Bug: 186280
    Description: Close potential security vulnerabilities in CGI code
    Reviewed by: Nathan and Noriko (Thanks!)
    Fix Description: These address a variety of issues with our CGIs.  The basic
    strategy is - Don't Trust The User - any data passed in as a GET/POST parameter
    is suspect.  I mostly looked at parameters which are filenames or filename
    components, but I also made sure that we don't try to dereference a null
    parameter or similar things such as that.  For filenames, I mostly just verified
    that path components contain path valid characters (e.g. not things like ../ or
    "" or potential attack strings), verify that the given filename exists in the
    given directory using opendir/readdir instead of just relying on PR_Access
    (which would report success on a path like
    /opt/fedora-ds/alias/../../../etc/passwd), and some attacks which could be based
    on using something like this:
    PR_snprintf(buf, sizeof(buf), "%s/alias", pathfromuser);
    If pathfromuser overflows buf, the /alias will not be appended and we could be
    using some bogus path.  I replaced most of these with PR_smprintf.
    Platforms tested: RHEL4
    Flag Day: no
    Doc impact: no
    QA impact: should be covered by regular nightly and manual testing
    New Tests integrated into TET: none