Bug#48319: Server crashes on "GRANT/REVOKE ... TO CURRENT_USER"

CURRENT_USER() in GRANT ... TO CURRENT_USER() only gave us a definer,
not a full user (i.e., password-element was not initiliazed). Hence
dereferencing the password led to a crash.

Properly initializes definers now, just so there are no misunderstandings.
Also does some magic so IDENTIFIED BY ... works with CURRENT_USER().

mysql-test/r/grant2.result:
  Show GRANT ... TO CURRENT_USER() no longer crashes.
  Show it to work with IDENTIFIED BY to boot.
mysql-test/t/grant2.test:
  Show GRANT ... TO CURRENT_USER() no longer crashes.
  Show it to work with IDENTIFIED BY to boot.
sql/sql_acl.cc:
  Make IDENTIFIED BY ... work with CURRENT_USER()
sql/sql_parse.cc:
  Zero password-part of definer just in case somebody mistakes this for
  a complete LEX_USER!

1 files changed, 27 insertions, 0 deletions

diff --git a/mysql-test/r/grant2.result b/mysql-test/r/grant2.result
index 7c2023127f0..12269f0cb1c 100644
--- a/mysql-test/r/grant2.result
+++ b/mysql-test/r/grant2.result
@@ -443,3 +443,30 @@ DROP TABLE db1.t1, db1.t2;
 DROP USER mysqltest1@localhost;
 DROP DATABASE db1;
 End of 5.0 tests
+USE mysql;
+SELECT LEFT(CURRENT_USER(),INSTR(CURRENT_USER(),'@')-1) INTO @u;
+SELECT MID(CURRENT_USER(),INSTR(CURRENT_USER(),'@')+1)  INTO @h;
+SELECT password FROM user WHERE user=@u AND host=@h INTO @pwd;
+SELECT user,host,password,insert_priv FROM user WHERE user=@u AND host=@h;
+user	host	password	insert_priv
+root	localhost		Y
+UPDATE user SET insert_priv='N' WHERE user=@u AND host=@h;
+SELECT user,host,password,insert_priv FROM user WHERE user=@u AND host=@h;
+user	host	password	insert_priv
+root	localhost		N
+GRANT INSERT ON *.* TO CURRENT_USER();
+SELECT user,host,password,insert_priv FROM user WHERE user=@u AND host=@h;
+user	host	password	insert_priv
+root	localhost		Y
+UPDATE user SET insert_priv='N' WHERE user=@u AND host=@h;
+GRANT INSERT ON *.* TO CURRENT_USER() IDENTIFIED BY 'keksdose';
+SELECT user,host,password,insert_priv FROM user WHERE user=@u AND host=@h;
+user	host	password	insert_priv
+root	localhost	*0BB7188CF0DE9B403BA66E9DD810D82652D002EB	Y
+UPDATE user SET password=@pwd WHERE user=@u AND host=@h;
+SELECT user,host,password,insert_priv FROM user WHERE user=@u AND host=@h;
+user	host	password	insert_priv
+root	localhost		Y
+FLUSH PRIVILEGES;
+USE test;
+End of 5.1 tests