证，但拒绝该特定用户的访问，则意味着该用户尚未被授予 LDAP 对该服务器的访问权限

/etc/sssd/sssd.conf您可以检查允许的用户和允许群组然后将用户名添加为“allowed_users”的条目，或者添加到“allowed_groups”中提到的 LDAP 组中

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