Remove privileges from MySQL database - mysql

Before you think this is a duplicate question, I believe I have a unique, even if it is somewhat dim-witted, case.
A few days ago, I upgraded the version of MySQL on my Ubuntu 10.04 server to 5.3.3 (it's ahead of the Ubuntu releases for 10.04). Today, I attempted to log into phpMyAdmin for something and discovered the somewhat dreaded Connection for controluser as defined in your configuration failed error.
After following descriptions from several SO questions on how to fix this, I have become stuck.
I attempted to reconfigure phpMyAdmin, with no success.
I attempted to uninstall phpMyAdmin and reinstall it, but it couldn't remove the privileges from the DB and failed.
I then attempted to manually remove the privileges of the user - somewhat foolishly, I might add - from the DB, then dropping the db, then the user (with flush privileges).
I dropped the whole install of phpMyAdmin completely (deleting the application and the /etc/phpmyadmin directory) and reinstalled (using apt-get) but it said the permissions for the phpmyadmin user already existed:
granting access to database phpmyadmin for phpmyadmin#localhost: already exists
So, here is what I'm left with. I have a grant that I cannot modify, nor revoke:
mysql> show grants for 'phpmyadmin'#'localhost';
+-------------------------------------------------------------------------------------------------------------------+
| Grants for phpmyadmin#localhost |
+-------------------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'phpmyadmin'#'localhost' IDENTIFIED BY PASSWORD '*46CFC7938B60837F46B610A2D10C248874555C14' |
| GRANT ALL PRIVILEGES ON `phpmyadmin`.* TO 'phpmyadmin'#'localhost' |
+-------------------------------------------------------------------------------------------------------------------+
2 rows in set (0.26 sec)
mysql> revoke usage on *.* from 'phpmyadmin'#'localhost';
ERROR 1141 (42000): There is no such grant defined for user 'phpmyadmin' on host 'localhost'
mysql> revoke usage on *.* from 'phpmyadmin'#'localhost' identified by 'trustno1';
ERROR 1141 (42000): There is no such grant defined for user 'phpmyadmin' on host 'localhost'
(Don't worry, I do not use this password anymore, but it was the password that was used previously and it is not the password I chose for the new phpmyadmin installation).
How do I totally remove these grants/privileges? I am happy to start again from scratch if need be (phpmyadmin that is, not the DB).

The USAGE-privilege in mysql simply means that there are no privileges for the user 'phpadmin'#'localhost' defined on global level *.*. Additionally the same user has ALL-privilege on database phpmyadmin phpadmin.*.
So if you want to remove all the privileges and start totally from scratch do the following:
Revoke all privileges on database level:
REVOKE ALL PRIVILEGES ON phpmyadmin.* FROM 'phpmyadmin'#'localhost';
Drop the user 'phpmyadmin'#'localhost'
DROP USER 'phpmyadmin'#'localhost';
Above procedure will entirely remove the user from your instance, this means you can recreate him from scratch.
To give you a bit background on what described above: as soon as you create a user the mysql.user table will be populated. If you look on a record in it, you will see the user and all privileges set to 'N'. If you do a show grants for 'phpmyadmin'#'localhost'; you will see, the allready familliar, output above. Simply translated to "no privileges on global level for the user". Now your grant ALL to this user on database level, this will be stored in the table mysql.db. If you do a SELECT * FROM mysql.db WHERE db = 'nameofdb'; you will see a 'Y' on every priv.
Above described shows the scenario you have on your db at the present. So having a user that only has USAGE privilege means, that this user can connect, but besides of SHOW GLOBAL VARIABLES; SHOW GLOBAL STATUS; he has no other privileges.

As a side note, the reason revoke usage on *.* from 'phpmyadmin'#'localhost'; does not work is quite simple : There is no grant called USAGE.
The actual named grants are in the MySQL Documentation
The grant USAGE is a logical grant. How? 'phpmyadmin'#'localhost' has an entry in mysql.user where user='phpmyadmin' and host='localhost'. Any row in mysql.user semantically means USAGE. Running DROP USER 'phpmyadmin'#'localhost'; should work just fine. Under the hood, it's really doing this:
DELETE FROM mysql.user WHERE user='phpmyadmin' and host='localhost';
DELETE FROM mysql.db WHERE user='phpmyadmin' and host='localhost';
FLUSH PRIVILEGES;
Therefore, the removal of a row from mysql.user constitutes running REVOKE USAGE, even though REVOKE USAGE cannot literally be executed.

