Fix for BUG#16899: Possible buffer overflow in handling of DEFINER-clause

  
User name (host name) has limit on length. The server code relies on these
limits when storing the names. The problem was that sometimes these limits
were not checked properly, so that could lead to buffer overflow.

The fix is to check length of user/host name in parser and if string is too
long, throw an error.

BitKeeper/etc/collapsed

 44d03f27qNdqJmARzBoP3Is_cN5e0w
+44ec850ac2k4y2Omgr92GiWPBAVKGQ

mysql-test/r/grant.result

@@ -867,3 +867,27 @@ insert into mysql.user select * from t2;
 flush privileges;
 drop table t2;
 drop table t1;
+GRANT CREATE ON mysqltest.* TO 1234567890abcdefGHIKL@localhost;
+ERROR HY000: String '1234567890abcdefGHIKL' is too long for user name (should be no longer than 16)
+GRANT CREATE ON mysqltest.* TO some_user_name@1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY;
+ERROR HY000: String '1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY' is too long for host name (should be no longer than 60)
+REVOKE CREATE ON mysqltest.* FROM 1234567890abcdefGHIKL@localhost;
+ERROR HY000: String '1234567890abcdefGHIKL' is too long for user name (should be no longer than 16)
+REVOKE CREATE ON mysqltest.* FROM some_user_name@1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY;
+ERROR HY000: String '1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY' is too long for host name (should be no longer than 60)
+GRANT CREATE ON t1 TO 1234567890abcdefGHIKL@localhost;
+ERROR HY000: String '1234567890abcdefGHIKL' is too long for user name (should be no longer than 16)
+GRANT CREATE ON t1 TO some_user_name@1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY;
+ERROR HY000: String '1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY' is too long for host name (should be no longer than 60)
+REVOKE CREATE ON t1 FROM 1234567890abcdefGHIKL@localhost;
+ERROR HY000: String '1234567890abcdefGHIKL' is too long for user name (should be no longer than 16)
+REVOKE CREATE ON t1 FROM some_user_name@1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY;
+ERROR HY000: String '1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY' is too long for host name (should be no longer than 60)
+GRANT EXECUTE ON PROCEDURE p1 TO 1234567890abcdefGHIKL@localhost;
+ERROR HY000: String '1234567890abcdefGHIKL' is too long for user name (should be no longer than 16)
+GRANT EXECUTE ON PROCEDURE p1 TO some_user_name@1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY;
+ERROR HY000: String '1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY' is too long for host name (should be no longer than 60)
+REVOKE EXECUTE ON PROCEDURE p1 FROM 1234567890abcdefGHIKL@localhost;
+ERROR HY000: String '1234567890abcdefGHIKL' is too long for user name (should be no longer than 16)
+REVOKE EXECUTE ON PROCEDURE t1 FROM some_user_name@1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY;
+ERROR HY000: String '1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY' is too long for host name (should be no longer than 60)

mysql-test/r/sp.result

@@ -5374,4 +5374,17 @@ a
 1
 use test|
 drop table t3|
+DROP PROCEDURE IF EXISTS bug16899_p1|
+DROP FUNCTION IF EXISTS bug16899_f1|
+CREATE DEFINER=1234567890abcdefGHIKL@localhost PROCEDURE bug16899_p1()
+BEGIN
+SET @a = 1;
+END|
+ERROR HY000: String '1234567890abcdefGHIKL' is too long for user name (should be no longer than 16)
+CREATE DEFINER=some_user_name@1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY
+FUNCTION bug16899_f1() RETURNS INT
+BEGIN
+RETURN 1;
+END|
+ERROR HY000: String '1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY' is too long for host name (should be no longer than 60)
 drop table t1,t2;

mysql-test/r/trigger.result

@@ -1089,4 +1089,17 @@ begin
 set @a:= 1;
 end|
 ERROR HY000: Triggers can not be created on system tables
+use test|
+DROP TABLE IF EXISTS t1;
+DROP TABLE IF EXISTS t2;
+CREATE TABLE t1(c INT);
+CREATE TABLE t2(c INT);
+CREATE DEFINER=1234567890abcdefGHIKL@localhost
+TRIGGER t1_bi BEFORE INSERT ON t1 FOR EACH ROW SET @a = 1;
+ERROR HY000: String '1234567890abcdefGHIKL' is too long for user name (should be no longer than 16)
+CREATE DEFINER=some_user_name@1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY
+TRIGGER t2_bi BEFORE INSERT ON t2 FOR EACH ROW SET @a = 2;
+ERROR HY000: String '1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY' is too long for host name (should be no longer than 60)
+DROP TABLE t1;
+DROP TABLE t2;
 End of 5.0 tests

