--- web/cgi-bin/docs.cgi 2000/11/09 22:03:56 1.3 +++ web/cgi-bin/docs.cgi 2001/02/08 21:17:47 1.4 @@ -19,10 +19,25 @@ my ($bottom) = "../bottom.inc"; my ($query) = new CGI; -my ($doc) = ($query->param('doc') =~ /^\s*(.*?\.txt)\s*$/); -$doc = "../documentation/".$doc; +# Note filenames may only have one dot in them, in the ".txt". +# This prevents malicious users using "../" to view files. +my ($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\.\/]+$/) { + print "Go Away, you nasty hax0r!"; + exit; +} +$doc = "../documentation/".$doc; print <<"END";