On Thu, Mar 23, 2017 at 10:25 AM, Thomas Garnier <thgarnie@xxxxxxxxxx> wrote: > This patch ensures a syscall does not return to user-mode with a kernel > address limit. If that happened, a process can corrupt kernel-mode > memory and elevate privileges. > > For example, it would mitigation this bug: > > - https://bugs.chromium.org/p/project-zero/issues/detail?id=990 > > The CONFIG_ARCH_NO_SYSCALL_VERIFY_PRE_USERMODE_STATE option is also > added so each architecture can optimize this change. > > Signed-off-by: Thomas Garnier <thgarnie@xxxxxxxxxx> Awesome. :) I've tested this on x86 and arm with the LKDTM patch I'll post in a moment. [ 46.977823] lkdtm: Performing direct entry CORRUPT_USER_DS [ 46.978966] lkdtm: setting bad task size limit [ 46.980302] ------------[ cut here ]------------ [ 46.981219] kernel BUG at ./include/linux/syscalls.h:200! Tested-by: Kees Cook <keescook@xxxxxxxxxxxx> (Also note, your Signed-off-by lines are missing in patches 2-4) -- Kees Cook Pixel Security -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
