[Adduser-devel] Bug#357978: adduser calls /usr/bin/chfn instead of invoking chfn from PATH

[Ian Jackson]

Marc Haber writes ("Bug#357978: adduser calls /usr/bin/chfn instead of invoking chfn from PATH"):
> Hm. We are using hard-coded paths since we avoid using a shell for
> subprocess invocation.

I'm afraid I don't understand this comment at all.  Honouring the PATH
just involves calling exec*p rather than exec*, and doesn't need to
use a subprocess.  The libc will search the PATH for you.

>  We're going to change to a PATH-honoring setup
> in one of the next versions, but we're going to set our own PATH on
> startup to avoid privilege escalation issues.

That's completely wrong.  adduser is running as root to start with and
isn't setuid.  It should honour its PATH completely.

Ian.