mariadb/mysys/my_open.c
Ravinder Thakur 2d16c5bd4b bug#11761752: DO NOT ALLOW USE OF ALTERNATE DATA STREAMS ON NTFS FILESYSTEM.
File names with colon are being disallowed because of the Alternate Data 
Stream (ADS) feature of NTFS that could be misused. ADS allows data to be 
written to alternate streams of a normal file. The data in alternate 
streams cannot be seen by normal tools on Windows (explorer, cmd.exe). As 
a result someone can use this feature to hide large amount of data in 
alternate streams and admins will have no easy way of figuring out the 
files that are using that disk space. The fix also disallows ADS in the 
scenarios where file name is passed as some dynamic variable.

An important thing about the fix is that it DOES NOT disallow ADS file 
names if they are not dynamic (i.e. if the file is created by using some 
option that needs local access to the MySQL server, for example error log
file). The reasoning is that if some MySQL option related to files 
requires access to the local machine (it is not dynamic), then user can very 
well create data in ADS by some other means. This fixes only those scenarios 
which can allow users to create data in ADS over the wire.

File names with colon are being disallowed only on Windows. UNIX 
(Linux in particular) supports NTFS, but it will not be a common 
scenario for someone to configure a NTFS file system to store MySQL 
data on Linux.

Changes in file bug11761752-master.opt are needed due to 
bug number 15937938.
2012-12-13 20:33:44 +05:30

192 lines
4.6 KiB
C

/* Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
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 */
#include "mysys_priv.h"
#include "mysys_err.h"
#include <my_dir.h>
#include <errno.h>
/*
Open a file
SYNOPSIS
my_open()
FileName Fully qualified file name
Flags Read | write
MyFlags Special flags
RETURN VALUE
File descriptor
*/
File my_open(const char *FileName, int Flags, myf MyFlags)
/* Path-name of file */
/* Read | write .. */
/* Special flags */
{
File fd;
DBUG_ENTER("my_open");
DBUG_PRINT("my",("Name: '%s' Flags: %d MyFlags: %d",
FileName, Flags, MyFlags));
#if defined(_WIN32)
fd= my_win_open(FileName, Flags);
#elif !defined(NO_OPEN_3)
fd = open(FileName, Flags, my_umask); /* Normal unix */
#else
fd = open((char *) FileName, Flags);
#endif
DBUG_RETURN(my_register_filename(fd, FileName, FILE_BY_OPEN,
EE_FILENOTFOUND, MyFlags));
} /* my_open */
/*
Close a file
SYNOPSIS
my_close()
fd File sescriptor
myf Special Flags
*/
int my_close(File fd, myf MyFlags)
{
int err;
DBUG_ENTER("my_close");
DBUG_PRINT("my",("fd: %d MyFlags: %d",fd, MyFlags));
mysql_mutex_lock(&THR_LOCK_open);
#ifndef _WIN32
do
{
err= close(fd);
} while (err == -1 && errno == EINTR);
#else
err= my_win_close(fd);
#endif
if (err)
{
DBUG_PRINT("error",("Got error %d on close",err));
my_errno=errno;
if (MyFlags & (MY_FAE | MY_WME))
my_error(EE_BADCLOSE, MYF(ME_BELL+ME_WAITTANG),my_filename(fd),errno);
}
if ((uint) fd < my_file_limit && my_file_info[fd].type != UNOPEN)
{
my_free(my_file_info[fd].name);
#if !defined(HAVE_PREAD) && !defined(_WIN32)
mysql_mutex_destroy(&my_file_info[fd].mutex);
#endif
my_file_info[fd].type = UNOPEN;
}
my_file_opened--;
mysql_mutex_unlock(&THR_LOCK_open);
DBUG_RETURN(err);
} /* my_close */
/*
Register file in my_file_info[]
SYNOPSIS
my_register_filename()
fd File number opened, -1 if error on open
FileName File name
type_file_type How file was created
error_message_number Error message number if caller got error (fd == -1)
MyFlags Flags for my_close()
RETURN
-1 error
# Filenumber
*/
File my_register_filename(File fd, const char *FileName, enum file_type
type_of_file, uint error_message_number, myf MyFlags)
{
DBUG_ENTER("my_register_filename");
if ((int) fd >= MY_FILE_MIN)
{
if ((uint) fd >= my_file_limit)
{
#if !defined(HAVE_PREAD)
my_errno= EMFILE;
#else
thread_safe_increment(my_file_opened,&THR_LOCK_open);
DBUG_RETURN(fd); /* safeguard */
#endif
}
else
{
mysql_mutex_lock(&THR_LOCK_open);
if ((my_file_info[fd].name = (char*) my_strdup(FileName,MyFlags)))
{
my_file_opened++;
my_file_total_opened++;
my_file_info[fd].type = type_of_file;
#if !defined(HAVE_PREAD) && !defined(_WIN32)
mysql_mutex_init(key_my_file_info_mutex, &my_file_info[fd].mutex,
MY_MUTEX_INIT_FAST);
#endif
mysql_mutex_unlock(&THR_LOCK_open);
DBUG_PRINT("exit",("fd: %d",fd));
DBUG_RETURN(fd);
}
mysql_mutex_unlock(&THR_LOCK_open);
my_errno= ENOMEM;
}
(void) my_close(fd, MyFlags);
}
else
my_errno= errno;
DBUG_PRINT("error",("Got error %d on open", my_errno));
if (MyFlags & (MY_FFNF | MY_FAE | MY_WME))
{
if (my_errno == EMFILE)
error_message_number= EE_OUT_OF_FILERESOURCES;
DBUG_PRINT("error",("print err: %d",error_message_number));
my_error(error_message_number, MYF(ME_BELL+ME_WAITTANG),
FileName, my_errno);
}
DBUG_RETURN(-1);
}
#ifdef EXTRA_DEBUG
void my_print_open_files(void)
{
if (my_file_opened | my_stream_opened)
{
uint i;
for (i= 0 ; i < my_file_limit ; i++)
{
if (my_file_info[i].type != UNOPEN)
{
fprintf(stderr, EE(EE_FILE_NOT_CLOSED), my_file_info[i].name, i);
fputc('\n', stderr);
}
}
}
}
#endif