BUG#49124 Security issue with /*!-versioned */ SQL statements on Slave

Backport to 5.0.

/*![:version:] Query Code */, where [:version:] is a sequence of 5 
digits representing the mysql server version(e.g /*!50200 ... */),
is a special comment that the query in it can be executed on those 
servers whose versions are larger than the version appearing in the 
comment. It leads to a security issue when slave's version is larger 
than master's. A malicious user can improve his privileges on slaves. 
Because slave SQL thread is running with SUPER privileges, so it can
execute queries that he/she does not have privileges on master.
      
This bug is fixed with the logic below: 
- To replace '!' with ' ' in the magic comments which are not applied on
  master. So they become common comments and will not be applied on slave.
      
- Example:
  'INSERT INTO t1 VALUES (1) /*!10000, (2)*/ /*!99999 ,(3)*/
   will be binlogged as
  'INSERT INTO t1 VALUES (1) /*!10000, (2)*/ /* 99999 ,(3)*/

mysql-test/r/rpl_conditional_comments.result

+stop slave;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+reset master;
+reset slave;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+start slave;
+CREATE TABLE t1(c1 INT);
+show binlog events from <binlog_start>;
+Log_name	Pos	Event_type	Server_id	End_log_pos	Info
+master-bin.000001	#	Query	#	#	use `test`; CREATE TABLE t1(c1 INT)
+
+# Case 1:
+# ------------------------------------------------------------------
+# In a statement, some CCs are applied while others are not. The CCs
+# which are not applied on master will be binlogged as common comments.
+/*!99999 --- */INSERT /*!INTO*/ /*!10000 t1 */ VALUES(10) /*!99999 ,(11)*/;
+show binlog events from <binlog_start>;
+Log_name	Pos	Event_type	Server_id	End_log_pos	Info
+master-bin.000001	#	Query	#	#	use `test`; /* 99999 --- */INSERT /*!INTO*/ /*!10000 t1 */ VALUES(10) /* 99999 ,(11)*/
+Comparing tables master:test.t1 and slave:test.t1
+
+# Case 2:
+# -----------------------------------------------------------------
+# Verify whether it can be binlogged correctly when executing prepared
+# statement.
+PREPARE stmt FROM 'INSERT INTO /*!99999 blabla*/ t1 VALUES(60) /*!99999 ,(61)*/';
+EXECUTE stmt;
+DROP TABLE t1;
+CREATE TABLE t1(c1 INT);
+EXECUTE stmt;
+Comparing tables master:test.t1 and slave:test.t1
+
+SET @value=62;
+PREPARE stmt FROM 'INSERT INTO /*!99999 blabla */ t1 VALUES(?) /*!99999 ,(63)*/';
+EXECUTE stmt USING @value;
+DROP TABLE t1;
+CREATE TABLE t1(c1 INT);
+EXECUTE stmt USING @value;
+show binlog events from <binlog_start>;
+Log_name	Pos	Event_type	Server_id	End_log_pos	Info
+master-bin.000001	#	Query	#	#	use `test`; INSERT INTO /* 99999 blabla*/ t1 VALUES(60) /* 99999 ,(61)*/
+master-bin.000001	#	Query	#	#	use `test`; DROP TABLE t1
+master-bin.000001	#	Query	#	#	use `test`; CREATE TABLE t1(c1 INT)
+master-bin.000001	#	Query	#	#	use `test`; INSERT INTO /* 99999 blabla*/ t1 VALUES(60) /* 99999 ,(61)*/
+master-bin.000001	#	Query	#	#	use `test`; INSERT INTO /* 99999 blabla */ t1 VALUES(62) /* 99999 ,(63)*/
+master-bin.000001	#	Query	#	#	use `test`; DROP TABLE t1
+master-bin.000001	#	Query	#	#	use `test`; CREATE TABLE t1(c1 INT)
+master-bin.000001	#	Query	#	#	use `test`; INSERT INTO /* 99999 blabla */ t1 VALUES(62) /* 99999 ,(63)*/
+Comparing tables master:test.t1 and slave:test.t1
+
+# Case 3:
+# -----------------------------------------------------------------
+# Verify it can restore the '!', if the it is an uncomplete conditional
+# comments
+SELECT c1 FROM /*!99999 t1 WHEREN;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '/*!99999 t1 WHEREN' at line 1
+DROP TABLE t1;

