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[209.132.180.67]) by mx.google.com with ESMTP id o137-v6si2547226pfg.362.2018.09.25.09.03.59; Tue, 25 Sep 2018 09:04:22 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel-dk.20150623.gappssmtp.com header.s=20150623 header.b=UXZT+IEP; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729714AbeIYWLl (ORCPT + 99 others); Tue, 25 Sep 2018 18:11:41 -0400 Received: from mail-it1-f194.google.com ([209.85.166.194]:50355 "EHLO mail-it1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729306AbeIYWLl (ORCPT ); Tue, 25 Sep 2018 18:11:41 -0400 Received: by mail-it1-f194.google.com with SMTP id j81-v6so16129476ite.0 for ; Tue, 25 Sep 2018 09:03:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=5GV4hMV5biu/RxQ0FvsNjPALRR2nr3ZmEGH7IGGYM6o=; b=UXZT+IEPIXmSNjFsb/R7lQZMVBEg8fdRi1K0a85aFAIdOcDn+jvBlSFYfUX4XSx9Wo ZdMcjB5qwrake++0L2VV6ZRrRbIhFzcjGWts7+TcQL040YqRPLEFqffjNbF1evnSauJZ Pio2tVNNz+hl6uV9moiglB6YI32QP3uQLhP8bWPin0qFP5yu6ROUcAcGLVFCdDfYt2FM RM5SbvEaYO2yDOUeRfksOYfam5lSCMry8aVf4I8DtGsb2In2DE5+9E53sO4L8Mra92go aykKE9LtYfPc1BW06HB8Wuc12Gq0t2x1YnaxEK3AeBWGQgsYBEOaZieafvKK74HohSfF Brtw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=5GV4hMV5biu/RxQ0FvsNjPALRR2nr3ZmEGH7IGGYM6o=; b=Orq8dyt2FtGXLmshAWPFrGomOWM1omrDFL63ejy74PpD47Nv2rrwwFjr1e3AMNjBQS 7WRT3yrACkl/pkkc9NIjygBg0byLSXcli87ZwzwwAYbuwbjK8NOhVCDjA00MvBDanfQj ZCaJZgfsAAGcp8gkIIMPpp3j8soneJmtYg0B5d15cpVMnddxKdaumV/vJ9OwG0+2cOjW w4MWuNoa+kvkpeN7J5q/lfmfaZ/bvA9nsRPeroF5b5nKYm4LEJphPpDy6NTLbO6lzO+q whvvetOgr3kDA/8HJKQvaNT0gYtJAxYMNejVYpuE9iGQg8owt9AYGoTtnTQ1H9N0MudZ 1OIA== X-Gm-Message-State: ABuFfojPW7vRrq9zecK9Jkfmdoxp6fEMbT94C43Wusqr0K/YOkpe04Bu 4RWpRKfeC4N/NWKtinEudQtP2bPJmiE= X-Received: by 2002:a24:7941:: with SMTP id z62-v6mr1370991itc.20.1537891410274; Tue, 25 Sep 2018 09:03:30 -0700 (PDT) Received: from [192.168.1.56] ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id v13-v6sm1083897ita.38.2018.09.25.09.03.28 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 25 Sep 2018 09:03:29 -0700 (PDT) Subject: Re: [PATCH crypto-next 07/23] block: cryptoloop: Remove VLA usage of skcipher To: Ard Biesheuvel , Kees Cook Cc: Herbert Xu , linux-block@vger.kernel.org, Eric Biggers , "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" , Linux Kernel Mailing List References: <20180919021100.3380-1-keescook@chromium.org> <20180919021100.3380-8-keescook@chromium.org> From: Jens Axboe Message-ID: <9c71afda-a668-10b3-842e-26f72e425691@kernel.dk> Date: Tue, 25 Sep 2018 10:03:27 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/25/18 3:25 AM, Ard Biesheuvel wrote: > On Mon, 24 Sep 2018 at 19:53, Kees Cook wrote: >> >> On Mon, Sep 24, 2018 at 4:52 AM, Ard Biesheuvel >> wrote: >>> On Wed, 19 Sep 2018 at 04:11, Kees Cook wrote: >>>> @@ -119,7 +119,7 @@ cryptoloop_transfer(struct loop_device *lo, int cmd, >>>> unsigned in_offs, out_offs; >>>> int err; >>>> >>>> - skcipher_request_set_tfm(req, tfm); >>>> + skcipher_request_set_sync_tfm(req, tfm); >>>> skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, >>>> NULL, NULL); >>>> >>> >>> Does this work? >> >> Everything is a direct wrapper for existing types and functions, so I >> wouldn't expect any functional change. I haven't been able to test >> this particular interface, though. cryptoloop is very deprecated, >> isn't it? >> > > Ah yes, I managed to confuse myself there. This looks all fine to me. > > In any case, this is another example where we may decide to fix the > code rather than retain the request allocation on the stack (but that > is Jens's call ultimately, I suppose) > > diff --git a/drivers/block/cryptoloop.c b/drivers/block/cryptoloop.c > index 7033a4beda66..5ed2167219ba 100644 > --- a/drivers/block/cryptoloop.c > +++ b/drivers/block/cryptoloop.c > @@ -110,7 +110,7 @@ cryptoloop_transfer(struct loop_device *lo, int cmd, > int size, sector_t IV) > { > struct crypto_skcipher *tfm = lo->key_data; > - SKCIPHER_REQUEST_ON_STACK(req, tfm); > + struct skcipher_request *req; > struct scatterlist sg_out; > struct scatterlist sg_in; > > @@ -119,7 +119,10 @@ cryptoloop_transfer(struct loop_device *lo, int cmd, > unsigned in_offs, out_offs; > int err; > > - skcipher_request_set_tfm(req, tfm); > + req = skcipher_request_alloc(tfm, GFP_NOIO); > + if (!req) > + return -ENOMEM; Is this going to be reliable? ->transfer() is called when we're doing IO, and you'd normally need a mempool backed allocation to make this safe and guarantee forward progress. -- Jens Axboe