From patchwork Mon Jan 7 02:47:42 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Biggers X-Patchwork-Id: 10749817 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-2.web.codeaurora.org (Postfix) with ESMTP id 1206613BF for ; Mon, 7 Jan 2019 02:49:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0172F286E7 for ; Mon, 7 Jan 2019 02:49:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E78822887F; Mon, 7 Jan 2019 02:49:41 +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=ham 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 7701E28761 for ; Mon, 7 Jan 2019 02:49:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726433AbfAGCtk (ORCPT ); Sun, 6 Jan 2019 21:49:40 -0500 Received: from mail.kernel.org ([198.145.29.99]:46468 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726425AbfAGCtk (ORCPT ); Sun, 6 Jan 2019 21:49:40 -0500 Received: from sol.localdomain (c-24-23-143-129.hsd1.ca.comcast.net [24.23.143.129]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 713D720868; Mon, 7 Jan 2019 02:49:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1546829379; bh=G9LU4d9+DsKiVZ+HZkOxOHVCmDTSojY+FH/M+ntXCuQ=; h=From:To:Subject:Date:In-Reply-To:References:From; b=kmEEaMhelSdHmv/16lJizvRaA11asIO/X935yZqQSwr80wdvdWkcfy9Tl9TO/gd5R nRxhKueGLVaX1gD0KWHfqYaOX2YKLR7vmxuKhqjCM0NQcqcbOAzTKTYYCcIJ7RC8aZ +IopvroAZlULSkT6tTXqMFr+OxizmZbMD8IpvX6M= From: Eric Biggers To: linux-crypto@vger.kernel.org, Herbert Xu Subject: [PATCH 1/3] crypto: hash - set CRYPTO_TFM_NEED_KEY if ->setkey() fails Date: Sun, 6 Jan 2019 18:47:42 -0800 Message-Id: <20190107024744.4952-2-ebiggers@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190107024744.4952-1-ebiggers@kernel.org> References: <20190107024744.4952-1-ebiggers@kernel.org> MIME-Version: 1.0 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 From: Eric Biggers Some algorithms have a ->setkey() method that is not atomic, in the sense that setting a key can fail after changes were already made to the tfm context. In this case, if a key was already set the tfm can end up in a state that corresponds to neither the old key nor the new key. It's not feasible to make all ->setkey() methods atomic, especially ones that have to key multiple sub-tfms. Therefore, make the crypto API set CRYPTO_TFM_NEED_KEY if ->setkey() fails and the algorithm requires a key, to prevent the tfm from being used until a new key is set. Note: we can't set CRYPTO_TFM_NEED_KEY for OPTIONAL_KEY algorithms, so ->setkey() for those must nevertheless be atomic. That's fine for now since only the crc32 and crc32c algorithms set OPTIONAL_KEY, and it's not intended that OPTIONAL_KEY be used much. [Cc stable mainly because when introducing the NEED_KEY flag I changed AF_ALG to rely on it; and unlike in-kernel crypto API users, AF_ALG previously didn't have this problem. So these "incompletely keyed" states became theoretically accessible via AF_ALG -- though, the opportunities for causing real mischief seem pretty limited.] Fixes: 9fa68f620041 ("crypto: hash - prevent using keyed hashes without setting key") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers --- crypto/ahash.c | 28 +++++++++++++++++++--------- crypto/shash.c | 18 +++++++++++++----- 2 files changed, 32 insertions(+), 14 deletions(-) diff --git a/crypto/ahash.c b/crypto/ahash.c index 5d320a811f750..ca0d3e281fefb 100644 --- a/crypto/ahash.c +++ b/crypto/ahash.c @@ -190,6 +190,21 @@ static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key, return ret; } +static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key, + unsigned int keylen) +{ + return -ENOSYS; +} + +static void ahash_set_needkey(struct crypto_ahash *tfm) +{ + const struct hash_alg_common *alg = crypto_hash_alg_common(tfm); + + if (tfm->setkey != ahash_nosetkey && + !(alg->base.cra_flags & CRYPTO_ALG_OPTIONAL_KEY)) + crypto_ahash_set_flags(tfm, CRYPTO_TFM_NEED_KEY); +} + int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key, unsigned int keylen) { @@ -201,20 +216,16 @@ int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key, else err = tfm->setkey(tfm, key, keylen); - if (err) + if (unlikely(err)) { + ahash_set_needkey(tfm); return err; + } crypto_ahash_clear_flags(tfm, CRYPTO_TFM_NEED_KEY); return 0; } EXPORT_SYMBOL_GPL(crypto_ahash_setkey); -static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key, - unsigned int keylen) -{ - return -ENOSYS; -} - static inline unsigned int ahash_align_buffer_size(unsigned len, unsigned long mask) { @@ -489,8 +500,7 @@ static int crypto_ahash_init_tfm(struct crypto_tfm *tfm) if (alg->setkey) { hash->setkey = alg->setkey; - if (!(alg->halg.base.cra_flags & CRYPTO_ALG_OPTIONAL_KEY)) - crypto_ahash_set_flags(hash, CRYPTO_TFM_NEED_KEY); + ahash_set_needkey(hash); } return 0; diff --git a/crypto/shash.c b/crypto/shash.c index 44d297b82a8fb..40311ccad3fae 100644 --- a/crypto/shash.c +++ b/crypto/shash.c @@ -53,6 +53,13 @@ static int shash_setkey_unaligned(struct crypto_shash *tfm, const u8 *key, return err; } +static void shash_set_needkey(struct crypto_shash *tfm, struct shash_alg *alg) +{ + if (crypto_shash_alg_has_setkey(alg) && + !(alg->base.cra_flags & CRYPTO_ALG_OPTIONAL_KEY)) + crypto_shash_set_flags(tfm, CRYPTO_TFM_NEED_KEY); +} + int crypto_shash_setkey(struct crypto_shash *tfm, const u8 *key, unsigned int keylen) { @@ -65,8 +72,10 @@ int crypto_shash_setkey(struct crypto_shash *tfm, const u8 *key, else err = shash->setkey(tfm, key, keylen); - if (err) + if (unlikely(err)) { + shash_set_needkey(tfm, shash); return err; + } crypto_shash_clear_flags(tfm, CRYPTO_TFM_NEED_KEY); return 0; @@ -373,7 +382,8 @@ int crypto_init_shash_ops_async(struct crypto_tfm *tfm) crt->final = shash_async_final; crt->finup = shash_async_finup; crt->digest = shash_async_digest; - crt->setkey = shash_async_setkey; + if (crypto_shash_alg_has_setkey(alg)) + crt->setkey = shash_async_setkey; crypto_ahash_set_flags(crt, crypto_shash_get_flags(shash) & CRYPTO_TFM_NEED_KEY); @@ -395,9 +405,7 @@ static int crypto_shash_init_tfm(struct crypto_tfm *tfm) hash->descsize = alg->descsize; - if (crypto_shash_alg_has_setkey(alg) && - !(alg->base.cra_flags & CRYPTO_ALG_OPTIONAL_KEY)) - crypto_shash_set_flags(hash, CRYPTO_TFM_NEED_KEY); + shash_set_needkey(hash, alg); return 0; }