From patchwork Thu Sep 14 08:12:51 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Biggers X-Patchwork-Id: 13384795 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8B568EDE994 for ; Thu, 14 Sep 2023 08:14:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235969AbjINIOy (ORCPT ); Thu, 14 Sep 2023 04:14:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56332 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236253AbjINIOy (ORCPT ); Thu, 14 Sep 2023 04:14:54 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 59CC3CD8; Thu, 14 Sep 2023 01:14:50 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C88CEC433CA; Thu, 14 Sep 2023 08:14:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1694679290; bh=mYxCTQ86ndfR+rG1ZcbI1ZmUOxowNicifI01Yc/k8I4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LV7fZB0rZqk2cvNIBfNYL2D33oreK0M1zQ1KB8VRklLb8/KFbhnpTkpesrBb/wD5l 7sUG+9PCGS8EUpen1ZDr8ChULNm2ucgrYD5vXclqazioUfLOVB3vrxaZJ1xkJGOx8e gmz1U/gegdppvfSVLPb/dmRZYsU8VTUDcnGgchOhSgVbdjvx9as0+EanPwd+nRhRyd SiM83ZWhTex1PD/YlhzByi2wLq+6HzBEkfW51I4DJAu3Vu1FdmocCcUZ4Xec6Jpg3j c2cQuygHevgwYOQpSL3dPp7JAWg2eHNgimNJwHeW8XF6LtzZg/e9cZdG+NMfJWRExA QoRocWk+jmrfA== From: Eric Biggers To: linux-fscrypt@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-btrfs@vger.kernel.org, Jaegeuk Kim , Theodore Ts'o Subject: [PATCH v2 1/5] fscrypt: make it extra clear that key_prefix is deprecated Date: Thu, 14 Sep 2023 01:12:51 -0700 Message-ID: <20230914081255.193502-2-ebiggers@kernel.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230914081255.193502-1-ebiggers@kernel.org> References: <20230914081255.193502-1-ebiggers@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org From: Eric Biggers fscrypt_operations::key_prefix should not be set by any filesystems that aren't setting it already. This is already documented, but apparently it's not sufficiently clear, as both ceph and btrfs have tried to set it. Rename the field to 'legacy_key_prefix_for_backcompat' and improve the documentation to hopefully make it clearer. Signed-off-by: Eric Biggers --- fs/crypto/keysetup_v1.c | 5 +++-- fs/ext4/crypto.c | 2 +- fs/f2fs/super.c | 2 +- fs/ubifs/crypto.c | 2 +- include/linux/fscrypt.h | 14 +++++++++----- 5 files changed, 15 insertions(+), 10 deletions(-) diff --git a/fs/crypto/keysetup_v1.c b/fs/crypto/keysetup_v1.c index 75dabd9b27f9b..df44d0d2d44ea 100644 --- a/fs/crypto/keysetup_v1.c +++ b/fs/crypto/keysetup_v1.c @@ -299,6 +299,7 @@ int fscrypt_setup_v1_file_key(struct fscrypt_info *ci, const u8 *raw_master_key) int fscrypt_setup_v1_file_key_via_subscribed_keyrings(struct fscrypt_info *ci) { + const struct super_block *sb = ci->ci_inode->i_sb; struct key *key; const struct fscrypt_key *payload; int err; @@ -306,8 +307,8 @@ int fscrypt_setup_v1_file_key_via_subscribed_keyrings(struct fscrypt_info *ci) key = find_and_lock_process_key(FSCRYPT_KEY_DESC_PREFIX, ci->ci_policy.v1.master_key_descriptor, ci->ci_mode->keysize, &payload); - if (key == ERR_PTR(-ENOKEY) && ci->ci_inode->i_sb->s_cop->key_prefix) { - key = find_and_lock_process_key(ci->ci_inode->i_sb->s_cop->key_prefix, + if (key == ERR_PTR(-ENOKEY) && sb->s_cop->legacy_key_prefix_for_backcompat) { + key = find_and_lock_process_key(sb->s_cop->legacy_key_prefix_for_backcompat, ci->ci_policy.v1.master_key_descriptor, ci->ci_mode->keysize, &payload); } diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c index 453d4da5de520..8cdb7bbc655b0 100644 --- a/fs/ext4/crypto.c +++ b/fs/ext4/crypto.c @@ -240,7 +240,7 @@ static void ext4_get_ino_and_lblk_bits(struct super_block *sb, } const struct fscrypt_operations ext4_cryptops = { - .key_prefix = "ext4:", + .legacy_key_prefix_for_backcompat = "ext4:", .get_context = ext4_get_context, .set_context = ext4_set_context, .get_dummy_policy = ext4_get_dummy_policy, diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index a8c8232852bb1..8de799a8bad04 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -3231,7 +3231,7 @@ static struct block_device **f2fs_get_devices(struct super_block *sb, } static const struct fscrypt_operations f2fs_cryptops = { - .key_prefix = "f2fs:", + .legacy_key_prefix_for_backcompat = "f2fs:", .get_context = f2fs_get_context, .set_context = f2fs_set_context, .get_dummy_policy = f2fs_get_dummy_policy, diff --git a/fs/ubifs/crypto.c b/fs/ubifs/crypto.c index 3125e76376ee6..fab90f9a8eaff 100644 --- a/fs/ubifs/crypto.c +++ b/fs/ubifs/crypto.c @@ -89,7 +89,7 @@ int ubifs_decrypt(const struct inode *inode, struct ubifs_data_node *dn, const struct fscrypt_operations ubifs_crypt_operations = { .flags = FS_CFLG_OWN_PAGES, - .key_prefix = "ubifs:", + .legacy_key_prefix_for_backcompat = "ubifs:", .get_context = ubifs_crypt_get_context, .set_context = ubifs_crypt_set_context, .empty_dir = ubifs_crypt_empty_dir, diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index c895b12737a19..70e0d4917dd59 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -73,12 +73,16 @@ struct fscrypt_operations { unsigned int flags; /* - * If set, this is a filesystem-specific key description prefix that - * will be accepted for "logon" keys for v1 fscrypt policies, in - * addition to the generic prefix "fscrypt:". This functionality is - * deprecated, so new filesystems shouldn't set this field. + * This field exists only for backwards compatibility reasons and should + * only be set by the filesystems that are setting it already. It + * contains the filesystem-specific key description prefix that is + * accepted for "logon" keys for v1 fscrypt policies. This + * functionality is deprecated in favor of the generic prefix + * "fscrypt:", which itself is deprecated in favor of the filesystem + * keyring ioctls such as FS_IOC_ADD_ENCRYPTION_KEY. Filesystems that + * are newly adding fscrypt support should not set this field. */ - const char *key_prefix; + const char *legacy_key_prefix_for_backcompat; /* * Get the fscrypt context of the given inode. From patchwork Thu Sep 14 08:12:52 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Biggers X-Patchwork-Id: 13384796 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id ADB7DEDE998 for ; Thu, 14 Sep 2023 08:14:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236355AbjINIOz (ORCPT ); Thu, 14 Sep 2023 04:14:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56348 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236330AbjINIOy (ORCPT ); Thu, 14 Sep 2023 04:14:54 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AF44C1BE6; Thu, 14 Sep 2023 01:14:50 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2B881C433CB; Thu, 14 Sep 2023 08:14:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1694679290; bh=cdkAH/oskwHvzF8j12szEYgbjRbtZUXjU97VQhihgfw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Epb0jzo2Y5M8tvOFynD8JdYf2XrKhRdrms+dV1TRYHtgizjmhz7JQ2z3sjbrROjmI ow1Z3JjCpFx+DVF2BeXs0MoGhA/VLhRLfH9+eFkYxZnif/TXqNNrpM3WzlywwuutI3 sk8Httf9+1G1RJzFnXV539Dj/L+L1GkhpuD+AxP1j0+HWIliJBoOEl89/mvdeOtE/P 4FgSh8tipx0+JLG9paJ1ZTqLosdS16lFUdHYL3dRYiiNT49f4Xo5DwgF3YOUCa0k7M Kq1KF0errdmA7q9LyRZogmL2LZMrXmy3+nMLl9vdPhqPzzohVQm2CVqo5fk3FPWsrK ki9XXhnpX4tsQ== From: Eric Biggers To: linux-fscrypt@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-btrfs@vger.kernel.org, Jaegeuk Kim , Theodore Ts'o Subject: [PATCH v2 2/5] fscrypt: make the bounce page pool opt-in instead of opt-out Date: Thu, 14 Sep 2023 01:12:52 -0700 Message-ID: <20230914081255.193502-3-ebiggers@kernel.