Bug #53371: COM_FIELD_LIST can be abused to bypass table level grants.

This is the 5.1 merge and extension of the fix.
The server was happily accepting paths in table name in all places a table
name is accepted (e.g. a SELECT). This allowed all users that have some 
privilege over some database to read all tables in all databases in all
mysql server instances that the server file system has access to.
Fixed by :
1. making sure no path elements are allowed in quoted table name when
constructing the path (note that the path symbols are still valid in table names
when they're properly escaped by the server).
2. checking the #mysql50# prefixed names the same way they're checked for
path elements in mysql-5.0.

1 files changed, 8 insertions, 1 deletions

diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index 11481933c8a..93d80164ffb 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -1310,6 +1310,13 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
     }
     thd->convert_string(&conv_name, system_charset_info,
 			packet, arg_length, thd->charset());
+    if (check_table_name(conv_name.str, conv_name.length, FALSE))
+    {
+      /* this is OK due to convert_string() null-terminating the string */
+      my_error(ER_WRONG_TABLE_NAME, MYF(0), conv_name.str);
+      break;
+    }
+
     table_list.alias= table_list.table_name= conv_name.str;
     packet= arg_end + 1;
 
@@ -6233,7 +6240,7 @@ TABLE_LIST *st_select_lex::add_table_to_list(THD *thd,
     DBUG_RETURN(0);				// End of memory
   alias_str= alias ? alias->str : table->table.str;
   if (!test(table_options & TL_OPTION_ALIAS) && 
-      check_table_name(table->table.str, table->table.length))
+      check_table_name(table->table.str, table->table.length, FALSE))
   {
     my_error(ER_WRONG_TABLE_NAME, MYF(0), table->table.str);
     DBUG_RETURN(0);