Re: [gentoo-user] bash wizardry needed: PATH and MANPATH grow and grow and grow

["Kevin O'Gorman" <kogorman@gmail.com>]

On 7/5/06, Boyd Stephen Smith Jr. <bss03@volumehost.net> wrote:
> On Saturday 03 June 2006 16:11, znx <znxster@gmail.com> wrote about 'Re:
> [gentoo-user] bash wizardry needed: PATH and MANPATH grow and grow and
> grow':
> > On 27/05/06, Kevin O'Gorman <kogorman@gmail.com> wrote:
> > >  Open to debate.  I'd think it's not very dangerous at the *end* of
> > > the PATH.
> >
> > True, I have modified the script so that a . may enter the PATH (etc)
> > only as the final entry. Also good point about ~/bin .. it is just as
> > dangerous.
>
> Actually, it's not as dangerous.  ~/bin is a well-known location that is
> (normally) only writable by the user themselves.  '.' is a floating
> location, that may (from time to time) refer to a directory that is
> world-writable like /tmp, /var/tmp, or /dev/shm.
>
> Having '.' in your path allows arbitrary guest users to run programs with
> your permissions.  Putting it at the end of your PATH prevents them from
> shadowing existing commands, but doesn't prevent them from taking
> advantage of typos.
>
> Having ~/bin or even just ~ in your PATH does not open this security hole
> unless you also make that directory world writable.

Good point.


I've also fooled around with the script a bit, and arrived at something that's
easier for me to read, and a bit more permissive.  YMMV


compresspath ()
{
    local var="${1:-PATH}"   # arg 1; default to $PATH
    local newpath=:
    local entry
    for entry in ${!var//:/ };    # change ":" to space (so separates words)
    do
        case $newpath in
            *:${entry}:*)         # already there -- do nothing
            ;;
            *)
                newpath=$newpath$entry:
            ;;
        esac
    done
    newpath="${newpath#:}";    # drop leading ":"
    newpath="${newpath%:}";   # drop trailing ":"
    eval "$var"'="${newpath}"'
}

++ kevin

-- 
Kevin O'Gorman, PhD
-- 
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