Date: Tue, 19 Nov 2002 10:41:30 +0100 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: Kris Kennaway <kris@obsecurity.org> Cc: kip@eventdriven.org, Bruce Evans <bde@zeta.org.au>, current@FreeBSD.ORG Subject: Re: Device permissions with DEVFS Message-ID: <17309.1037698890@critter.freebsd.dk> In-Reply-To: Your message of "Tue, 19 Nov 2002 00:27:58 PST." <20021119082758.GA3738@rot13.obsecurity.org>
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In message <20021119082758.GA3738@rot13.obsecurity.org>, Kris Kennaway writes: > >On Tue, Nov 19, 2002 at 12:16:49AM -0800, Kip Macy wrote: >> This doesn't sound like an intrinsic limitation of >> devfs, just an issue with how it is structured now. s/structured/used by drivers/ >> There should just be a central file for all the=20 >> devices which devfs sucks in at build (or maybe boot)=20 >> time specifying the appropriate permissions and any >> other configuration information. > >No, the default permissions are specified in the driver source code >via make_dev(). I guess one cannot be trapped in an airport for more than 24 hours before people start fighting over ones code :-) A major design-goal of DEVFS is to avoid that or more central files have to know about all device drivers. Adding a new such file is not acceptable. On the other hand, knowing special UID and GID values in the kernel is quite a hack as well. IMO, the current situation is a fair compromise: 1. (+) We do not need MAKEDEV anymore. 2. (-) For some time yet we will still need majors. 3. (-) We embed magic UID and GID values in the kernel to make /dev come up with the most sensible defaults. 4. (+) The devfs(8) facility allows people to override these defaults in a race-free manner. In addition it allows the user to define entirely new and wonderful policies. Summary: Don't expect changes in DEVFS, but do put pressure on driver authors to get sensible defaults used. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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