Unix Programming - Re: program calls rcmd() twice, _second_ call works for root but not normal users

Author

Re: program calls rcmd() twice, _second_ call works for root but not normal users

Barry Margolin

2005-06-17, 2:52 am

In article <d8sre4$j4q$1@naig.caltech.edu>,
David Mathog <mathog@caltech.edu> wrote:

> Now the odd part: this modified rsh works just fine for root but for any
> other user the rcmd call works once (for the first host) and
> then gives a
>
> rcmd: socket: Permission denied
>
> when it attempts a second rcmd call.

I'm very surprised the first call works. rcmd() has to be run by root,
because it uses a privileged port as the local port. This is necessary
for the remote system to trust the userid information, since rcmd()
doesn't send any authentication information.

--
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***