Getcomments FAQ

This is a list of frequently asked questions about Getcomments.

If you have any questions that are not answered here, feel free to e-mail me at "hoagland@cs.ucdavis.edu".

If you feel you have something to contribute to this FAQ, please place it here.

Questions

o Configuration Problem Questions
o Getcomments Possibilities Questions
o Miscellaneous Questions

Configuration Problem Questions

1. I have put getcomments.pl into place. Now when I try to execute it by submitting a form, I get an error like "Error 500 Internal error: execve() failed". What's going wrong?

2. After submitting I form to Getcomments, I get a message starting with "could not chdir". What's up?

3. After submitting I form to Getcomments, I get a message starting with "could not open count". I do not have the above problem though. What's going wrong?

4. <something> works when I try running getcomments.pl from the command line, but doesn't work when I do it from the form. Why is this?

Getcomments Possibilities Questions

1. Will Getcomments run on a non-Unix machine?

2. Can I have different users/forms use the same Getcomments script?

Miscellaneous Questions

1. Somebody asked: If I make the directory in which getcomments resides readable/writeable to the outside world in order to facilitate the writing of comments, is this directory not wide open to anything the outside world cares to do? In other words, how do I protect my HTML and other files from vandals?


Answers

Configuration Problem Answers

1. It sounds like your server could not locate Perl. Here is what you do:
  1. Locate the perl executable on your computer. Depending on what shell you use, "which perl" might work.
  2. Look at the first line of the getcomments.pl file.
  3. Change the path in this line to the full path to the perl executable. If they already match, the this was not the problem.

2. Your _comment_dir field is not set properly. Set it to the actual location (not URL) of your comment directory.

3. It sounds like your file permissions are wrong somewhere. The files that Getcomments changes need to be writeable by whatever user/group your server runs as when accessing pages. So make sure your comment directory has the "x" bit set for the world (try "chmod +x <comment dir>") and your "count" file has the "w" bit set for the world (try "chmod +w count")

4. It sounds like your file permissions are wrong somewhere. Remember that the permissions need to be set for user/group your server runs as when accessing pages, or the world. The configuration "out of the box" should be correct.

Getcomments Possiblities Answers

1. No. But I welcome any ports to non-Unix machines.

2. Certainly. Just set up the control fields and format files of different forms to each situation.

Miscellaneous Answers

1. I answered:
As a researcher in computer security I would say there is reason to
take note of the situation and it is good that you are interested.

However you probably don't need to worry too much.

If as is the default setup, the only thing in the publicly writeable
directory is the comments and the count of the number of comments,
the degree of potential damage is limited.

Possible bad happenings from the outside:
1) New files being added to the directory.  The means by which to do
this are limited presently, however theoretically possible.
2) Garbage added to the comments file.  This can be done through
legitimate means.  After all, when you ask for comments, you invite
people to append their text to your file.
3) Files being deleted in the directory.  Similar to 1).  If you are real
concerned, make backups regularly.

Threats from people who have accounts on your system or crackers
that have broken into your system are more realistic as any of the 3
things above can easily be achieved.  Unfortunately, under UNIX there
really isn't anything that can be done.

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James Hoagland
University of California, Davis / Computer Science Department / hoagland@cs.ucdavis.edu
27 June 1995