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230914081255.193502-1-ebiggers@kernel.org> References: <20230914081255.193502-1-ebiggers@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org From: Eric Biggers Replace FS_CFLG_OWN_PAGES with a bit flag 'needs_bounce_pages' which has the opposite meaning. I.e., filesystems now opt into the bounce page pool instead of opt out. Make fscrypt_alloc_bounce_page() check that the bounce page pool has been initialized. I believe the opt in makes more sense, since nothing else in fscrypt_operations is opt out, and these days filesystems can choose to use blk-crypto which doesn't need the fscrypt bounce page pool. Also, I happen to be planning to add two more flags, and I wanted to fix the "FS_CFLG_" name anyway as it wasn't prefixed with "FSCRYPT_". Signed-off-by: Eric Biggers --- fs/ceph/crypto.c | 1 + fs/crypto/crypto.c | 9 ++++++++- fs/ext4/crypto.c | 1 + fs/f2fs/super.c | 1 + fs/ubifs/crypto.c | 1 - include/linux/fscrypt.h | 19 ++++++++++--------- 6 files changed, 21 insertions(+), 11 deletions(-) diff --git a/fs/ceph/crypto.c b/fs/ceph/crypto.c index e4d5cd56a80b9..cc63f1e6fdef6 100644 --- a/fs/ceph/crypto.c +++ b/fs/ceph/crypto.c @@ -133,6 +133,7 @@ static const union fscrypt_policy *ceph_get_dummy_policy(struct super_block *sb) } static struct fscrypt_operations ceph_fscrypt_ops = { + .needs_bounce_pages = 1, .get_context = ceph_crypt_get_context, .set_context = ceph_crypt_set_context, .get_dummy_policy = ceph_get_dummy_policy, diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c index 6a837e4b80dcb..803347a5d0a6d 100644 --- a/fs/crypto/crypto.c +++ b/fs/crypto/crypto.c @@ -49,6 +49,13 @@ EXPORT_SYMBOL(fscrypt_enqueue_decrypt_work); struct page *fscrypt_alloc_bounce_page(gfp_t gfp_flags) { + if (WARN_ON_ONCE(!fscrypt_bounce_page_pool)) { + /* + * Oops, the filesystem called a function that uses the bounce + * page pool, but it forgot to set needs_bounce_pages. + */ + return NULL; + } return mempool_alloc(fscrypt_bounce_page_pool, gfp_flags); } @@ -325,7 +332,7 @@ int fscrypt_initialize(struct super_block *sb) return 0; /* No need to allocate a bounce page pool if this FS won't use it. */ - if (sb->s_cop->flags & FS_CFLG_OWN_PAGES) + if (!sb->s_cop->needs_bounce_pages) return 0; mutex_lock(&fscrypt_init_mutex); diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c index 8cdb7bbc655b0..a9221be67f2a7 100644 --- a/fs/ext4/crypto.c +++ b/fs/ext4/crypto.c @@ -240,6 +240,7 @@ static void ext4_get_ino_and_lblk_bits(struct super_block *sb, } const struct fscrypt_operations ext4_cryptops = { + .needs_bounce_pages = 1, .legacy_key_prefix_for_backcompat = "ext4:", .get_context = ext4_get_context, .set_context = ext4_set_context, diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 8de799a8bad04..276535af5bf3c 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -3231,6 +3231,7 @@ static struct block_device **f2fs_get_devices(struct super_block *sb, } static const struct fscrypt_operations f2fs_cryptops = { + .needs_bounce_pages = 1, .legacy_key_prefix_for_backcompat = "f2fs:", .get_context = f2fs_get_context, .set_context = f2fs_set_context, diff --git a/fs/ubifs/crypto.c b/fs/ubifs/crypto.c index fab90f9a8eaff..f0ca403777d9a 100644 --- a/fs/ubifs/crypto.c +++ b/fs/ubifs/crypto.c @@ -88,7 +88,6 @@ int ubifs_decrypt(const struct inode *inode, struct ubifs_data_node *dn, } const struct fscrypt_operations ubifs_crypt_operations = { - .flags = FS_CFLG_OWN_PAGES, .legacy_key_prefix_for_backcompat = "ubifs:", .get_context = ubifs_crypt_get_context, .set_context = ubifs_crypt_set_context, diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 70e0d4917dd59..32290e5fa9abb 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -59,18 +59,19 @@ struct fscrypt_name { #ifdef CONFIG_FS_ENCRYPTION -/* - * If set, the fscrypt bounce page pool won't be allocated (unless another - * filesystem needs it). Set this if the filesystem always uses its own bounce - * pages for writes and therefore won't need the fscrypt bounce page pool. - */ -#define FS_CFLG_OWN_PAGES (1U << 1) - /* Crypto operations for filesystems */ struct fscrypt_operations { - /* Set of optional flags; see above for allowed flags */ - unsigned int flags; + /* + * If set, then fs/crypto/ will allocate a global bounce page pool. The + * bounce page pool is required by the following functions: + * + * - fscrypt_encrypt_pagecache_blocks() + * - fscrypt_zeroout_range() for files not using inline crypto + * + * If the filesystem doesn't use those, it doesn't need to set this. + */ + unsigned int needs_bounce_pages : 1; /* * This field exists only for backwards compatibility reasons and should From patchwork Thu Sep 14 08:12:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Biggers X-Patchwork-Id: 13384797 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F2C37EDE99B for ; Thu, 14 Sep 2023 08:14:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236370AbjINIO4 (ORCPT ); Thu, 14 Sep 2023 04:14:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56358 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236331AbjINIOz (ORCPT ); Thu, 14 Sep 2023 04:14:55 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0FEC7CD8; Thu, 14 Sep 2023 01:14:51 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 82D28C433CD; Thu, 14 Sep 2023 08:14:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1694679290; bh=RAiVZPublUwjcJuMfMGOxmIRZcVfSyOVrgtX9Ga/1do=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qLrzR7uF9eUw+cLDmeDe0Pz5r9agG/iG6ygBeNtKPqUZLSyUNgdx61ZhqBC6ZA2Su c457mPTQ0Txo/eXX9XmwxJy4TxemYt/rBg9xTEQuGDn6iogf9T+bppbvVvm3CCRoAU OlExjI5snUC7QM3KenicFSNZPT6s9chdabsBa5yQ4YFcEbtPwm4JRT7mvjb3sHdPnU TJFkdL5tnwgl+ImuKPf9Q1XFxTYunUkxpu/NgJUIFmYqwKP5ubOZIXZM8zrHeWMhTc A6amiVS7nGYfLYgm3OoLLuCnjLYare8aOb3lNoLVqi55LEqSK37/TTOVxzAU7RKxrl ObBpSngIyZA4g== From: Eric Biggers To: linux-fscrypt@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-btrfs@vger.kernel.org, Jaegeuk Kim , Theodore Ts'o Subject: [PATCH v2 3/5] fscrypt: use s_maxbytes instead of filesystem lblk_bits Date: Thu, 14 Sep 2023 01:12:53 -0700 Message-ID: <20230914081255.193502-4-ebiggers@kernel.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230914081255.193502-1-ebiggers@kernel.org> References: <20230914081255.193502-1-ebiggers@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org From: Eric Biggers For a given filesystem, the number of bits used by the maximum file logical block number is computable from the maximum file size and block size. These values are always present in struct super_block. Therefore, compute it this way instead of using the value from fscrypt_operations::get_ino_and_lblk_bits. Since filesystems always have to set the super_block fields anyway, this avoids having to provide this information redundantly via fscrypt_operations. This change is in preparation for adding support for sub-block data units. For that, the value that is needed will become "the maximum file data unit index". A hardcoded value won't suffice for that; it will need to be computed anyway. Signed-off-by: Eric Biggers --- fs/crypto/fscrypt_private.h | 10 ++++++++++ fs/crypto/inline_crypt.c | 7 ++----- fs/crypto/policy.c | 20 +++++++++++--------- 3 files changed, 23 insertions(+), 14 deletions(-) diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index 2d63da48635ab..4b113214b53af 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -296,6 +296,16 @@ union fscrypt_iv { void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num, const struct fscrypt_info *ci); +/* + * Return the number of bits used by the maximum file logical block number that + * is possible on the given filesystem. + */ +static inline int +fscrypt_max_file_lblk_bits(const struct super_block *sb) +{ + return fls64(sb->s_maxbytes - 1) - sb->s_blocksize_bits; +} + /* fname.c */ bool __fscrypt_fname_encrypted_size(const union fscrypt_policy *policy, u32 orig_len, u32 max_len, diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c index 8bfb3ce864766..7d9f6c167de58 100644 --- a/fs/crypto/inline_crypt.c +++ b/fs/crypto/inline_crypt.c @@ -41,9 +41,8 @@ static struct block_device **fscrypt_get_devices(struct super_block *sb, static unsigned int fscrypt_get_dun_bytes(const struct fscrypt_info *ci) { - struct super_block *sb = ci->ci_inode->i_sb; + const struct super_block *sb = ci->ci_inode->i_sb; unsigned int flags = fscrypt_policy_flags(&ci->ci_policy); - int ino_bits = 64, lblk_bits = 64; if (flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) return offsetofend(union fscrypt_iv, nonce); @@ -55,9 +54,7 @@ static unsigned int fscrypt_get_dun_bytes(const struct fscrypt_info *ci) return sizeof(__le32); /* Default case: