Re: [PATCH v3 0/7] crypto: x86: Fix indirect function call casts

From: Kees Cook
Date: Tue May 07 2019 - 17:09:03 EST


On Tue, May 7, 2019 at 10:00 AM Eric Biggers <ebiggers@xxxxxxxxxx> wrote:
> > Given the above, the current efforts to improve the Linux security,
> > and the upcoming kernel support to compilers with CFI features, this
> > creates macros to be used to build the needed function definitions,
> > to be used in camellia, cast6, serpent, twofish, and aesni.
>
> So why not change the function prototypes to be compatible with common_glue_*_t
> instead, rather than wrapping them with another layer of functions? Is it
> because indirect calls into asm code won't be allowed with CFI?

I don't know why they're not that way to begin with. But given that
the casting was already happening, this is just moving it to a place
where CFI won't be angry. :)

> > crypto: x86/crypto: Use new glue function macros
>
> This one should be "x86/serpent", not "x86/crypto".

Oops, yes, that's my typo. I'll fix for v4. Do the conversions
themselves look okay (the changes are pretty mechanical)? If so,
Herbert, do you want a v4 with the typo fix, or do you want to fix
that up yourself?

Thanks!

--
Kees Cook