Messages in this thread |  | | From | Kees Cook <> | Date | Sat, 15 Apr 2017 10:41:28 -0700 | Subject | Re: [PATCH] misc: lkdtm: Add volatile to intentional NULL pointer reference |
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On Fri, Apr 14, 2017 at 2:15 PM, Matthias Kaehlcke <mka@chromium.org> wrote: > From: Michael Davidson <md@google.com> > > Add a volatile qualifier where a NULL pointer is deliberately > dereferenced to trigger a panic. > > Without the volatile qualifier clang will issue the following warning: > "indirection of non-volatile null pointer will be deleted, > not trap [-Wnull-dereference]" and replace the pointer reference > with a __builtin_trap() (which generates a ud2 instruction on x86_64). > > Signed-off-by: Michael Davidson <md@google.com> > Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Thanks!
Acked-by: Kees Cook <keescook@chromium.org>
Greg, please add this to drivers/misc when you get a chance. :)
-Kees
> --- > drivers/misc/lkdtm_bugs.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/misc/lkdtm_bugs.c b/drivers/misc/lkdtm_bugs.c > index e3f4cd8876b5..d734d75afade 100644 > --- a/drivers/misc/lkdtm_bugs.c > +++ b/drivers/misc/lkdtm_bugs.c > @@ -67,7 +67,7 @@ void lkdtm_WARNING(void) > > void lkdtm_EXCEPTION(void) > { > - *((int *) 0) = 0; > + *((volatile int *) 0) = 0; > } > > void lkdtm_LOOP(void) > -- > 2.12.2.762.g0e3151a226-goog >
-- Kees Cook Pixel Security
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