Received-SPF: pass (google.com: domain of linux-crypto-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Fri, 29 Oct 2021 17:21:24 +0200
From:   Nicolas Toromanoff <nicolas.toromanoff@foss.st.com>
To:     Marek Vasut <marex@denx.de>
CC:     Nicolas Toromanoff <nicolas.toromanoff@foss.st.com>,
        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>
Subject: Re: [PATCH 4/8] crypto: stm32/cryp - fix race condition
In-Reply-To: <1ec60d9c-1ab4-8a92-1c6d-8093232ca039@denx.de>
Message-ID: <alpine.DEB.2.21.2110291708040.20378@gnbcxd0088.gnb.st.com>
References: <20211029135454.4383-1-nicolas.toromanoff@foss.st.com> <20211029135454.4383-5-nicolas.toromanoff@foss.st.com> <1ec60d9c-1ab4-8a92-1c6d-8093232ca039@denx.de>
User-Agent: Alpine 2.21 (DEB 202 2017-01-01)
MIME-Version: 1.0
Content-Type: text/plain; charset="US-ASCII"; format=flowed
Precedence: bulk

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

while(true) do ; modprobe stm32-cryp && modprobe -r stm32-cryp ; done

ran a whole day without a crash, nor a detected error.

-- 
Nicolas.