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Subject: Re: [PATCH 4/8] crypto: stm32/cryp - fix race condition
To:     Nicolas Toromanoff <nicolas.toromanoff@foss.st.com>
Cc:     Herbert Xu <herbert@gondor.apana.org.au>,
        "David S . Miller" <davem@davemloft.net>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        linux-crypto@vger.kernel.org,
        linux-stm32@st-md-mailman.stormreply.com,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
References: <20211029135454.4383-1-nicolas.toromanoff@foss.st.com>
 <20211029135454.4383-5-nicolas.toromanoff@foss.st.com>
 <1ec60d9c-1ab4-8a92-1c6d-8093232ca039@denx.de>
 <alpine.DEB.2.21.2110291708040.20378@gnbcxd0088.gnb.st.com>
From:   Marek Vasut <marex@denx.de>
Message-ID: <f8de0493-29f3-550c-611e-97b7ee36e628@denx.de>
Date:   Fri, 29 Oct 2021 18:48:43 +0200
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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.