MDEV-4307 Support at least 48 utf8 characters in username in server and PAM

Extend plugin auth api to support up to 512 bytes in the user names.
Use the API versioning to support old auth plugins too!

3 files changed, 84 insertions, 4 deletions

diff --git a/sql/sql_acl.cc b/sql/sql_acl.cc
index 04d797b3ba1..d1cdf35bb5a 100644
--- a/sql/sql_acl.cc
+++ b/sql/sql_acl.cc
@@ -52,6 +52,8 @@
 #include "sql_db.h"
 #include "sql_array.h"
 
+#include "sql_plugin_compat.h"
+
 bool mysql_user_table_is_in_short_password_format= false;
 
 static const
@@ -9027,7 +9029,20 @@ static int do_auth_once(THD *thd, const LEX_STRING *auth_plugin_name,
   if (plugin)
   {
     st_mysql_auth *auth= (st_mysql_auth *) plugin_decl(plugin)->info;
-    res= auth->authenticate_user(mpvio, &mpvio->auth_info);
+    switch (auth->interface_version) {
+    case 0x0200:
+      res= auth->authenticate_user(mpvio, &mpvio->auth_info);
+      break;
+    case 0x0100:
+      {
+        MYSQL_SERVER_AUTH_INFO_0x0100 compat;
+        compat.downgrade(&mpvio->auth_info);
+        res= auth->authenticate_user(mpvio, (MYSQL_SERVER_AUTH_INFO *)&compat);
+        compat.upgrade(&mpvio->auth_info);
+      }
+      break;
+    default: DBUG_ASSERT(0);
+    }
 
     if (unlock_plugin)
       plugin_unlock(thd, plugin);
@@ -9078,8 +9093,6 @@ bool acl_authenticate(THD *thd, uint connect_errors,
                                                              : COM_CONNECT;
   DBUG_ENTER("acl_authenticate");
 
-  compile_time_assert(MYSQL_USERNAME_LENGTH == USERNAME_LENGTH);
-
   bzero(&mpvio, sizeof(mpvio));
   mpvio.read_packet= server_mpvio_read_packet;
   mpvio.write_packet= server_mpvio_write_packet;
diff --git a/sql/sql_plugin.cc b/sql/sql_plugin.cc
index bf3537c0ed9..f540431b4e9 100644
--- a/sql/sql_plugin.cc
+++ b/sql/sql_plugin.cc
@@ -35,6 +35,8 @@
 #include <mysql/plugin_auth.h>
 #include "lock.h"                               // MYSQL_LOCK_IGNORE_TIMEOUT
 #include <mysql/plugin_auth.h>
+#include "sql_plugin_compat.h"
+
 #define REPORT_TO_LOG  1
 #define REPORT_TO_USER 2
 
@@ -135,7 +137,7 @@ static int min_plugin_info_interface_version[MYSQL_MAX_PLUGIN_TYPE_NUM]=
   MYSQL_INFORMATION_SCHEMA_INTERFACE_VERSION,
   MYSQL_AUDIT_INTERFACE_VERSION,
   MYSQL_REPLICATION_INTERFACE_VERSION,
-  MYSQL_AUTHENTICATION_INTERFACE_VERSION
+  MIN_AUTHENTICATION_INTERFACE_VERSION
 };
 static int cur_plugin_info_interface_version[MYSQL_MAX_PLUGIN_TYPE_NUM]=
 {
diff --git a/sql/sql_plugin_compat.h b/sql/sql_plugin_compat.h
new file mode 100644
index 00000000000..8c6014f8dc6
--- /dev/null
+++ b/sql/sql_plugin_compat.h
@@ -0,0 +1,65 @@
+/* Copyright (C) 2013 Sergei Golubchik and Monty Program Ab
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
+
+/* old plugin api structures, used for backward compatibility */
+
+#define upgrade_var(X) latest->X= X
+#define upgrade_str(X) strmake(latest->X, X, sizeof(X))
+#define downgrade_var(X) X= latest->X
+#define downgrade_str(X) strmake(X, latest->X, sizeof(X)-1)
+
+/**************************************************************/
+/* Authentication API, version 0x0100 *************************/
+#define MIN_AUTHENTICATION_INTERFACE_VERSION 0x0100
+
+struct MYSQL_SERVER_AUTH_INFO_0x0100 {
+  char *user_name;
+  unsigned int user_name_length;
+  const char *auth_string;
+  unsigned long auth_string_length;
+  char authenticated_as[49]; 
+  char external_user[512];
+  int  password_used;
+  const char *host_or_ip;
+  unsigned int host_or_ip_length;
+
+  void upgrade(MYSQL_SERVER_AUTH_INFO *latest)
+  {
+    upgrade_var(user_name);
+    upgrade_var(user_name_length);
+    upgrade_var(auth_string);
+    upgrade_var(auth_string_length);
+    upgrade_str(authenticated_as);
+    upgrade_str(external_user);
+    upgrade_var(password_used);
+    upgrade_var(host_or_ip);
+    upgrade_var(host_or_ip_length);
+  }
+  void downgrade(MYSQL_SERVER_AUTH_INFO *latest)
+  {
+    downgrade_var(user_name);
+    downgrade_var(user_name_length);
+    downgrade_var(auth_string);
+    downgrade_var(auth_string_length);
+    downgrade_str(authenticated_as);
+    downgrade_str(external_user);
+    downgrade_var(password_used);
+    downgrade_var(host_or_ip);
+    downgrade_var(host_or_ip_length);
+  }
+};
+
+/**************************************************************/
+