Bug 36818: Escape characters in file names uploaded

To test:
1/ create a file named something like 'execute`curl blog.bigballofwax.co.nz`.zip'
   Where the domain is one you can watch the logs from
2/ Upload this file as a cover image
3/ Check /var/lib/koha/sitename/tmp/koha_sitename/ and see unescaped filenames
4/ Choose process, check the logs of the webserver see the connection has been made
5/ Apply the patch
5/ Repeat 2 & 3 and see the filename is now escaped
6/ Choose process and check no errors but no no remote execution occurs
7/ Test uploading actual zip file and images still works

Signed-off-by: Amit Gupta <amit.gupta@informaticsglobal.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
(cherry picked from commit 14bdaae3f257a321f8ec0d32c6b1e9bc6ed6033d)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>

Koha/Uploader.pm

@@ -264,6 +264,7 @@ sub _dir {
 sub _hook {
     my ( $self, $filename, $buffer, $bytes_read, $data ) = @_;
     $filename= Encode::decode_utf8( $filename ); # UTF8 chars in filename
+    $filename =~ s/[^A-Za-z0-9\-\.]//g;
     $self->_compute( $filename, $buffer );
     my $fh = $self->_fh( $filename ) // $self->_create_file( $filename );
     print $fh $buffer if $fh;