From mboxrd@z Thu Jan 1 00:00:00 1970 From: ron minnich Subject: Re: [PATCH 3/3] p9auth: add p9auth driver Date: Sat, 24 Apr 2010 09:25:08 -0700 Message-ID: References: <20100421012749.GA21338@us.ibm.com> <20100421012908.GB24251@us.ibm.com> <20100421030406.GB10258@kroah.com> <20100421034532.GA9254@us.ibm.com> <20100424033614.GA4180@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20100424033614.GA4180@us.ibm.com> Sender: linux-security-module-owner@vger.kernel.org To: "Serge E. Hallyn" Cc: "Eric W. Biederman" , Greg KH , lkml , David Howells , Ashwin Ganti , rsc@swtch.com, ericvh@gmail.com, linux-security-module@vger.kernel.org, jt.beard@gmail.com, Andrew Morton , Andrew Morgan , oleg@us.ibm.com, Eric Paris , linux-api@vger.kernel.org, Randy Dunlap List-Id: linux-api@vger.kernel.org On Fri, Apr 23, 2010 at 8:36 PM, Serge E. Hallyn wro= te: > An fs actually seems overkill for two write-only files for > process-related information. =A0Would these actually be candidates > for new /proc files? > > =A0 =A0 =A0 =A0/proc/grantcred - replaces /dev/caphash, for privilege= d > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0tasks to tell the kernel about new set= uid > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0capabilities > =A0 =A0 =A0 =A0/proc/self/usecred - replaces /dev/capuse for unprivil= eged > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0tasks to make use of a setuid capabili= ty An fs is fine. To relate this to Plan 9, where it all began, might be useful. There's no equivalent in Plan 9 to Linux/Unix devices of the major/minor number etc. variety. In-kernel drivers and out-of-kernel servers both end up providing the services (i.e. file name spaces) that we see in a Linux file system. So the Plan 9 driver for the capability device really does match closely in function and interface to a Linux kernel-based file system. Hence, making devcap a file system is entirely appropriate, because it best fits the way it works in Plan 9: a kernel driver that provides two files. It's pretty easy to write a Linux VFS anyway, so it makes sense from that point of view. Eric, that was a great suggestion. ron -- To unsubscribe from this list: send the line "unsubscribe linux-securit= y-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html