Home / server / Questions / 183403
Accepted
John
Asked: 2010-09-22 17:26:46 +0800 CST

Set gid bit not working

  • 772

I have these permissions on a folder.

drwxr-sr-x  2 root    sharedmaster  4096 2010-09-22 10:36 rantest99

I have user tony which is in the group sharedmaster. When I try to mkdir from tony it says permission denied. Why is that?

I have set the gid bit on directory so that new directory has group read write permissions. Where am I wrong.

linux ubuntu setgid

3 Answers

  1. I believe you need to chmod g+w rantest99.

    Edit:

    chmod g+w dirname makes a directory writable by members of the group. This is what chmod g+s dirname does:

    From info coreutils 'Directory Setuid and Setgid'

    27.4 Directories and the Set-User-ID and Set-Group-ID Bits ==========================================================

    On most systems, if a directory's set-group-ID bit is set, newly created subfiles inherit the same group as the directory, and newly created subdirectories inherit the set-group-ID bit of the parent directory. On a few systems, a directory's set-user-ID bit has a similar effect on the ownership of new subfiles and the set-user-ID bits of new subdirectories. These mechanisms let users share files more easily, by lessening the need to use 'chmod' or 'chown' to share new files.

    • 4
  2. Best Answer

    In addition granting write access on the parent directory you almost certainly need to adjust the umask of the user which is probably set to filter away group/other write access.

    You probably want to set a umask of 0002.

    • 3

  3. paste error please.

    test@u1004s02:/tmp$ ls -ald 1
drwxr-sr-x 2 root test 4096 Sep 22 05:49 1
test@u1004s02:/tmp$ id
uid=1001(test) gid=1001(test) groups=1001(test)
test@u1004s02:/tmp$ cd 1  
test@u1004s02:/tmp/1$

    About setgid: http://en.wikipedia.org/wiki/Setuid#setuid_and_setgid_on_directories

    • 0