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Date:   Fri, 9 Sep 2022 17:07:41 +0800
From:   Herbert Xu <herbert@gondor.apana.org.au>
To:     Ignat Korchagin <ignat@cloudflare.com>
Cc:     "David S . Miller" <davem@davemloft.net>,
        linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
        kernel-team@cloudflare.com
Subject: Re: [PATCH v2] crypto: akcipher - default implementation for setting
 a private key
Message-ID: <YxsCXdftDX2OPJ9r@gondor.apana.org.au>
References: <20220831183706.1600-1-ignat@cloudflare.com>
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On Wed, Aug 31, 2022 at 07:37:06PM +0100, Ignat Korchagin wrote:
> Changes from v1:
>   * removed the default implementation from set_pub_key: it is assumed that
>     an implementation must always have this callback defined as there are
>     no use case for an algorithm, which doesn't need a public key
> 
> Many akcipher implementations (like ECDSA) support only signature
> verifications, so they don't have all callbacks defined.
> 
> Commit 78a0324f4a53 ("crypto: akcipher - default implementations for
> request callbacks") introduced default callbacks for sign/verify
> operations, which just return an error code.
> 
> However, these are not enough, because before calling sign the caller would
> likely call set_priv_key first on the instantiated transform (as the
> in-kernel testmgr does). This function does not have a default stub, so the
> kernel crashes, when trying to set a private key on an akcipher, which
> doesn't support signature generation.
> 
> I've noticed this, when trying to add a KAT vector for ECDSA signature to
> the testmgr.
> 
> With this patch the testmgr returns an error in dmesg (as it should)
> instead of crashing the kernel NULL ptr dereference.
> 
> Fixes: 78a0324f4a53 ("crypto: akcipher - default implementations for request callbacks")
> Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
> ---
>  crypto/akcipher.c | 8 ++++++++
>  1 file changed, 8 insertions(+)

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt