BUG# 9148: Denial of service

The problem was that on Windows the access method indicates that access to file 
such as "com1" and "lpt1" is allowed (since they are device names) and
this causes mysql to attempt to open them as databases or tables.

The fix was to write our own my_access method that uses other Win32 functions
to determine if the given argument is indeed a file and has to requested
mode.

VC++Files/mysys/mysys.dsp

@@ -186,6 +186,11 @@ SOURCE=.\array.c
 !ENDIF
 
 # End Source File
+ 
+# Begin Source File
+SOURCE=".\my_access.c"
+# End Source File
+ 
 # Begin Source File
 
 SOURCE=".\charset-def.c"

VC++Files/mysys/mysys_ia64.dsp

@@ -163,6 +163,13 @@ LIB32=link.exe -lib
 # Name "mysys - WinIA64 Max"
 # Name "mysys - WinIA64 TLS_DEBUG"
 # Name "mysys - WinIA64 TLS"
+
+# Begin Source File
+
+SOURCE=.\my_access.c
+
+# End Source File
+ 
 # Begin Source File
 
 SOURCE=.\array.c

include/my_sys.h

@@ -573,6 +573,11 @@ extern char *_my_strdup_with_length(const byte *from, uint length,
 				    const char *sFile, uint uLine,
 				    myf MyFlag);
 
+#ifdef __WIN__
+extern int my_access(const char *path, int amode);
+#else
+#define my_access access
+#endif
 
 #ifndef TERMINATE
 extern void TERMINATE(FILE *file);

mysql-test/r/reserved_win_names.require

+Variable_name	Value
+lower_case_table_names 1	

mysql-test/r/reserved_win_names.result

+use COM1;
+ERROR 42000: Unknown database 'com1'
+use LPT1;
+ERROR 42000: Unknown database 'lpt1'
+use PRN;
+ERROR 42000: Unknown database 'prn'
+

mysql-test/t/reserved_win_names-master.opt

+--lower_case_table_names=1

mysql-test/t/reserved_win_names.test

+#
+# Test of reserved Windows names
+#
+--require r/reserved_win_names.require
+
+--error 1049
+use COM1;
+--error 1049
+use LPT1;
+--error 1049
+use PRN;
+

mysys/Makefile.am

@@ -53,7 +53,7 @@ libmysys_a_SOURCES =	my_init.c my_getwd.c mf_getdate.c \
 			my_net.c my_semaphore.c my_port.c my_sleep.c \
 			charset.c charset-def.c my_bitmap.c my_bit.c md5.c \
 			my_gethostbyname.c rijndael.c my_aes.c sha1.c \
-			my_handler.c my_netware.c my_windac.c 
+			my_handler.c my_netware.c my_windac.c my_access.c 
 EXTRA_DIST =		thr_alarm.c thr_lock.c my_pthread.c my_thr_init.c \
 			thr_mutex.c thr_rwlock.c
 libmysys_a_LIBADD =	@THREAD_LOBJECTS@

mysys/mf_pack.c

@@ -226,7 +226,7 @@ void symdirget(char *dir)
 {
   char buff[FN_REFLEN];
   char *pos=strend(dir);
-  if (dir[0] && pos[-1] != FN_DEVCHAR && access(dir, F_OK))
+  if (dir[0] && pos[-1] != FN_DEVCHAR && !my_access(dir, F_OK))
   {
     File file;
     uint length;

mysys/my_access.c

+/* Copyright (C) 2000 MySQL 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; either version 2 of the License, or
+   (at your option) any later version.
+
+   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
+
+#include "mysys_priv.h"
+
+#ifdef __WIN__
+
+/*
+ * Check a file or path for accessability.
+ *
+ * SYNOPSIS
+ * 	file_access()
+ * 	pathpath to check
+ * 	amodemode to check
+ *
+ * 	DESCRIPTION
+ * 	This function wraps the normal access method because the access 
+ * 	available in MSVCRT> +reports that filenames such as LPT1 and 
+ * 	COM1 are valid (they are but should not be so for us).
+ *
+ * 	RETURN VALUES
+ * 	0     ok
+ * 	-1    error
+ */
+int my_access(const char *path, int amode) 
+{ 
+	WIN32_FILE_ATTRIBUTE_DATA fileinfo;
+	BOOL result;
+	
+	result = GetFileAttributesEx(path, GetFileExInfoStandard, 
+			&fileinfo);
+	if (! result) 
+		return -1;
+	if ((fileinfo.dwFileAttributes & FILE_ATTRIBUTE_READONLY) &&
+			(amode & 2))
+		return -1;
+	return 0;
+}
+
+#endif

sql/sql_db.cc

@@ -946,7 +946,7 @@ bool mysql_change_db(THD *thd, const char *name)
   length=unpack_dirname(path,path);		// Convert if not unix
   if (length && path[length-1] == FN_LIBCHAR)
     path[length-1]=0;				// remove ending '\'
-  if (access(path,F_OK))
+  if (my_access(path,F_OK))
   {
     net_printf(thd,ER_BAD_DB_ERROR,dbname);
     my_free(dbname,MYF(0));