Better handle bad db_metadata value

Summary:
There is implicit require for db_metadata: it should be a json object , such as "{"shard": "<shard_name>", "rs": "<replicaset_id>"}"

If The db_metadata value is a json array, such as "[{"shard": "<shard_name>", "rs": "<replicaset_id>"}]", rapidjson will SIGSEGV when treating a json array as a json object and accessing members in the "object".

add checks to verify the db_metadata is a json object.

Reviewed By: abhinav04sharma, zhichengzhu

Differential Revision: D16569064

fbshipit-source-id: 61c3761

mysql-test/r/db_metadata.result

@@ -7,6 +7,10 @@ drop database if exists test7;
 drop database if exists test8;
 drop database if exists test9;
 drop database if exists test10;
+drop database if exists test11;
+drop database if exists test12;
+drop database if exists test13;
+drop database if exists test14;
 create database test2;
 show create database test2;
 Database	Create Database
@@ -157,7 +161,7 @@ def	test7	{"shard":"test7_shard"}
 def	test8	
 def	test9	{"shard":"test9_shard"}
 create database test10 db_metadata = "invalid_json";
-ERROR HY000: Invalid JSON for DB_METADATA attribute: invalid_json.
+ERROR HY000: Invalid JSON object for DB_METADATA attribute: invalid_json.
 select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 catalog_name	schema_name	db_metadata
 def	information_schema	
@@ -174,7 +178,7 @@ def	test7	{"shard":"test7_shard"}
 def	test8	
 def	test9	{"shard":"test9_shard"}
 create database test11 db_metadata = "{\'shard\':\'test11_shard\'}";
-ERROR HY000: Invalid JSON for DB_METADATA attribute: {'shard':'test11_shard'}.
+ERROR HY000: Invalid JSON object for DB_METADATA attribute: {'shard':'test11_shard'}.
 select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 catalog_name	schema_name	db_metadata
 def	information_schema	
@@ -216,6 +220,25 @@ CREATE DATABASE `test13` /*!40100 DEFAULT CHARACTER SET latin1 DB_METADATA '{"sh
 show create database test13;
 Database	Create Database
 test13	CREATE DATABASE `test13` /*!40100 DEFAULT CHARACTER SET latin1 DB_METADATA '{"sha''\\"rd":"test13''_sh\\"ard"}' */
+create database test14 db_metadata = "[{\"shard\":\"test14_shard\", \"data\":\"1234\"}]";
+ERROR HY000: Invalid JSON object for DB_METADATA attribute: [{"shard":"test14_shard", "data":"1234"}].
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
+catalog_name	schema_name	db_metadata
+def	information_schema	
+def	mtr	
+def	mysql	
+def	performance_schema	
+def	test	
+def	test12	{"sha'rd":"test12\"_shard"}
+def	test13	{"sha'\"rd":"test13'_sh\"ard"}
+def	test2	
+def	test3	
+def	test4	
+def	test5	{"shard":"test5_shard"}
+def	test6	{"shard":"test6_shard"}
+def	test7	{"shard":"test7_shard"}
+def	test8	
+def	test9	{"shard":"test9_shard"}
 alter database test3 character set ascii;
 show create database test3;
 Database	Create Database
@@ -543,7 +566,7 @@ def	test7	{"shard":"test7_shard_altered"}
 def	test8	
 def	test9	{"shard":"test9_shard_altered"}
 alter database test9 db_metadata = "invalid_json";
-ERROR HY000: Invalid JSON for DB_METADATA attribute: invalid_json.
+ERROR HY000: Invalid JSON object for DB_METADATA attribute: invalid_json.
 select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
 catalog_name	schema_name	db_metadata
 def	information_schema	
@@ -611,6 +634,26 @@ default-character-set=latin1
 default-collation=latin1_swedish_ci
 db-read-only=0
 db-metadata={"shard":"test10_shard_altered"}
+alter database test10 db_metadata = "[{\"shard\":\"test10_shard\", \"data\":\"1234\"}]";
+ERROR HY000: Invalid JSON object for DB_METADATA attribute: [{"shard":"test10_shard", "data":"1234"}].
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
+catalog_name	schema_name	db_metadata
+def	information_schema	
+def	mtr	
+def	mysql	
+def	performance_schema	
+def	test	
+def	test10	{"shard":"test10_shard_altered"}
+def	test12	{"sha'rd":"test12\"_shard"}
+def	test13	{"sha'\"rd":"test13'_sh\"ard"}
+def	test2	
+def	test3	{"shard":"test3_shard_altered"}
+def	test4	{"shard":"test4_shard_altered"}
+def	test5	{"shard":"Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Really long shard name. Fin"}
+def	test6	{"shard":"test6_shard_altered"}
+def	test7	{"shard":"test7_shard_altered"}
+def	test8	
+def	test9	{"shard":"test9_shard_altered"}
 drop database if exists test2;
 drop database if exists test3;
 drop database if exists test4;
@@ -623,3 +666,4 @@ drop database if exists test10;
 drop database if exists test11;
 drop database if exists test12;
 drop database if exists test13;
+drop database if exists test14;

