Bug#44365 valgrind warnings with encrypt() function

replaced String->c_ptr() with String->c_ptr_safe()

mysql-test/r/func_encrypt.result

@@ -183,3 +183,15 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 Warnings:
 Note	1003	select des_decrypt(des_encrypt('hello',4),'password2') AS `des_decrypt(des_encrypt("hello",4),'password2')`,des_decrypt(des_encrypt('hello','hidden')) AS `des_decrypt(des_encrypt("hello","hidden"))`
+drop table if exists t1;
+create table t1 (f1 smallint(6) default null, f2  mediumtext character set utf8)
+engine=myisam default charset=latin1;
+insert into t1 values (null,'contraction\'s');
+insert into t1 values (-15818,'requirement\'s');
+select encrypt(f1,f2) as a from t1,(select encrypt(f1,f2) as b from t1) a;
+a
+NULL
+re3VF.eOzS/lg
+NULL
+re3VF.eOzS/lg
+drop table t1;

mysql-test/t/func_encrypt.test

@@ -88,3 +88,16 @@ select hex(des_decrypt(des_encrypt("hello","hidden")));
 explain extended select des_decrypt(des_encrypt("hello",4),'password2'), des_decrypt(des_encrypt("hello","hidden"));
 
 # End of 4.1 tests
+
+#
+# Bug#44365 valgrind warnings with encrypt() function
+#
+--disable_warnings
+drop table if exists t1;
+--enable_warnings
+create table t1 (f1 smallint(6) default null, f2  mediumtext character set utf8)
+engine=myisam default charset=latin1;
+insert into t1 values (null,'contraction\'s');
+insert into t1 values (-15818,'requirement\'s');
+select encrypt(f1,f2) as a from t1,(select encrypt(f1,f2) as b from t1) a;
+drop table t1;

sql/item_strfunc.cc

@@ -1693,10 +1693,10 @@ String *Item_func_encrypt::val_str(String *str)
     String *salt_str=args[1]->val_str(&tmp_value);
     if ((null_value= (args[1]->null_value || salt_str->length() < 2)))
       return 0;
-    salt_ptr= salt_str->c_ptr();
+    salt_ptr= salt_str->c_ptr_safe();
   }
   pthread_mutex_lock(&LOCK_crypt);
-  char *tmp= crypt(res->c_ptr(),salt_ptr);
+  char *tmp= crypt(res->c_ptr_safe(),salt_ptr);
   if (!tmp)
   {
     pthread_mutex_unlock(&LOCK_crypt);