First we have to test unix socket in mariadb:

unix_socket

To disable it use: disable_unix_socket, or unix_socket=OFF in my.cnf [mariadb]

Q1) configure root to use unix_socket ?

On fresh datadir when connecting to server I got:


./client/mysql
select user(), current_user;
+----------------+----------------+
| user()         | current_user   |
+----------------+----------------+
| anel@localhost | anel@localhost |
+----------------+----------------+

MariaDB [(none)]> show grants; +-----------------------------------------------------------------------------------------------------------------------------------------+ | Grants for anel@localhost | +-----------------------------------------------------------------------------------------------------------------------------------------+ | GRANT ALL PRIVILEGES ON . TO 'anel'@'localhost' IDENTIFIED VIA mysql_native_password USING 'invalid' OR unix_socket WITH GRANT OPTION | +-----------------------------------------------------------------------------------------------------------------------------------------+ 1 row in set (0.000 sec)

MariaDB [(none)]> select user,host from mysql.user\G 1. row User: Host: localhost 2. row User: anel Host: localhost 3. row User: root Host: localhost 4. row User: Host: ubuntu 4 rows in set (0.002 sec)

M ariaDB [(none)]> select * from mysql.global_priv\G 1. row Host: localhost User: root Priv: {"access":18446744073709551615,"plugin":"mysql_native_password","authentication_string":"invalid","auth_or":[{},{"plugin":"unix_socket"}]} 2. row Host: localhost User: anel Priv: {"access":18446744073709551615,"plugin":"mysql_native_password","authentication_string":"invalid","auth_or":[{},{"plugin":"unix_socket"}]} 3. row Host: localhost User: Priv: {} 4. row Host: ubuntu User: Priv: {} 4 rows in set (0.000 sec)


+ Now let's try to connect with other user, not created yet `melisa`:
```sql
./client/mysql -u melisa
MariaDB [(none)]> select user(), current_user;
+------------------+--------------+
| user()           | current_user |
+------------------+--------------+
| melisa@localhost | @localhost   |
+------------------+--------------+
1 row in set (0.000 sec)

MariaDB [(none)]> show grants;
+--------------------------------------+
| Grants for @localhost                |
+--------------------------------------+
| GRANT USAGE ON *.* TO ''@'localhost' |
+--------------------------------------+
1 row in set (0.000 sec)

MariaDB [(none)]> select user,host from mysql.user\G
ERROR 1142 (42000): SELECT command denied to user ''@'localhost' for table 'user'

Let's connect with root:

./client/mysql -u root
2019-10-23  2:52:14 14 [Warning] Access denied for user 'root'@'localhost'
ERROR 1698 (28000): Access denied for user 'root'@'localhost'

Now I have created user melisa (create user melisa identified by password, and it will create melisa@% (for all hosts)) and granted privileges:


*************************** 5. row ***************************
Host: %
User: melisa
Priv: {"access":0,"plugin":"mysql_native_password","authentication_string":"*279018759837D91FAB7BB5939852F3E940F3334B","password_last_changed":1571825125}
5 rows in set (0.000 sec)

MariaDB [(none)]> select user,host from mysql.user\G 1. row User: melisa Host: %

Grant privileges

MariaDB [(none)]> show grants for melisa; +-------------------------------------------------------------------------------------------------------+ | Grants for melisa@% | +-------------------------------------------------------------------------------------------------------+ | GRANT USAGE ON . TO 'melisa'@'%' IDENTIFIED BY PASSWORD '279018759837D91FAB7BB5939852F3E940F3334B' | +-------------------------------------------------------------------------------------------------------+ MariaDB [(none)]> grant all on . to melisa@localhost; ERROR 1133 (28000): Can't find any matching row in the user table MariaDB [(none)]> grant all on .* to 'melisa'@'%'; Query OK, 0 rows affected (0.001 sec) MariaDB [(none)]> flush privileges;

   + #### But I cannot to connect 
```sql
./client/mysql -umelisa -p
Enter password: 
2019-10-23  3:26:42 29 [Warning] Access denied for user 'melisa'@'localhost' (using password: YES)
ERROR 1045 (28000): Access denied for user 'melisa'@'localhost' (using password: YES)

I thought the problem was that bind_address is undefined and we have to change it in our config file to 0.0.0.0:

MariaDB [(none)]> show variables like 'bind%';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| bind_address  |       |
+---------------+-------+

but wasn't.

QUESTION 1.1) Why I'm logged in as `anonymous`?

Because we are starting the server with --skip-grant-tables (this option can be set in my.cnf also), and by default we are in anonymous mode.

In my case I'm not starting the server with skipping the grant tables and I used correct user (melisa )but again I'm anonymous (it is default user) ?