mysql-test/r/db_metadata_reset.result

@@ -68,8 +68,51 @@ test4	CREATE DATABASE `test4` /*!40100 DEFAULT CHARACTER SET latin1 */
 show create database test6;
 Database	Create Database
 test6	CREATE DATABASE `test6` /*!40100 DEFAULT CHARACTER SET latin1 */
+create database test7 db_metadata = "{\"shard\":\"test7_shard\"}";
+show create database test7;
+Database	Create Database
+test7	CREATE DATABASE `test7` /*!40100 DEFAULT CHARACTER SET latin1 DB_METADATA '{"shard":"test7_shard"}' */
+set @start_binlog_trx_meta_data= @@global.binlog_trx_meta_data;
+set @start_log_warnings = @@global.log_warnings;
+set @@global.binlog_trx_meta_data= 1;
+set @@global.log_warnings= 2;
+select catalog_name, schema_name, default_character_set_name, default_collation_name, sql_path from information_schema.schemata;
+catalog_name	schema_name	default_character_set_name	default_collation_name	sql_path
+def	information_schema	utf8	utf8_general_ci	NULL
+def	mtr	latin1	latin1_swedish_ci	NULL
+def	mysql	latin1	latin1_swedish_ci	NULL
+def	performance_schema	utf8	utf8_general_ci	NULL
+def	test	latin1	latin1_swedish_ci	NULL
+def	test2	latin1	latin1_swedish_ci	NULL
+def	test3	utf8	utf8_general_ci	NULL
+def	test4	latin1	latin1_swedish_ci	NULL
+def	test5	utf16	utf16_general_ci	NULL
+def	test6	latin1	latin1_swedish_ci	NULL
+def	test7	latin1	latin1_swedish_ci	NULL
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
+catalog_name	schema_name	db_metadata
+def	information_schema	
+def	mtr	
+def	mysql	
+def	performance_schema	
+def	test	
+def	test2	
+def	test3	{"shard":"test3_shard"}
+def	test4	
+def	test5	{"shard":"test5_shard"}
+def	test6	
+def	test7	[{"shard": "test3_shard", "data2": "date2_shard"}]
+show create database test7;
+Database	Create Database
+test7	CREATE DATABASE `test7` /*!40100 DEFAULT CHARACTER SET latin1 DB_METADATA '[{"shard": "test3_shard", "data2": "date2_shard"}]' */
+use test7;
+create table t7 (a int, b int, primary key(a,b));
+drop table t7;
+set @@global.binlog_trx_meta_data = @start_binlog_trx_meta_data;
+set @@global.log_warnings = @start_log_warnings;
 drop database if exists test2;
 drop database if exists test3;
 drop database if exists test4;
 drop database if exists test5;
 drop database if exists test6;
+drop database if exists test7;

mysql-test/t/db_metadata.test

@@ -12,6 +12,10 @@ drop database if exists test7;
 drop database if exists test8;
 drop database if exists test9;
 drop database if exists test10;
+drop database if exists test11;
+drop database if exists test12;
+drop database if exists test13;
+drop database if exists test14;
 --enable_warnings
 
 --disable_query_log
@@ -104,6 +108,11 @@ drop database test13;
 eval $db_create;
 show create database test13;
 
+# create database with JSON array 
+--error ER_DB_METADATA_INVALID_JSON
+create database test14 db_metadata = "[{\"shard\":\"test14_shard\", \"data\":\"1234\"}]";
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
+
 # alter database tests
 
 # alter database character set
@@ -235,6 +244,11 @@ alter database test10 read_only = false;
 show create database test10;
 --exec cat $MYSQLD_DATADIR/test10/db.opt
 
+# alter database with JSON array 
+--error ER_DB_METADATA_INVALID_JSON
+alter database test10 db_metadata = "[{\"shard\":\"test10_shard\", \"data\":\"1234\"}]";
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
+
 # cleanup
 --disable_warnings
 drop database if exists test2;
@@ -249,4 +263,5 @@ drop database if exists test10;
 drop database if exists test11;
 drop database if exists test12;
 drop database if exists test13;
+drop database if exists test14;
 --enable_warnings

mysql-test/t/db_metadata_reset.test

@@ -1,5 +1,6 @@
 # Test per-database database-metadata attribute
 --source include/have_innodb.inc
+--source include/have_log_bin.inc
 connection default;
 
 --disable_query_log
@@ -51,11 +52,44 @@ select catalog_name, schema_name, db_metadata from information_schema.schemata_e
 show create database test4;
 show create database test6;
 