Related

how to revoke privileges for a MySQL user

There is a MySQL user with database level privileges, as shown in the screen shot below. However, when an attempt is made to revoke privileges for this user, an error 1141 is the result. Why is this error being generated? How can the privileges be revoked?
I entered show grants for 'api_user'#'localhost'; and got the ERROR 1141 message.
Edit:
Here I entered REVOKE ALL PRIVILEGES FROM 'api_user'#'localhost'; and got a syntax error message.
Since the user only has grants on a single database, I think you need to specify that database in the REVOKE command:
REVOKE ALL PRIVILEGES ON api_example.* FROM api_user#localhost;
If that doesn't work, try dropping the user:
DROP USER api_user#localhost;
From the documentation:
The DROP USER statement removes one or more MySQL accounts and their privileges. It removes privilege rows for the account from all grant tables.
If the grant tables hold privilege rows that contain mixed-case database or table names and the lower_case_table_names system variable is set to a nonzero value, REVOKE cannot be used to revoke these privileges. It will be necessary to manipulate the grant tables directly. (GRANT will not create such rows when lower_case_table_names is set, but such rows might have been created prior to setting the variable.)
MySQL Revoke LowerCase

Set privilages to certain database for newly created user

I have foo_bar_test database existing on my mysql server on host 127.0.0.1.
But there's no user that can access it but root, and I don't want to use root user anywhere in my code. So I created new user, fb_test, and granted him privileges for this database:
create user fb_test#'127.0.0.1' identified by password 'some_password';
grant all on 'foo_bar_test.*' to fb_test#'127.0.0.1';
flush privileges;
Ok, that should work, but when I log in as this user, I don't have any database available!
What's wrong?
I checked it using show grants for fb_test#'127.0.0.1', but it shows some strange results:
grant usage on *.* to fb_test#'127.0.0.1' identified by password '*another_password_dont_know_which_one'
How do I solve this?
you have an error in grant statement. Use the query:
grant all on 'foo_bar_test'.* to fb_test#'127.0.0.1';
In fact your grant command results an error which I think you ignored.

mysql - How to grant read only permissions to a user?

