Manual merge from mysql-5.1 for Bug#11764168 (56976: Severe denial

of service in prepared statements).

sql/sql_prepare.cc:
  At mysql_stmt_get_longdata(): instead of pushing an internal
  error handler (as done in 5.1-tree) we save, set and restore
  the statement's diagnostics area and warning info.

6 files changed, 49 insertions, 0 deletions

diff --git a/mysql-test/r/mysqld--help-notwin.result b/mysql-test/r/mysqld--help-notwin.result
index 6659a291e0b..b4faa833c1b 100644
--- a/mysql-test/r/mysqld--help-notwin.result
+++ b/mysql-test/r/mysqld--help-notwin.result
@@ -309,6 +309,10 @@ The following options may be given as the first argument:
  max_join_size records return an error
  --max-length-for-sort-data=# 
  Max number of bytes in sorted records
+ --max-long-data-size=# 
+ The maximum BLOB length to send to server from
+ mysql_send_long_data API. Deprecated option; use
+ max_allowed_packet instead.
  --max-prepared-stmt-count=# 
  Maximum number of prepared statements in the server
  --max-relay-log-size=# 
@@ -830,6 +834,7 @@ max-error-count 64
 max-heap-table-size 16777216
 max-join-size 18446744073709551615
 max-length-for-sort-data 1024
+max-long-data-size 1048576
 max-prepared-stmt-count 16382
 max-relay-log-size 0
 max-seeks-for-key 18446744073709551615
diff --git a/mysql-test/r/mysqld--help-win.result b/mysql-test/r/mysqld--help-win.result
index 240c29294e2..361d30620f7 100644
--- a/mysql-test/r/mysqld--help-win.result
+++ b/mysql-test/r/mysqld--help-win.result
@@ -308,6 +308,10 @@ The following options may be given as the first argument:
  max_join_size records return an error
  --max-length-for-sort-data=# 
  Max number of bytes in sorted records
+ --max-long-data-size=# 
+ The maximum BLOB length to send to server from
+ mysql_send_long_data API. Deprecated option; use
+ max_allowed_packet instead.
  --max-prepared-stmt-count=# 
  Maximum number of prepared statements in the server
  --max-relay-log-size=# 
@@ -833,6 +837,7 @@ max-error-count 64
 max-heap-table-size 16777216
 max-join-size 18446744073709551615
 max-length-for-sort-data 1024
+max-long-data-size 1048576
 max-prepared-stmt-count 16382
 max-relay-log-size 0
 max-seeks-for-key 18446744073709551615
diff --git a/mysql-test/r/variables.result b/mysql-test/r/variables.result
index 5d6caf21182..96db86262c2 100644
--- a/mysql-test/r/variables.result
+++ b/mysql-test/r/variables.result
@@ -1540,6 +1540,9 @@ ERROR HY000: Cannot drop default keycache
 SET @@global.key_cache_block_size=0;
 Warnings:
 Warning	1292	Truncated incorrect key_cache_block_size value: '0'
+select @@max_long_data_size;
+@@max_long_data_size
+1048576
 SET @@global.max_binlog_cache_size=DEFAULT;
 SET @@global.max_join_size=DEFAULT;
 SET @@global.key_buffer_size=@kbs;
diff --git a/mysql-test/suite/sys_vars/r/max_long_data_size_basic.result b/mysql-test/suite/sys_vars/r/max_long_data_size_basic.result
new file mode 100644
index 00000000000..679a0d3611f
--- /dev/null
+++ b/mysql-test/suite/sys_vars/r/max_long_data_size_basic.result
@@ -0,0 +1,14 @@
+select @@global.max_long_data_size=20;
+@@global.max_long_data_size=20
+0
+select @@session.max_long_data_size;
+ERROR HY000: Variable 'max_long_data_size' is a GLOBAL variable
+SELECT @@global.max_long_data_size = VARIABLE_VALUE
+FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES
+WHERE VARIABLE_NAME='max_long_data_size';
+@@global.max_long_data_size = VARIABLE_VALUE
+1
+set global max_long_data_size=1;
+ERROR HY000: Variable 'max_long_data_size' is a read only variable
+set session max_long_data_size=1;
+ERROR HY000: Variable 'max_long_data_size' is a read only variable
diff --git a/mysql-test/suite/sys_vars/t/max_long_data_size_basic.test b/mysql-test/suite/sys_vars/t/max_long_data_size_basic.test
new file mode 100644
index 00000000000..eefa61bd4b7
--- /dev/null
+++ b/mysql-test/suite/sys_vars/t/max_long_data_size_basic.test
@@ -0,0 +1,17 @@
+select @@global.max_long_data_size=20;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+select @@session.max_long_data_size;
+
+# Show that value of the variable matches the value in the GLOBAL I_S table
+SELECT @@global.max_long_data_size = VARIABLE_VALUE
+FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES
+WHERE VARIABLE_NAME='max_long_data_size';
+
+#
+# show that it's read-only
+#
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+set global max_long_data_size=1;
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+set session max_long_data_size=1;
+
diff --git a/mysql-test/t/variables.test b/mysql-test/t/variables.test
index 2b20bbdc13b..173f8aeaa58 100644
--- a/mysql-test/t/variables.test
+++ b/mysql-test/t/variables.test
@@ -1281,6 +1281,11 @@ SET @@global.max_join_size=0;
 SET @@global.key_buffer_size=0;
 SET @@global.key_cache_block_size=0;
 
+#
+# Bug#56976: added new start-up parameter
+#
+select @@max_long_data_size;
+
 # cleanup
 SET @@global.max_binlog_cache_size=DEFAULT;
 SET @@global.max_join_size=DEFAULT;