HOW YOU CAN SET PERMISSION IN LINUX
~~~~~~~~~~~~~~~~~~~~~~~~~~PERMISSIONS~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Permissions:- permissions on a user are of two
types_______________________________
Permissions owner group
permission umask
1_Directory permissions. | drwxr-xr-x root
root 755 0022
2_File permissions. | -rw-r--r-- root root 644 0022
A FILE HAVE NOT THE EXECUTE PERMISSIONS BECOUSE WRITE
Read – {4} PERMISSION FOR FILE ACTS AS A EXECUTES PERMISSION.
Write –{2} + = 7
which is the full permission for the file or the directory.
Execute{1}
1_ r:- read permission. {4} |for directory drwxr-xr-x
2_ w:- write permission. {2} |
3_ x:- execute permission.{1} | this {d} shows
that this permission is for directory
4_ -:_ no permission. {-} |for file -rw-r--r-- this is the permission for file.
Now permission of a file is
applied on the {user}, {group}
and {other user} they have all different
permissions to understand below _________________........
Take a directory it has 9 digit permission
like :--------
Directory for Users
for Groups for Other users
defaults permis..
Redhat d rwx r-x r-x per.. 7 5 5
421 421 421 for U G O umask0 2 2 this {d} shows {7} full permission {5} read,
execute for
{5} read , execute for the other this is a directory for the users/ owner all groups users which are not member of any group.
File for Users for
Groups for Other
users default permission
server {-} rw- r-- r-- per .. 6 4 4
421 421 421 for
G U O
Umask 0 2 2
At
first position {-} read, write per.. only read for all groups only
read for all other users
Shows
that it’s a file for users/owner
{{{{ }}}}}}}}}}}}}}}}}}}
EXPLAIN SOME OF HOW THE PERMISSIONS APPLIED
____________________________
ROOT USER OR GROUP USER
OR ALL OTHER USERS WHO NOT BELONG THE
OWNER OF THE FILE MEMBERS OF THE FROUP TO ANY GROUP.
|
|
|
rwx rwx rwx
for dir..
7rwx 5r-x 5r-x full per.. 7rwx 7rwx 7rwx
for file 6rw- 4r-- 4r-- full per… 6rw- 6rw- 6rw- because
file didn’t need execute permission only write or read permission can execute the file.
These are the simple
permissions for a file or directory by a user for groups and other user
Now how to apply permissions
Go to the directory in which directory or file to
which permissions are applied then run the commands
Like we have to apply permission on /data
file
# cd /
/]# chmod 777{ or any of permission u
wants} file or dir.. name
like
/]# chmod 744 /data
Or
/]# chmod 644 myfile
OWNERSHIP to give
ownership of a file or directory to any other user BY ROOT ONLY
# chown pop
[filename]
Username
The user
who makes he file he has the full rights
on his file he can do any thing with his file.
And if root
write {0} in the permissions at any permissions place. Then user belogs to thet
permission even can`t open his own file because {0} refers to no
permission
This security
of {0} also acts on the groups level security if __0777 then users under group
can do nothing.
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
The default roots id is {0}
Every user has its own
primary/private group when we add this into a group then this group is its
secondary group. And then this user is member of both of the groups
primary and secondary.
After add it to secondary group then the group
level security is applied on this that
is as _____
THSES PERMISSIONS
IMPLIMENTS ONLY ON THE GROUPS AND USERS UNDER GROUPS.
1_ SUID____ Set User
Identification. {4}
2_ SGID___ Set Group identification {2}
3_STICKBIT _for restriction to
delete {1}
These permissions acts only
on the groups and the users under the group its add as a first digit for the
permissions like
To give a user under a group
to read permission only on the other members of this group
File is pop
# chmod 4777 pop
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