Linux Special Permissions Set_gid

Special Permissions Set_gid

Set_gid special permissions, which are functions in the user group permission bit, are also represented by an S.

In addition, Set_gid special permissions can also function in the directory. The function is that regardless of which user is currently logged on, as long as the directory is set to Set_gid permissions, then the new subdirectory and sub-files in this directory belong to the group consistent with the directory. PS: In a Linux system, by default, the user is logged in, the newly created files and directories (sub-files, subdirectories) belong to the user group where the user is located.

1. Action on the document

[[email protected] ~]# ls -l /usr/bin/ls-rwsr-xr-x. 1 root root  117656 11 Month   6 2016 /usr/bin/ls[[email protected] ~]# chmod u-s  /usr/bin/ls[[email protected] ~]# !lsls -l /usr/bin/ls-rwxr-xr-x. 1  Root root 117656 11 Month   6 2016 /usr/bin/ls[[email protected] ~]#  chmod g+s /usr/bin/ls[[email protected] ~]# !lsls -l /usr/bin/ Ls-rwxr-sr-x. 1 root root 117656 11 Month   6 2016 /usr/bin/ls[[email  protected] ~]# 

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2. Role in the directory

1.  directory does not set Set_gid permissions >  which user login  ,  new File/directory (sub-file/subdirectory) belongs to the user's group >  chestnuts 1:  Login to normal user Allin 

[[email protected] tmp]$ mkdir 234/[[email protected] tmp]$ ls -ld  234/drwxrwxr-x. 2 allin1 allin1 6 6 Month    9 10:52 234/[[ Email protected] tmp]$ mkdir 234/123/[[email protected] tmp]$ ls -ld  234/123/drwxrwxr-x. 2 allin1 allin1 6 6 Month    9 10:53 234 /123/[[email protected] tmp]$ touch 234/1[[email protected] tmp]$ ls - L 234/1-rw-rw-r--.  1 allin1 allin1 0 6 Month    9 10:53 234/1 [[email protected] tmp]$ 

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> Chestnut 2: Login to root user

[[Email protected] ~]# cd /tmp/[[email protected] tmp]# ls111  1. txt  222  234  allin2  allinlinux   Systemd-private-0f4b60569c224727b1ec0153a8598630-vmtoolsd.service-qcx2tt  tmp[[email protected]  tmp]# mkdir 345/[[email protected] tmp]# ls -ld 345/drwxr-xr-x.  2 root root 6 6 Month    9 10:56 345/[[email protected] tmp]#  mkdir 345/123/[[email protected] tmp]# ls -ld 345/123/drwxr-xr-x. 2  root root 6 6 Month    9 10:56 345/123/[[email protected]  Tmp]# touch 345/1[[email protected] tmp]# ls -l 345/1-rw-r--r--.  1  root root 0 6 Month    9 10:56 345/1[[email protected] tmp]#

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2. Directory settings Set_gid permissions > Regardless of which user is logged in, in the directory where the Set_gid permissions are set, the new sub-file/subdirectory is in the same group as the directory and is not affected by the login user. > Preset scenario: In the/tmp/directory, create a new directory/666/, change its owning group to User1, then set Set_uidquanxian for the directory, and finally use the root user. Observation results:

[[email protected] tmp]# ls -l  Total dosage  4drwxrwxr--.  4 root    root   45 6 month    8 21:20 111-rw-rw-r--.  1 root    root   65 6 Month    8 21:16 1.txtdrwxr-xr-x. 2  root   root    6 6 Month    8 20:11  222drwxrwxr-x. 3 allin1 allin1 26 6 Month    9 10:53 234drwxr-xr-x .  3 root   root   26 6 Month    9 10:56  345drwxr-xr-x. 4 root   root   40 6 Month    6  21:32 allin2drwxrwxrwx. 2 allin1 user1  19 6 Month    8 14:58  allinlinuxdrwx------.  3 root   root   17 6 Month     8 14:15 systemd-private-0f4b60569c224727b1ec0153a8598630-vmtoolsd.service-qcx2ttdrwxr-xr-x. 4 root   root    28 6 Month    6 17:16 tmp[[email protected] tmp]# mkdir  666/[[email protected] tmp]# ls -ld 666/drwxr-xr-x. 2 root root  6 6 month    9 11:01 666/[[email protected] tmp]# chown : user1 666/[[email protected] tmp]# ls -ld 666/drwxr-xr-x. 2 root  User1 6 6 Month    9 11:01 666/[[email protected] tmp]# chmod  g+s 666/[[email protected] tmp]# ls -ld 666/drwxr-sr-x. 2 root  user1 6 6 Month    9 11:08 666/[[email protected] tmp]#

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> Chestnut 1: Login Superuser root

[Email protected] tmp]# mkdir 666/111/[[email protected] tmp]# ls-ld 666/111/drwxr-sr-x. 2 Root user1 6 June 9 11:10 666/111/[[email protected] tmp]# touch 666/1[[email protected] tmp]# ls-l 666/1-rw-r--r--. 1 root user1 0 June 9 11:10 666/1[[email protected] tmp]#

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This article is from the "Linux Road" blog, make sure to keep this source http://allin28.blog.51cto.com/12931477/1933859

Linux Special Permissions Set_gid