From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Biggers Date: Wed, 09 Jan 2019 17:34:55 +0000 Subject: Re: [PATCH 1/5 v2] PM / hibernate: Create snapshot keys handler Message-Id: <20190109173454.GB249140@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="windows-1250" Content-Transfer-Encoding: base64 List-Id: References: <20190103143227.9138-1-jlee@suse.com> <1894062.aDvIuj92vB@tauon.chronox.de> <20190109082103.GA8586@sol.localdomain> <2344329.gmPllosFfp@tauon.chronox.de> In-Reply-To: <2344329.gmPllosFfp@tauon.chronox.de> To: Stephan Mueller Cc: James Bottomley , Andy Lutomirski , Herbert Xu , "Lee, Chun-Yi" , "Rafael J . Wysocki" , Pavel Machek , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, keyrings@vger.kernel.org, "Rafael J. Wysocki" , Chen Yu , Oliver Neukum , Ryan Chen , David Howells , Giovanni Gherdovich , Randy Dunlap , Jann Horn , Andy Lutomirski T24gV2VkLCBKYW4gMDksIDIwMTkgYXQgMTE6MTc6NDVBTSArMDEwMCwgU3RlcGhhbiBNdWVsbGVy IHdyb3RlOgo+IEFtIE1pdHR3b2NoLCA5LiBKYW51YXIgMjAxOSwgMDk6MjE6MDQgQ0VUIHNjaHJp ZWIgRXJpYyBCaWdnZXJzOgo+IAo+IEhpIEVyaWMsCj4gPiAKPiA+IEZXSVcsIGl0J3MgYmVlbiB2 ZXJ5IHNsb3cgZ29pbmcgc2luY2UgSSd2ZSBiZWVuIHdvcmtpbmcgb24gb3RoZXIgcHJvamVjdHMK PiA+IGFuZCBJIGFsc28gbmVlZCB0byBiZSB2ZXJ5IHN1cmUgdG8gZ2V0IHRoZSBBUEkgY2hhbmdl cyByaWdodCwgYnV0IEkgc3RpbGwKPiA+IHBsYW4gdG8gY2hhbmdlIHRoZSBLREYgaW4gZnNjcnlw dCAoYS5rLmEuIGV4dDQvZjJmcy91YmlmcyBlbmNyeXB0aW9uKSB0bwo+ID4gSEtERi1TSEE1MTIg YXMgcGFydCBvZiBhIGxhcmdlciBzZXQgb2YgaW1wcm92ZW1lbnRzIHRvIGhvdyBmc2NyeXB0Cj4g PiBlbmNyeXB0aW9uIGtleXMgYXJlIG1hbmFnZWQuIEkgc2VudCB0aGUgbGFzdCBwYXRjaHNldCBh IHllYXIgYWdvCj4gPiAoaHR0cHM6Ly9tYXJjLmluZm8vP2w9bGludXgtZnNkZXZlbCZtFTA4Nzk0 OTMyMDYyNTcpIGJ1dCBJJ20gd29ya2luZyB0bwo+ID4gcmV2aXZlIGl0LiAgSW4gdGhlIHdvcmst aW4tcHJvZ3Jlc3MgdmVyc2lvbiBpbiBteSBnaXQgdHJlZSwgdGhpcyBpcyB0aGUKPiA+IGNvbW1p dCB0aGF0IGFkZHMgYSBIS0RGIGltcGxlbWVudGF0aW9uIGFzIGZzL2NyeXB0by9oa2RmLmM6Cj4g PiBodHRwczovL2dpdC5rZXJuZWwub3JnL3B1Yi9zY20vbGludXgva2VybmVsL2dpdC9lYmlnZ2Vy cy9saW51eC5naXQvY29tbWl0Lz9pZOhhNzg3NjcxMzFjOTcxN2VlODM4ZjBjNGUzMDc5NDhkNjVh NDQyNwo+ID4gSXQgYmFzaWNhbGx5IGp1c3Qgd3JhcHMgYSBjcnlwdG9fc2hhc2ggZm9yICJobWFj KHNoYTUxMikiLgo+ID4gCj4gPiBJJ2QgYmUgZmluZSB3aXRoIHVzaW5nIGEgY29tbW9uIGltcGxl bWVudGF0aW9uIGluc3RlYWQsIHByb3ZpZGVkIHRoYXQgaXQKPiA+IGdpdmVzIHRoZSBzYW1lIGZ1 bmN0aW9uYWxpdHksIGluY2x1ZGluZyBzdXBwb3J0aW5nIHVzZXItc3BlY2lmaWVkIHNhbHQgYW5k Cj4gPiBhcHBsaWNhdGlvbi1zcGVjaWZpYyBpbmZvIHN0cmluZ3MsIGFuZCBpc24ndCBzbG93ZXIg b3IgbW9yZSBjb21wbGV4IHRvIHVzZS4KPiA+IAo+ID4gKFRoaXMgY29tbWVudCBpcyBzb2xlbHkg