From patchwork Tue Jul 24 16:49:25 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 10542615 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D5F7F1822 for ; Tue, 24 Jul 2018 16:52:00 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C56BE2909C for ; Tue, 24 Jul 2018 16:52:00 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C286E29183; Tue, 24 Jul 2018 16:52:00 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5BA04291F3 for ; Tue, 24 Jul 2018 16:52:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388582AbeGXR7S (ORCPT ); Tue, 24 Jul 2018 13:59:18 -0400 Received: from mail-pg1-f194.google.com ([209.85.215.194]:39861 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388595AbeGXR5N (ORCPT ); Tue, 24 Jul 2018 13:57:13 -0400 Received: by mail-pg1-f194.google.com with SMTP id g2-v6so3297524pgs.6 for ; Tue, 24 Jul 2018 09:49:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=Ok95ycGnZuw2CZpO4KgRNxj4QX0cXIlEQlrBt5ewdsw=; b=jQ5y83FYcXRBUM77JJA0nyUNgrejZPE5lJ0JT0iizxWJfPIBVNOrdtpeO7rT+b2lsv +bjOyNg4sn32L5cfKvZIdvHZhJj8DFiyCgt6UyipV5eZBsz7wNOkN0Bulbb9Gj/WzKGr ZuhcetVCR/7gfa6Kfm6K+hpLj/2AObwWbUbIA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=Ok95ycGnZuw2CZpO4KgRNxj4QX0cXIlEQlrBt5ewdsw=; b=RHSvLJPw0TpQ5h2ZB/5uj1L1/6mJ+2tG96fI8+vpzMp7Kze94X+M2gQSqwILnDQQNG mtIEP4HKnIfBL8x5HHSOeR2RmtnbgQ4daKxUijwB1BgC9EhYsokKukRWSB9dRQP7xPQ4 7kFVGGzFBUmjIsYTtwO+W+OX5fIkUp2Z2BsKeFyPLqUxYMOVjiRdq/o4VPiSnx4G++cx bgxtefvSxoafPpHN+pvtpiAjsq1YCHJKtUIyzG5JJbIrQFO27nvxhuQcMOEDe0eM2ogI RMTCeLwkazGXl6GCrkUZgYh8YP6dStsIgTXPIO0YC2+pUJSsjgBH2EtDMHwnwynBPeb0 WK0A== X-Gm-Message-State: AOUpUlG9m/MlKia3tN+VdZ3Rvf79iedvZ8jFP/JeZ3y6+macMJvk2Cc9 p1fU/Z4L41XH08F1Ht2raSAcag== X-Google-Smtp-Source: AAOMgpc6VqDh6VDKEj14IbS01oeHnKpI3OsjZNoP+Pml6OkQrZbvFlPFHd08eIo2+U87sWqzc4srfA== X-Received: by 2002:a65:4384:: with SMTP id m4-v6mr5659689pgp.265.1532450992012; Tue, 24 Jul 2018 09:49:52 -0700 (PDT) Received: from www.outflux.net (173-164-112-133-Oregon.hfc.comcastbusiness.net. [173.164.112.133]) by smtp.gmail.com with ESMTPSA id x65-v6sm6984082pfk.140.2018.07.24.09.49.45 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 24 Jul 2018 09:49:47 -0700 (PDT) From: Kees Cook To: Herbert Xu Cc: Kees Cook , Arnd Bergmann , Eric Biggers , "Gustavo A. R. Silva" , Alasdair Kergon , Rabin Vincent , Tim Chen , "Rafael J. Wysocki" , Pavel Machek , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Philipp Reisner , Lars Ellenberg , Jens Axboe , Giovanni Cabiddu , Mike Snitzer , Paul Mackerras , Greg Kroah-Hartman , David Howells , Johannes Berg , Tudor-Dan Ambarus , Jia-Ju Bai , Andrew Morton , Geert Uytterhoeven , Josh Poimboeuf , David Woodhouse , Will Deacon , dm-devel@redhat.com, linux-pm@vger.kernel.org, linux-crypto@vger.kernel.org, drbd-dev@lists.linbit.com, linux-block@vger.kernel.org, qat-linux@intel.com, linux-ppp@vger.kernel.org, netdev@vger.kernel.org, devel@driverdev.osuosl.org, linux-afs@lists.infradead.org, linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v6 07/18] crypto: shash: Remove VLA usage in unaligned hashing Date: Tue, 24 Jul 2018 09:49:25 -0700 Message-Id: <20180724164936.37477-8-keescook@chromium.