           ./client/mysql -u melisa
            MariaDB [(none)]> select * from mysql.global_priv\G
ERROR 1142 (42000): SELECT command denied to user ''@'localhost' for table 'global_priv'

show grants;
+--------------------------------------+
| Grants for @localhost                |
+--------------------------------------+
| GRANT USAGE ON *.* TO ''@'localhost' |
+--------------------------------------+

QUESTION 2.2) Why this is not working and should be?

     MariaDB [(none)]> select current_user();
    +----------------+
    | current_user() |
    +----------------+
    | @localhost     |
    +----------------+
    1 row in set (0.000 sec)

    MariaDB [(none)]> grant all *.* to current_user();  # ERROR !

The problem was that there existed anonymous users :

MariaDB [(none)]> select user,host from mysql.user where user='';
+------+-----------+
| User | Host      |
+------+-----------+
|      | localhost |
|      | ubuntu    |
+------+-----------+

And anonymous user with localhost has precedence over any host (%). I deleted anonymous user, flushed privileges and it worked.

MariaDB [(none)]> select user(), current_user;
+------------------+--------------+
| user()           | current_user |
+------------------+--------------+
| melisa@localhost | melisa@%     |
+------------------+--------------+

To wrap up:
- Be careful about anonymous user.
Q2) What if unix_socket is not enabled and we are going from scratch? (like changing the root password)

https://mariadb.com/kb/en/library/authentication-from-mariadb-104/#cookbook
- Documentation says to start mysqld with --skip-grant-table #(there should be some user, if there is no user I don't know?) and it will have full access to all tables (after FLUSH PRIVILEGES?)!
- login with user and run FLUSH PRIVILEGES to disable grant-tables and allows to change stored password for root example.
- run set password for root@localhost = password('mypass')
  
  TESTING
  
  Now I have created some user; melisa (grant usage) and unix_socket is disabled: ./client/mysql -u melisa
VARIANT 1) Not using the --skip-grant-tables:
```
MariaDB [(none)]> select current_user, user();
+--------------+------------------+
| current_user | user()           |
+--------------+------------------+
| @localhost   | melisa@localhost |
+--------------+------------------+
```
QUESTION 2.2) How to get all options or system_variables (MYSQLD/client) which are configured ?
- I would like to see is mariadb option: skip-option checked ?
- After running: ./sql/mysqld --help --verbose at the we have:
```
        To see what values a running MySQL server is using, type
        'mysqladmin variables' instead of 'mysqld --verbose --help'.
```
  If I try this:
```
   >> ./sql/mysqld --help --verbose | grep skip-grant  
        2019-10-18  2:48:59 0 [Note] Plugin 'FEEDBACK' is disabled.
       2019-10-18  2:48:59 0 [Warning] Could not open mysql.plugin table. Some options may be missing from the help text
                  --skip-grant-tables Start without grant tables. This gives all users FULL
                skip-grant-tables                           FALSE
```
  ./client/mysqladmin variables | grep skip #--# not started with skip-grant-tables | replicate_events_marked_for_skip | REPLICATE | | skip_external_locking | ON | | skip_name_resolve | OFF | | skip_networking | OFF | | skip_show_database | OFF | | slave_skip_errors | OFF | | sql_slave_skip_counter | 0
- To see the variables (some options are variables also): show variables (https://mariadb.com/kb/en/library/show-variables/) is showing system variables from client (https://mariadb.com/kb/en/library/server-system-variables/)!
QUESTION 2.4) Killing the second mysqld with --v works, while killing the second with --skip-grant-tables doesn't work, why ?

Note: About status of mariadb options switch:
- If the server is already being run, it turns out we can not see the status of option (skip-grant-tables) (asked on zulip).
- To check the status of an option before running the server, check mysqld --help --verbose | grep grant-tables
- There is a difference between variables and options, although some options are variables !!!
VARIANT 2) Now we are using the --skip-grant-tables:
```
    $$ ./client/mysql
    MariaDB [(none)]> select user(),current_user();
    +--------+----------------+
    | user() | current_user() |
    +--------+----------------+
    | anel@  | @              |
    +--------+----------------+
```
```
    $$ ./client/mysql -u melisa
    MariaDB [(none)]> select user(),current_user();
    +---------+----------------+
    | user()  | current_user() |
    +---------+----------------+
    | melisa@ | @              |
    +---------+----------------+

    MariaDB [(none)]> show grants;
    ERROR 1290 (HY000): The MariaDB server is running with the --skip-grant-tables option so it cannot execute this statement

    *** There is no need to FLUSH PRIVILEGES, we can see everything, we have full access ***
    MariaDB [(none)]> select * from mysql.global_priv\G
    *************************** 1. row ***************************
    Host: localhost
    User: root
    Priv: {"access":18446744073709551615,"plugin":"mysql_native_password","authentication_string":"invalid","auth_or":[{},{"plugin":"unix_socket"}]}
    *************************** 2. row ***************************
    Host: localhost
    User: anel
    Priv: {"access":18446744073709551615,"plugin":"mysql_native_password","authentication_string":"invalid","auth_or":[{},{"plugin":"unix_socket"}]}
    *************************** 3. row ***************************
    Host: localhost
    User: 
    Priv: {}
    *************************** 4. row ***************************
    Host: ubuntu
    User: 
    Priv: {}
    *************************** 5. row ***************************
    Host: %
    User: melisa
    Priv: {"access":0,"plugin":"mysql_native_password","authentication_string":"*279018759837D91FAB7BB5939852F3E940F3334B","password_last_changed":1571387954}
    5 rows in set (0.001 sec)
```
Q3)
libmysqld.c:

