Bug #35087: Inserting duplicate values at one time with DES_ENCRYPT leads

  to wrong results
      
3 problems found with DES_ENCRYPT/DES_DECRYPT :

1. The max length was not calculated properly. Fixed in fix_length_and_dec()
2. DES_ENCRYPT had a side effect of sometimes reallocating and changing 
the value of its argument. Fixed by explicitly pre-allocating the necessary
space to pad the argument with trailing '*' (stars) when calculating the 
DES digest.
3. in DES_ENCRYPT the string buffer for the result value was not 
reallocated to the correct size and only string length was assigned to it. 
Fixed by making sure there's enough space to hold the result.

mysql-test/r/func_des_encrypt.result

 select des_encrypt('hello');
 des_encrypt('hello')
 €Ö2nV“Ø}
+#
+# Bug #11643: des_encrypt() causes server to die
+#
+CREATE TABLE t1 (des VARBINARY(200) NOT NULL DEFAULT '') ENGINE=MyISAM;
+INSERT INTO t1 VALUES ('1234'), ('12345'), ('123456'), ('1234567');
+UPDATE t1 SET des=DES_ENCRYPT('1234');
+SELECT LENGTH(des) FROM t1;
+LENGTH(des)
+9
+9
+9
+9
+SELECT DES_DECRYPT(des) FROM t1;
+DES_DECRYPT(des)
+1234
+1234
+1234
+1234
+SELECT 
+LENGTH(DES_ENCRYPT('1234')), 
+LENGTH(DES_ENCRYPT('12345')), 
+LENGTH(DES_ENCRYPT('123456')), 
+LENGTH(DES_ENCRYPT('1234567'));
+LENGTH(DES_ENCRYPT('1234'))	LENGTH(DES_ENCRYPT('12345'))	LENGTH(DES_ENCRYPT('123456'))	LENGTH(DES_ENCRYPT('1234567'))
+9	9	9	9
+SELECT 
+DES_DECRYPT(DES_ENCRYPT('1234')), 
+DES_DECRYPT(DES_ENCRYPT('12345')), 
+DES_DECRYPT(DES_ENCRYPT('123456')), 
+DES_DECRYPT(DES_ENCRYPT('1234567'));
+DES_DECRYPT(DES_ENCRYPT('1234'))	DES_DECRYPT(DES_ENCRYPT('12345'))	DES_DECRYPT(DES_ENCRYPT('123456'))	DES_DECRYPT(DES_ENCRYPT('1234567'))
+1234	12345	123456	1234567
+DROP TABLE t1;
+End of 5.0 tests

mysql-test/t/func_des_encrypt.test

@@ -9,3 +9,31 @@
 select des_encrypt('hello');
 
 # End of 4.1 tests
+
+--echo #
+--echo # Bug #11643: des_encrypt() causes server to die
+--echo #
+
+CREATE TABLE t1 (des VARBINARY(200) NOT NULL DEFAULT '') ENGINE=MyISAM;
+
+INSERT INTO t1 VALUES ('1234'), ('12345'), ('123456'), ('1234567');
+
+UPDATE t1 SET des=DES_ENCRYPT('1234');
+
+SELECT LENGTH(des) FROM t1;
+SELECT DES_DECRYPT(des) FROM t1;
+
+SELECT 
+ LENGTH(DES_ENCRYPT('1234')), 
+ LENGTH(DES_ENCRYPT('12345')), 
+ LENGTH(DES_ENCRYPT('123456')), 
+ LENGTH(DES_ENCRYPT('1234567'));
+SELECT 
+ DES_DECRYPT(DES_ENCRYPT('1234')), 
+ DES_DECRYPT(DES_ENCRYPT('12345')), 
+ DES_DECRYPT(DES_ENCRYPT('123456')), 
+ DES_DECRYPT(DES_ENCRYPT('1234567'));
+
+DROP TABLE t1;
+
+--Echo End of 5.0 tests

sql/item_strfunc.cc

@@ -473,17 +473,21 @@ String *Item_func_des_encrypt::val_str(String *str)
      string marking change of string length.
   */
 
-  tail=  (8-(res_length) % 8);			// 1..8 marking extra length
+  tail= 8 - (res_length % 8);                   // 1..8 marking extra length
   res_length+=tail;
+  tmp_arg.realloc(res_length);
+  tmp_arg.length(0);
+  tmp_arg.append(res->ptr(), res->length());
   code= ER_OUT_OF_RESOURCES;
-  if (tail && res->append(append_str, tail) || tmp_value.alloc(res_length+1))
+  if (tmp_arg.append(append_str, tail) || tmp_value.alloc(res_length+1))
     goto error;
-  (*res)[res_length-1]=tail;			// save extra length
+  tmp_arg[res_length-1]=tail;                   // save extra length
+  tmp_value.realloc(res_length+1);
   tmp_value.length(res_length+1);
   tmp_value[0]=(char) (128 | key_number);
   // Real encryption
   bzero((char*) &ivec,sizeof(ivec));
-  DES_ede3_cbc_encrypt((const uchar*) (res->ptr()),
+  DES_ede3_cbc_encrypt((const uchar*) (tmp_arg.ptr()),
 		       (uchar*) (tmp_value.ptr()+1),
 		       res_length,
 		       &keyschedule.ks1,

sql/item_strfunc.h

@@ -306,13 +306,17 @@ public:
 
 class Item_func_des_encrypt :public Item_str_func
 {
-  String tmp_value;
+  String tmp_value,tmp_arg;
 public:
   Item_func_des_encrypt(Item *a) :Item_str_func(a) {}
   Item_func_des_encrypt(Item *a, Item *b): Item_str_func(a,b) {}
   String *val_str(String *);
   void fix_length_and_dec()
-  { maybe_null=1; max_length = args[0]->max_length+8; }
+  {
+    maybe_null=1;
+    /* 9 = MAX ((8- (arg_len % 8)) + 1) */
+    max_length = args[0]->max_length + 9;
+  }
   const char *func_name() const { return "des_encrypt"; }
 };
 
@@ -323,7 +327,12 @@ public:
   Item_func_des_decrypt(Item *a) :Item_str_func(a) {}
   Item_func_des_decrypt(Item *a, Item *b): Item_str_func(a,b) {}
   String *val_str(String *);
-  void fix_length_and_dec() { maybe_null=1; max_length = args[0]->max_length; }
+  void fix_length_and_dec()
+  {
+    maybe_null=1;
+    /* 9 = MAX ((8- (arg_len % 8)) + 1) */
+    max_length = args[0]->max_length - 9;
+  }
   const char *func_name() const { return "des_decrypt"; }
 };