Significance/reason of using SUID, SGIDand Sticky bit ?

tofee · 03-23-2006, 04:07 AM

hi there,

what is the reason/significance of using SUID, SGID and Sticky Bit ? the concept is not clear to me.

can anyone pls make me understand the concept of using those ?( if possible..with example ?)

thanx..

jschiwal · 03-23-2006, 04:47 AM

An example of a program that has the SUID bit set is "passwd". This allows a user to change their own password, which is stored in a file that is only writable by root.

The sticky bit is set on world writable directories. It prevents a user from deleting a file that they don't own.
The directory itself is a file, and since the directory is world writable, a user would otherwise be able to delete the file. An example is the /tmp directory.

ls /tmp -l -d
drwxrwxrwt 31 root root 1200 2006-03-23 04:37 /tmp

SGID programs will make your effective gid the same as the program. It is more usefull in a multiuser environment to allow access to files by all members of a group.

Techsystemquery · 08-22-2012, 04:32 AM

Toffe,

This link have explanation SUID, SGID and Sticky bit with examples. hope it helps you.

http://www.expertslogin.com/linux-ad...bit-suid-guid/

Mr. Alex · 08-22-2012, 06:56 AM

I use SUID for "halt" and "reboot" so I don't need sudo before them.