Gallery2:How to configure open basedir for G2

How to configure open_basedir for G2

Note

For shared webhosting, we recommend chroot + apache2 + php-fastcgi + suexec as a fast, secure environment. open_basedir is just one component that can improve considerably security.

PHP open_basedir is a good means to improve security in a shared webhosting environment (or if you host multiple G2 installations for multiple users). With open_basedir, account owner X will no longer be able to access files of account owner Y. Without open_basedir (or other similar security precautions), user X can read the config.php file of user Y, user X can delete the albums of user Y etc. (of course this doesn't apply to a properly configured chroot + php-fastcgi + suexec webserver).

From http://www.php.net/manual/en/security.apache.php:
There is a better solution than starting every virtual host in a seperate instance, which is wasting ressources.
You can set open_basedir dynamically for every virtual host you have, so every PHP script on a virtual host is jailed to its document root.
Example:
<VirtualHost www.example.com>
  ServerName www.example.com
  DocumentRoot /www-home/example.com
[...]
  <Location />
   php_admin_value open_basedir    \ "/www-home/example.com/:/usr/lib/php/"
  </Location>
</VirtualHost>
If you set safe_mode on, then the script can only use binaries in given directories (make a special dir only with the binaries your customers may use).
Now no user of a virtual host can read/write/modify the data of another user on your machine.

If you use open_basedir in conjunction with symlinks, then you'll encounter a problem with the current installation of G2. Summary of the open_basedir + symlink problem: There's a problem with symbolic links and open_basedir. If you're using one of the two, it works, but both at the same time will result in this problem.

Explanation of the php dev

The explanation of the php dev at http://bugs.php.net/bug.php?id=30188 was correct:

Bug report: My setup

document root is: "/home/wejn/x/docs/html/".

While "/home/wejn/x/docs/html/" is symlink to:
"/home/wejn/x/docs1/html/".

I have safe_mode enabled and open_basedir set to
"/home/wejn/x/docs/html:/home/wejn/x/docs1/html".

With this setup I'm unable to perform:

copy("/home/wejn/x/docs/html/x", "/home/wejn/x/docs/html/y");''

The PHP dev's answer

''Using "/home/wejn/x/docs/html:/home/wejn/x/docs1/html" as value of
open_basedir is senseless, as it's similar to
"/home/wejn/x/docs/html:/home/wejn/x/docs/html", because open_basedir's
values are resolved too.

Obviously PHP cannot resolve "/home/wejn/x/docs1/html/y" as it even
doesn't exist, so it compares non-existing "/home/wejn/x/docs1/html/y"
to "/home/wejn/x/docs/html/" and reports that they aren't the same.''

• You can file a feature request for G2, such that we do a touch before each copy, fopen, ... it's a small fix in modules/core/classes/GalleryPlatform.class and modules/core/classes/GalleryPlatform/*Platform.class