mysql_real_connect(MYSQL mysql,const char host, const char user, const char passwd, const char db, uint port, const char unix_socket,ulong client_flag)

takes passwd string
There is also in /usr/include/pwd.h ???

ifdef HAVE_GETPWUID

struct passwd getpwuid(uid_t); char getlogin(void);

endif
getenv(MYSQL_PWD) -> /usr/include/stdlib.c
mysql.cc

get_one_option()

argument, opt_password

< /proc/$(pidof mysql)/environ tr '\0' '\n' | grep MYSQL_PWD ???

TESTING THE PATCH

73 environment values in vector:


(gdb) bt
+bt
#0  main (argc=3, argv=0x7fffffffdba8, envp=0x7fffffffdbc8) at client/mysql.cc:1147
(gdb) p envp[73]
+p envp[73]
$14 = 0x7fffffffefa7 "GTK_IM_MODULE=ibus"
(gdb)

get_tty_password (opt_message=0x0) at mysys/get_password.c:149 (gdb) bt +bt

0 get_tty_password (opt_message=0x0) at mysys/get_password.c:149

1 0x00005555555b6da7 in get_options (argc=0, argv=0x555555c012c8) at client/mysql.cc:1977

2 0x00005555555b56bd in main (argc=4, argv=0x555555c012c0, envp=0x7fffffffdbc0) at client/mysql.cc:1199



I don't get it how to catch if on /proc/$pid/cmdline ?
cat /proc/77478/cmdline | strings -1
./sql/mysqld

an3l / my_playground

PR:1360 MYSQL_PWD env variable #12

Q1) configure root to use unix_socket ?

Grant privileges

QUESTION 1.1) Why I'm logged in as `anonymous`?

QUESTION 2.2) Why this is not working and should be?

Q2) What if unix_socket is not enabled and we are going from scratch? (like changing the root password)

TESTING

VARIANT 1) Not using the --skip-grant-tables:

QUESTION 2.2) How to get all options or system_variables (MYSQLD/client) which are configured ?

QUESTION 2.4) Killing the second mysqld with --v works, while killing the second with --skip-grant-tables doesn't work, why ?

Note: About status of mariadb options switch:

VARIANT 2) Now we are using the `--skip-grant-tables`:

ifdef HAVE_GETPWUID

endif

TESTING THE PATCH

0 get_tty_password (opt_message=0x0) at mysys/get_password.c:149

1 0x00005555555b6da7 in get_options (argc=0, argv=0x555555c012c8) at client/mysql.cc:1977

2 0x00005555555b56bd in main (argc=4, argv=0x555555c012c0, envp=0x7fffffffdbc0) at client/mysql.cc:1199

an3l / my_playground

PR:1360 MYSQL_PWD env variable #12

Q1) configure root to use unix_socket ?

Grant privileges

QUESTION 1.1) Why I'm logged in as anonymous?

QUESTION 2.2) Why this is not working and should be?

Q2) What if unix_socket is not enabled and we are going from scratch? (like changing the root password)

TESTING

VARIANT 1) Not using the --skip-grant-tables:

QUESTION 2.2) How to get all options or system_variables (MYSQLD/client) which are configured ?

QUESTION 2.4) Killing the second mysqld with --v works, while killing the second with --skip-grant-tables doesn't work, why ?

Note: About status of mariadb options switch:

VARIANT 2) Now we are using the --skip-grant-tables:

ifdef HAVE_GETPWUID

endif

TESTING THE PATCH

0 get_tty_password (opt_message=0x0) at mysys/get_password.c:149

1 0x00005555555b6da7 in get_options (argc=0, argv=0x555555c012c8) at client/mysql.cc:1977

2 0x00005555555b56bd in main (argc=4, argv=0x555555c012c0, envp=0x7fffffffdbc0) at client/mysql.cc:1199

QUESTION 1.1) Why I'm logged in as `anonymous`?

VARIANT 2) Now we are using the `--skip-grant-tables`: