Compile error with SPL_FIT_FULL_CHECK and SPL_LOAD_FIT_FULL enabled

[Johann Neuhauser]

> -----Original Message-----
> From: Simon Glass [mailto:sjg at chromium.org]
> Sent: Tuesday, February 8, 2022 6:13 PM
> 
> Hi Johann,
> 
Hi Simon,

thanks for your fast answer.

> On Tue, 8 Feb 2022 at 08:44, Johann Neuhauser
> <jneuhauser at dh-electronics.com> wrote:
> >
> > Dear developers and Simon,
> >
> > we wanna run secure boot with U-Boot's SPL_FIT_SIGNATURE and FIT_SIGNATURE on our STM32MP1 boards and discovered the CVE-2021-27097.
> 
> That is already fixed in 2021.04 so you can just use a mainline U-Boot
> to avoid it.
> 
So we don't need the FIT_FULL_CHECK config symbols to mitigate against
CVE-2021-27097 andwe're save if we use anything after 2021.04?

> > To mitigate this vulnerability we wanna enable SPL_LOAD_FIT_FULL and SPL_FIT_FULL_CHECK.
> > If I compile any U-Boot SPL with the mentioned config symbols after commit 6f3c2d8a, it fails always with the following error message:
> >
> > Used defconfig: stm32mp15_dhcom_basic_defconfig (+ mentioned configs enabled)
> > ```
> > ...
> >   LD      spl/lib/built-in.o
> >   LD      spl/u-boot-spl
> > /usr/bin/arm-linux-gnueabihf-ld.bfd: common/built-in.o: in function `fit_check_format':
> > /mnt/work/dev/u-boot/common/image-fit.c:1591: undefined reference to `fdt_check_full'
> > make[1]: *** [scripts/Makefile.spl:432: spl/u-boot-spl] Error 1
> > make: *** [Makefile:1941: spl/u-boot-spl] Error 2
> > ```
> > After diging around to find the cause, we're out of ideas.
> > Does anyone have a clue why the needed function is not compiled in libfdt for the spl build?
> 
> SPL_OF_LIBFDT_ASSUME_MASK is set to 0xff so this check is not enabled.
> I suspect that the value of that setting should change to 0 or 1 if
> the full check is enabled.
> 
I have come across this symbol before, but I did not pay any attention to it and
rather looked for the problem in Makefile's related to SPL build.
Many thanks for the hint.

> Regards,
> Simon

Best regards,
Johann