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Subject: Re: cbc mode broken in rk3288 driver
To:     Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" 
        <linux-crypto@vger.kernel.org>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Eric Biggers <ebiggers@kernel.org>
References: <CAKv+Gu8mjM7o+CuP9VrGX+cuix_zRupfozUoDbEWXHVGsW8syw@mail.gmail.com>
From:   Elon Zhang <zhangzj@rock-chips.com>
Message-ID: <cdf08891-3b55-e123-1e13-23866af3b289@rock-chips.com>
Date:   Fri, 23 Aug 2019 15:10:09 +0800
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Hi Ard,

I will try to fix this bug. Furthermore, I will submit a patch to  set 
crypto node default disable in rk3288.dtsi.

On 8/20/2019 23:45, Ard Biesheuvel wrote:
> Hello all,
>
> While playing around with the fuzz tests on kernelci.org (which has a
> couple of rk3288 based boards for boot testing), I noticed that the
> rk3288 cbc mode driver is still broken (both AES and DES fail).
>
> For instance, one of the runs failed with
>
>   alg: skcipher: cbc-aes-rk encryption test failed (wrong result) on
> test vector \"random: len=6848 klen=32\", cfg=\"random: may_sleep
> use_digest src_divs=[93.41%@+1655, 2.19%@+3968, 4.40%@+22]\"
>
> (but see below for the details of a few runs)
>
> However, more importantly, it looks like the driver violates the
> scatterlist API, by assuming that sg entries are always mapped and
> that sg_virt() and/or page_address(sg_page()) can always be called on
> arbitrary scatterlist entries
>
> The failures in question all occur with inputs whose size > PAGE_SIZE,
> so it looks like the PAGE_SIZE limit is interacting poorly with the
> way the next IV is obtained.
>
> Broken CBC is a recipe for disaster, and so this should really be
> fixed, or the driver disabled.
>