root用户登陆ssh报错 /bin/bash: Permission denied

CentOS7.5  ssh服务升级后，sshd服务状态正常，root用户登陆成功

Xshell 7 (Build 0157)
Copyright (c) 2020 NetSarang Computer, Inc. All rights reserved.

Type `help' to learn how to use Xshell prompt.
[C:\~]$ 

Connecting to 127.0.0.1:XXXXX...
Connection established.
To escape to local shell, press 'Ctrl+Alt+]'.
Warning: The host key of 127.0.0.1 (port: 27159) is not registered.
The host key is saved automatically, for you have set the session properties [SSH - Save host key at first connection].


O & M session login successful
Last login: Tue May 14 16:26:34 2024 from XXX.XX.XX.XX
/bin/bash: Permission denied

Connection closed.

Disconnected from remote host(root(SSH)@XXX.XX.XXX.XX(XXX.XX.XXX.XX)) at 16:31:15.

Type `help' to learn how to use Xshell prompt.
[C:\~]$ 

这个query是一个SSH连接的日志，显示了连接到127.0.0.1:XXXXX的过程。在成功登录后，出现了"/bin/bash: Permission denied"的错误，表示没有权限执行bash命令。最后，连接被关闭。

# 检查 /bin/bash 权限正常
drwxr-xr-x.  14 root root  167 Apr 20  2022 usr
dr-xr-xr-x.   2 root root 28672 May 14 16:46 bin
-rwxr-xr-x. 1 root root 964544 Apr 11  2018 bash

查看/etc/ssh/sshd_config的参数PermitRootLogin或PasswordAuthentication配置

cat /etc/ssh/sshd_config

发现没有以下

PermitRootLogin yes
PubkeyAuthentication yes
PasswordAuthentication yes

追加设置后重启sshd服务，连接成功