Bug 14408: Path Traversal error

Bug 14408: Path Traversal error

Counter counter patch
Please test well, including with the null byte %00, this uses a whitelisting to only allow files ending with .tt
and not allowing ../etc

Note the previous patch tries to protect against /etc/passwd
but //etc/passwd is now vulnerable.  I do think a whitelist is safer than trying to do a blacklist

/cgi-bin/koha/svc/virtualshelves/search
/cgi-bin/koha/svc/members/search

Are vulnerable

To test:
1/ Hit /cgi-bin/koha/svc/members/search?template_path=members/tables/members_results.tt
  Notice you get a valid JSON response
2/ Hit
/search?template_path=..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2fetc%2fpasswd
  (You may have add more ..%2f or remove them to get the correct path)
  Notice you can see the contents of the /etc/passwd file
3/ Hit
/cgi-bin/koha/svc/members/search?template_path=test%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2fetc%2fpasswd
4/ Apply patch
5/ Hit the first url again, notice it still works
6/ Hit the second url notice it now errors with a file not found
7/ Hit the third url notice it now errors with a file not found

Repeat for the other script also

Signed-off-by: Jonathan Druart <jonathan.druart@koha-community.org>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>