Re: [PATCH 4/8] crypto: stm32/cryp - fix race condition

[Marek Vasut]

On 10/29/21 5:21 PM, Nicolas Toromanoff wrote:
> On Fri, 29 Oct 2021, Marek Vasut wrote:
>
> > On 10/29/21 3:54 PM, Nicolas Toromanoff wrote:
> > > Erase key before finalizing request.
> > > Fixes: 9e054ec21ef8 ("crypto: stm32 - Support for STM32 CRYP crypto 
> > > module")
> >
> > Can you be a bit more specific in your commit messages ? That applies 
> > to the entire patchset. It is absolutely impossible to tell what race 
> > is fixed here or why it is fixed by exactly this change. This applies 
> > to the entire series.
>
> I'll send a v2 with better commit messages.
>
> for this specific patch:
> We reset the saved key before the crypto_finalize_*() call. Otherwise a 
> still pending crypto action could be ran with a wrong key = {0};
>
> > And while I am at it, does the CRYP finally pass at least the most 
> > basic kernel boot time crypto tests or does running those still 
> > overwrite kernel memory and/or completely crash or lock up the machine ?
>
> All extra tests (finally) pass.
>
> With a kernel config :
>    # CONFIG_CRYPTO_MANAGER_DISABLE_TESTS is not set
>    CONFIG_CRYPTO_MANAGER_EXTRA_TESTS=y
>    CONFIG_CRYPTO_DEV_STM32_CRYP=m

Can you also do a boot test with CRYP compiled into the kernel ?
I recall that is how the original bug was reported -- the machine 
crashed completely on boot even before reaching userspace, or the kernel 
crashed on memory corruption before reaching userspace.