My related question is when it is ever safe to use suid to change the user id of an Apache Perl CGI script to a user with some administrative privileges.

I want to use Lincoln Stein's user_manage Perl module to allow Apache users to remotely change their own passwords. Stein provides some different ways to do it. One way involves:

Designate a directory that will hold the various password and group files, for example /etc/httpd/security. Make it owned and writable by a specially-designated "web administrator" account, for example "www". Now, running as root, change the ownership of user_manage to "www" and set its "s" bit:
Is there any danger in doing so? My concern is that the user_manage documentation may be assuming that "everyone knows" not to engage in a particular coding practice when running suid, but I am still a beginner (<1 year Perl/Unix) and I don't know. I intend to use CGI.pm param() to parse the form variables after they are submitted, and I intend to avoid doing foolish things like 
my $form_variable = param("form_variable");
`form_variable`;

[download]

I also will prevent users from uploading form variables which contain values other than letters and numbers. Just to be safe, I may also ban words like 'eval' and 'system' from form variables along with parentheses and backticks.

In reply to Re: Re: change process's effective uid by sierrathedog04
in thread change process's effective uid by Anonymous Monk

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.