IVs are just the file logical block number */ - if (sb->s_cop->get_ino_and_lblk_bits) - sb->s_cop->get_ino_and_lblk_bits(sb, &ino_bits, &lblk_bits); - return DIV_ROUND_UP(lblk_bits, 8); + return DIV_ROUND_UP(fscrypt_max_file_lblk_bits(sb), 8); } /* diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c index f4456ecb3f877..36bffc4d6228d 100644 --- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -119,8 +119,7 @@ static bool supported_direct_key_modes(const struct inode *inode, static bool supported_iv_ino_lblk_policy(const struct fscrypt_policy_v2 *policy, const struct inode *inode, - const char *type, - int max_ino_bits, int max_lblk_bits) + const char *type, int max_ino_bits) { struct super_block *sb = inode->i_sb; int ino_bits = 64, lblk_bits = 64; @@ -154,13 +153,18 @@ static bool supported_iv_ino_lblk_policy(const struct fscrypt_policy_v2 *policy, sb->s_cop->get_ino_and_lblk_bits(sb, &ino_bits, &lblk_bits); if (ino_bits > max_ino_bits) { fscrypt_warn(inode, - "Can't use %s policy on filesystem '%s' because its inode numbers are too long", + "Can't use %s policy on filesystem '%s' because its maximum inode number is too large", type, sb->s_id); return false; } - if (lblk_bits > max_lblk_bits) { + + /* + * IV_INO_LBLK_64 and IV_INO_LBLK_32 both require that file logical + * block numbers fit in 32 bits. + */ + if (fscrypt_max_file_lblk_bits(sb) > 32) { fscrypt_warn(inode, - "Can't use %s policy on filesystem '%s' because its block numbers are too long", + "Can't use %s policy on filesystem '%s' because its maximum file size is too large", type, sb->s_id); return false; } @@ -239,8 +243,7 @@ static bool fscrypt_supported_v2_policy(const struct fscrypt_policy_v2 *policy, return false; if ((policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) && - !supported_iv_ino_lblk_policy(policy, inode, "IV_INO_LBLK_64", - 32, 32)) + !supported_iv_ino_lblk_policy(policy, inode, "IV_INO_LBLK_64", 32)) return false; /* @@ -250,8 +253,7 @@ static bool fscrypt_supported_v2_policy(const struct fscrypt_policy_v2 *policy, * implementation limit is 32 bits. */ if ((policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) && - !supported_iv_ino_lblk_policy(policy, inode, "IV_INO_LBLK_32", - 32, 32)) + !supported_iv_ino_lblk_policy(policy, inode, "IV_INO_LBLK_32", 32)) return false; if (memchr_inv(policy->__reserved, 0, sizeof(policy->__reserved))) { From patchwork Thu Sep 14 08:12:54 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Biggers X-Patchwork-Id: 13384798 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4A45EEDE98F for ; Thu, 14 Sep 2023 08:15:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236404AbjINIPF (ORCPT ); Thu, 14 Sep 2023 04:15:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56378 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236352AbjINIOz (ORCPT ); Thu, 14 Sep 2023 04:14:55 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 796391BE6; Thu, 14 Sep 2023 01:14:51 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D9B6CC433CC; Thu, 14 Sep 2023 08:14:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1694679291; bh=8faNDw+GOJRWczEDSbzCDhk91ZpNbMMHeLKRuECXN2o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=unbAEKy1HMONJfoSVoOu4s0IXItaJZMM8cuDgvR5xyP7EQUooffUXLYkpEMYcu5Xd IMP5btd0WRcI1BiYirRlOwrmXQjArMiF5xydT4kXP8satBrLVqbcJ0P+TAnUeY/94S kKHJV9lTPskWdL04NAW8zNfUxHD8BF8HEjzjnkU6QoYxAMtsbQBTMVYevaipeWcRja Wywr30LsGI1tUcXk/E5E28GgpNrhtCrX0a6HU+vHiVNJhUAA+RWYZv7o7ALCOGX+Sh LQTMm4IA3+ofWV4Uybom0h0xMinJ7f7B9RNgKX9phjPKqYSEKXK/c8BFr8uZOT9Nkh k6hJNfCkA5wCg== From: Eric Biggers To: linux-fscrypt@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-btrfs@vger.kernel.org, Jaegeuk Kim , Theodore Ts'o Subject: [PATCH v2 4/5] fscrypt: replace get_ino_and_lblk_bits with just has_32bit_inodes Date: Thu, 14 Sep 2023 01:12:54 -0700 Message-ID: <20230914081255.193502-5-ebiggers@kernel.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230914081255.193502-1-ebiggers@kernel.org> References: <20230914081255.193502-1-ebiggers@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org From: Eric Biggers Now that fs/crypto/ computes the filesystem's lblk_bits from its maximum file size, it is no longer necessary for filesystems to provide lblk_bits via fscrypt_operations::get_ino_and_lblk_bits. It is still necessary for fs/crypto/ to retrieve ino_bits from the filesystem. However, this is used only to decide whether inode numbers fit in 32 bits. Also, ino_bits is static for all relevant filesystems, i.e. it doesn't depend on the filesystem instance. Therefore, in the interest of keeping things as simple as possible, replace 'get_ino_and_lblk_bits' with a flag 'has_32bit_inodes'. This can always be changed back to a function if a filesystem needs it to be dynamic, but for now a static flag is all that's needed. Signed-off-by: Eric Biggers --- fs/crypto/policy.c | 33 +++++++++++++++------------------ fs/ext4/crypto.c | 9 +-------- fs/f2fs/super.c | 9 +-------- include/linux/fscrypt.h | 26 +++++++++++--------------- 4 files changed, 28 insertions(+), 49 deletions(-) diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c index 36bffc4d6228d..c8072a634af8f 100644 --- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -118,11 +118,11 @@ static bool supported_direct_key_modes(const struct inode *inode, } static bool supported_iv_ino_lblk_policy(const struct fscrypt_policy_v2 *policy, - const struct inode *inode, - const char *type, int max_ino_bits) + const struct inode *inode) { + const char *type = (policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) + ? "IV_INO_LBLK_64" : "IV_INO_LBLK_32"; struct super_block *sb = inode->i_sb; - int ino_bits = 64, lblk_bits = 64; /* * IV_INO_LBLK_* exist only because of hardware limitations, and @@ -149,9 +149,15 @@ static bool supported_iv_ino_lblk_policy(const struct fscrypt_policy_v2 *policy, type, sb->s_id); return false; } - if (sb->s_cop->get_ino_and_lblk_bits) - sb->s_cop->get_ino_and_lblk_bits(sb, &ino_bits, &lblk_bits); - if (ino_bits > max_ino_bits) { + + /* + * IV_INO_LBLK_64 requires that inode numbers fit in 32 bits. + * IV_INO_LBLK_32 hashes the inode number, so in principle it can + * support any length; however, currently the inode number is gotten + * from inode::i_ino which is 'unsigned long'. So for now the + * implementation limit is 32 bits, the same as IV_INO_LBLK_64. + */ + if (!sb->s_cop->has_32bit_inodes) { fscrypt_warn(inode, "Can't use %s policy on filesystem '%s' because its maximum inode number is too large", type, sb->s_id); @@ -242,18 +248,9 @@ static bool fscrypt_supported_v2_policy(const struct fscrypt_policy_v2 *policy, policy->filenames_encryption_mode)) return false; - if ((policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) && - !supported_iv_ino_lblk_policy(policy, inode, "IV_INO_LBLK_64", 32)) - return false; - - /* - * IV_INO_LBLK_32 hashes the inode number, so in principle it can - * support any ino_bits. However, currently the inode number is gotten - * from inode::i_ino which is 'unsigned long'. So for now the - * implementation limit is 32 bits. - */ - if ((policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) && - !supported_iv_ino_lblk_policy(policy, inode, "IV_INO_LBLK_32", 32)) + if ((policy->flags & (FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 | + FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) && + !supported_iv_ino_lblk_policy(policy, inode)) return false; if (memchr_inv(policy->__reserved, 0, sizeof(policy->__reserved))) { diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c index a9221be67f2a7..2859d9569aa74 100644 --- a/fs/ext4/crypto.c +++ b/fs/ext4/crypto.c @@ -232,20 +232,13 @@ static bool ext4_has_stable_inodes(struct super_block *sb) return ext4_has_feature_stable_inodes(sb); } -static void ext4_get_ino_and_lblk_bits(struct super_block *sb, - int *ino_bits_ret, int *lblk_bits_ret) -{ - *ino_bits_ret = 8 * sizeof(EXT4_SB(sb)->s_es->s_inodes_count); - *lblk_bits_ret = 8 * sizeof(ext4_lblk_t); -} - const struct fscrypt_operations ext4_cryptops = { .needs_bounce_pages = 1, + .has_32bit_inodes = 1, .legacy_key_prefix_for_backcompat = "ext4:", .get_context = ext4_get_context, .set_context = ext4_set_context, .get_dummy_policy = ext4_get_dummy_policy, .empty_dir = ext4_empty_dir, .has_stable_inodes = ext4_has_stable_inodes, - .get_ino_and_lblk_bits = ext4_get_ino_and_lblk_bits, }; diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 276535af5bf3c..7e8e510ef77af 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -3203,13 +3203,6 @@ static bool f2fs_has_stable_inodes(struct super_block *sb) return true; } -static void f2fs_get_ino_and_lblk_bits(struct super_block *sb, - int *ino_bits_ret, int *lblk_bits_ret) -{ - *ino_bits_ret = 8 * sizeof(nid_t); - *lblk_bits_ret = 8 * sizeof(block_t); -} - static struct block_device **f2fs_get_devices(struct super_block *sb, unsigned int *num_devs) { @@ -3232,13 +3225,13 @@ static struct block_device **f2fs_get_devices(struct super_block *sb, static const struct fscrypt_operations f2fs_cryptops = { .needs_bounce_pages = 1, + .has_32bit_inodes = 1, .legacy_key_prefix_for_backcompat = "f2fs:", .get_context = f2fs_get_context, .set_context = f2fs_set_context, .get_dummy_policy = f2fs_get_dummy_policy, .empty_dir = f2fs_empty_dir, .has_stable_inodes = f2fs_has_stable_inodes, - .get_ino_and_lblk_bits = f2fs_get_ino_and_lblk_bits, .get_devices = f2fs_get_devices, }; #endif diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 32290e5fa9abb..32a3b59bea276 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -73,6 +73,17 @@ struct fscrypt_operations { */ unsigned int needs_bounce_pages : 1; + /* + * If set, then fs/crypto/ will allow the use of encryption settings + * that assume inode numbers fit in 32 bits (i.e. + * FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{32,64}), provided that the other + * prerequisites for these settings are also met. This is only useful + * if the filesystem wants to support inline encryption hardware that is + * limited to 32-bit or 64-bit data unit numbers and where programming + * keyslots is very slow. + */ + unsigned int has_32bit_inodes : 1; + /* * This field exists only for backwards compatibility reasons and should * only be set by the filesystems that are setting it already. It @@ -150,21 +161,6 @@ struct fscrypt_operations { */ bool (*has_stable_inodes)(struct super_block *sb); - /* - * Get the number of bits that the filesystem uses to represent inode - * numbers and file logical block numbers. - * - * By default, both of these are assumed to be 64-bit. This function - * can be implemented to declare that either or both of these numbers is - * shorter, which may allow the use of the - * FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{32,64} flags and/or the use of - * inline crypto hardware whose maximum DUN length is less than 64 bits - * (e.g., eMMC v5.2 spec compliant hardware). This function only needs - * to be implemented if support for one of these features is needed. - */ - void (*get_ino_and_lblk_bits)(struct super_block *sb, - int *ino_bits_ret, int *lblk_bits_ret); - /* * Return an array of pointers to the block devices to which the * filesystem may write encrypted file contents, NULL if the filesystem From patchwork Thu Sep 14 08:12:55 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Biggers X-Patchwork-Id: 13384799 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6AA27EDE994 for ; Thu, 14 Sep 2023 08:15:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236426AbjINIPM (ORCPT ); Thu, 14 Sep 2023 04:15:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56382 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236358AbjINIO4 (ORCPT ); Thu, 14 Sep 2023 04:14:56 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CB1D21BF9; Thu, 14 Sep 2023 01:14:51 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3EC40C433C7; Thu, 14 Sep 2023 08:14:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1694679291; bh=/YNLyiUhJxmM3kIF6rM3Y2gkaC/u1NY8pUKLJGZuEoc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iBluGjZCxVM4ZalLAgkRVJUWEBPP1rMR5DGNlw0JSdtl8+kQKIrp1MnmZlzdrVEJp HFwbOry7ZLUYYOAKn3zhP8NAHKqiy4/PyoH/iB4UYylzjJnD8rUYsYtG9l/ZOFVLbq vqkVi+JNQrx6CMYgfimfO1c5n9g/nitYHwfnbW/JnJguSbr1uvkApJjHuErsKshFnS 7FVY2INVgMEuB74vnQkph++AlwzVQ6xOVAphDXx78t4ei0+PJzJL+dTw10rqOnufmX tiFeAHiXDUpSqtsO8zLZkA/eQh20miznaAlwSU7To7jeNUKlSNLk3LKrtUVmei61NT syj9yuf25dnBA== From: Eric Biggers To: linux-fscrypt@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-btrfs@vger.kernel.org, Jaegeuk Kim , Theodore Ts'o Subject: [PATCH v2 5/5] fscrypt: support crypto data unit size less than filesystem block size Date: Thu, 14 Sep 2023 01:12:55 -0700 Message-ID: <20230914081255.193502-6-ebiggers@kernel.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230914081255.193502-1-ebiggers@kernel.org> References: <20230914081255.193502-1-ebiggers@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org From: Eric Biggers Until now, fscrypt has always used the filesystem block size as the granularity of file contents encryption. Two scenarios have come up where a sub-block granularity of contents encryption would be useful: 1. Inline encryption hardware that only supports a crypto data unit size that is less than the filesystem block size. 2. Support for direct I/O at a granularity less than the filesystem block size, for example at the block device's logical block size in order to match the traditional direct I/O alignment requirement. (1) first came up with older eMMC inline crypto hardware that only supports a crypto data unit size of 512 bytes. That specific case ultimately went away because all systems with that hardware continued using out of tree code and never actually upgraded to the upstream inline crypto framework. But, now it's coming back in a new way: some current UFS controllers only support a data unit size of 4096 bytes, and there is a proposal to increase the filesystem block size to 16K. (2) was discussed as a "nice to have" feature, though not essential, when support for direct I/O on encrypted files was being upstreamed. Still, the fact that this feature has come up several times does suggest it would be wise to have available. Therefore, this patch implements it by using one of the reserved bytes in fscrypt_policy_v2 to allow users to select a sub-block data unit size. Supported data unit sizes are powers of 2 between 512 and the filesystem block size, inclusively. Support is implemented for both the FS-layer and inline crypto cases. This patch focuses on the basic support for sub-block data units. Some things are out of scope of this patch but may be addressed later: - Supporting sub-block data units in combination with FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64, in most cases. Unfortunately this combination usually causes data unit indices to exceed 32 bits, and thus fscrypt_supported_policy() correctly disallows it. The users who potentially need this combination are using f2fs. To support it, f2fs would need to provide an option to slightly reduce its max file size. - Supporting sub-block data units in combination with FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32. This has the same problem described above, but also it will need special code to make DUN wraparound still happen on a FS block boundary. - Supporting use case (2) mentioned above. The encrypted direct I/O code will need to stop requiring and assuming FS block alignment. This won't be hard, but it belongs in a separate patch. - Supporting this feature on filesystems other than ext4 and f2fs. (Filesystems declare support for it via their fscrypt_operations.) On UBIFS, sub-block data units don't make sense because UBIFS encrypts variable-length blocks as a result of compression. CephFS could support it, but a bit more work would be needed to make the fscrypt_*_block_inplace functions play nicely with sub-block data units. I don't think there's a use case for this on CephFS anyway. Signed-off-by: Eric Biggers --- Documentation/filesystems/fscrypt.rst | 116 +++++++++++++++------ fs/crypto/bio.c | 39 ++++---- fs/crypto/crypto.c | 139 ++++++++++++++------------ fs/crypto/fscrypt_private.h | 53 +++++++--- fs/crypto/inline_crypt.c | 20 +++- fs/crypto/keysetup.c | 3 + fs/crypto/policy.c | 34 ++++++- fs/ext4/crypto.c | 1 + fs/f2fs/super.c | 1 + include/linux/fscrypt.h | 12 +++ include/uapi/linux/fscrypt.h | 3 +- 11 files changed, 288 insertions(+), 133 deletions(-) diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst index a624e92f2687f..42898f187246d 100644 --- a/Documentation/filesystems/fscrypt.rst +++ b/Documentation/filesystems/fscrypt.rst @@ -261,9 +261,9 @@ DIRECT_KEY policies The Adiantum encryption mode (see `Encryption modes and usage`_) is suitable for both contents and filenames encryption, and it accepts -long IVs --- long enough to hold both an 8-byte logical block number -and a 16-byte per-file nonce. Also, the overhead of each Adiantum key -is greater than that of an AES-256-XTS key. +long IVs --- long enough to hold both an 8-byte data unit index and a +16-byte per-file nonce. Also, the overhead of each Adiantum key is +greater than that of an AES-256-XTS key. Therefore, to improve performance and save memory, for Adiantum a "direct key" configuration is supported. When the user has enabled @@ -300,8 +300,8 @@ IV_INO_LBLK_32 policies IV_INO_LBLK_32 policies work like IV_INO_LBLK_64, except that for IV_INO_LBLK_32, the inode number is hashed with SipHash-2-4 (where the -SipHash key is derived from the master key) and added to the file -logical block number mod 2^32 to produce a 32-bit IV. +SipHash key is derived from the master key) and added to the file data +unit index mod 2^32 to produce a 32-bit IV. This format is optimized for use with inline encryption hardware compliant with the eMMC v5.2 standard, which supports only 32 IV bits @@ -451,31 +451,62 @@ acceleration is recommended: Contents encryption ------------------- -For file contents, each filesystem block is encrypted independently. -Starting from Linux kernel 5.5, encryption of filesystems with block -size less than system's page size is supported. - -Each block's IV is set to the logical block number within the file as -a little endian number, except that: - -- With CBC mode encryption, ESSIV is also used. Specifically, each IV - is encrypted with AES-256 where the AES-256 key is the SHA-256 hash - of the file's data encryption key. - -- With `DIRECT_KEY policies`_, the file's nonce is appended to the IV. - Currently this is only allowed with the Adiantum encryption mode. - -- With `IV_INO_LBLK_64 policies`_, the logical block number is limited - to 32 bits and is placed in bits 0-31 of the IV. The inode number - (which is also limited to 32 bits) is placed in bits 32-63. - -- With `IV_INO_LBLK_32 policies`_, the logical block number is limited - to 32 bits and is placed in bits 0-31 of the IV. The inode number - is then hashed and added mod 2^32. - -Note that because file logical block numbers are included in the IVs, -filesystems must enforce that blocks are never shifted around within -encrypted files, e.g. via "collapse range" or "insert range". +For contents encryption, each file's contents is divided into "data +units". Each data unit is encrypted independently. The IV for each +data unit incorporates the zero-based index of the data unit within +the file. This ensures that each data unit within a file is encrypted +differently, which is essential to prevent leaking information. + +Note: the encryption depending on the offset into the file means that +operations like "collapse range" and "insert range" that rearrange the +extent mapping of files are not supported on encrypted files. + +There are two cases for the sizes of the data units: + +* Fixed-size data units. This is how all filesystems other than UBIFS + work. A file's data units are all the same size; the last data unit + is zero-padded if needed. By default, the data unit size is equal + to the filesystem block size. On some filesystems, users can select + a sub-block data unit size via the ``log2_data_unit_size`` field of + the encryption policy; see `FS_IOC_SET_ENCRYPTION_POLICY`_. + +* Variable-size data units. This is what UBIFS does. Each "UBIFS + data node" is treated as a crypto data unit. Each contains variable + length, possibly compressed data, zero-padded to the next 16-byte + boundary. Users cannot select a sub-block data unit size on UBIFS. + +In the case of compression + encryption, the compressed data is +encrypted. UBIFS compression works as described above. f2fs +compression works a bit differently; it compresses a number of +filesystem blocks into a smaller number of filesystem blocks. +Therefore a f2fs-compressed file still uses fixed-size data units, and +it is encrypted in a similar way to a file containing holes. + +As mentioned in `Key hierarchy`_, the default encryption setting uses +per-file keys. In this case, the IV for each data unit is simply the +index of the data unit in the file. However, users can select an +encryption setting that does not use per-file keys. For these, some +kind of file identifier is incorporated into the IVs as follows: + +- With `DIRECT_KEY policies`_, the data unit index is placed in bits + 0-63 of the IV, and the file's nonce is placed in bits 64-191. + +- With `IV_INO_LBLK_64 policies`_, the data unit index is placed in + bits 0-31 of the IV, and the file's inode number is placed in bits + 32-63. This setting is only allowed when data unit indices and + inode numbers fit in 32 bits. + +- With `IV_INO_LBLK_32 policies`_, the file's inode number is hashed + and added to the data unit index. The resulting value is truncated + to 32 bits and placed in bits 0-31 of the IV. This setting is only + allowed when data unit indices and inode numbers fit in 32 bits. + +The byte order of the IV is always little endian. + +If the user selects FSCRYPT_MODE_AES_128_CBC for the contents mode, an +ESSIV layer is automatically included. In this case, before the IV is +passed to AES-128-CBC, it is encrypted with AES-256 where the AES-256 +key is the SHA-256 hash of the file's contents encryption key. Filenames encryption -------------------- @@ -544,7 +575,8 @@ follows:: __u8 contents_encryption_mode; __u8 filenames_encryption_mode; __u8 flags; - __u8 __reserved[4]; + __u8 log2_data_unit_size; + __u8 __reserved[3]; __u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE]; }; @@ -586,6 +618,28 @@ This structure must be initialized as follows: The DIRECT_KEY, IV_INO_LBLK_64, and IV_INO_LBLK_32 flags are mutually exclusive. +- ``log2_data_unit_size`` is the log2 of the data unit size in bytes, + or 0 to select the default data unit size. The data unit size is + the granularity of file contents encryption. For example, setting + ``log2_data_unit_size`` to 12 causes file contents be passed to the + underlying encryption algorithm (such as AES-256-XTS) in 4096-byte + data units, each with its own IV. + + Not all filesystems support setting ``log2_data_unit_size``. ext4 + and f2fs support it since Linux v6.7. On filesystems that support + it, the supported nonzero values are 9 through the log2 of the + filesystem block size, inclusively. The default value of 0 selects + the filesystem block size. + + The main use case for ``log2_data_unit_size`` is for selecting a + data unit size smaller than the filesystem block size for + compatibility with inline encryption hardware that only supports + smaller data unit sizes. ``/sys/block/$disk/queue/crypto/`` may be + useful for checking which data unit sizes are supported by a + particular system's inline encryption hardware. + + Leave this field zeroed unless you are certain you need it. + - For v2 encryption policies, ``__reserved`` must be zeroed. - For v1 encryption policies, ``master_key_descriptor`` specifies how diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c index 62e1a3dd83574..c8cf77065272e 100644 --- a/fs/crypto/bio.c +++ b/fs/crypto/bio.c @@ -111,10 +111,14 @@ static int fscrypt_zeroout_range_inline_crypt(const struct inode *inode, int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, sector_t pblk, unsigned int len) { - const unsigned int blockbits = inode->i_blkbits; - const unsigned int blocksize = 1 << blockbits; - const unsigned int blocks_per_page_bits = PAGE_SHIFT - blockbits; - const unsigned int blocks_per_page = 1 << blocks_per_page_bits; + const struct fscrypt_info *ci = inode->i_crypt_info; + const unsigned int du_bits = ci->ci_data_unit_bits; + const unsigned int du_size = 1U << du_bits; + const unsigned int du_per_page_bits = PAGE_SHIFT - du_bits; + const unsigned int du_per_page = 1U << du_per_page_bits; + u64 du_index = (u64)lblk << (inode->i_blkbits - du_bits); + u64 du_remaining = (u64)len << (inode->i_blkbits - du_bits); + sector_t sector = pblk << (inode->i_blkbits - SECTOR_SHIFT); struct page *pages[16]; /* write up to 16 pages at a time */ unsigned int nr_pages; unsigned int i; @@ -130,8 +134,8 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, len); BUILD_BUG_ON(ARRAY_SIZE(pages) > BIO_MAX_VECS); - nr_pages = min_t(unsigned int, ARRAY_SIZE(pages), - (len + blocks_per_page - 1) >> blocks_per_page_bits); + nr_pages = min_t(u64, ARRAY_SIZE(pages), + (du_remaining + du_per_page - 1) >> du_per_page_bits); /* * We need at least one page for ciphertext. Allocate the first one @@ -154,21 +158,22 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, bio = bio_alloc(inode->i_sb->s_bdev, nr_pages, REQ_OP_WRITE, GFP_NOFS); do { - bio->bi_iter.bi_sector = pblk << (blockbits - 9); + bio->bi_iter.bi_sector = sector; i = 0; offset = 0; do { - err = fscrypt_crypt_block(inode, FS_ENCRYPT, lblk, - ZERO_PAGE(0), pages[i], - blocksize, offset, GFP_NOFS); + err = fscrypt_crypt_data_unit(ci, FS_ENCRYPT, du_index, + ZERO_PAGE(0), pages[i], + du_size, offset, + GFP_NOFS); if (err) goto out; - lblk++; - pblk++; - len--; - offset += blocksize; - if (offset == PAGE_SIZE || len == 0) { + du_index++; + sector += 1U << (du_bits - SECTOR_SHIFT); + du_remaining--; + offset += du_size; + if (offset == PAGE_SIZE || du_remaining == 0) { ret = bio_add_page(bio, pages[i++], offset, 0); if (WARN_ON_ONCE(ret != offset)) { err = -EIO; @@ -176,13 +181,13 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, } offset = 0; } - } while (i != nr_pages && len != 0); + } while (i != nr_pages && du_remaining != 0); err = submit_bio_wait(bio); if (err) goto out; bio_reset(bio, inode->i_sb->s_bdev, REQ_OP_WRITE); - } while (len != 0); + } while (du_remaining != 0); err = 0; out: bio_put(bio); diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c index 803347a5d0a6d..f8aa692a295c9 100644 --- a/fs/crypto/crypto.c +++ b/fs/crypto/crypto.c @@ -77,14 +77,14 @@ void fscrypt_free_bounce_page(struct page *bounce_page) EXPORT_SYMBOL(fscrypt_free_bounce_page); /* - * Generate the IV for the given logical block number within the given file. - * For filenames encryption, lblk_num == 0. + * Generate the IV for the given data unit index within the given file. + * For filenames encryption, index == 0. * * Keep this in sync with fscrypt_limit_io_blocks(). fscrypt_limit_io_blocks() * needs to know about any IV generation methods where the low bits of IV don't - * simply contain the lblk_num (e.g., IV_INO_LBLK_32). + * simply contain the data unit index (e.g., IV_INO_LBLK_32). */ -void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num, +void fscrypt_generate_iv(union fscrypt_iv *iv, u64 index, const struct fscrypt_info *ci) { u8 flags = fscrypt_policy_flags(&ci->ci_policy); @@ -92,29 +92,29 @@ void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num, memset(iv, 0, ci->ci_mode->ivsize); if (flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) { - WARN_ON_ONCE(lblk_num > U32_MAX); + WARN_ON_ONCE(index > U32_MAX); WARN_ON_ONCE(ci->ci_inode->i_ino > U32_MAX); - lblk_num |= (u64)ci->ci_inode->i_ino << 32; + index |= (u64)ci->ci_inode->i_ino << 32; } else if (flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) { - WARN_ON_ONCE(lblk_num > U32_MAX); - lblk_num = (u32)(ci->ci_hashed_ino + lblk_num); + WARN_ON_ONCE(index > U32_MAX); + index = (u32)(ci->ci_hashed_ino + index); } else if (flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) { memcpy(iv->nonce, ci->ci_nonce, FSCRYPT_FILE_NONCE_SIZE); } - iv->lblk_num = cpu_to_le64(lblk_num); + iv->index = cpu_to_le64(index); } -/* Encrypt or decrypt a single filesystem block of file contents */ -int fscrypt_crypt_block(const struct inode *inode, fscrypt_direction_t rw, - u64 lblk_num, struct page *src_page, - struct page *dest_page, unsigned int len, - unsigned int offs, gfp_t gfp_flags) +/* Encrypt or decrypt a single "data unit" of file contents. */ +int fscrypt_crypt_data_unit(const struct fscrypt_info *ci, + fscrypt_direction_t rw, u64 index, + struct page *src_page, struct page *dest_page, + unsigned int len, unsigned int offs, + gfp_t gfp_flags) { union fscrypt_iv iv; struct skcipher_request *req = NULL; DECLARE_CRYPTO_WAIT(wait); struct scatterlist dst, src; - struct fscrypt_info *ci = inode->i_crypt_info; struct crypto_skcipher *tfm = ci->ci_enc_key.tfm; int res = 0; @@ -123,7 +123,7 @@ int fscrypt_crypt_block(const struct inode *inode, fscrypt_direction_t rw, if (WARN_ON_ONCE(len % FSCRYPT_CONTENTS_ALIGNMENT != 0)) return -EINVAL; - fscrypt_generate_iv(&iv, lblk_num, ci); + fscrypt_generate_iv(&iv, index, ci); req = skcipher_request_alloc(tfm, gfp_flags); if (!req) @@ -144,28 +144,29 @@ int fscrypt_crypt_block(const struct inode *inode, fscrypt_direction_t rw, res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait); skcipher_request_free(req); if (res) { - fscrypt_err(inode, "%scryption failed for block %llu: %d", - (rw == FS_DECRYPT ? "De" : "En"), lblk_num, res); + fscrypt_err(ci->ci_inode, + "%scryption failed for data unit %llu: %d", + (rw == FS_DECRYPT ? "De" : "En"), index, res); return res; } return 0; } /** - * fscrypt_encrypt_pagecache_blocks() - Encrypt filesystem blocks from a - * pagecache page - * @page: The locked pagecache page containing the block(s) to encrypt - * @len: Total size of the block(s) to encrypt. Must be a nonzero - * multiple of the filesystem's block size. - * @offs: Byte offset within @page of the first block to encrypt. Must be - * a multiple of the filesystem's block size. - * @gfp_flags: Memory allocation flags. See details below. + * fscrypt_encrypt_pagecache_blocks() - Encrypt data from a pagecache page + * @page: the locked pagecache page containing the data to encrypt + * @len: size of the data to encrypt, in bytes + * @offs: offset within @page of the data to encrypt, in bytes + * @gfp_flags: memory allocation flags; see details below * - * A new bounce page is allocated, and the specified block(s) are encrypted into - * it. In the bounce page, the ciphertext block(s) will be located at the same - * offsets at which the plaintext block(s) were located in the source page; any - * other parts of the bounce page will be left uninitialized. However, normally - * blocksize == PAGE_SIZE and the whole page is encrypted at once. + * This allocates a new bounce page and encrypts the given data into it. The + * length and offset of the data must be aligned to the file's crypto data unit + * size. Alignment to the filesystem block size fulfills this requirement, as + * the filesystem block size is always a multiple of the data unit size. + * + * In the bounce page, the ciphertext data will be located at the same offset at + * which the plaintext data was located in the source page. Any other parts of + * the bounce page will be left uninitialized. * * This is for use by the filesystem's ->writepages() method. * @@ -183,28 +184,29 @@ struct page *fscrypt_encrypt_pagecache_blocks(struct page *page, { const struct inode *inode = page->mapping->host; - const unsigned int blockbits = inode->i_blkbits; - const unsigned int blocksize = 1 << blockbits; + const struct fscrypt_info *ci = inode->i_crypt_info; + const unsigned int du_bits = ci->ci_data_unit_bits; + const unsigned int du_size = 1U << du_bits; struct page *ciphertext_page; - u64 lblk_num = ((u64)page->index << (PAGE_SHIFT - blockbits)) + - (offs >> blockbits); + u64 index = ((u64)page->index << (PAGE_SHIFT - du_bits)) + + (offs >> du_bits); unsigned int i; int err; if (WARN_ON_ONCE(!PageLocked(page))) return ERR_PTR(-EINVAL); - if (WARN_ON_ONCE(len <= 0 || !IS_ALIGNED(len | offs, blocksize))) + if (WARN_ON_ONCE(len <= 0 || !IS_ALIGNED(len | offs, du_size))) return ERR_PTR(-EINVAL); ciphertext_page = fscrypt_alloc_bounce_page(gfp_flags); if (!ciphertext_page) return ERR_PTR(-ENOMEM); - for (i = offs; i < offs + len; i += blocksize, lblk_num++) { - err = fscrypt_crypt_block(inode, FS_ENCRYPT, lblk_num, - page, ciphertext_page, - blocksize, i, gfp_flags); + for (i = offs; i < offs + len; i += du_size, index++) { + err = fscrypt_crypt_data_unit(ci, FS_ENCRYPT, index, + page, ciphertext_page, + du_size, i, gfp_flags); if (err) { fscrypt_free_bounce_page(ciphertext_page); return ERR_PTR(err); @@ -231,30 +233,33 @@ EXPORT_SYMBOL(fscrypt_encrypt_pagecache_blocks); * arbitrary page, not necessarily in the original pagecache page. The @inode * and @lblk_num must be specified, as they can't be determined from @page. * + * This is not compatible with fscrypt_operations::supports_subblock_data_units. + * * Return: 0 on success; -errno on failure */ int fscrypt_encrypt_block_inplace(const struct inode *inode, struct page *page, unsigned int len, unsigned int offs, u64 lblk_num, gfp_t gfp_flags) { - return fscrypt_crypt_block(inode, FS_ENCRYPT, lblk_num, page, page, - len, offs, gfp_flags); + if (WARN_ON_ONCE(inode->i_sb->s_cop->supports_subblock_data_units)) + return -EOPNOTSUPP; + return fscrypt_crypt_data_unit(inode->i_crypt_info, FS_ENCRYPT, + lblk_num, page, page, len, offs, + gfp_flags); } EXPORT_SYMBOL(fscrypt_encrypt_block_inplace); /** - * fscrypt_decrypt_pagecache_blocks() - Decrypt filesystem blocks in a - * pagecache folio - * @folio: The locked pagecache folio containing the block(s) to decrypt - * @len: Total size of the block(s) to decrypt. Must be a nonzero - * multiple of the filesystem's block size. - * @offs: Byte offset within @folio of the first block to decrypt. Must be - * a multiple of the filesystem's block size. + * fscrypt_decrypt_pagecache_blocks() - Decrypt data from a pagecache folio + * @folio: the pagecache folio containing the data to decrypt + * @len: size of the data to decrypt, in bytes + * @offs: offset within @folio of the data to decrypt, in bytes * - * The specified block(s) are decrypted in-place within the pagecache folio, - * which must still be locked and not uptodate. - * - * This is for use by the filesystem's ->readahead() method. + * Decrypt data that has just been read from an encrypted file. The data must + * be located in a pagecache folio that is still locked and not yet uptodate. + * The length and offset of the data must be aligned to the file's crypto data + * unit size. Alignment to the filesystem block size fulfills this requirement, + * as the filesystem block size is always a multiple of the data unit size. * * Return: 0 on success; -errno on failure */ @@ -262,25 +267,26 @@ int fscrypt_decrypt_pagecache_blocks(struct folio *folio, size_t len, size_t offs) { const struct inode *inode = folio->mapping->host; - const unsigned int blockbits = inode->i_blkbits; - const unsigned int blocksize = 1 << blockbits; - u64 lblk_num = ((u64)folio->index << (PAGE_SHIFT - blockbits)) + - (offs >> blockbits); + const struct fscrypt_info *ci = inode->i_crypt_info; + const unsigned int du_bits = ci->ci_data_unit_bits; + const unsigned int du_size = 1U << du_bits; + u64 index = ((u64)folio->index << (PAGE_SHIFT - du_bits)) + + (offs >> du_bits); size_t i; int err; if (WARN_ON_ONCE(!folio_test_locked(folio))) return -EINVAL; - if (WARN_ON_ONCE(len <= 0 || !IS_ALIGNED(len | offs, blocksize))) + if (WARN_ON_ONCE(len <= 0 || !IS_ALIGNED(len | offs, du_size))) return -EINVAL; - for (i = offs; i < offs + len; i += blocksize, lblk_num++) { + for (i = offs; i < offs + len; i += du_size, index++) { struct page *page = folio_page(folio, i >> PAGE_SHIFT); - err = fscrypt_crypt_block(inode, FS_DECRYPT, lblk_num, page, - page, blocksize, i & ~PAGE_MASK, - GFP_NOFS); + err = fscrypt_crypt_data_unit(ci, FS_DECRYPT, index, page, + page, du_size, i & ~PAGE_MASK, + GFP_NOFS); if (err) return err; } @@ -302,14 +308,19 @@ EXPORT_SYMBOL(fscrypt_decrypt_pagecache_blocks); * arbitrary page, not necessarily in the original pagecache page. The @inode * and @lblk_num must be specified, as they can't be determined from @page. * + * This is not compatible with fscrypt_operations::supports_subblock_data_units. + * * Return: 0 on success; -errno on failure */ int fscrypt_decrypt_block_inplace(const struct inode *inode, struct page *page, unsigned int len, unsigned int offs, u64 lblk_num) { - return fscrypt_crypt_block(inode, FS_DECRYPT, lblk_num, page, page, - len, offs, GFP_NOFS); + if (WARN_ON_ONCE(inode->i_sb->s_cop->supports_subblock_data_units)) + return -EOPNOTSUPP; + return fscrypt_crypt_data_unit(inode->i_crypt_info, FS_DECRYPT, + lblk_num, page, page, len, offs, + GFP_NOFS); } EXPORT_SYMBOL(fscrypt_decrypt_block_inplace); diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index 4b113214b53af..e3f7e956e22c4 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -47,7 +47,8 @@ struct fscrypt_context_v2 { u8 contents_encryption_mode; u8 filenames_encryption_mode; u8 flags; - u8 __reserved[4]; + u8 log2_data_unit_size; + u8 __reserved[3]; u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE]; u8 nonce[FSCRYPT_FILE_NONCE_SIZE]; }; @@ -165,6 +166,26 @@ fscrypt_policy_flags(const union fscrypt_policy *policy) BUG(); } +static inline int +fscrypt_policy_v2_du_bits(const struct fscrypt_policy_v2 *policy, + const struct inode *inode) +{ + return policy->log2_data_unit_size ?: inode->i_blkbits; +} + +static inline int +fscrypt_policy_du_bits(const union fscrypt_policy *policy, + const struct inode *inode) +{ + switch (policy->version) { + case FSCRYPT_POLICY_V1: + return inode->i_blkbits; + case FSCRYPT_POLICY_V2: + return fscrypt_policy_v2_du_bits(&policy->v2, inode); + } + BUG(); +} + /* * For encrypted symlinks, the ciphertext length is stored at the beginning * of the string in little-endian format. @@ -211,6 +232,13 @@ struct fscrypt_info { bool ci_inlinecrypt; #endif + /* + * log2 of the data unit size (granularity of contents encryption) of + * this file. This is computable from ci_policy and ci_inode but is + * cached here for efficiency. Only used for regular files. + */ + u8 ci_data_unit_bits; + /* * Encryption mode used for this inode. It corresponds to either the * contents or filenames encryption mode, depending on the inode type. @@ -265,10 +293,11 @@ typedef enum { /* crypto.c */ extern struct kmem_cache *fscrypt_info_cachep; int fscrypt_initialize(struct super_block *sb); -int fscrypt_crypt_block(const struct inode *inode, fscrypt_direction_t rw, - u64 lblk_num, struct page *src_page, - struct page *dest_page, unsigned int len, - unsigned int offs, gfp_t gfp_flags); +int fscrypt_crypt_data_unit(const struct fscrypt_info *ci, + fscrypt_direction_t rw, u64 index, + struct page *src_page, struct page *dest_page, + unsigned int len, unsigned int offs, + gfp_t gfp_flags); struct page *fscrypt_alloc_bounce_page(gfp_t gfp_flags); void __printf(3, 4) __cold @@ -283,8 +312,8 @@ fscrypt_msg(const struct inode *inode, const char *level, const char *fmt, ...); union fscrypt_iv { struct { - /* logical block number within the file */ - __le64 lblk_num; + /* zero-based index of data unit within the file */ + __le64 index; /* per-file nonce; only set in DIRECT_KEY mode */ u8 nonce[FSCRYPT_FILE_NONCE_SIZE]; @@ -293,17 +322,17 @@ union fscrypt_iv { __le64 dun[FSCRYPT_MAX_IV_SIZE / sizeof(__le64)]; }; -void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num, +void fscrypt_generate_iv(union fscrypt_iv *iv, u64 index, const struct fscrypt_info *ci); /* - * Return the number of bits used by the maximum file logical block number that - * is possible on the given filesystem. + * Return the number of bits used by the maximum file