I have a mysql user, whom I want to grant all the READ permission on a db schema.
One way is this :
GRANT SELECT, SHOW_VIEW ON test.* TO 'readuser'#'%';
Is there a way to group all read operations in grant ?
If there is any single privilege that stands for ALL READ operations on database.
It depends on how you define "all read."
"Reading" from tables and views is the SELECT privilege. If that's what you mean by "all read" then yes:
GRANT SELECT ON *.* TO 'username'#'host_or_wildcard' IDENTIFIED BY 'password';
However, it sounds like you mean an ability to "see" everything, to "look but not touch." So, here are the other kinds of reading that come to mind:
"Reading" the definition of views is the SHOW VIEW privilege.
"Reading" the list of currently-executing queries by other users is the PROCESS privilege.
"Reading" the current replication state is the REPLICATION CLIENT privilege.
Note that any or all of these might expose more information than you intend to expose, depending on the nature of the user in question.
If that's the reading you want to do, you can combine any of those (or any other of the available privileges) in a single GRANT statement.
GRANT SELECT, SHOW VIEW, PROCESS, REPLICATION CLIENT ON *.* TO ...
However, there is no single privilege that grants some subset of other privileges, which is what it sounds like you are asking.
If you are doing things manually and looking for an easier way to go about this without needing to remember the exact grant you typically make for a certain class of user, you can look up the statement to regenerate a comparable user's grants, and change it around to create a new user with similar privileges:
mysql> SHOW GRANTS FOR 'not_leet'#'localhost';
+------------------------------------------------------------------------------------------------------------------------------------+
| Grants for not_leet#localhost |
+------------------------------------------------------------------------------------------------------------------------------------+
| GRANT SELECT, REPLICATION CLIENT ON *.* TO 'not_leet'#'localhost' IDENTIFIED BY PASSWORD '*xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx' |
+------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
Changing 'not_leet' and 'localhost' to match the new user you want to add, along with the password, will result in a reusable GRANT statement to create a new user.
Of, if you want a single operation to set up and grant the limited set of privileges to users, and perhaps remove any unmerited privileges, that can be done by creating a stored procedure that encapsulates everything that you want to do. Within the body of the procedure, you'd build the GRANT statement with dynamic SQL and/or directly manipulate the grant tables themselves.
In this recent question on Database Administrators, the poster wanted the ability for an unprivileged user to modify other users, which of course is not something that can normally be done -- a user that can modify other users is, pretty much by definition, not an unprivileged user -- however -- stored procedures provided a good solution in that case, because they run with the security context of their DEFINER user, allowing anybody with EXECUTE privilege on the procedure to temporarily assume escalated privileges to allow them to do the specific things the procedure accomplishes.
GRANT SELECT ON *.* TO 'user'#'localhost' IDENTIFIED BY 'password';
This will create a user with SELECT privilege for all database including Views.
Note for MySQL 8 it's different
You need to do it in two steps:
CREATE USER 'readonly_user'#'localhost' IDENTIFIED BY 'some_strong_password';
GRANT SELECT, SHOW VIEW ON *.* TO 'readonly_user'#'localhost';
flush privileges;
Various permissions that you can grant to a user are
ALL PRIVILEGES- This would allow a MySQL user all access to a designated database (or if no database is selected, across the system)
CREATE- allows them to create new tables or databases
DROP- allows them to them to delete tables or databases
DELETE- allows them to delete rows from tables
INSERT- allows them to insert rows into tables
SELECT- allows them to use the Select command to read through databases
UPDATE- allow them to update table rows
GRANT OPTION- allows them to grant or remove other users' privileges
To provide a specific user with a permission, you can use this framework:
GRANT [type of permission] ON [database name].[table name] TO ‘[username]’#'localhost’;
I found this article very helpful
A step by step guide I found here.
To create a read-only database user account for MySQL
At a UNIX prompt, run the MySQL command-line program, and log in as an administrator by typing the following command:
mysql -u root -p
Type the password for the root account.
At the mysql prompt, do one of the following steps:
To give the user access to the database from any host, type the following command:
grant select on database_name.* to 'read-only_user_name'#'%' identified by 'password';
If the collector will be installed on the same host as the database, type the following command:
grant select on database_name.* to 'read-only_user_name' identified by 'password';
This command gives the user read-only access to the database from the local host only.
If you know the host name or IP address of the host that the collector is will be installed on, type the following command:
grant select on database_name.* to 'read-only_user_name'#'host_name or IP_address' identified by 'password';
The host name must be resolvable by DNS or by the local hosts file.
At the mysql prompt, type the following command:
flush privileges;
Type quit.
The following is a list of example commands and confirmation messages:
mysql> grant select on dbname.* to 'readonlyuser'#'%' identified
by 'pogo$23';
Query OK, 0 rows affected (0.11 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> quit
Even user has got answer and #Michael - sqlbot has covered mostly points very well in his post but one point is missing, so just trying to cover it.
If you want to provide read permission to a simple user (Not admin kind of)-
GRANT SELECT, EXECUTE ON DB_NAME.* TO 'user'#'localhost' IDENTIFIED BY 'PASSWORD';
Note: EXECUTE is required here, so that user can read data if there is a stored procedure which produce a report (have few select statements).
Replace localhost with specific IP from which user will connect to DB.
Additional Read Permissions are-
SHOW VIEW : If you want to show view schema.
REPLICATION CLIENT : If user need to check replication/slave status.
But need to give permission on all DB.
PROCESS : If user need to check running process. Will work with all
DB only.
If you want the view to be read only after granting the read permission you can use the ALGORITHM = TEMPTABLE in you view DDL definition.
solution: here's some useful cookbook for creating a readonly user on mysql.
# 1. connect as an admin on database / cluster
mysql -u root -h mydb.123456789012.us-east-1.rds.amazonaws.com
# 2. create user protected with strong password with global access ('%') or local access ('localhost')
mysql> CREATE USER 'ro_user'#'%' IDENTIFIED BY 'abcd1234%^&#';
# 3. grant SELECT privileges for relevant user
mysql> GRANT SELECT ON *.* TO 'ro_user'#'%' WITH GRANT OPTION;
# 4. reload grant tables on database
mysql> FLUSH PRIVILEGES;
# 5. verify grant are placed as expected
mysql> show grants for 'ro_user'#'%';
// output:
// +------------------------------------------------------+
// | Grants for ro_user#% |
// +------------------------------------------------------+
// | GRANT SELECT ON *.* TO 'ro_user'#'%' WITH GRANT OPTION |
// +------------------------------------------------------+
// 1 row in set (0.00 sec)
mysql> exit

