From: Casey Schaufler Subject: Re: Make RCU dcache work with CONFIG_SECURITY=y Date: Fri, 22 Apr 2011 14:32:52 -0700 Message-ID: <4DB1F404.1060504@schaufler-ca.com> References: <1303431801-10540-1-git-send-email-andi@firstfloor.org> <20110422211649.GW16484@one.firstfloor.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Linus Torvalds , linux-fsdevel@vger.kernel.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, npiggin@kernel.dk, shaohua.li@intel.com, sds@tycho.nsa.gov, jmorris@namei.org, linux-security-module@vger.kernel.org, Eric Paris , Casey Schaufler To: Andi Kleen Return-path: In-Reply-To: <20110422211649.GW16484@one.firstfloor.org> Sender: linux-security-module-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On 4/22/2011 2:16 PM, Andi Kleen wrote: > On Fri, Apr 22, 2011 at 11:26:09AM -0700, Linus Torvalds wrote: >> On Thu, Apr 21, 2011 at 5:23 PM, Andi Kleen wrote: >>> I didn't find good test suites for the security modules, so >>> there wasn't a lot of testing on this unfortunately >>> (the selinux one for LTP doesn't seem to work). Some close >>> review of these changes is needed. >>> >>> On the other hand the VFS changes itself are very straight forward >>> and the 1/1 patch is very straight forward (and a win in itself) >>> >>> The bottom line is with this patchkit a CONFIG_SECURITY=y >>> kernel has as good VFS performance as a kernel with CONFIG_SECURITY >>> disabled. >> Gaah. My immediate reaction to the patch-series was "This is great, I >> was really hoping we could get all those annoying cases sorted out, >> and I'll queue them for the next merge window". >> >> Having then actually read through the patches a bit more, I then got >> convinced that at least the first patch should probably be applied >> right away and be marked for stable, since it looks pretty damn >> obvious to me, and it might already on its own fix the performance >> regression for some configurations (although realistically I guess few >> enough people really do the "selinux=0" thing, so the big advantage is >> making easier to backport the other patches later if we don't do them >> now). > Yes I agree. The first patch is (nearly) a no-brainer and already > has significant benefits. I would like to see it in .39. > >> Comments? I'd really like to see/hear feedback like "yeah, this looks >> really obviously safe" vs "yeah, looks good, but I really don't feel >> very comfortable with it" from the security people. > Especially SMACK review is needed. I am happy to get all the help I can on this. I am not now nor have I ever been especially comfortable with sophisticated locking models. Where possible I have written code with minimal locking requirements, but sometimes you just can't avoid it. I have been fortunate in that several people have offered advice in the past. > Or maybe selinux only for now, > already got one ack for that. > > (BTW I have some doubts on the locking in smack in general, > but that's a separate issue -- see other thread) > > -Andi >