From: Dave Watson Subject: Re: [PATCH v3 net-next 3/4] tls: kernel TLS support Date: Wed, 12 Jul 2017 11:34:35 -0700 Message-ID: <20170712183435.GA34250@davejwatson-mba.dhcp.thefacebook.com> References: <20170614183739.GA80368@davejwatson-mba.dhcp.thefacebook.com> <20170711062953.GE2631@secunet.com> <20170711185311.GA200@davejwatson-mba.dhcp.thefacebook.com> <20170712072012.GK2631@secunet.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: Ilya Lesokhin , Aviad Yehezkel , Boris Pismenny , Liran Liss , Matan Barak , David Miller , , Tom Herbert , , , Hannes Frederic Sowa , Eric Dumazet , Alexei Starovoitov , , To: Steffen Klassert Return-path: Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:40621 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752347AbdGLSfM (ORCPT ); Wed, 12 Jul 2017 14:35:12 -0400 Content-Disposition: inline In-Reply-To: <20170712072012.GK2631@secunet.com> Sender: linux-crypto-owner@vger.kernel.org List-ID: On 07/12/17 09:20 AM, Steffen Klassert wrote: > On Tue, Jul 11, 2017 at 11:53:11AM -0700, Dave Watson wrote: > > On 07/11/17 08:29 AM, Steffen Klassert wrote: > > > Sorry for replying to old mail... > > > > +int tls_set_sw_offload(struct sock *sk, struct tls_context *ctx) > > > > +{ > > > > > > ... > > > > > > > + > > > > + if (!sw_ctx->aead_send) { > > > > + sw_ctx->aead_send = crypto_alloc_aead("gcm(aes)", 0, 0); > > > > + if (IS_ERR(sw_ctx->aead_send)) { > > > > + rc = PTR_ERR(sw_ctx->aead_send); > > > > + sw_ctx->aead_send = NULL; > > > > + goto free_rec_seq; > > > > + } > > > > + } > > > > + > > > > > > When I look on how you allocate the aead transformation, it seems > > > that you should either register an asynchronous callback with > > > aead_request_set_callback(), or request for a synchronous algorithm. > > > > > > Otherwise you will crash on an asynchronous crypto return, no? > > > > The intention is for it to be synchronous, and gather directly from > > userspace buffers. It looks like calling > > crypto_alloc_aead("gcm(aes)", 0, CRYPTO_ALG_ASYNC) is the correct way > > to request synchronous algorithms only? > > Yes, but then you loose the aes-ni based algorithms because they are > asynchronous. If you want to have good crypto performance, it is > better to implement the asynchronous callbacks. Right, the trick is we want both aesni, and to guarantee that we are done using the input buffers before sendmsg() returns. For now I can set a callback, and wait on a completion. The initial use case of userspace openssl integration shouldn't hit the aesni async case anyway (!irq_fpu_usable())