mysql-test/t/rpl_conditional_comments.test

+###############################################################################
+# After the patch for BUG#49124:
+#  - Use ' ' instead of '!' in the conditional comments which are not applied on
+#  master. So they become common comments and will not be applied on slave.
+#
+#  - Example:
+#  'INSERT INTO t1 VALUES (1) /*!10000, (2)*/ /*!99999 ,(3)*/
+#  will be binlogged as
+#  'INSERT INTO t1 VALUES (1) /*!10000, (2)*/ /* 99999 ,(3)*/'.
+###############################################################################
+source include/master-slave.inc;
+
+CREATE TABLE t1(c1 INT);
+source include/show_binlog_events.inc;
+let $binlog_start= query_get_value(SHOW MASTER STATUS, Position, 1);
+
+--echo
+--echo # Case 1:
+--echo # ------------------------------------------------------------------
+--echo # In a statement, some CCs are applied while others are not. The CCs
+--echo # which are not applied on master will be binlogged as common comments.
+
+/*!99999 --- */INSERT /*!INTO*/ /*!10000 t1 */ VALUES(10) /*!99999 ,(11)*/;
+
+source include/show_binlog_events.inc;
+let $binlog_start= query_get_value(SHOW MASTER STATUS, Position, 1);
+sync_slave_with_master;
+let $diff_table_1=master:test.t1;
+let $diff_table_2=slave:test.t1;
+source include/diff_tables.inc;
+
+--echo
+--echo # Case 2:
+--echo # -----------------------------------------------------------------
+--echo # Verify whether it can be binlogged correctly when executing prepared
+--echo # statement.
+PREPARE stmt FROM 'INSERT INTO /*!99999 blabla*/ t1 VALUES(60) /*!99999 ,(61)*/';
+EXECUTE stmt;
+DROP TABLE t1;
+CREATE TABLE t1(c1 INT);
+EXECUTE stmt;
+
+sync_slave_with_master;
+let $diff_table_1=master:test.t1;
+let $diff_table_2=slave:test.t1;
+source include/diff_tables.inc;
+
+--echo
+SET @value=62;
+PREPARE stmt FROM 'INSERT INTO /*!99999 blabla */ t1 VALUES(?) /*!99999 ,(63)*/';
+EXECUTE stmt USING @value;
+DROP TABLE t1;
+CREATE TABLE t1(c1 INT);
+EXECUTE stmt USING @value;
+
+source include/show_binlog_events.inc;
+let $binlog_start= query_get_value(SHOW MASTER STATUS, Position, 1);
+
+sync_slave_with_master;
+let $diff_table_1=master:test.t1;
+let $diff_table_2=slave:test.t1;
+source include/diff_tables.inc;
+
+--echo
+--echo # Case 3:
+--echo # -----------------------------------------------------------------
+--echo # Verify it can restore the '!', if the it is an uncomplete conditional
+--echo # comments
+--error 1064
+SELECT c1 FROM /*!99999 t1 WHEREN;
+
+DROP TABLE t1;
+source include/master-slave-end.inc;

sql/mysql_priv.h

@@ -751,7 +751,7 @@ bool do_rename(THD *thd, TABLE_LIST *ren_table, char *new_db,
 bool mysql_change_db(THD *thd, const LEX_STRING *new_db_name,
                      bool force_switch);
 
-void mysql_parse(THD *thd, const char *inBuf, uint length,
+void mysql_parse(THD *thd, char *rawbuf, uint length,
                  const char ** semicolon);
 
 bool mysql_test_parse_for_slave(THD *thd,char *inBuf,uint length);