mysql-test/r/view.result

@@ -2850,3 +2850,14 @@ Tables_in_test
 t1
 DROP TABLE t1;
 DROP VIEW IF EXISTS v1;
+DROP TABLE IF EXISTS t1;
+DROP VIEW IF EXISTS v1;
+DROP VIEW IF EXISTS v2;
+CREATE TABLE t1(a INT, b INT);
+CREATE DEFINER=1234567890abcdefGHIKL@localhost
+VIEW v1 AS SELECT a FROM t1;
+ERROR HY000: String '1234567890abcdefGHIKL' is too long for user name (should be no longer than 16)
+CREATE DEFINER=some_user_name@1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY
+VIEW v2 AS SELECT b FROM t1;
+ERROR HY000: String '1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY' is too long for host name (should be no longer than 60)
+DROP TABLE t1;

mysql-test/t/grant.test

@@ -681,3 +681,52 @@ drop table t2;
 drop table t1;
 
 
+#
+# Test for BUG#16899: Possible buffer overflow in handling of DEFINER-clause.
+#
+# These checks are intended to ensure that appropriate errors are risen when
+# illegal user name or hostname is specified in user-clause of GRANT/REVOKE
+# statements.
+#
+
+# Working with database-level privileges.
+
+--error ER_WRONG_STRING_LENGTH
+GRANT CREATE ON mysqltest.* TO 1234567890abcdefGHIKL@localhost;
+
+--error ER_WRONG_STRING_LENGTH
+GRANT CREATE ON mysqltest.* TO some_user_name@1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY;
+
+--error ER_WRONG_STRING_LENGTH
+REVOKE CREATE ON mysqltest.* FROM 1234567890abcdefGHIKL@localhost;
+
+--error ER_WRONG_STRING_LENGTH
+REVOKE CREATE ON mysqltest.* FROM some_user_name@1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY;
+
+# Working with table-level privileges.
+
+--error ER_WRONG_STRING_LENGTH
+GRANT CREATE ON t1 TO 1234567890abcdefGHIKL@localhost;
+
+--error ER_WRONG_STRING_LENGTH
+GRANT CREATE ON t1 TO some_user_name@1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY;
+
+--error ER_WRONG_STRING_LENGTH
+REVOKE CREATE ON t1 FROM 1234567890abcdefGHIKL@localhost;
+
+--error ER_WRONG_STRING_LENGTH
+REVOKE CREATE ON t1 FROM some_user_name@1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY;
+
+# Working with routine-level privileges.
+
+--error ER_WRONG_STRING_LENGTH
+GRANT EXECUTE ON PROCEDURE p1 TO 1234567890abcdefGHIKL@localhost;
+
+--error ER_WRONG_STRING_LENGTH
+GRANT EXECUTE ON PROCEDURE p1 TO some_user_name@1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY;
+
+--error ER_WRONG_STRING_LENGTH
+REVOKE EXECUTE ON PROCEDURE p1 FROM 1234567890abcdefGHIKL@localhost;
+
+--error ER_WRONG_STRING_LENGTH
+REVOKE EXECUTE ON PROCEDURE t1 FROM some_user_name@1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY;

mysql-test/t/sp.test

@@ -6286,6 +6286,32 @@ select * from (select 1 as a) as t1 natural join (select * from test.t3) as t2|
 use test|
 drop table t3|
 
+
+#
+# Test for BUG#16899: Possible buffer overflow in handling of DEFINER-clause.
+#
+
+# Prepare.
+
+--disable_warnings
+DROP PROCEDURE IF EXISTS bug16899_p1|
+DROP FUNCTION IF EXISTS bug16899_f1|
+--enable_warnings
+
+--error ER_WRONG_STRING_LENGTH
+CREATE DEFINER=1234567890abcdefGHIKL@localhost PROCEDURE bug16899_p1()
+BEGIN
+  SET @a = 1;
+END|
+
+--error ER_WRONG_STRING_LENGTH
+CREATE DEFINER=some_user_name@1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY
+  FUNCTION bug16899_f1() RETURNS INT
+BEGIN
+  RETURN 1;
+END|
+
+
 #
 # BUG#NNNN: New bug synopsis
 #

mysql-test/t/trigger.test

@@ -1301,6 +1301,36 @@ create trigger wont_work after update on event for each row
 begin
  set @a:= 1;
 end|
+use test|
 delimiter ;|
 
