On Fri, Mar 17, 2023 at 12:18:01PM -0600, Gustavo A. R. Silva wrote:
> Zero-length arrays as fake flexible arrays are deprecated and we are
> moving towards adopting C99 flexible-array members instead.
>
> Address the following warning found with GCC-13 and
> -fstrict-flex-arrays=3 enabled:
> drivers/gpu/drm/i915/gem/i915_gem_context.c: In function ‘set_proto_ctx_engines.isra’:
> drivers/gpu/drm/i915/gem/i915_gem_context.c:769:41: warning: array subscript n is outside array bounds of ‘struct i915_engine_class_instance[0]’ [-Warray-bounds=]
> 769 | if (copy_from_user(&ci, &user->engines[n], sizeof(ci))) {
> | ^~~~~~~~~~~~~~~~~
> ./include/uapi/drm/i915_drm.h:2494:43: note: while referencing ‘engines’
> 2494 | struct i915_engine_class_instance engines[0];
>
> This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
> routines on memcpy() and help us make progress towards globally
> enabling -fstrict-flex-arrays=3 [1].
>
> Link: https://github.com/KSPP/linux/issues/21
> Link: https://github.com/KSPP/linux/issues/271
> Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1]
> Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
--
Kees Cook