data unit index that is + * possible on the given filesystem, using the given data unit size. */ static inline int -fscrypt_max_file_lblk_bits(const struct super_block *sb) +fscrypt_max_file_dun_bits(const struct super_block *sb, int du_bits) { - return fls64(sb->s_maxbytes - 1) - sb->s_blocksize_bits; + return fls64(sb->s_maxbytes - 1) - du_bits; } /* fname.c */ diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c index 7d9f6c167de58..43d8eb7f017a7 100644 --- a/fs/crypto/inline_crypt.c +++ b/fs/crypto/inline_crypt.c @@ -39,10 +39,16 @@ static struct block_device **fscrypt_get_devices(struct super_block *sb, return devs; } +static unsigned int fscrypt_get_du_size(const struct fscrypt_info *ci) +{ + return 1U << ci->ci_data_unit_bits; +} + static unsigned int fscrypt_get_dun_bytes(const struct fscrypt_info *ci) { const struct super_block *sb = ci->ci_inode->i_sb; unsigned int flags = fscrypt_policy_flags(&ci->ci_policy); + int dun_bits; if (flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) return offsetofend(union fscrypt_iv, nonce); @@ -53,8 +59,9 @@ static unsigned int fscrypt_get_dun_bytes(const struct fscrypt_info *ci) if (flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) return sizeof(__le32); - /* Default case: IVs are just the file logical block number */ - return DIV_ROUND_UP(fscrypt_max_file_lblk_bits(sb), 8); + /* Default case: IVs are just the file data unit index */ + dun_bits = fscrypt_max_file_dun_bits(sb, ci->ci_data_unit_bits); + return DIV_ROUND_UP(dun_bits, 8); } /* @@ -126,7 +133,7 @@ int fscrypt_select_encryption_impl(struct fscrypt_info *ci) * crypto configuration that the file would use. */ crypto_cfg.crypto_mode = ci->ci_mode->blk_crypto_mode; - crypto_cfg.data_unit_size = sb->s_blocksize; + crypto_cfg.data_unit_size = fscrypt_get_du_size(ci); crypto_cfg.dun_bytes = fscrypt_get_dun_bytes(ci); devs = fscrypt_get_devices(sb, &num_devs); @@ -165,7 +172,8 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, return -ENOMEM; err = blk_crypto_init_key(blk_key, raw_key, crypto_mode, - fscrypt_get_dun_bytes(ci), sb->s_blocksize); + fscrypt_get_dun_bytes(ci), + fscrypt_get_du_size(ci)); if (err) { fscrypt_err(inode, "error %d initializing blk-crypto key", err); goto fail; @@ -232,10 +240,12 @@ EXPORT_SYMBOL_GPL(__fscrypt_inode_uses_inline_crypto); static void fscrypt_generate_dun(const struct fscrypt_info *ci, u64 lblk_num, u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE]) { + u64 index = lblk_num << (ci->ci_inode->i_blkbits - + ci->ci_data_unit_bits); union fscrypt_iv iv; int i; - fscrypt_generate_iv(&iv, lblk_num, ci); + fscrypt_generate_iv(&iv, index, ci); BUILD_BUG_ON(FSCRYPT_MAX_IV_SIZE > BLK_CRYPTO_MAX_IV_SIZE); memset(dun, 0, BLK_CRYPTO_MAX_IV_SIZE); diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index 361f41ef46c78..8d016e2e090c0 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -580,6 +580,9 @@ fscrypt_setup_encryption_info(struct inode *inode, WARN_ON_ONCE(mode->ivsize > FSCRYPT_MAX_IV_SIZE); crypt_info->ci_mode = mode; + crypt_info->ci_data_unit_bits = + fscrypt_policy_du_bits(&crypt_info->ci_policy, inode); + res = setup_file_encryption_key(crypt_info, need_dirhash_key, &mk); if (res) goto out; diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c index c8072a634af8f..114e4c3aa3beb 100644 --- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -165,10 +165,11 @@ static bool supported_iv_ino_lblk_policy(const struct fscrypt_policy_v2 *policy, } /* - * IV_INO_LBLK_64 and IV_INO_LBLK_32 both require that file logical - * block numbers fit in 32 bits. + * IV_INO_LBLK_64 and IV_INO_LBLK_32 both require that file data unit + * indices fit in 32 bits. */ - if (fscrypt_max_file_lblk_bits(sb) > 32) { + if (fscrypt_max_file_dun_bits(sb, + fscrypt_policy_v2_du_bits(policy, inode)) > 32) { fscrypt_warn(inode, "Can't use %s policy on filesystem '%s' because its maximum file size is too large", type, sb->s_id); @@ -243,6 +244,31 @@ static bool fscrypt_supported_v2_policy(const struct fscrypt_policy_v2 *policy, return false; } + if (policy->log2_data_unit_size) { + if (!inode->i_sb->s_cop->supports_subblock_data_units) { + fscrypt_warn(inode, + "Filesystem does not support configuring crypto data unit size"); + return false; + } + if (policy->log2_data_unit_size > inode->i_blkbits || + policy->log2_data_unit_size < SECTOR_SHIFT /* 9 */) { + fscrypt_warn(inode, + "Unsupported log2_data_unit_size in encryption policy: %d", + policy->log2_data_unit_size); + return false; + } + if (policy->log2_data_unit_size != inode->i_blkbits && + (policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) { + /* + * Not safe to enable yet, as we need to ensure that DUN + * wraparound can only occur on a FS block boundary. + */ + fscrypt_warn(inode, + "Sub-block data units not yet supported with IV_INO_LBLK_32"); + return false; + } + } + if ((policy->flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) && !supported_direct_key_modes(inode, policy->contents_encryption_mode, policy->filenames_encryption_mode)) @@ -329,6 +355,7 @@ static int fscrypt_new_context(union fscrypt_context *ctx_u, ctx->filenames_encryption_mode = policy->filenames_encryption_mode; ctx->flags = policy->flags; + ctx->log2_data_unit_size = policy->log2_data_unit_size; memcpy(ctx->master_key_identifier, policy->master_key_identifier, sizeof(ctx->master_key_identifier)); @@ -389,6 +416,7 @@ int fscrypt_policy_from_context(union fscrypt_policy *policy_u, policy->filenames_encryption_mode = ctx->filenames_encryption_mode; policy->flags = ctx->flags; + policy->log2_data_unit_size = ctx->log2_data_unit_size; memcpy(policy->__reserved, ctx->__reserved, sizeof(policy->__reserved)); memcpy(policy->master_key_identifier, diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c index 2859d9569aa74..5013b9d67026a 100644 --- a/fs/ext4/crypto.c +++ b/fs/ext4/crypto.c @@ -235,6 +235,7 @@ static bool ext4_has_stable_inodes(struct super_block *sb) const struct fscrypt_operations ext4_cryptops = { .needs_bounce_pages = 1, .has_32bit_inodes = 1, + .supports_subblock_data_units = 1, .legacy_key_prefix_for_backcompat = "ext4:", .get_context = ext4_get_context, .set_context = ext4_set_context, diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 7e8e510ef77af..8e9b452c8b4b6 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -3226,6 +3226,7 @@ static struct block_device **f2fs_get_devices(struct super_block *sb, static const struct fscrypt_operations f2fs_cryptops = { .needs_bounce_pages = 1, .has_32bit_inodes = 1, + .supports_subblock_data_units = 1, .legacy_key_prefix_for_backcompat = "f2fs:", .get_context = f2fs_get_context, .set_context = f2fs_set_context, diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 32a3b59bea276..0a1e2db426c0c 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -84,6 +84,18 @@ struct fscrypt_operations { */ unsigned int has_32bit_inodes : 1; + /* + * If set, then fs/crypto/ will allow users to select a crypto data unit + * size that is less than the filesystem block size. This is done via + * the log2_data_unit_size field of the fscrypt policy. This flag is + * not compatible with filesystems that encrypt variable-length blocks + * (i.e. blocks that aren't all equal to filesystem's block size), for + * example as a result of compression. It's also not compatible with + * the fscrypt_encrypt_block_inplace() and + * fscrypt_decrypt_block_inplace() functions. + */ + unsigned int supports_subblock_data_units : 1; + /* * This field exists only for backwards compatibility reasons and should * only be set by the filesystems that are setting it already. It diff --git a/include/uapi/linux/fscrypt.h b/include/uapi/linux/fscrypt.h index fd1fb0d5389d3..7a8f4c2901873 100644 --- a/include/uapi/linux/fscrypt.h +++ b/include/uapi/linux/fscrypt.h @@ -71,7 +71,8 @@ struct fscrypt_policy_v2 { __u8 contents_encryption_mode; __u8 filenames_encryption_mode; __u8 flags; - __u8 __reserved[4]; + __u8 log2_data_unit_size; + __u8 __reserved[3]; __u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE]; };