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Re: configuring and debugging swish.cgi with IIS on Windows, and

From: Bill Moseley <moseley(at)not-real.hank.org>
Date: Tue Jun 10 2003 - 19:18:22 GMT
On Tue, Jun 10, 2003 at 10:33:35AM -0700, Nathan Vonnahme wrote:
> 
> I have to use IIS (arggg), 

I always wonder about that.  Throw linux and Apache on an old P133
that's too slow for Windows, use samba and you have a nice stable web 
server platform.


>         swish_binary    => 'C:\"Program Files"\SWISH-E\swish-e.exe',        # Location of swish-e binary
>         swish_index     => 'C:\Program Files\SWISH-E\index.swish-e',    # Location of your index file
> 
> The space in "Program Files" needs to be quoted in the first, but not
> in the second, because of the way DOS and Perl interact. 

Huh, interesting.  Under Windows it uses IPC::Open2, which still goest 
through the shell. I see a line that does:

  my @command = map { s/"/\\"/g; $_ }  $self->{prog}, $self->swish_command_array;

I think I was trying to prevent Windows from swallowing up quotes (like 
ones used in phrase searches).

That still stinks.  I just looked at the SWISH::Filter.pm module and it 
does:

   my @command = map { s/"/\\"/g; qq["$_"] }  @args;

So quotes are escaped and then then entire parameter is placed inside 
double quotes.  Would that fix your problem above?  Then you wouldn't 
need to add that quotes in the "swish_binary" above.


> ALSO, I had to modify doc2txt.pm and pdf2xml.pm (at least... maybe
> more I don't remember) to quote the filename when they use system() or
> backticks (``), since some directory names have spaces.  E.g. in
> doc2txt.pm:
> 
> 80c80
> <     my $content = `$catdoc "$file"`;

Ok.  This has come up before, and I can't remember if I had a reason not 
to do that or if I just never got around to it.

There's also in pdf2html:

   open $sym, "pdfinfo $file |" || die "$0: Failed to open $file $!";
   open $sym, "pdftotext $file - |" or die "$0: failed to run pdftotext: $!";

Those should be quoted, too.

> Windows doesn't allow doublequotes in file or directory names so that
> should be an OK way to do it even though it doesn't escape anything. 
> It might be better to add a more robust argument escaping method to
> prevent filenames with special characters from doing unexpected things
> (or better would be to not use backticks to avoid the shell
> completely).

Well, without fork/exec on Windows it's hard.  I'm sure there's some 
Win32 specific functions to do that, but I have never looked into it.  I 
spent a *year* posting to Win32 CGI lists asking how to securely run an 
external program (like swish-e) from a CGI script and never got any 
response.

> In some cases the current code could be a security hole
> on unix, because a user whose documents are indexed could execute
> arbitrary code as the webserver user by naming a document 'haha; rm
> -rf /; youlose.doc' or whatever.

Yes, that's true.  If you are indexing with the file system (not 
spidering) and can't trust the files you are indexing, yes.

> If the webserver user has
> sufficiently few rights it shouldn't be possible to cause a lot of
> damage that way though.

Please feel free to look over the utilities with Windows in mind:

   filters/SWISH/Filter.pm (see run_program() )
   files in prog-bin and filter-bin

There's also risk using the FileFilter directive if you don't escape 
correctly.

> I just wanted to share my hard-won experience with the archive, and
> maybe these hints/changes could make it into at least the Windows
> release.  Thanks to all you who have developed swish!

Thanks for the comments!


-- 
Bill Moseley
moseley@hank.org
Received on Tue Jun 10 19:18:31 2003