Re: [Exim] exim & intetd

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Autor: Philip Hazel
Datum:  
To: nick slussar
CC: exim-users
Betreff: Re: [Exim] exim & intetd
On Mon, 24 Dec 2001, nick slussar wrote:

> bug was discussed about a month ago on debian-russian, and <dbg>
> suggested, that the qhole point is in the way exim tries to find out
> whether it has been launched from inetd or from init.d, and if it's
> launched from inetd, it will check relays, etc.


Unfortunately I don't subscribe to debian-russian. This is the first
I've heard of this problem.

> look at this piece of code from exim:
>
>  if (smtp_input && (real_uid == root_uid ||
>      (exim_uid_set && real_uid == exim_uid)))
>    {
>    int size = sizeof(inetd_sock);
>    if (getpeername(0, (struct sockaddr *)(&inetd_sock), &size) == 0)
>      {
>      int family = ((struct sockaddr *)(&inetd_sock))->sa_family;
>      if (family == AF_INET || family == AF_INET6) is_inetd = TRUE;
>      }
>    }

>
> obvious, that with such combination of real/effective uid's, as in our
> situation, it be never able to identify that it has been launched from
> inetd.


I cannot now remember why I wrote it that way, but there must have been
some reason.

> suggested simple fix is to call getpeername always, without relying on
> uid combination.


But that would mean that any unprivileged user could call Exim and pass
it a socket on its standard input, and it would think it was being
called from inetd. Seems to me that that is an undesirable situation.

--
Philip Hazel            University of Cambridge Computing Service,
ph10@???      Cambridge, England. Phone: +44 1223 334714.