On Fri, Nov 27, 2015 at 12:03 PM, Kees Cook <keescook@xxxxxxxxxxxx> wrote: > On Fri, Nov 27, 2015 at 10:00 AM, Linus Torvalds > <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: >> On Thu, Nov 26, 2015 at 11:59 PM, Ingo Molnar <mingo@xxxxxxxxxx> wrote: >>> >>> * Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote: >>> >>>> > Can you see any fragility in such a technique? >>>> >>>> After Linus shot down my rdmsr/rwmsr decoding patch, good luck... >>> >>> I think that case was entirely different, but I've Cc:-ed Linus to shoot my idea >>> down if it's crap. >> >> Yeah, no, I hate it. I'm with the PaX team on this one - I think there >> are three valid responses, and I think we might want to have a dynamic >> config option (kernel command line or proc or whatever) to pick >> between the two: >> >> - just oops and kill the machine, like for any other unhandled kernel >> page fault. This is probably what you should have on a server > > This is how the v2 series works now. > >> - print a warning and a backtrace, and just mark the page read-write >> so that the machine survives, but we get notified and can fix whatever >> broken code > > This seems very easy to add. Should I basically reverse the effects of > mark_rodata_ro(), or should I only make the new ro-after-init section > as RW? (I think the former would be easier.) I'd suggest verifying that the page in question is .data..ro_after_init and, if so, marking that one page RW. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