+
+#
+# Test for BUG#16899: Possible buffer overflow in handling of DEFINER-clause.
+#
+
+# Prepare.
+
+--disable_warnings
+DROP TABLE IF EXISTS t1;
+DROP TABLE IF EXISTS t2;
+--enable_warnings
+
+CREATE TABLE t1(c INT);
+CREATE TABLE t2(c INT);
+
+--error ER_WRONG_STRING_LENGTH
+CREATE DEFINER=1234567890abcdefGHIKL@localhost
+  TRIGGER t1_bi BEFORE INSERT ON t1 FOR EACH ROW SET @a = 1;
+
+--error ER_WRONG_STRING_LENGTH
+CREATE DEFINER=some_user_name@1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY
+  TRIGGER t2_bi BEFORE INSERT ON t2 FOR EACH ROW SET @a = 2;
+
+# Cleanup.
+
+DROP TABLE t1;
+DROP TABLE t2;
+
+
 --echo End of 5.0 tests

mysql-test/t/view.test

@@ -2718,3 +2718,30 @@ DROP TABLE t1;
 --disable_warnings
 DROP VIEW IF EXISTS v1;
 --enable_warnings
+
+
+#
+# Test for BUG#16899: Possible buffer overflow in handling of DEFINER-clause.
+#
+
+# Prepare.
+
+--disable_warnings
+DROP TABLE IF EXISTS t1;
+DROP VIEW IF EXISTS v1;
+DROP VIEW IF EXISTS v2;
+--enable_warnings
+
+CREATE TABLE t1(a INT, b INT);
+
+--error ER_WRONG_STRING_LENGTH
+CREATE DEFINER=1234567890abcdefGHIKL@localhost
+  VIEW v1 AS SELECT a FROM t1;
+
+--error ER_WRONG_STRING_LENGTH
+CREATE DEFINER=some_user_name@1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY
+  VIEW v2 AS SELECT b FROM t1;
+
+# Cleanup.
+
+DROP TABLE t1;

sql/mysql_priv.h

@@ -557,6 +557,7 @@ void get_default_definer(THD *thd, LEX_USER *definer);
 LEX_USER *create_default_definer(THD *thd);
 LEX_USER *create_definer(THD *thd, LEX_STRING *user_name, LEX_STRING *host_name);
 LEX_USER *get_current_user(THD *thd, LEX_USER *user);
+bool check_string_length(LEX_STRING *str, const char *err_msg, uint max_length);
 
 enum enum_mysql_completiontype {
   ROLLBACK_RELEASE=-2, ROLLBACK=1,  ROLLBACK_AND_CHAIN=7,

sql/share/errmsg.txt

@@ -5623,3 +5623,9 @@ ER_NO_TRIGGERS_ON_SYSTEM_SCHEMA
 	eng "Triggers can not be created on system tables"
 ER_REMOVED_SPACES
         eng "Leading spaces are removed from name '%s'"
+ER_USERNAME
+	eng "user name"
+ER_HOSTNAME
+	eng "host name"
+ER_WRONG_STRING_LENGTH
+	eng "String '%-.70s' is too long for %s (should be no longer than %d)"

sql/sql_acl.cc

@@ -2900,14 +2900,6 @@ bool mysql_table_grant(THD *thd, TABLE_LIST *table_list,
       result= TRUE;
       continue;
     }  
-    if (Str->host.length > HOSTNAME_LENGTH ||
-	Str->user.length > USERNAME_LENGTH)
-    {
-      my_message(ER_GRANT_WRONG_HOST_OR_USER, ER(ER_GRANT_WRONG_HOST_OR_USER),
-                 MYF(0));
-      result= TRUE;
-      continue;
-    }
     /* Create user if needed */
     error=replace_user_table(thd, tables[0].table, *Str,
 			     0, revoke_grant, create_new_users,
@@ -3112,15 +3104,6 @@ bool mysql_routine_grant(THD *thd, TABLE_LIST *table_list, bool is_proc,
       result= TRUE;
       continue;
     }  
-    if (Str->host.length > HOSTNAME_LENGTH ||
-	Str->user.length > USERNAME_LENGTH)
-    {
-      if (!no_error)
-	my_message(ER_GRANT_WRONG_HOST_OR_USER, ER(ER_GRANT_WRONG_HOST_OR_USER),
-                   MYF(0));
-      result= TRUE;
-      continue;
-    }
     /* Create user if needed */
     error=replace_user_table(thd, tables[0].table, *Str,
 			     0, revoke_grant, create_new_users,
@@ -3246,14 +3229,6 @@ bool mysql_grant(THD *thd, const char *db, List <LEX_USER> &list,
       result= TRUE;
       continue;
     }  
-    if (Str->host.length > HOSTNAME_LENGTH ||
-	Str->user.length > USERNAME_LENGTH)
-    {
-      my_message(ER_GRANT_WRONG_HOST_OR_USER, ER(ER_GRANT_WRONG_HOST_OR_USER),
-                 MYF(0));
-      result= -1;
-      continue;
-    }
     if (replace_user_table(thd, tables[0].table, *Str,
                            (!db ? rights : 0), revoke_grant, create_new_users,
                            test(thd->variables.sql_mode &
@@ -4144,14 +4119,6 @@ bool mysql_show_grants(THD *thd,LEX_USER *lex_user)
     DBUG_RETURN(TRUE);
   }
 
