From patchwork Mon Jun 25 21:10:24 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 10487321 X-Patchwork-Delegate: herbert@gondor.apana.org.au Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id A45276038C for ; Mon, 25 Jun 2018 21:12:11 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 963A22869B for ; Mon, 25 Jun 2018 21:12:11 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8A88A286A8; Mon, 25 Jun 2018 21:12:11 +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 346D92869B for ; Mon, 25 Jun 2018 21:12:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752474AbeFYVLm (ORCPT ); Mon, 25 Jun 2018 17:11:42 -0400 Received: from mail-pg0-f65.google.com ([74.125.83.65]:46497 "EHLO mail-pg0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754980AbeFYVKs (ORCPT ); Mon, 25 Jun 2018 17:10:48 -0400 Received: by mail-pg0-f65.google.com with SMTP id q14-v6so2836308pgt.13 for ; Mon, 25 Jun 2018 14:10:48 -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=PbwSt8IMbUmiAnJPK0uuLHHvB9/qjp0V2xYcxgegYD4=; b=fr1CduVB1/5v34K7SXFRFl6hAA7+DVm9T9LIogF23zAtTG8UycUcMgyFrngt2RxvTG y2jf0UStdogBGrCfnVMBFs/Z3beLSja8yXnIP4yybArIQITX0uTsHmMHGxvHKeePOKrm WFWe2xq2vruI4yXXAAkLgvPplNEn6AdKv/aNM= 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=PbwSt8IMbUmiAnJPK0uuLHHvB9/qjp0V2xYcxgegYD4=; b=BSPd9TdXtYyaVGLZR8PCVab/7pQ0eT3vKw8iwRoo2twQ1LKS5LxJhR8HTdV0F2XugK j63NvsWOKgesOkdoKXUE0F4QILXQSOw86jc522Nfy6E/YL/+4b4gQrrwWLzn3oWKo4jh VAvFgK5TQpyeWGeChkiUr8MG49WRBm2LM+Ev213Q4yjkb0FMOiKnINcMXpMVMGqTKyMz MuGJ3FPgHFictZ/pgxq3xSRVl/13iDYhMsCN3AJEOswWvc85LRC9EM/UUpk4Yo3l3YJ7 wHShmkwZvzASqA/oBTEleJ7bt5ZIexq+cwbMyUgAu4AlxzUqFC6Ezq7/cUWXNFinKPui uiEg== X-Gm-Message-State: APt69E3LTSU7dDIIcSbLuaqP/KS03medog5NBNvl/3T4s5HxvA14PpJI Lv7qeG1bOQ6bIqz1pg2X0SZrVQ== X-Google-Smtp-Source: ADUXVKIbl8p2B4qPAzrO4KEvhKjTIYF6iVPudD4v5zCedSeguJ4Pt9x4EKPN8yiOa+CKRu/5awxvAQ== X-Received: by 2002:a62:6406:: with SMTP id y6-v6mr14571609pfb.204.1529961047692; Mon, 25 Jun 2018 14:10:47 -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 c12-v6sm22800661pfi.177.2018.06.25.14.10.39 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 25 Jun 2018 14:10:41 -0700 (PDT) From: Kees Cook To: Herbert Xu Cc: Kees Cook , "David S. Miller" , linux-crypto@vger.kernel.org, "Gustavo A. R. Silva" , Arnd Bergmann , Eric Biggers , Alasdair Kergon , Giovanni Cabiddu , Lars Persson , Mike Snitzer , Rabin Vincent , Tim Chen , qat-linux@intel.com, dm-devel@redhat.com, linux-kernel@vger.kernel.org Subject: [PATCH v2 09/11] crypto: shash: Remove VLA usage in unaligned hashing Date: Mon, 25 Jun 2018 14:10:24 -0700 Message-Id: <20180625211026.15819-10-keescook@chromium.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180625211026.15819-1-keescook@chromium.org> References: <20180625211026.15819-1-keescook@chromium.org> Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@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 Cc: Herbert Xu Cc: "David S. Miller" Cc: linux-crypto@vger.kernel.org Signed-off-by: Kees Cook --- crypto/shash.c | 19 ++++++++----------- include/linux/compiler-gcc.h | 1 - 2 files changed, 8 insertions(+), 12 deletions(-) diff --git a/crypto/shash.c b/crypto/shash.c index ab6902c6dae7..8081c5e03770 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 +81,13 @@ 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; + u8 ubuf[MAX_ALGAPI_ALIGNMASK + 1]; 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 +119,13 @@ 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; + u8 ubuf[SHASH_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__))