CentOS 檔案權限問題

user登入時出現6個 -bash: /dev/null: Permission denied

用last指令查不到任何登入entry

$ last

wtmp begins Tue Mar 17 14:47:27 2020

$ lastb

btmp begins Thu Mar 12 12:22:03 2020

查 /var/log/wtmp 發現被symbolic link到 /dev/null 去了

$ ls -al wtmp

lrwxrwxrwx. 1 root root 9 Mar  6  2019 wtmp -> /dev/null

移除symbolic link並重建wtmp (權限為 -rw-rw-r--. 1 root utmp)

rm /var/log/wtmp

touch /var/log/wtmp

chgrp utmp /var/log/wtmp

chmod g+w /var/log/wtmp

查看 /dev/null 發現權限錯了(正確為crw-rw-rw-. 1 root root)

[sywang@kitty log]$ ls -al /dev/null

crw-rw-r--. 1 root utmp 1, 3 Mar 17 14:47 /dev/null

  

重建 /dev/null

# rm -f /dev/null

# mknod -m 666 /dev/null c 1 3

/var/log/btmp權限亦不對(正確為-rw-------. 1 root utmp)

$ ls -al /var/log/btmp

-rw-rw-rw-. 1 root utmp 0 Mar 12 12:22 /var/log/btmp

移除並重建 /var/log/btmp 就開始寫資料進來了

$ sudo rm btmp

$ sudo touch btmp

$ sudo chgrp utmp btmp

$ sudo chmod og-r btmp

$ ls -al btmp

-rw-------. 1 root utmp 0 Mar 24 17:22 btmp

$ sudo lastb

root     ssh:notty    51.91.136.174    Tue Mar 24 17:25 - 17:25  (00:00)

dave     ssh:notty    121.92.broadband Tue Mar 24 17:24 - 17:24  (00:00)

dave     ssh:notty    121.92.broadband Tue Mar 24 17:24 - 17:24  (00:00)

testing  ssh:notty    202.51.110.214   Tue Mar 24 17:24 - 17:24  (00:00)

testing  ssh:notty    202.51.110.214   Tue Mar 24 17:24 - 17:24  (00:00)

qh       ssh:notty    51.68.89.100     Tue Mar 24 17:24 - 17:24  (00:00)

qh       ssh:notty    51.68.89.100     Tue Mar 24 17:24 - 17:24  (00:00)

bettina  ssh:notty    16.ip-164-132-57 Tue Mar 24 17:24 - 17:24  (00:00)

bettina  ssh:notty    16.ip-164-132-57 Tue Mar 24 17:24 - 17:24  (00:00)

參考網頁: https://blog.51cto.com/ydw1118/983658