From mboxrd@z Thu Jan 1 00:00:00 1970 From: labbott@redhat.com (Laura Abbott) Date: Mon, 13 Mar 2017 14:59:23 -0700 Subject: [RFC PATCH 00/12] Ion cleanup in preparation for moving out of staging In-Reply-To: References: <1488491084-17252-1-git-send-email-labbott@redhat.com> <20170303132949.GC31582@dhcp22.suse.cz> <20170306074258.GA27953@dhcp22.suse.cz> <20170306104041.zghsicrnadoap7lp@phenom.ffwll.local> <20170306105805.jsq44kfxhsvazkm6@sirena.org.uk> <20170306160437.sf7bksorlnw7u372@phenom.ffwll.local> <26bc57ae-d88f-4ea0-d666-2c1a02bf866f@redhat.com> <6d3d52ba-29a9-701f-2948-00ce28282975@redhat.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 03/13/2017 02:29 PM, Rob Clark wrote: > On Mon, Mar 13, 2017 at 5:09 PM, Laura Abbott wrote: >>> Hm, we might want to expose all the heaps as individual >>> /dev/ion_$heapname nodes? Should we do this from the start, since >>> we're massively revamping the uapi anyway (imo not needed, current >>> state seems to work too)? >>> -Daniel >>> >> >> I thought about that. One advantage with separate /dev/ion_$heap >> is that we don't have to worry about a limit of 32 possible >> heaps per system (32-bit heap id allocation field). But dealing >> with an ioctl seems easier than names. Userspace might be less >> likely to hardcode random id numbers vs. names as well. > > > other advantage, I think, is selinux (brought up elsewhere on this > thread).. heaps at known fixed PAs are useful for certain sorts of > attacks so being able to restrict access more easily seems like a good > thing > > BR, > -R > Some other kind of filtering (BPF/LSM/???) might work as well (http://kernsec.org/files/lss2015/vanderstoep.pdf ?) The fixed PA issue is a larger problem. We're never going to be able to get away from "this heap must exist at address X" problems but the location of CMA in general should be randomized. I haven't actually come up with a good proposal to this though. I'd like for Ion to be a framework for memory allocation and not security exploits. Hopefully this isn't a pipe dream. Thanks, Laura