sql/sql_lex.cc

@@ -109,7 +109,7 @@ st_parsing_options::reset()
 }
 
 Lex_input_stream::Lex_input_stream(THD *thd,
-                                   const char* buffer,
+                                   char* buffer,
                                    unsigned int length)
 : m_thd(thd),
   yylineno(1),
@@ -580,7 +580,7 @@ int MYSQLlex(void *arg, void *yythd)
         state=MY_LEX_COMMENT;
         break;
       }
-      yylval->lex_str.str=(char*) (lip->ptr=lip->tok_start);// Set to first chr
+      yylval->lex_str.str=lip->ptr=(char*)lip->tok_start;// Set to first chr
       yylval->lex_str.length=1;
       c=yyGet();
       if (c != ')')
@@ -946,6 +946,9 @@ int MYSQLlex(void *arg, void *yythd)
       state = MY_LEX_START;		// Try again
       break;
     case MY_LEX_LONG_COMMENT:		/* Long C comment? */
+    {
+      char *version_mark= NULL;
+
       if (yyPeek() != '*')
       {
 	state=MY_LEX_CHAR;		// Probable division
@@ -956,6 +959,8 @@ int MYSQLlex(void *arg, void *yythd)
       if (yyPeek() == '!')		// MySQL command in comment
       {
 	ulong version=MYSQL_VERSION_ID;
+        version_mark= lip->ptr;
+
 	yySkip();
 	state=MY_LEX_START;
 	if (my_isdigit(cs,yyPeek()))
@@ -964,9 +969,18 @@ int MYSQLlex(void *arg, void *yythd)
 	}
 	if (version <= MYSQL_VERSION_ID)
 	{
-	  lex->in_comment=1;
+          lex->in_comment=1;
+          version_mark= NULL;
 	  break;
 	}
+        else
+        {
+          /*
+            Patch and skip the conditional comment to avoid it
+            being propagated infinitely (eg. to a slave).
+          */
+          *version_mark= ' ';
+        }
       }
       /*
         Discard:
@@ -995,8 +1009,13 @@ int MYSQLlex(void *arg, void *yythd)
       }
       /* Unbalanced comments with a missing '*' '/' are a syntax error */
       if (! comment_closed)
+      {
+        if (version_mark != NULL)
+          *version_mark= '!';
         return (ABORT_SYM);
+      }
       break;
+    }
     case MY_LEX_END_LONG_COMMENT:
       if (lex->in_comment && yyPeek() == '/')
       {

sql/sql_lex.h

@@ -935,7 +935,7 @@ struct st_parsing_options
 class Lex_input_stream
 {
 public:
-  Lex_input_stream(THD *thd, const char* buff, unsigned int length);
+  Lex_input_stream(THD *thd, char* buff, unsigned int length);
   ~Lex_input_stream();
 
   /** Current thread. */
@@ -951,7 +951,7 @@ public:
   LEX_YYSTYPE yylval;
 
   /** Pointer to the current position in the input stream. */
-  const char* ptr;
+  char* ptr;
 
   /** Starting position of the last token parsed. */
   const char* tok_start;
@@ -966,7 +966,7 @@ public:
   const char* tok_start_prev;
 
   /** Begining of the query text in the input stream. */
-  const char* buf;
+  char* buf;
 
   /** Current state of the lexical analyser. */
   enum my_lex_states next_state;
@@ -1355,7 +1355,7 @@ public:
 class Parser_state
 {
 public:
-  Parser_state(THD *thd, const char* buff, unsigned int length)
+  Parser_state(THD *thd, char* buff, unsigned int length)
     : m_lip(thd, buff, length), m_yacc()
   {}
 

sql/sql_parse.cc

@@ -6414,13 +6414,13 @@ void mysql_init_multi_delete(LEX *lex)
 /**
   Parse a query.
   @param thd Current thread
-  @param inBuf Begining of the query text
+  @param rawbuf Begining of the query text
   @param length Length of the query text
   @param [out] semicolon For multi queries, position of the character of
   the next query in the query text.
 */
 
-void mysql_parse(THD *thd, const char *inBuf, uint length,
+void mysql_parse(THD *thd, char *rawbuf, uint length,
                  const char ** found_semicolon)
 {
   DBUG_ENTER("mysql_parse");
@@ -6446,14 +6446,14 @@ void mysql_parse(THD *thd, const char *inBuf, uint length,
   lex_start(thd);
   mysql_reset_thd_for_next_command(thd);
 
-  if (query_cache_send_result_to_client(thd, (char*) inBuf, length) <= 0)
+  if (query_cache_send_result_to_client(thd, rawbuf, length) <= 0)
   {
     LEX *lex= thd->lex;
 
     sp_cache_flush_obsolete(&thd->sp_proc_cache);
     sp_cache_flush_obsolete(&thd->sp_func_cache);
 
-    Parser_state parser_state(thd, inBuf, length);
+    Parser_state parser_state(thd, rawbuf, length);
     thd->m_parser_state= &parser_state;
 
     int err= MYSQLparse(thd);
@@ -6538,13 +6538,13 @@ void mysql_parse(THD *thd, const char *inBuf, uint length,
     1	can be ignored
 */
 
-bool mysql_test_parse_for_slave(THD *thd, char *inBuf, uint length)
+bool mysql_test_parse_for_slave(THD *thd, char *rawbuf, uint length)
 {
   LEX *lex= thd->lex;
   bool error= 0;
   DBUG_ENTER("mysql_test_parse_for_slave");
 
-  Parser_state parser_state(thd, inBuf, length);
+  Parser_state parser_state(thd, rawbuf, length);
   thd->m_parser_state= &parser_state;
 
   lex_start(thd);