From patchwork Mon Jul 12 06:04:15 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 475845 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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 85797C07E9E for ; Mon, 12 Jul 2021 07:04:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6846A613FA for ; Mon, 12 Jul 2021 07:04:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242691AbhGLHGz (ORCPT ); Mon, 12 Jul 2021 03:06:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:40564 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243898AbhGLHGC (ORCPT ); Mon, 12 Jul 2021 03:06:02 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 349D761152; Mon, 12 Jul 2021 07:02:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626073357; bh=wDNvjMGxrpeAQg0xXJVXW97Rx7+AUJ9+PX7Q1PWNhRI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=G7nNZCMQrSJ4+DpOBdNIwWpL1OBU536eiWkhgblKBQi//dipYSmzkWND50eXvdM2J u7cdL1TyLXs0DiGWyv5obBFOSws9vh2Sy1zvrZftSnxU7DP5J/lxaMCcaieTuV9uf6 J42/KqzgKFHf4H4SRRGNg4Da9hqtvRtpTaTLOHU4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sami Tolvanen , Eric Biggers , Ard Biesheuvel , Eric Biggers , Herbert Xu , Sasha Levin Subject: [PATCH 5.12 172/700] crypto: shash - avoid comparing pointers to exported functions under CFI Date: Mon, 12 Jul 2021 08:04:15 +0200 Message-Id: <20210712060950.489526727@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712060924.797321836@linuxfoundation.org> References: <20210712060924.797321836@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Ard Biesheuvel [ Upstream commit 22ca9f4aaf431a9413dcc115dd590123307f274f ] crypto_shash_alg_has_setkey() is implemented by testing whether the .setkey() member of a struct shash_alg points to the default version, called shash_no_setkey(). As crypto_shash_alg_has_setkey() is a static inline, this requires shash_no_setkey() to be exported to modules. Unfortunately, when building with CFI, function pointers are routed via CFI stubs which are private to each module (or to the kernel proper) and so this function pointer comparison may fail spuriously. Let's fix this by turning crypto_shash_alg_has_setkey() into an out of line function. Cc: Sami Tolvanen Cc: Eric Biggers Signed-off-by: Ard Biesheuvel Reviewed-by: Eric Biggers Reviewed-by: Sami Tolvanen Signed-off-by: Herbert Xu Signed-off-by: Sasha Levin --- crypto/shash.c | 18 +++++++++++++++--- include/crypto/internal/hash.h | 8 +------- 2 files changed, 16 insertions(+), 10 deletions(-) diff --git a/crypto/shash.c b/crypto/shash.c index 2e3433ad9762..0a0a50cb694f 100644 --- a/crypto/shash.c +++ b/crypto/shash.c @@ -20,12 +20,24 @@ static const struct crypto_type crypto_shash_type; -int shash_no_setkey(struct crypto_shash *tfm, const u8 *key, - unsigned int keylen) +static int shash_no_setkey(struct crypto_shash *tfm, const u8 *key, + unsigned int keylen) { return -ENOSYS; } -EXPORT_SYMBOL_GPL(shash_no_setkey); + +/* + * Check whether an shash algorithm has a setkey function. + * + * For CFI compatibility, this must not be an inline function. This is because + * when CFI is enabled, modules won't get the same address for shash_no_setkey + * (if it were exported, which inlining would require) as the core kernel will. + */ +bool crypto_shash_alg_has_setkey(struct shash_alg *alg) +{ + return alg->setkey != shash_no_setkey; +} +EXPORT_SYMBOL_GPL(crypto_shash_alg_has_setkey); static int shash_setkey_unaligned(struct crypto_shash *tfm, const u8 *key, unsigned int keylen) diff --git a/include/crypto/internal/hash.h b/include/crypto/internal/hash.h index 0a288dddcf5b..25806141db59 100644 --- a/include/crypto/internal/hash.h +++ b/include/crypto/internal/hash.h @@ -75,13 +75,7 @@ void crypto_unregister_ahashes(struct ahash_alg *algs, int count); int ahash_register_instance(struct crypto_template *tmpl, struct ahash_instance *inst); -int shash_no_setkey(struct crypto_shash *tfm, const u8 *key, - unsigned int keylen); - -static inline bool crypto_shash_alg_has_setkey(struct shash_alg *alg) -{ - return alg->setkey != shash_no_setkey; -} +bool crypto_shash_alg_has_setkey(struct shash_alg *alg); static inline bool crypto_shash_alg_needs_key(struct shash_alg *alg) {