b24gdGhlIHRhbmdlbnRpYWwgZGlzY3Vzc2lvbiBhYm91dCBLREYKPiA+IGltcGxlbWVudGF0aW9u czsgSSd2ZSBub3QgbG9va2VkIGF0IHRoZSBoaWJlcm5hdGlvbiBpbWFnZSBlbmNyeXB0aW9uIHN0 dWZmCj4gPiB5ZXQuKQo+IAo+IFRoYW5rcyBmb3IgdGhlIGNsYXJpZmljYXRpb24uIEkgaGF2ZSBz dGFydGVkIGEgZ2VuZXJpYyBIS0RGIGltcGxlbWVudGF0aW9uIGZvciAKPiB0aGUga2VybmVsIGNy eXB0byBBUEkgd2hpY2ggbGVhZCB0byB0aGUgcXVlc3Rpb25zIGFib3ZlLiBJIHdvdWxkIHRoZW4g YWxzbyB0cnkgCj4gdG8gcHJvdmlkZSBhIEhLREYgcHJvcG9zYWwuCj4gCj4gVG8gdXNlIHRoZSAo SClLREYsIEkgY3VycmVudGx5IGVudmlzaW9uIDIgY2FsbHMgYXBhcnQgZnJvbSBhbGxvYy9mcmVl LiBUaGUgCj4gZm9sbG93aW5nIGNvZGUgd291bGQgc2VydmUgYXMgYW4gZXhhbXBsZS4KPiAKPiAg KiBFeGFtcGxlIHdpdGhvdXQgcHJvcGVyIGVycm9yIGhhbmRsaW5nOgo+ICAqICAgICAgY2hhciAq a2V5aW5nX21hdGVyaWFsID0gIlx4MDBceDExXHgyMlx4MzNceDQ0XHg1NVx4NjZceDc3IjsKPiAg KiAgICAgIGNoYXIgKmxhYmVsX2NvbnRleHQgPSAiXHhkZVx4YWRceGJlXHhlZlx4MDBceGRlXHhh ZFx4YmVceGVmIjsKPiAgKiAgICAgIGtkZiA9IGNyeXB0b19hbGxvY19ybmcobmFtZSwgMCwgMCk7 Cj4gICogICAgICBjcnlwdG9fcm5nX3Jlc2V0KGtkZiwga2V5aW5nX21hdGVyaWFsLCA4KTsKPiAg KiAgICAgIGNyeXB0b19ybmdfZ2VuZXJhdGUoa2RmLCBsYWJlbF9jb250ZXh0LCA5LCBvdXRidWYs IG91dGJ1Zmxlbik7Cj4gCj4gVGhhdCBob3BlZnVsbHkgc2hvdWxkIGJlIHNpbXBsZSBlbm91Z2gu Cj4gCj4gRm9yIEhLREYsIGFzIG1lbnRpb25lZCwgSSB3b3VsZCBlbnZpc2lvbiB0byB1c2UgYSBz dHJ1Y3QgaW5zdGVhZCBvZiBhIGNoYXIgKiAKPiBmb3IgdGhlIGxhYmVsX2NvbnRleHQgdG8gY29t bXVuaWNhdGUgSUtNLCBTYWx0LCBhbmQgdGhlIGxhYmVsL2luZm8gCj4gaW5mb3JtYXRpb24uCj4g Cj4gQ2lhbwo+IFN0ZXBoYW4KPiAKClRoYXQgd291bGQgbm90IG1lZXQgbXkgcGVyZm9ybWFuY2Ug cmVxdWlyZW1lbnRzIGFzIEkgd2FudCB0byBwcmVjb21wdXRlCkhLREYtRXh0cmFjdCwgYW5kIHRo ZW4gZG8gSEtERi1FeHBhbmQgbWFueSB0aW1lcy4gIEFsc28gdGhlIEhLREYtRXhwYW5kIHBhcnQK c2hvdWxkIGJlIHRocmVhZC1zYWZlIGFuZCBub3QgcmVxdWlyZSBhbGxvY2F0aW5nIG1lbW9yeSwg ZXNwZWNpYWxseSBub3QgYSB3aG9sZQpjcnlwdG9fc2hhc2ggdGZtIGV2ZXJ5IHRpbWUuCgpTbyBw cmVzdW1hYmx5IHdpdGggY3J5cHRvX3JuZywgY3J5cHRvX3JuZ19yZXNldCgpIHdvdWxkIG5lZWQg dG8gdGFrZSB0aGUgaW5wdXQKa2V5cmluZyBtYXRlcmlhbCBhbmQgc2FsdCBhbmQgZG8gSEtERi1F eHRyYWN0IChsaWtlIG15IGZzY3J5cHRfaW5pdF9oa2RmKCkpLCBhbmQKY3J5cHRvX3JuZ19nZW5l cmF0ZSgpIHdvdWxkIG5lZWQgdG8gdGFrZSB0aGUgYXBwbGljYXRpb24tc3BlY2lmaWMgaW5mbyBz dHJpbmcKYW5kIGRvIEhLREYtRXhwYW5kIChsaWtlIG15IGZzY3J5cHRfaGtkZl9leHBhbmQoKSku CgpJdCBpcyB1Z2x5IHRob3VnaC4gIFBsZWFzZSBhbHNvIGNvbnNpZGVyIGp1c3QgaGF2aW5nIHNp bXBsZSBjcnlwdG9faGtkZl8qKCkKaGVscGVyIGZ1bmN0aW9ucyB3aGljaCB3cmFwIGEgSE1BQyB0 Zm0gYWxvbmcgdGhlIGxpbmVzIG9mIG15IHBhdGNoLCByYXRoZXIgdGhhbgpzaG9laG9ybmluZyBp dCBpbnRvIHRoZSBjcnlwdG9fcm5nIEFQSS4KCi0gRXJpYw== From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FSL_HELO_FAKE,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 