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A little doubt regarding setgid and Unix access right flags.

 
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# 1  
Old 03-17-2010
A little doubt regarding setgid and Unix access right flags.
Hi all!

I have a folder with permissions 2770 (SETGID)

Code:
drwxrws---   2 loguser   admins            5 Mar 17 11:11 mydir

Inside that folder there are some files with permissions 0640:

Code:
-rw-r-----   1 loguser   admins            0 Mar 17 11:11 monday.log
-rw-r-----   1 loguser   admins            0 Mar 17 11:11 tuesday.log
-rw-r-----   1 loguser   admins            0 Mar 17 11:11 wednesday.log


"mike" is a member of the "admins" group.

When I login as mike, go through the above folder and try to delete a file it shows:

Code:
override protection 640 (yes/no)?

And if I input "yes" it will let me delete the file.

Why is it letting "mike" delete the file, even when the file uses "0640" (read-only for the group)

I hope you could help me clarify this. Smilie

Thanks.
# 2  
Old 03-17-2010
Because Mike has write permissions (2770) to the directory - being a member of the admins group. SETGIO really has nothing to do with it.

Code:
# useradd -d /home/test1 -g users -s $(which ksh) test1
# useradd -d /home/test2 -g users -s $(which ksh) test2
# su - test1

$ cd /home/test1
$ mkdir A
$ chmod 2777 A
$ touch A/1 A/2
$ exit

# su - test2

$ cd ~test1/A
$ ll
total 0
-rw-r--r-- 1 test1 users 0 Mar 17 05:43 1
-rw-r--r-- 1 test1 users 0 Mar 17 05:43 2

$ rm 1
rm: remove write-protected regular empty file `1'? y
$ ll
total 0
-rw-r--r-- 1 test1 users 0 Mar 17 05:43 2
$ exit

# su - test1

$ chmod 2755 A
$ exit

# su - test2
$ cd ~test1/A
$ rm 2
rm: remove write-protected regular empty file `2'? y
rm: cannot remove `2': Permission denied

# 3  
Old 03-17-2010
Wow, that really cleared my doubts. Thanks a lot.
 
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