Re: [PATCH] iwlwifi: calib: Refactor iwl_calib_result usage for clarity

Kees Cook [off-list ref] writes:

In preparation for FORTIFY_SOURCE performing run-time destination buffer
bounds checking for memcpy(), refactor the use of struct iwl_calib_result:

- Have struct iwl_calib_result contain struct iwl_calib_cmd since
  functions expect to operate on the "data" flex array in "cmd", which
  follows the "hdr" member.
- Switch argument passing around to use struct iwl_calib_cmd instead of
  struct iwl_calib_hdr to prepare functions to see the "data" member.
- Change iwl_calib_set()'s "len" argument to a size_t since it is always
  unsigned and is normally receiving the output of sizeof().
- Add an explicit length sanity check in iwl_calib_set().
- Adjust the memcpy() to avoid copying across the now visible composite
  flex array structure.

This avoids the future run-time warning:

  memcpy: detected field-spanning write (size 8) of single field "&res->hdr" (size 4)

Cc: Luca Coelho <redacted>
Cc: Kalle Valo <redacted>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Lee Jones <redacted>
Cc: Johannes Berg <redacted>
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
Reported-by: Andy Lavr <redacted>
Signed-off-by: Kees Cook <redacted>

Gregory, as this fixes a future warning can I take this directly to
wireless-next?

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