13001C43387 for ; Wed, 9 Jan 2019 17:35:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D306F20859 for ; Wed, 9 Jan 2019 17:34:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547055299; bh=XCMs1JHLKW8yUEThiH5H4LK1zaopKG2S5ef0xFv4hC8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=B58gmGdcDjtvOr+njK8A4VY5/kbst6t4m/kRP9cRhgPlELY3RGNcfWrjv2qWccZ+/ vqESCEOqdvsb7KY7M5HqPRXYBm+fLFhzAbGOqFQ2wQe7TJYnxNC5QGtuyoDS9XOEET 8g9XHUongg91qUC6FGtz2TqlhlT1u4yy42iTMKYk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726966AbfAIRe7 (ORCPT ); Wed, 9 Jan 2019 12:34:59 -0500 Received: from mail.kernel.org ([198.145.29.99]:33700 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726446AbfAIRe6 (ORCPT ); Wed, 9 Jan 2019 12:34:58 -0500 Received: from gmail.com (unknown [104.132.1.77]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9D055206BB; Wed, 9 Jan 2019 17:34:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547055297; bh=XCMs1JHLKW8yUEThiH5H4LK1zaopKG2S5ef0xFv4hC8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nVjxO7sH1XLw16NC/hIOJg64WVq5Rgo87CrLQhYdrxGZuSmuMYaBVXT4gcZj8KgPd Ab56kcbpQTk2xHTrYlm3gaTPKMOToWx+z0pZGkEBBGTuXv9TGYQxPIlweh5tElQXxO vrx9qu0OW4MKDhEdRGXf8gZYbXG3C57X3wPS2E+M= Date: Wed, 9 Jan 2019 09:34:55 -0800 From: Eric Biggers To: Stephan Mueller Cc: James Bottomley , Andy Lutomirski , Herbert Xu , "Lee, Chun-Yi" , "Rafael J . Wysocki" , Pavel Machek , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, keyrings@vger.kernel.org, "Rafael J. Wysocki" , Chen Yu , Oliver Neukum , Ryan Chen , David Howells , Giovanni Gherdovich , Randy Dunlap , Jann Horn , Andy Lutomirski Subject: Re: [PATCH 1/5 v2] PM / hibernate: Create snapshot keys handler Message-ID: <20190109173454.GB249140@gmail.com> References: <20190103143227.9138-1-jlee@suse.com> <1894062.aDvIuj92vB@tauon.chronox.de> <20190109082103.GA8586@sol.localdomain> <2344329.gmPllosFfp@tauon.chronox.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2344329.gmPllosFfp@tauon.chronox.de> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 09, 2019 at 11:17:45AM +0100, Stephan Mueller wrote: > Am Mittwoch, 9. Januar 2019, 09:21:04 CET schrieb Eric Biggers: > > Hi Eric, > > > > FWIW, it's been very slow going since I've been working on other projects > > and I also need to be very sure to get the API changes right, but I still > > plan to change the KDF in fscrypt (a.k.a. ext4/f2fs/ubifs encryption) to > > HKDF-SHA512 as part of a larger set of improvements