Subject: Re: lpd and filter programs
To: None <tech-userlevel@NetBSD.ORG>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
List: tech-userlevel
Date: 07/30/1998 07:56:24
> Your request to mount would need a major redesign of /etc/fstab and
> mount, because this would open many secutity holes otherwise. I.e.:
>   cp /bin/sh to $ZIP/sh;
>   chown root $ZIP/sh;
>   chmod a+s $ZIP/sh;
>   unmount $ZIP;
>   #go to a system with ZIP and you are not root
>   mount $ZIP;
>   $ZIP/sh; #you are root now;

Not if mounts done by non-root are forcibly either (a) done nosuid (and
nodev) or (b) done such that all ownerships on the mounted filesystem
are overridden to the IDs of the user who did the mount (they'd still
have to have nodev forced).  And neither one is "a major redesign";
indeed, (a) could be done with existing machinery.

					der Mouse

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