On Mon, Feb 24, 2014 at 07:01:54PM +0400, Slawa Olhovchenkov wrote: > On Mon, Feb 24, 2014 at 03:30:14PM +0100, Baptiste Daroussin wrote:
> > On Mon, Feb 24, 2014 at 06:17:37PM +0400, Slawa Olhovchenkov wrote: > > > On Sun, Feb 23, 2014 at 10:11:56PM +0100, Baptiste Daroussin wrote: > > > > As some of you may have noticed, I have imorted a couple of days > > > > ago dma (DragonFly Mail Agent) in base. I have been asked to > > > > explain my motivation so here they are. > > > What's about suid, security separations & etc? > > What do you mean? dma is changing user as soon as possible, dma will > > be capsicumized, what else do you want as informations? > sendmail (in the past) have same behaviour (run as root and chage > user). > This is some security risk. > For many scenario change user is not simple (for example -- send file > from local user A to local user B, file with permsion 0400). > sendmail will be forced to change behaviour -- mailnull suid program > for place mail into queue and root daemon for deliver to user. > This is more complex. > Can be dma avoid this way? I'm a bit disappointed that dma uses setuid/setgid binaries, although it is not a regression because sendmail also uses this Unix misfeature. To avoid the large attack surface of set*id binaries (the untrusted user can set many process parameters, pass strange file descriptors, send signals, etc), I think it is better to implement trusted submission differently. A privileged daemon (not necessarily running as root) can listen on a Unix domain socket and use getpeereid(3) to verify the credentials of the client. Note that the largest gain with set*id binaries is obtained when the last set*id binary is removed; we are pretty far from that. -- Jilles Tjoelker _______________________________________________ email@example.com mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"