+# create database with db_metadatae
+create database test7 db_metadata = "{\"shard\":\"test7_shard\"}";
+show create database test7;
+# modify database with bad db_metadatae
+# db_metadata should be a json object, but now we modify it with json array
+--exec echo "db-metadata=[{\"shard\": \"test3_shard\", \"data2\": \"date2_shard\"}]" > $MYSQLD_DATADIR/test7/db.opt
+
+# Restart server to get rid of the dboptions cache
+--source include/restart_mysqld.inc
+set @start_binlog_trx_meta_data= @@global.binlog_trx_meta_data;
+set @start_log_warnings = @@global.log_warnings;
+
+# show db_metadata
+set @@global.binlog_trx_meta_data= 1;
+set @@global.log_warnings= 2;
+select catalog_name, schema_name, default_character_set_name, default_collation_name, sql_path from information_schema.schemata;
+select catalog_name, schema_name, db_metadata from information_schema.schemata_ext;
+show create database test7;
+
+# suppress error during THD::gen_trx_metadata
+--disable_query_log
+call mtr.add_suppression("Exception while adding meta data");
+call mtr.add_suppression("Exception while reading meta data: \\[\\{\"shard\": \"test3_shard\", \"data2\": \"date2_shard\"\\}\\]");
+--enable_query_log
+
+# bad db-metadata won't crash mysqld or trigger assert
+use test7;
+create table t7 (a int, b int, primary key(a,b));
+drop table t7;
+set @@global.binlog_trx_meta_data = @start_binlog_trx_meta_data;
+set @@global.log_warnings = @start_log_warnings;
+
 # cleanup
 --disable_warnings
 drop database if exists test2;
 drop database if exists test3;
 drop database if exists test4;
 drop database if exists test5;
 drop database if exists test6;
+drop database if exists test7;
 --enable_warnings

sql/binlog.cc

@@ -8718,6 +8718,14 @@ std::string THD::gen_trx_metadata()
   std::string json = buf.GetString();
   boost::trim(json);
 
+  // verify doc json document
+  if (!doc.IsObject())
+  {
+      // NO_LINT_DEBUG
+      sql_print_error("Bad JSON format after adding meta data: %s",
+                      json.c_str());
+      DBUG_RETURN("");
+  }
   std::string comment_str= std::string("/*")
                            .append(TRX_META_DATA_HEADER)
                            .append(json)
@@ -8772,7 +8780,11 @@ bool THD::add_db_metadata(rapidjson::Document &meta_data_root)
   if (!local_db_metadata.empty())
   {
     rapidjson::Document db_metadata_root;
-    if (db_metadata_root.Parse(local_db_metadata.c_str()).HasParseError())
+    // rapidjson doesn't like calling GetObject() on json non-object value
+    // The local_db_metadata format should similar to the following example:
+    // {"shard":"<shard_name>", "replicaset":"<replicaset_id>"}
+    if (db_metadata_root.Parse(local_db_metadata.c_str()).HasParseError() ||
+        !db_metadata_root.IsObject())
     {
       // NO_LINT_DEBUG
       sql_print_error("Exception while reading meta data: %s",

sql/share/errmsg-utf8.txt

@@ -7336,7 +7336,7 @@ ER_DB_METADATA_TOO_LONG
   eng "Metadata for the database is too long. Max length is %d bytes"
 
 ER_DB_METADATA_INVALID_JSON
-  eng "Invalid JSON for DB_METADATA attribute: %s."
+  eng "Invalid JSON object for DB_METADATA attribute: %s."
 
 ER_DB_METADATA_READ_ERROR
   eng "Error reading db metadata option: '%-.64s'"

sql/sql_class.cc

@@ -5794,7 +5794,10 @@ static std::string get_shard_id(const std::string& db_metadata)
   try {
 #ifdef HAVE_RAPIDJSON
     rapidjson::Document db_metadata_root;
-    if (db_metadata_root.Parse(db_metadata.c_str()).HasParseError()) {
+    // The local_db_metadata format should be:
+    // {"shard":"<shard_name>", "replicaset":"<replicaset_id>"}
+    if (db_metadata_root.Parse(db_metadata.c_str()).HasParseError() ||
+        !db_metadata_root.IsObject()) {
       return {};
     }
     const auto iter= db_metadata_root.FindMember("shard");

sql/sql_yacc.yy

@@ -6586,7 +6586,8 @@ db_metadata_str:
             {
               #ifdef HAVE_RAPIDJSON
               rapidjson::Document db_metadata_root;
-              if (db_metadata_root.Parse($3.str).HasParseError())
+              if (db_metadata_root.Parse($3.str).HasParseError() ||
+                  !db_metadata_root.IsObject())
               {
                 my_error(ER_DB_METADATA_INVALID_JSON, MYF(0), $3.str);
                 MYSQL_YYABORT;