On Thu, Oct 1, 2015 at 4:17 AM, Ingo Molnar <mingo@xxxxxxxxxx> wrote: > > * Dave Hansen <dave@xxxxxxxx> wrote: > >> > If yes then this could be a significant security feature / usecase for pkeys: Which CPUs (will) have pkeys? >> > executable sections of shared libraries and binaries could be mapped with pkey >> > access disabled. If I read the Intel documentation correctly then that should >> > be possible. >> >> Agreed. I've even heard from some researchers who are interested in this: >> >> https://www.infsec.cs.uni-saarland.de/wp-content/uploads/sites/2/2014/10/nuernberger2014ccs_disclosure.pdf > > So could we try to add an (opt-in) kernel option that enables this transparently > and automatically for all PROT_EXEC && !PROT_WRITE mappings, without any > user-space changes and syscalls necessary? I would like this very much. :) > Beyond the security improvement, this would enable this hardware feature on most > x86 Linux distros automatically, on supported hardware, which is good for testing. > > Assuming it boots up fine on a typical distro, i.e. assuming that there are no > surprises where PROT_READ && PROT_EXEC sections are accessed as data. I can't wait to find out what implicitly expects PROT_READ from PROT_EXEC mappings. :) -Kees -- Kees Cook Chrome OS Security -- 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>