to how fscrypt > > encryption keys are managed. I sent the last patchset a year ago > > (https://marc.info/?l=linux-fsdevel&m=150879493206257) but I'm working to > > revive it. In the work-in-progress version in my git tree, this is the > > commit that adds a HKDF implementation as fs/crypto/hkdf.c: > > https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux.git/commit/?id=e8a78767131c9717ee838f0c4e307948d65a4427 > > It basically just wraps a crypto_shash for "hmac(sha512)". > > > > I'd be fine with using a common implementation instead, provided that it > > gives the same functionality, including supporting user-specified salt and > > application-specific info strings, and isn't slower or more complex to use. > > > > (This comment is solely on the tangential discussion about KDF > > implementations; I've not looked at the hibernation image encryption stuff > > yet.) > > Thanks for the clarification. I have started a generic HKDF implementation for > the kernel crypto API which lead to the questions above. I would then also try > to provide a HKDF proposal. > > To use the (H)KDF, I currently envision 2 calls apart from alloc/free. The > following code would serve as an example. > > * Example without proper error handling: > * char *keying_material = "\x00\x11\x22\x33\x44\x55\x66\x77"; > * char *label_context = "\xde\xad\xbe\xef\x00\xde\xad\xbe\xef"; > * kdf = crypto_alloc_rng(name, 0, 0); > * crypto_rng_reset(kdf, keying_material, 8); > * crypto_rng_generate(kdf, label_context, 9, outbuf, outbuflen); > > That hopefully should be simple enough. > > For HKDF, as mentioned, I would envision to use a struct instead of a char * > for the label_context to communicate IKM, Salt, and the label/info > information. > > Ciao > Stephan > That would not meet my performance requirements as I want to precompute HKDF-Extract, and then do HKDF-Expand many times. Also the HKDF-Expand part should be thread-safe and not require allocating memory, especially not a whole crypto_shash tfm every time. So presumably with crypto_rng, crypto_rng_reset() would need to take the input keyring material and salt and do HKDF-Extract (like my fscrypt_init_hkdf()), and crypto_rng_generate() would need to take the application-specific info string and do HKDF-Expand (like my fscrypt_hkdf_expand()). It is ugly though. Please also consider just having simple crypto_hkdf_*() helper functions which wrap a HMAC tfm along the lines of my patch, rather than shoehorning it into the crypto_rng API. - Eric