On Thu, Oct 22, 2020 at 8:25 PM Sergei Golubchik wrote:

Hi, Daniel!

On Oct 22, Daniel Black wrote:

...

SHOW CREATE USER; dilignently uses this value in its output generating the SQL:

MariaDB [(none)]> show create user;

+---------------------------------------------------------------------------------------------------+ | CREATE USER for dan@localhost | +---------------------------------------------------------------------------------------------------+ | CREATE USER `dan`@`localhost` IDENTIFIED VIA mysql_native_password USING 'invalid' OR unix_socket | +---------------------------------------------------------------------------------------------------+

Attempting to execute this before this patch resutls in:

MariaDB [(none)]> CREATE USER `dan2`@`localhost` IDENTIFIED VIA mysql_native_password USING 'invalid' OR unix_socket; ERROR 1372 (HY000): Password hash should be a 41-digit hexadecimal number

As such deep the the implementation of mysql_native_password we make "invalid" valid (pun intended) such that the above create user will succeed.

native_password_get_salt is only called in the context of set_user_salt, so all setting of native passwords to hashed content of 'invalid', quite literally create an invalid password.

So other forms of "invalid" are valid SQL in creating invalid passwords:

MariaDB [(none)]> set password = 'invalid'; Query OK, 0 rows affected (0.001 sec)

MariaDB [(none)]> alter user dan@localhost IDENTIFIED BY PASSWORD 'invalid'; Query OK, 0 rows affected (0.000 sec)

diff --git a/sql/sql_acl.cc b/sql/sql_acl.cc index d94016b7815..3cd7a67ae1a 100644 --- a/sql/sql_acl.cc +++ b/sql/sql_acl.cc @@ -14539,6 +14539,12 @@ static int native_password_get_salt(const char *hash, size_t hash_length,

if (hash_length != SCRAMBLED_PASSWORD_CHAR_LENGTH) { + if (hash_length == 7 && strcmp(hash, "invalid") == 0) + { + memcpy(out, "invalid", 7); + *out_length= 7; + return 0; + }

okay. After you said ASAN, I think I can see why this could be problematic.

You can, of course, pad it to SCRAMBLED_PASSWORD_CHAR_LENGTH, but then you'll create a *valid* scramble that would correspond to some actual password.

yikes.

One option would be to allow "invalid" literal in set_user_auth(), before even any plugin checks. But I'm unsure of the implications.

Updated: bb-10.4-danielblack-MDEV-22974-mysql_native_password-make-invalid-valid with 2 commits: first addresses this review: https://github.com/MariaDB/server/commit/9a478b11de26fb43f8a7df4253f80d549cd... In native_password_get_salt we set a scramble of an invalid length. We check the length in native_password_authenticate before even looking at the contents of the scrambled password. This keeps the implementation confined to the native_auth implementation. second - d5ddbdcf61218a0a45228d2f22fe4dd77a7fe7c8 accepts the mysql invalid password forms (and becomes slightly more strict on our invalid forms (those not beginning with '*'))