Not really security related per se, but I think that it's wise to set a maximum file size that you'll accept so that someone doesn't try to fill up your disk.

You can do this easily (if you're using CGI.pm) with something like:

# Limit file sizes to 1 MB
use constant MAX_FILE_SIZE => 1_048_576;
$CGI::POST_MAX = MAX_FILE_SIZE;

[download]

You may also want to set a size limit on the directory that is holding the uploaded files. This could be done with something like:

# 100 MB limit on the size of the upload dir
use constant MAX_DIR_SIZE => 100 * 1_048_576;

sub dir_size {
    my $dir      = shift;
    my $dir_size = 0;
    my $file;

    # Loop through files and sum the sizes; doesn't descend down subdi
+rs.
    opendir DIR, $dir or die "Unable to open $dir: $!\n";
    $dir_size += -s "$dir/$file" while defined( $file = readdir DIR );
    closedir DIR;

    return $dir_size;
}

die 'Upload directory is full.'
  if ( dir_size('/path/to/dir') + $ENV{CONTENT_LENGTH} > MAX_DIR_SIZE 
+);

[download]

In reply to Re: Thoughts on file upload... by mikeirw
in thread Thoughts on file upload... by mojobozo

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.