Re: inheritable set [was Re: caps in elf headers: use the sticky bit!]

Brandon S. Allbery KF8NH (allbery@kf8nh.apk.net)
Sat, 17 Apr 1999 21:04:39 -0400


In message <Pine.GSO.4.10.9904172025150.21850-100000@weyl.math.psu.edu>, Alexan
der Viro writes:
+-----
| > Capabilities defined that loosely aren't particularly useful. A better
| > real-world example of a capability useful for mail programs would be: the
| > ability to create and remove files owned by the process's uid in certain
| > directories.
|
| You don't need *anything* special for that. You don't need
| capabilities - file descriptor of the directory will work just fine. Let
| the daemon pass it to applications via SCM_RIGHTS (after proper
| authentication, indeed) and call fchdir() in the application. Make the
| directory inaccessible to anybody except the daemon (no exec for group
| and world on parent) and there you go. You'll need to protect the thing
| from reaching it via /proc/* - not a big deal.
+--->8

...and a major rewrite of existing mailers to work with this. Capabilities
make for a much smaller rewrite (remove uid management, as it's no longer
needed).

-- 
brandon s. allbery	[os/2][linux][solaris][japh]	 allbery@kf8nh.apk.net
system administrator	     [WAY too many hats]	   allbery@ece.cmu.edu
carnegie mellon / electrical and computer engineering			 KF8NH
     We are Linux. Resistance is an indication that you missed the point.

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