Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S941835AbcJZM3s (ORCPT ); Wed, 26 Oct 2016 08:29:48 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:55501 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S941798AbcJZM3p (ORCPT ); Wed, 26 Oct 2016 08:29:45 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Biggers , Theodore Tso Subject: [PATCH 4.8 130/140] fscrypto: make XTS tweak initialization endian-independent Date: Wed, 26 Oct 2016 14:23:10 +0200 Message-Id: <20161026122226.018228087@linuxfoundation.org> X-Mailer: git-send-email 2.10.1 In-Reply-To: <20161026122220.384323763@linuxfoundation.org> References: <20161026122220.384323763@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2331 Lines: 64 4.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Biggers commit fb4454376df9d820d95452d71dd83da6971f9338 upstream. The XTS tweak (or IV) was initialized differently on little endian and big endian systems. Because the ciphertext depends on the XTS tweak, it was not possible to use an encrypted filesystem created by a little endian system on a big endian system and vice versa, even if they shared the same PAGE_SIZE. Fix this by always using little endian. This will break hypothetical big endian users of ext4 or f2fs encryption. However, all users we are aware of are little endian, and it's believed that "real" big endian users are unlikely to exist yet. So this might as well be fixed now before it's too late. Signed-off-by: Eric Biggers Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/crypto/crypto.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) --- a/fs/crypto/crypto.c +++ b/fs/crypto/crypto.c @@ -152,7 +152,10 @@ static int do_page_crypto(struct inode * struct page *src_page, struct page *dest_page, gfp_t gfp_flags) { - u8 xts_tweak[FS_XTS_TWEAK_SIZE]; + struct { + __le64 index; + u8 padding[FS_XTS_TWEAK_SIZE - sizeof(__le64)]; + } xts_tweak; struct skcipher_request *req = NULL; DECLARE_FS_COMPLETION_RESULT(ecr); struct scatterlist dst, src; @@ -172,17 +175,15 @@ static int do_page_crypto(struct inode * req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, fscrypt_complete, &ecr); - BUILD_BUG_ON(FS_XTS_TWEAK_SIZE < sizeof(index)); - memcpy(xts_tweak, &index, sizeof(index)); - memset(&xts_tweak[sizeof(index)], 0, - FS_XTS_TWEAK_SIZE - sizeof(index)); + BUILD_BUG_ON(sizeof(xts_tweak) != FS_XTS_TWEAK_SIZE); + xts_tweak.index = cpu_to_le64(index); + memset(xts_tweak.padding, 0, sizeof(xts_tweak.padding)); sg_init_table(&dst, 1); sg_set_page(&dst, dest_page, PAGE_SIZE, 0); sg_init_table(&src, 1); sg_set_page(&src, src_page, PAGE_SIZE, 0); - skcipher_request_set_crypt(req, &src, &dst, PAGE_SIZE, - xts_tweak); + skcipher_request_set_crypt(req, &src, &dst, PAGE_SIZE, &xts_tweak); if (rw == FS_DECRYPT) res = crypto_skcipher_decrypt(req); else