From: Kamil Konieczny Subject: Re: [PATCH v3 0/5] crypto: ahash.c: Require export/import in ahash Date: Thu, 15 Feb 2018 19:06:53 +0100 Message-ID: References: <20180118183404.12583-1-k.konieczny@partner.samsung.com> <20180215154132.GA7352@gondor.apana.org.au> <6b29116a-c39c-9813-34a0-d5c05bd30c9d@denx.de> <32069edc-e816-6ab0-f057-b1dab5d30db4@partner.samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: linux-crypto@vger.kernel.org, "David S. Miller" , Bartlomiej Zolnierkiewicz , Sonic Zhang , Fabio Estevam , Shawn Guo , Tom Lendacky , Jan Engelhardt , Arvind Yadav , Linus Walleij , Joakim Bech , linux-kernel@vger.kernel.org To: Marek Vasut , Herbert Xu Return-path: In-reply-to: Content-language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org On 15.02.2018 18:06, Marek Vasut wrote: > On 02/15/2018 06:00 PM, Kamil Konieczny wrote: >> >> >> On 15.02.2018 17:27, Marek Vasut wrote: >>> On 02/15/2018 04:41 PM, Herbert Xu wrote: >>>> On Thu, Jan 18, 2018 at 07:33:59PM +0100, Kamil Konieczny wrote: >>>>> First four patches add empty hash export and import functions to each driver, >>>>> with the same behaviour as in crypto framework. The last one drops them from >>>>> crypto framework. Last one for ahash.c depends on all previous. >>>>> >>>>> Changes in v3: >>>>> added change for bfin_crc.c >>>>> make this a patchset, instead of unreleated patches >>>>> make commit message more descriptive >>>>> >>>>> Kamil Konieczny (5): >>>>> crypto: mxs-dcp: Add empty hash export and import >>>>> crypto: n2_core: Add empty hash export and import >>>>> crypto: ux500/hash: Add empty export and import >>>>> crypto: bfin_crc: Add empty hash export and import >>>>> crypto: ahash.c: Require export/import in ahash >>>>> >>>>> crypto/ahash.c | 18 ++---------------- >>>>> drivers/crypto/bfin_crc.c | 12 ++++++++++++ >>>>> drivers/crypto/mxs-dcp.c | 14 ++++++++++++++ >>>>> drivers/crypto/n2_core.c | 12 ++++++++++++ >>>>> drivers/crypto/ux500/hash/hash_core.c | 18 ++++++++++++++++++ >>>>> 5 files changed, 58 insertions(+), 16 deletions(-) >>>> >>>> All applied. Thanks. >>> >>> This makes no sense, cfr my comment on 5/5 >>> >>> Seems like if the driver doesn't implement those, the core can easily >>> detect that and perform the necessary action. Moving the checks out of >>> core seems like the wrong thing to do, rather you should enhance the >>> checks in core if they're insufficient in my opinion. >> >> The bug can only be in driver which will not implement those two functions, >> but we already had all drivers with those due to patches 1..4 >> All other drivers do have them. > > The core can very well check if these functions are not populated and > return ENOSYS > >> Additionally, with crypto we want minimize code and run as fast as possible. > > So you remove all NULL pointer checks ? Esp. in security-sensitive code? > What is the impact of this non-critical path code on performance? > > Come on ... > Why you want checks for something that not exist ? Those without them will not work and will do Oops in crypto testmgr, so such drivers should not be used nor accepted in drivers/crypto Ask yourself why crypto do not check for NULL in ahash digest or other required ahash functions. >> Moving checks out of core will impose on driver author need for implement >> those functions, or declare them empty, but in case of empty ones >> crypto will not work properly with such driver. > > You can very well impose that in the core, except you don't duplicate > the code. Now size of crypto core is reduced. -- Best regards, Kamil Konieczny Samsung R&D Institute Poland