CODEWITHSUNDEEP
perlfile-uploadcgi
Edward Antrobus
Edward Antrobus

Reputation: 31

Perl "undefined value as a HASH reference" error

Based on this article, I wrote the a perl script to allow document files to be uploaded to my site. But I am getting "Can't use an undefined value as a HASH reference at upload.cgi line 38." (line 38 is the one above the unless clause). For reference, my web host has Perl 5.8.8 installed.

#!/usr/bin/perl -wT  

use strict;  
use CGI qw/param uploadInfo/;
use CGI::Carp qw ( fatalsToBrowser );  
use File::Basename;  

$CGI::POST_MAX = 1024 *1024 * 50;  #Max file size 50MB
my $safe_filename_characters = "a-zA-Z0-9_.-";  
my $upload_dir = "/home/antrobus/Originals";  

my $query = new CGI;  
my $filename = $query->param("manuscript");  

if ( !$filename )  
{  
 print $query->header ( );  
 print "The file is too large. Please email me to arrange other means of providing your manuscript.";  
 exit;  
}  

my ( $name, $path, $extension ) = fileparse ( $filename, '\..*' );  
$filename = $name . $extension;  
$filename =~ tr/ /_/;  
$filename =~ s/[^$safe_filename_characters]//g;  

if ( $filename =~ /^([$safe_filename_characters]+)$/ )  
{  
 $filename = $1;  
}  
else  
{  
 die "Filename contains invalid characters";  
}  

my @allowedtypes = qw(application/msword application/vnd.openxmlformats-officedocument.wordprocessingml.document application/vnd.oasis.opendocument.text application/rtf);
my $type = uploadInfo($filename)->{'Content-Type'};
unless ($type = @allowedtypes)
{  
 print $query->header ( );  
 print "Filetype not allowed. Please upload doc, docx, odt, or rtf files only.";  
 exit;  
}  

my $upload_filehandle = $query->upload("manuscript");  

open ( UPLOADFILE, ">$upload_dir/$filename" ) or die "$!";  
binmode UPLOADFILE;  

while ( <$upload_filehandle> )  
{  
 print UPLOADFILE;  
}  

close UPLOADFILE;  

print $query->header ( );  
print qq~;  
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd">  
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">  
 <head>  
   <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />  
   <title>File Uploaded!</title>  
   <style type="text/css">  
     img {border: none;}  
   </style>  
 </head>  
 <body>  
   <p>Thanks for uploading your manuscript!</p>  
 </body>  
</html>  
~;

Upvotes: 1

Views: 3402

Answers (2)

Edward Antrobus
Edward Antrobus

Reputation: 31

Found the answer here. Apparently taint checking messes disrupts the ability to check the mime content type. Copying $filename to another variable before taint checking and using the other variable works...accept that it accepts any file type, not just the four accepted ones (but that's another question!)

Upvotes: 1

Nikhil Jain
Nikhil Jain

Reputation: 8352

If you want to have MIME content type

Do it like ,

$type = $query->uploadInfo($filename)->{'Content-Type'}; #CGI object was missing

see CGI for more detail, from CGI, genearlly

$filename = $q->param('uploaded_file');
$type = $q->uploadInfo($filename)->{'Content-Type'};
unless ($type eq 'text/html') {
        die "HTML FILES ONLY!";
}

Upvotes: 2

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