On 10/01/2015 03:48 PM, Linus Torvalds wrote: > On Thu, Oct 1, 2015 at 6:33 PM, Dave Hansen <d...@sr71.net> wrote: >> >> Here it is in a quite fugly form (well, it's not opt-in). Init crashes >> if I boot with this, though. >> >> I'll see if I can turn it in to a bit more of an opt-in and see what's >> actually going wrong. ... > That said, I don't understand your patch. Why check PROT_WRITE? We've > had :"execute but not write" forever. It's "execute and not *read*" > that is interesting.
I was thinking that almost anybody doing a PROT_WRITE|PROT_EXEC really *is* going to write to it so they'll notice pretty fast if we completely deny them access to it. Also, a quick ftrace showed that most mmap() callers that set PROT_EXEC also set PROT_READ. I'm just assuming that folks are setting PROT_READ but aren't _really_ going to read it, so we can safely deny them all access other than exec. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