-  if (lex_user->host.length > HOSTNAME_LENGTH ||
-      lex_user->user.length > USERNAME_LENGTH)
-  {
-    my_message(ER_GRANT_WRONG_HOST_OR_USER, ER(ER_GRANT_WRONG_HOST_OR_USER),
-               MYF(0));
-    DBUG_RETURN(TRUE);
-  }
-
   rw_rdlock(&LOCK_grant);
   VOID(pthread_mutex_lock(&acl_cache->lock));
 

sql/sql_parse.cc

@@ -7533,16 +7533,34 @@ LEX_USER *create_definer(THD *thd, LEX_STRING *user_name, LEX_STRING *host_name)
 
 LEX_USER *get_current_user(THD *thd, LEX_USER *user)
 {
-  LEX_USER *curr_user;
   if (!user->user.str)  // current_user
-  {
-    if (!(curr_user= (LEX_USER*) thd->alloc(sizeof(LEX_USER))))
-    {
-      my_error(ER_OUTOFMEMORY, MYF(0), sizeof(LEX_USER));
-      return 0;
-    }
-    get_default_definer(thd, curr_user);
-    return curr_user;
-  }
+    return create_default_definer(thd);
+
   return user;
 }
+
+
+/*
+  Check that length of a string does not exceed some limit.
+
+  SYNOPSIS
+    check_string_length()
+      str         string to be checked
+      err_msg     error message to be displayed if the string is too long
+      max_length  max length
+
+  RETURN
+    FALSE   the passed string is not longer than max_length
+    TRUE    the passed string is longer than max_length
+*/
+
+bool check_string_length(LEX_STRING *str, const char *err_msg,
+                         uint max_length)
+{
+  if (str->length <= max_length)
+    return FALSE;
+
+  my_error(ER_WRONG_STRING_LENGTH, MYF(0), str->str, err_msg, max_length);
+
+  return TRUE;
+}

sql/sql_yacc.yy

@@ -7511,6 +7511,9 @@ user:
 	  $$->user = $1;
 	  $$->host.str= (char *) "%";
 	  $$->host.length= 1;
+
+	  if (check_string_length(&$$->user, ER(ER_USERNAME), USERNAME_LENGTH))
+	    YYABORT;
 	}
 	| ident_or_text '@' ident_or_text
 	  {
@@ -7518,6 +7521,11 @@ user:
 	    if (!($$=(LEX_USER*) thd->alloc(sizeof(st_lex_user))))
 	      YYABORT;
 	    $$->user = $1; $$->host=$3;
+
+	    if (check_string_length(&$$->user, ER(ER_USERNAME), USERNAME_LENGTH) ||
+	        check_string_length(&$$->host, ER(ER_HOSTNAME),
+					       HOSTNAME_LENGTH))
+	      YYABORT;
 	  }
 	| CURRENT_USER optional_braces
 	{
@@ -8995,15 +9003,9 @@ definer:
            */
           YYTHD->lex->definer= 0;
 	}
-	| DEFINER_SYM EQ CURRENT_USER optional_braces
+	| DEFINER_SYM EQ user
 	{
-          if (! (YYTHD->lex->definer= create_default_definer(YYTHD)))
-            YYABORT;
-	}
-	| DEFINER_SYM EQ ident_or_text '@' ident_or_text
-	{
-          if (!(YYTHD->lex->definer= create_definer(YYTHD, &$3, &$5)))
-            YYABORT;
+	  YYTHD->lex->definer= get_current_user(YYTHD, $3);
 	}
 	;