Received-SPF: pass (google.com: domain of linux-crypto-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Wed, 31 Aug 2022 16:56:44 +0800
From:   Herbert Xu <herbert@gondor.apana.org.au>
To:     Ignat Korchagin <ignat@cloudflare.com>
Cc:     "David S . Miller" <davem@davemloft.net>,
        linux-crypto <linux-crypto@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        kernel-team <kernel-team@cloudflare.com>
Subject: Re: [PATCH] crypto: akcipher - default implementations for setting
 private/public keys
Message-ID: <Yw8iTNjGlsP1LpNG@gondor.apana.org.au>
References: <20220729165954.991-1-ignat@cloudflare.com>
 <Yv9dvvy0rK/1T0sU@gondor.apana.org.au>
 <CALrw=nEh7LX3DSCa3FTu8BYr4QWx+W2h3Jei9Qo67+XXH-Vegw@mail.gmail.com>
 <Yw3Rneo6Ik1QEfbG@gondor.apana.org.au>
 <CALrw=nGJgMACrFVy+FVVCDb4H3wNUN2E-GLZaXzLsm3ReOUeVg@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CALrw=nGJgMACrFVy+FVVCDb4H3wNUN2E-GLZaXzLsm3ReOUeVg@mail.gmail.com>
Precedence: bulk

On Tue, Aug 30, 2022 at 11:48:23AM +0100, Ignat Korchagin wrote:
>
> I vaguely remember some initial research in quantum-resistant
> signatures, which used HMAC for "signing" thus don't have any public
> keys. But it is way beyond my expertise to comment on the practicality
> and availability of such schemes.

We could always add this again should an algorithm requiring
it be introduced.

> I'm more concerned here about a buggy "third-party" RSA driver, which
> may not implement the callback and which gets prioritised by the
> framework, thus giving the ability to trigger a NULL-ptr dereference
> from userspace via keyctl(2). I think the Crypto API framework should
> be a bit more robust to handle such a case, but I also understand that
> there are a lot of "if"s in this scenario and we can say it is up to
> crypto driver not to be buggy. Therefore, consider my opinion as not
> strong and I can post a v2, which does not provide a default stub for
> set_pub_key, if you prefer.

If you're concerned with buggy algorithms/drivers, we should
ensure that the self-tests catch this.

Cheers,
-- 
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