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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_MUTT autolearn=unavailable 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 92429C31E54 for ; Sun, 16 Jun 2019 19:11:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7314F20870 for ; Sun, 16 Jun 2019 19:11:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560712275; bh=itRunmQMhZsdhS/rynSumhBn1ggqw1d3eRVhGjzZi/4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=gWwA45w+DtRZnRdDjk45dENPFaeoP+8xWoc95lo9nnjBvKo78c1wqeEbZ6C9/4SuG UaNZTTqt5mDY0/yYqlbkQKf0Rc6hCF2FnLJ1GZ1XH3QjQj3oeAeZjzjapf/ZqgCGxq cu/m1RmsAl1WMeBr9bE7nw/9WvH+1sEYIrJ5qwE4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727287AbfFPTLO (ORCPT ); Sun, 16 Jun 2019 15:11:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:59728 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726085AbfFPTLO (ORCPT ); Sun, 16 Jun 2019 15:11:14 -0400 Received: from sol.localdomain (c-24-5-143-220.hsd1.ca.comcast.net [24.5.143.220]) (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 9B1A720862; Sun, 16 Jun 2019 19:11:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560712273; bh=itRunmQMhZsdhS/rynSumhBn1ggqw1d3eRVhGjzZi/4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oP86ai9bw7KgYwO8d0UxikG9JaRAX+Eg6S9dXhqTNx49Ys9ME3+0EfsDYpiEjlO30 XFx3TkthydjMHCN/BQHBLc9odyeyh6R8PzBkjsBs1FxW8V2TjxY2TdnOeQqPIN5oVq UToQl6q3a9B2+GhDaOe68ge0xm2+pWJfdCZVlwUI= Date: Sun, 16 Jun 2019 12:11:12 -0700 From: Eric Biggers To: Ard Biesheuvel Cc: linux-wireless@vger.kernel.org, johannes@sipsolutions.net, linux-crypto@vger.kernel.org, herbert@gondor.apana.org.au Subject: Re: [PATCH] lib80211: use crypto API ccm(aes) transform for CCMP processing Message-ID: <20190616191044.GB923@sol.localdomain> References: <20190614092922.22517-1-ard.biesheuvel@linaro.org> <20190616190136.GA923@sol.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190616190136.GA923@sol.localdomain> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org On Sun, Jun 16, 2019 at 12:01:38PM -0700, Eric Biggers wrote: > Hi Ard, > > On Fri, Jun 14, 2019 at 11:29:22AM +0200, Ard Biesheuvel wrote: > > -static void ccmp_init_blocks(struct crypto_cipher *tfm, > > - struct ieee80211_hdr *hdr, > > - u8 * pn, size_t dlen, u8 * b0, u8 * auth, u8 * s0) > > +static void ccmp_init_blocks(struct ieee80211_hdr *hdr, > > + u8 * pn, size_t dlen, u8 * b0, u8 * aad) > > { > > u8 *pos, qc = 0; > > size_t aad_len; > > int a4_included, qc_included; > > - u8 aad[2 * AES_BLOCK_LEN]; > > > > a4_included = ieee80211_has_a4(hdr->frame_control); > > qc_included = ieee80211_is_data_qos(hdr->frame_control); > > @@ -131,17 +123,19 @@ static void ccmp_init_blocks(struct crypto_cipher *tfm, > > aad_len += 2; > > } > > > > - /* CCM Initial Block: > > - * Flag (Include authentication header, M=3 (8-octet MIC), > > - * L=1 (2-octet Dlen)) > > - * Nonce: 0x00 | A2 | PN > > - * Dlen */ > > - b0[0] = 0x59; > > + /* In CCM, the initial vectors (IV) used for CTR mode encryption and CBC > > + * mode authentication are not allowed to collide, yet both are derived > > + * from this vector b0. We only set L := 1 here to indicate that the > > + * data size can be represented in (L+1) bytes. The CCM layer will take > > + * care of storing the data length in the top (L+1) bytes and setting > > + * and clearing the other bits as is required to derive the two IVs. > > + */ > > + b0[0] = 0x1; > > + > > + /* Nonce: QC | A2 | PN */ > > b0[1] = qc; > > memcpy(b0 + 2, hdr->addr2, ETH_ALEN); > > memcpy(b0 + 8, pn, CCMP_PN_LEN); > > - b0[14] = (dlen >> 8) & 0xff; > > - b0[15] = dlen & 0xff; > > > > /* AAD: > > * FC with bits 4..6 and 11..13 masked to zero; 14 is always one > > @@ -166,16 +160,6 @@ static void ccmp_init_blocks(struct crypto_cipher *tfm, > > aad[a4_included ? 30 : 24] = qc; > > /* rest of QC masked */ > > } > > - > > - /* Start with the first block and AAD */ > > - lib80211_ccmp_aes_encrypt(tfm, b0, auth); > > - xor_block(auth, aad, AES_BLOCK_LEN); > > - lib80211_ccmp_aes_encrypt(tfm, auth, auth); > > - xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN); > > - lib80211_ccmp_aes_encrypt(tfm, auth, auth); > > - b0[0] &= 0x07; > > - b0[14] = b0[15] = 0; > > - lib80211_ccmp_aes_encrypt(tfm, b0, s0); > > } > > How about shifting the contents of aad over by 2 bytes and returning the AAD > length from this function instead? It's confusing to still manually format the > AAD length for CCM mode, when actually it's ignored now. > > Also I suggest fixing up the naming: > > ccmp_init_blocks() => ccmp_init_iv_and_aad() > b0 => iv > Okay, couple more things. The 'dlen' parameter is no longer used so should be removed. Also consider constifying 'hdr' and 'pn' to make it clear what's input vs. output. Also, xor_block() is no longer used so should be removed. - Eric