--- web/cgi-bin/docs.cgi 2000/10/25 23:56:27 1.1 +++ web/cgi-bin/docs.cgi 2003/05/15 20:48:01 1.6 @@ -13,17 +13,32 @@ use CGI; $| = 1; # Settings -my ($left) = "../left.inc" ; -my ($title) = "../title.inc"; -my ($bottom) = "../bottom.inc"; +my ($left) = "../htdocs/left.inc" ; +my ($title) = "../htdocs/title.inc"; +my ($bottom) = "../htdocs/bottom.inc"; my ($query) = new CGI; -my ($doci) = ($query->param('doc') =~ /^\s*(.*?\.txt)\s*$/); -my ($doc) = "../documentation/$doci"; -print "content-type: text/html\n\n"; +# Note filenames may only have one dot in them, in the ".txt". +# This prevents malicious users using "../" to view files. +my ($doc) = ($query->param('doc') =~ /^\s*([^\.]*?\.txt)\s*$/); +print "Content-type: text/html\n\n"; + +unless (defined $doc) { + print "The link to this page was broken - it must specify a .txt file."; + exit; +} + +# Prevent hackers from supplying a malformed document string. +# I.e. only allow normal characters, slashes and dots. +unless ($doc =~ /^[a-zA-Z_\-0-9\.\/]+$/) { + print "Malformed request"; + exit; +} +$doc = "../htdocs/documentation/".$doc; + print <<"END"; @@ -31,7 +46,7 @@ print <<"END"; docs.cgi Web-based text file viewer and formatter. Created by pjm2 19/10/2000 - Last modified 19/10/2000 + Last modified 02/11/2000 --> @@ -50,7 +65,7 @@ print <<"END"; END -&print_file($left); +&print_html($left); print <<"END"; @@ -58,14 +73,10 @@ print <<"END"; END -&print_file($title); - -print "
\n";
+&print_html($title);
 &print_file($doc);
-print "
\n"; +&print_html($bottom); -&print_file($bottom); - print <<"END"; @@ -79,16 +90,40 @@ END exit 0; +# Print a file, whilst escaping HTML: - sub print_file ($) { + my ($urls) = '(' . join ('|', qw{ + http + telnet + gopher + file + wais + ftp + } ) + . ')'; + + my ($ltrs) = '\w'; + my ($gunk) = '/#~:.?+=&%@!\-'; + my ($punc) = '.:?\-'; + my ($any) = "${ltrs}${gunk}${punc}"; my ($filename) = @_; - print `cat $filename`; -} - -sub print_file_old ($) { - my ($filename) = @_; open(FILE, $filename) or die "Cannot open $filename: $!\n"; - while (my ($line) = ) { - print $line; + print "
\n";
+    # Use $_ implicitly throughout.
+    while () {
+        # Must do the next line first!
+        s/&/&/g;
+        s//>/g;
+        s/"/"/g;
+        s/\b($urls:[$any]+?)(?=[$punc]*[^$any]|$)/$1<\/a>/igox;
+        print;
     }
+    print "
"; } +# Print a file without escaping HTML: - +sub print_html ($) { + my ($filename) = @_; + print `cat $filename 2>&1`; +}