Revoke privileges from user in mySQL

For every new user we create in mySQL using the statement
CREATE USER newuser#localhost IDENTIFIED BY 'password';
"SHOW GRANTS" is showing only "USAGE ON *.* " privilege.
But the user is able to select,insert,.. on "test" and "information_schema" databases and I'm unable to revoke these privileges on "test" using the revoke statement given below.
REVOKE ALL ON test.* FROM newuser#localhost;
ERROR 1141 (42000) : There is no such grant defined for user 'guest' on host 'localhost'
I just don't want the newuser to access the test and information_schema databases.
http://dev.mysql.com/doc/refman/5.6/en/default-privileges.html
By default, the mysql.db table contains rows that permit access by
any user to the test database and other databases with names that
start with test_. (...) This means that
such databases can be used even by accounts that otherwise possess no
privileges. If you want to remove any-user access to test databases,
do so as follows:
mysql> DELETE FROM mysql.db WHERE Db LIKE 'test%';
mysql> FLUSH PRIVILEGES;
(...)
With the preceding change, only users who have global database
privileges or privileges granted explicitly for the test database can
use it.
The information_schema database is a read-only pseudo database built on-the-fly on request. Users will always be able to consult this database, but it only presents entries to which they already have access to otherwise.

unable to alter routine in mysql

problem: unable to alter routines.
I'm using mysql 5.1.47. I created a user called 'testuser' and db's called "abc1,abc2,abc3".
At first I tried
GRANT ALL ON *.* TO 'testuser'#'%';(also::> GRANT ALL PRIVILEGES ON *.* TO 'testuser'#'%';)
FLUSH PRIVILEGES;
tried this also
GRANT ALL ON *.* TO 'testuser'#'%' IDENTIFIED BY 'passwd';
FLUSH PRIVILEGES;
This works fine and user testuser was able to create,alter routines.
Then I revoked all the privileges and even deleted the user testuser and again created testuser. Then I tried:
GRANT ALL ON abc1.* TO 'testuser'#'%';
tried this also
GRANT ALL ON abc1.* TO 'testuser'#'%' IDENTIFIED BY 'passwd';
GRANT ALTER ROUTINE ON abc1.* TO 'testuser'#'%';
FLUSH PRIVILEGES;
By using above methods (particular Db) I'm unable to alter routine.I tried all the hosts like localhost,%,127.0.0.1,local ip. I tried to alter routine using workbench, and it is blank without any error.
But testuser is able to create routine and able to edit routine created by testuser. But other routines which are created by some other users are not able to edit by testuser (both routines are in same db).
But when i give access to all db like:
GRANT ALL ON *.* TO 'testuser'#'%';
FLUSH PRIVILEGES;
then testuser is able to edit all the routines. Please help me to fix this issue.
Thanks.
vijai
You may need to flush priviliges:
flush privileges;
Or you may need something other than '%' (which I think might mean 'anything other than localhost')
I don't create any complicated grants in my work... but in testing systems, I always add 3 grants (3rd is for misconfigured /etc/hosts files which on some incorrectly configured systems map "localhost" to the first NIC IP):
grant all privileges on dbnamehere.* to username#'%' identified by 'passwordhere';
grant all privileges on dbnamehere.* to username#'localhost' identified by 'passwordhere';
grant all privileges on dbnamehere.* to username#'127.0.0.1' identified by 'passwordhere';
update mysql.user set password=OLD_PASSWORD('passwordhere') where user='username';
flush privileges;
I ran into a similar problem, where I created a new account for a junior developer via SQL Workbench with the following privileges on a specific schema: Alter, Alter Routine, Create, Create Routine, Delete, Execute, Insert, Select, Show View, Update.
I also executed flush privileges from the work bench to ensure that the latest privileges were applied, but everytime he would right click on a stored procedure and choose "Send to Sql Editor" -> Procedure Call nothing would show up. We tried changing all sorts of options and still couldn't get it to show up.
He was able to create new procedures and then edit these procedures, but could not edit or do anything except call existing procedures written by other users. FYI, I'll add that he didn't have any DB Administrative Roles assigned.
After fiddling around and researching, I got the notion to try providing privileges on the mysql schema, since that schema has the definitions of the stored procedures in the proc table. I started out by giving all privileges and whittled it down to just the "select" privilege on this schema, and after that, the developer was able to right click on the procedures and "Send to Sql Editor" -> Procedure Call as well as alter procedures.
I'm not 100% sure if this exactly solves your problem, but it does address a couple of items.
I'll also add that it is our security policy to provide the least amount of privileges possible for a user to do their work effectively, so reducing the number of privileges supplied is something to carefully consider.