Bug#20543 select on information_schema strange warnings, view, different schemas/users

The fix is: if user has privileges to view fields and user has any
(insert,select,delete,update) privileges on underlying view 
then 'show fields' and select from I_S.COLUMNS table are sucsessful.


mysql-test/r/information_schema_db.result:
  Bug#20543 select on information_schema strange warnings, view, different schemas/users
  test result
mysql-test/t/information_schema_db.test:
  Bug#20543 select on information_schema strange warnings, view, different schemas/users
  test case
sql/sql_acl.cc:
  Bug#20543 select on information_schema strange warnings, view, different schemas/users
  checked that user has privileges on underlying view and if it's true
  set allowed_show to true for top view.
sql/sql_show.cc:
  Bug#20543 select on information_schema strange warnings, view, different schemas/users
  removed unnecessary rights check.'tables->allowed_show' check is used instead
sql/sql_view.cc:
  Bug#20543 select on information_schema strange warnings, view, different schemas/users
  skip the check of SHOW_VIEW_ACL privilege on underlying view. It is done later during
  execution of find_field_in_table_ref function.
sql/table.h:
  Bug#20543 select on information_schema strange warnings, view, different schemas/users
  'allowed_show' is set during rights check for view. If true then user has privileges 
  for 'show create view', etc

4 files changed, 25 insertions, 21 deletions

diff --git a/sql/sql_acl.cc b/sql/sql_acl.cc
index ae5ea210a47..6e25878671d 100644
--- a/sql/sql_acl.cc
+++ b/sql/sql_acl.cc
@@ -3787,9 +3787,24 @@ bool check_column_grant_in_table_ref(THD *thd, TABLE_LIST * table_ref,
   if (table_ref->view || table_ref->field_translation)
   {
     /* View or derived information schema table. */
+    ulong view_privs;
     grant= &(table_ref->grant);
     db_name= table_ref->view_db.str;
     table_name= table_ref->view_name.str;
+    if (table_ref->belong_to_view && 
+        (thd->lex->sql_command == SQLCOM_SHOW_FIELDS ||
+         thd->lex->sql_command == SQLCOM_SHOW_CREATE))
+    {
+      view_privs= get_column_grant(thd, grant, db_name, table_name, name);
+      if (view_privs & VIEW_ANY_ACL)
+      {
+        table_ref->belong_to_view->allowed_show= TRUE;
+        return FALSE;
+      }
+      table_ref->belong_to_view->allowed_show= FALSE;
+      my_message(ER_VIEW_NO_EXPLAIN, ER(ER_VIEW_NO_EXPLAIN), MYF(0));
+      return TRUE;
+    }
   }
   else
   {
diff --git a/sql/sql_show.cc b/sql/sql_show.cc
index cabb04c5f16..6e78596d679 100644
--- a/sql/sql_show.cc
+++ b/sql/sql_show.cc
@@ -3110,31 +3110,18 @@ static int get_schema_views_record(THD *thd, struct st_table_list *tables,
   if (tables->view)
   {
     Security_context *sctx= thd->security_ctx;
-    ulong grant= SHOW_VIEW_ACL;
-#ifndef NO_EMBEDDED_ACCESS_CHECKS
-    char *save_table_name= tables->table_name;
-    if (!my_strcasecmp(system_charset_info, tables->definer.user.str,
-                       sctx->priv_user) &&
-        !my_strcasecmp(system_charset_info, tables->definer.host.str,
-                       sctx->priv_host))
-      grant= SHOW_VIEW_ACL;
-    else
+    if (!tables->allowed_show)
     {
-      tables->table_name= tables->view_name.str;
-      if (check_access(thd, SHOW_VIEW_ACL , base_name,
-                       &tables->grant.privilege, 0, 1,
-                       test(tables->schema_table)))
-        grant= get_table_grant(thd, tables);
-      else
-        grant= tables->grant.privilege;
+      if (!my_strcasecmp(system_charset_info, tables->definer.user.str,
+                         sctx->priv_user) &&
+          !my_strcasecmp(system_charset_info, tables->definer.host.str,
+                         sctx->priv_host))
+        tables->allowed_show= TRUE;
     }
-    tables->table_name= save_table_name;
-#endif
-
     restore_record(table, s->default_values);
     table->field[1]->store(tables->view_db.str, tables->view_db.length, cs);
     table->field[2]->store(tables->view_name.str, tables->view_name.length, cs);
-    if (grant & SHOW_VIEW_ACL)
+    if (tables->allowed_show)
     {
       char buff[2048];
       String qwe_str(buff, sizeof(buff), cs);
diff --git a/sql/sql_view.cc b/sql/sql_view.cc
index 1561ade78af..90a6cba53f4 100644
--- a/sql/sql_view.cc
+++ b/sql/sql_view.cc
@@ -934,7 +934,8 @@ bool mysql_make_view(THD *thd, File_parser *parser, TABLE_LIST *table)
       }
     }
     else if (!table->prelocking_placeholder &&
-             old_lex->sql_command == SQLCOM_SHOW_CREATE)
+             old_lex->sql_command == SQLCOM_SHOW_CREATE &&
+             !table->belong_to_view)
     {
       if (check_table_access(thd, SHOW_VIEW_ACL, table, 0))
         goto err;
diff --git a/sql/table.h b/sql/table.h
index eb34867c390..41ab7e7bec8 100644
--- a/sql/table.h
+++ b/sql/table.h
@@ -569,6 +569,7 @@ typedef struct st_table_list
     tables. Unlike 'next_local', this in this list views are *not*
     leaves. Created in setup_tables() -> make_leaves_list().
   */
+  bool allowed_show;
   st_table_list	*next_leaf;
   Item          *where;                 /* VIEW WHERE clause condition */
   Item          *check_option;          /* WITH CHECK OPTION condition */