From bab4ff1ae52762e5eeb828d89cc7cd3b6e94f3aa Mon Sep 17 00:00:00 2001
From: Davi Arnaut <Davi.Arnaut@Sun.COM>
Date: Mon, 9 Feb 2009 16:17:58 -0200
Subject: [PATCH] Bug#42634: % character in query can cause mysqld signal 11
 segfault

The problem is that a unfiltered user query was being passed as
the format string parameter of sql_print_warning which later
performs printf-like formatting, leading to crashes if the user
query contains formatting instructions (ie: %s). Also, it was
using THD::query as the source of the user query, but this
variable is not meaningful in some situations -- in a delayed
insert, it points to the table name.

The solution is to pass the user query as a parameter for the
format string and use the function parameter query_arg as the
source of the user query.

mysql-test/suite/binlog/r/binlog_unsafe.result:
  Add test case result for Bug#42634
mysql-test/suite/binlog/t/binlog_unsafe.test:
  Add test case for Bug#42634
sql/sql_class.cc:
  Don't pass the user query as a format string.
---
 mysql-test/suite/binlog/r/binlog_unsafe.result |  7 +++++++
 mysql-test/suite/binlog/t/binlog_unsafe.test   | 14 ++++++++++++++
 sql/sql_class.cc                               |  8 +++-----
 3 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/mysql-test/suite/binlog/r/binlog_unsafe.result b/mysql-test/suite/binlog/r/binlog_unsafe.result
index 1f7b217dc31..7c0980ba77c 100644
--- a/mysql-test/suite/binlog/r/binlog_unsafe.result
+++ b/mysql-test/suite/binlog/r/binlog_unsafe.result
@@ -220,3 +220,10 @@ Warning	1592	Statement is not safe to log in statement format.
 Warning	1592	Statement is not safe to log in statement format.
 DROP PROCEDURE p1;
 DROP TABLE t1;
+DROP TABLE IF EXISTS t1;
+CREATE TABLE t1 (a VARCHAR(100), b VARCHAR(100));
+INSERT INTO t1 VALUES ('a','b');
+UPDATE t1 SET b = '%s%s%s%s%s%s%s%s%s%s%s%s%s%s' WHERE a = 'a' LIMIT 1;
+Warnings:
+Warning	1592	Statement is not safe to log in statement format.
+DROP TABLE t1;
diff --git a/mysql-test/suite/binlog/t/binlog_unsafe.test b/mysql-test/suite/binlog/t/binlog_unsafe.test
index 0d7059bc31f..f58233d4fef 100644
--- a/mysql-test/suite/binlog/t/binlog_unsafe.test
+++ b/mysql-test/suite/binlog/t/binlog_unsafe.test
@@ -257,3 +257,17 @@ delimiter ;|
 CALL p1();
 DROP PROCEDURE p1;
 DROP TABLE t1;
+
+#
+# Bug#42634: % character in query can cause mysqld signal 11 segfault
+#
+
+--disable_warnings
+DROP TABLE IF EXISTS t1;
+--enable_warnings
+
+CREATE TABLE t1 (a VARCHAR(100), b VARCHAR(100));
+INSERT INTO t1 VALUES ('a','b');
+UPDATE t1 SET b = '%s%s%s%s%s%s%s%s%s%s%s%s%s%s' WHERE a = 'a' LIMIT 1;
+DROP TABLE t1;
+
diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index 06f1c644be0..118dc5af68f 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -3660,16 +3660,14 @@ int THD::binlog_query(THD::enum_binlog_query_type qtype, char const *query_arg,
   if (lex->is_stmt_unsafe() &&
       variables.binlog_format == BINLOG_FORMAT_STMT)
   {
-    DBUG_ASSERT(this->query != NULL);
     push_warning(this, MYSQL_ERROR::WARN_LEVEL_WARN,
                  ER_BINLOG_UNSAFE_STATEMENT,
                  ER(ER_BINLOG_UNSAFE_STATEMENT));
     if (!(binlog_flags & BINLOG_FLAG_UNSAFE_STMT_PRINTED))
     {
-      char warn_buf[MYSQL_ERRMSG_SIZE];
-      my_snprintf(warn_buf, MYSQL_ERRMSG_SIZE, "%s Statement: %s",
-                  ER(ER_BINLOG_UNSAFE_STATEMENT), this->query);
-      sql_print_warning(warn_buf);
+      sql_print_warning("%s Statement: %.*s",
+                        ER(ER_BINLOG_UNSAFE_STATEMENT),
+                        MYSQL_ERRMSG_SIZE, query_arg);
       binlog_flags|= BINLOG_FLAG_UNSAFE_STMT_PRINTED;
     }
   }