20220911-fixes-re-multi-test

[douzzer]

wolfssl/wolfcrypt/sp_int.h and wolfcrypt/src/sp_int.c:

add struct sp_int_minimal, with same structure as struct sp_int but only one digit, to allow error-free access to sp_ints allocated with ALLOC_SP_INT() with fewer than SP_INT_DIGITS digits, and use the new type in _sp_zero() and sp_init_size() to eliminate -Werror=array-bounds on _sp_zero() under gcc-13.

tested with wolfssl-mult-test.sh ... super-quick-check fips-140-3-dev-optest-acvp-sp-asm-gcc-latest linuxkm-mainline-pie-gcc-latest at testing commit 7ccf1f2c3b9 (PR#346).

also adds support for $KBUILD_EXTRA_FLAGS to linuxkm/Makefile, needed to activate linuxkm-mainline-pie-gcc-latest.

[douzzer]

@SparkiDev note all tests have passed on this. The "pending" on Options-A and FIPSv2 Regression are Jenkins->github integration glitches.

[SparkiDev]

Tried gcc-13 with -Werror=array-bounds with --enable-all and it didn't fail. (Not FIPS or kernel.)
What else do I have to do?

[douzzer]

So far I've only gotten it to trigger in the linuxkm build. That's what the copy-paste is from.

My guess is it's something to do with the options that Kbuild is passing to gcc.

Anyway the new linuxkm-mainline-pie-gcc-latest scenario in wolfssl-multi-test.sh exercises it, but only after this PR merges (the $(KBUILD_EXTRA_FLAGS) stuff in linuxkm/Makefile is needed).

[SparkiDev]

What are the KBUILD_EXTRA_FLAGS?
grep found nothing so I assume it is something you add.
List them if possible.

[douzzer]

That's the recipe in linuxkm-mainline-pie-gcc-latest, referenced in the initial PR message. That new scenario is already merged. It is, in relevant part:

    KBUILD_EXTRA_FLAGS="CC=$GCC_LATEST HOSTCC=$GCC_LATEST" do_scenario_no_check "$scenario" CC="$GCC_LATEST" HOSTCC="$GCC_LATEST" "${ENABLE_ALL_TEST_FLAGS[@]}" --enable-aesni --enable-sp-asm --enable-linuxkm --enable-linuxkm-pie --enable-reproducible-build --enable-crypttests --with-linux-source="${linux[$linux_cur]}"

The only difference between the long-existing linuxkm-mainline-pie scenario and the new one is the KBUILD_EXTRA_FLAGS=... at the start, and the CC="$GCC_LATEST" HOSTCC="$GCC_LATEST" args to configure.