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=1.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,FSL_HELO_FAKE, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=no 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 4C5F2ECDFB3 for ; Tue, 17 Jul 2018 16:44:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 01E1920693 for ; Tue, 17 Jul 2018 16:44:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="KtKtcUjG" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 01E1920693 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729730AbeGQRRb (ORCPT ); Tue, 17 Jul 2018 13:17:31 -0400 Received: from mail-pg1-f196.google.com ([209.85.215.196]:32829 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729668AbeGQRRb (ORCPT ); Tue, 17 Jul 2018 13:17:31 -0400 Received: by mail-pg1-f196.google.com with SMTP id r5-v6so692535pgv.0; Tue, 17 Jul 2018 09:44:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=3LVliLGUXjJx6K5xTmsCB+TKQAknILrDDERvjEifRfM=; b=KtKtcUjGAdjyGmcjyoFyYy9yiiwTnPn//AU3FLkUDu+U9wvuo0HQ/9b7A2oY+tnxz0 ngCGKFkzTG3vO/1QRSMWxW9cirTj7HHDqS3pIqkG2ll2Xfuds8aTRQvOysQYScrzF6aw T0SBrOztOU4phES6xYtNLh1wWHsyX0vSTAfFCLs7C3VQD5GRMhXa0VbPY7o6EW4oqGwF eNYdWqHZGx4ivzBKyHrKUi8cEBCI//K2voJw9x7d566s5hr5Fgc9HXsgNBuzaSz4+EqI zB0p8XeqC9+fqfAUR/4kGePDeOraXgw0ybJY6fox5da2YVncboVhuq5oXfCefOyTPue8 zeGA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=3LVliLGUXjJx6K5xTmsCB+TKQAknILrDDERvjEifRfM=; b=NYFlO89s+2vV2rbZ+Czkubohimr0QoEqG7kkFkpWQgMHWDkExadSj7Urbj8WUbYksf GQ9PtMmlhqoWEWMj/fBhKRiayHJSdHXJPNf1YIhutqF1Mu4EZ0XKyw/BAMiW0vLQ2tce 9V5g7nbZ046hB+woaDXYkscNGW3qFiIjOIIrjX7BHuRNYNELzvPicmUuPVAl78ZRdQI5 mUETmpUhjJV9EXzlaJ7spBW4/Fg3zm/ieodk3mk7aNFIf0XNMSNpRAFh9ERJFVGHoT8E sdPHN8oRjY8LfQuTDlqvnPJtOH37bCAc9nYtZkSzNWibro7tkhoi6NdrFHlLvETuDPro mX+g== X-Gm-Message-State: AOUpUlF3o8nqyF4yK3nmcHnxG67N2DFdOgY0VGIUdOTcWkhxuEdAcJCW SSdK3Oc4wTNMJ9s+NF97rQY= X-Google-Smtp-Source: AAOMgpdkesPzs2KmkWA7XQgW35SdCiuaVtVX/ojOT0TQz09/Itp+qxP7Z4pGdV49dDSxdo+e2ArUlw== X-Received: by 2002:a65:66d7:: with SMTP id c23-v6mr2280659pgw.427.1531845840501; Tue, 17 Jul 2018 09:44:00 -0700 (PDT) Received: from gmail.com ([2620:15c:17:3:dc28:5c82:b905:e8a8]) by smtp.gmail.com with ESMTPSA id l84-v6sm3862872pfg.3.2018.07.17.09.43.59 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 17 Jul 2018 09:44:00 -0700 (PDT) Date: Tue, 17 Jul 2018 09:43:58 -0700 From: Eric Biggers To: Kees Cook Cc: Herbert Xu , Giovanni Cabiddu , Arnd Bergmann , "Gustavo A. R. Silva" , Mike Snitzer , Eric Biggers , qat-linux@intel.com, linux-kernel@vger.kernel.org, dm-devel@redhat.com, linux-crypto@vger.kernel.org, Lars Persson , Tim Chen , Alasdair Kergon , Rabin Vincent Subject: Re: [dm-devel] [PATCH v5 10/11] crypto: ahash: Remove VLA usage for AHASH_REQUEST_ON_STACK Message-ID: <20180717164358.GC75957@gmail.com> References: <20180717042150.37761-1-keescook@chromium.org> <20180717042150.37761-11-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180717042150.37761-11-keescook@chromium.org> User-Agent: Mutt/1.10+35 (c786a508) (2018-06-22) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 16, 2018 at 09:21:49PM -0700, Kees Cook wrote: > In the quest to remove all stack VLA usage from the kernel[1], this caps > the ahash request size similar to the other limits and adds a sanity > check at initialization. AHASH_REQUEST_ON_STACK is special, though: it > is only ever used for shash-wrapped ahash, so its size is bounded only > by non-async hashes. A manual inspection of this shows the largest to be: > sizeof(struct shash_desc) + SHASH_MAX_DESCSIZE > > [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com > > Signed-off-by: Kees Cook > --- > crypto/shash.c | 9 ++++++++- > include/crypto/hash.h | 10 +++++++++- > 2 files changed, 17 insertions(+), 2 deletions(-) > > diff --git a/crypto/shash.c b/crypto/shash.c > index 8d4746b14dd5..e344560458cb 100644 > --- a/crypto/shash.c > +++ b/crypto/shash.c > @@ -355,6 +355,7 @@ int crypto_init_shash_ops_async(struct crypto_tfm *tfm) > struct crypto_ahash *crt = __crypto_ahash_cast(tfm); > struct crypto_shash **ctx = crypto_tfm_ctx(tfm); > struct crypto_shash *shash; > + size_t reqsize; > > if (!crypto_mod_get(calg)) > return -EAGAIN; > @@ -365,6 +366,12 @@ int crypto_init_shash_ops_async(struct crypto_tfm *tfm) > return PTR_ERR(shash); > } > > + reqsize = sizeof(struct shash_desc) + crypto_shash_descsize(shash); > + if (WARN_ON(reqsize > AHASH_MAX_REQSIZE)) { > + crypto_mod_put(calg); > + return -EINVAL; > + } 'crypto_free_shash(shash);' instead of 'crypto_mod_put(calg);' - Eric