On Fri, 2015-11-06 at 12:52 -0800, Kees Cook wrote: > On Thu, Nov 5, 2015 at 10:44 AM, Daniel Cashman <dcashman@xxxxxxxxxxx> wrote: > > On 11/04/2015 10:30 AM, Daniel Cashman wrote: > > > On 11/3/15 3:21 PM, Kees Cook wrote: > > > > On Tue, Nov 3, 2015 at 3:14 PM, Daniel Cashman <dcashman@xxxxxxxxxxx> wrote: > > > > > On 11/03/2015 11:19 AM, Kees Cook wrote: > > > > > > Do you have patches for x86 and arm64? > > > > > > > > > > I was holding off on those until I could gauge upstream reception. If > > > > > desired, I could put those together and add them as [PATCH 3/4] and > > > > > [PATCH 4/4]. > > > > > > > > If they're as trivial as I'm hoping, yeah, let's toss them in now. If > > > > not, skip 'em. PowerPC, MIPS, and s390 should be relatively simple > > > > too, but one or two of those have somewhat stranger calculations when > > > > I looked, so their Kconfigs may not be as clean. > > > > > > Creating the patches should be simple, it's the choice of minimum and > > > maximum values for each architecture that I'd be most concerned about. > > > I'll put them together, though, and the ranges can be changed following > > > discussion with those more knowledgeable, if needed. I also don't have > > > devices on which to test the PowerPC, MIPS and s390 changes, so I'll > > > need someone's help for that. > > > > Actually, in preparing the x86 and arm64 patches, it became apparent > > that the current patch-set does not address 32-bit executables running > > on 64-bit systems (compatibility mode), since only one procfs > > mmap_rnd_bits variable is created and exported. Some possible solutions: > > How about a single new CONFIG+sysctl that is the compat delta. For > example, on x86, it's 20 bits. Then we don't get splashed with a whole > new set of min/maxes, but we can reasonably control compat? Do you mean in addition to mmap_rnd_bits? So we'd end up with mmap_rnd_bits and also mmap_rnd_bits_compat_delta? (naming TBD) If so yeah I think that would work. It would have the nice property of allowing you to add some more randomness to all processes by bumping mmap_rnd_bits. But at the same time if you want to add a lot more randomness to 64-bit processes, but just a bit (or none) to 32-bit processes you can also do that. cheers -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>