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180724164936.37477-1-keescook@chromium.org> References: <20180724164936.37477-1-keescook@chromium.org> Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP In the quest to remove all stack VLA usage from the kernel[1], this uses the newly defined max alignment to perform unaligned hashing to avoid VLAs, and drops the helper function while adding sanity checks on the resulting buffer sizes. Additionally, the __aligned_largest macro is removed since this helper was the only user. [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com Signed-off-by: Kees Cook --- crypto/shash.c | 27 ++++++++++++++++----------- include/linux/compiler-gcc.h | 1 - 2 files changed, 16 insertions(+), 12 deletions(-) diff --git a/crypto/shash.c b/crypto/shash.c index 86d76b5c626c..d21f04d70dce 100644 --- a/crypto/shash.c +++ b/crypto/shash.c @@ -73,13 +73,6 @@ int crypto_shash_setkey(struct crypto_shash *tfm, const u8 *key, } EXPORT_SYMBOL_GPL(crypto_shash_setkey); -static inline unsigned int shash_align_buffer_size(unsigned len, - unsigned long mask) -{ - typedef u8 __aligned_largest u8_aligned; - return len + (mask & ~(__alignof__(u8_aligned) - 1)); -} - static int shash_update_unaligned(struct shash_desc *desc, const u8 *data, unsigned int len) { @@ -88,11 +81,17 @@ static int shash_update_unaligned(struct shash_desc *desc, const u8 *data, unsigned long alignmask = crypto_shash_alignmask(tfm); unsigned int unaligned_len = alignmask + 1 - ((unsigned long)data & alignmask); - u8 ubuf[shash_align_buffer_size(unaligned_len, alignmask)] - __aligned_largest; + /* + * We cannot count on __aligned() working for large values: + * https://patchwork.kernel.org/patch/9507697/ + */ + u8 ubuf[MAX_ALGAPI_ALIGNMASK * 2]; u8 *buf = PTR_ALIGN(&ubuf[0], alignmask + 1); int err; + if (WARN_ON(buf + unaligned_len > ubuf + sizeof(ubuf))) + return -EINVAL; + if (unaligned_len > len) unaligned_len = len; @@ -124,11 +123,17 @@ static int shash_final_unaligned(struct shash_desc *desc, u8 *out) unsigned long alignmask = crypto_shash_alignmask(tfm); struct shash_alg *shash = crypto_shash_alg(tfm); unsigned int ds = crypto_shash_digestsize(tfm); - u8 ubuf[shash_align_buffer_size(ds, alignmask)] - __aligned_largest; + /* + * We cannot count on __aligned() working for large values: + * https://patchwork.kernel.org/patch/9507697/ + */ + u8 ubuf[MAX_ALGAPI_ALIGNMASK + HASH_MAX_DIGESTSIZE]; u8 *buf = PTR_ALIGN(&ubuf[0], alignmask + 1); int err; + if (WARN_ON(buf + ds > ubuf + sizeof(ubuf))) + return -EINVAL; + err = shash->final(desc, buf); if (err) goto out; diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index f1a7492a5cc8..1f1cdef36a82 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -125,7 +125,6 @@ */ #define __pure __attribute__((pure)) #define __aligned(x) __attribute__((aligned(x))) -#define __aligned_largest __attribute__((aligned)) #define __printf(a, b) __attribute__((format(printf, a, b))) #define __scanf(a, b) __attribute__((format(scanf, a, b))) #define __attribute_const__ __attribute__((__const__))