Re: [PATCH 0/2] fortify: Add run-time WARN for cross-field memcpy()

From: Nathan Chancellor
Date: Thu Sep 01 2022 - 16:05:32 EST


Hi Kees,

On Wed, Aug 31, 2022 at 11:59:12PM -0700, Kees Cook wrote:
> Hi,
>
> I'm hoping to at least get this into -next to see how noisy it ends up
> being. I've tracked down several false positives that are getting fixed,
> but I'd like to see this get wider testing. For details, see patch 1,
> but this is the run-time half of the recent FORTIFY_SOURCE memcpy()
> bounds checking work.
>
> -Kees
>
> Kees Cook (2):
> fortify: Add run-time WARN for cross-field memcpy()
> lkdtm: Update tests for memcpy() run-time warnings
>
> drivers/misc/lkdtm/fortify.c | 96 +++++++++++++++++++++----
> include/linux/fortify-string.h | 70 +++++++++++++++++-
> tools/testing/selftests/lkdtm/tests.txt | 8 ++-
> 3 files changed, 155 insertions(+), 19 deletions(-)
>
> --
> 2.34.1
>

I took these two patches for a spin on four of my test machines (one
arm64 and three x86_64, kernel compiled with tip of tree clang) and I
did not see any warnings. Not to say there are not any lurking but my
set of drivers did not appear to trigger anything.

Tested-by: Nathan Chancellor <nathan@xxxxxxxxxx>

Cheers,
Nathan