From patchwork Mon Oct 28 07:20:30 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Satya Tangirala X-Patchwork-Id: 11214761 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id F20C3139A for ; Mon, 28 Oct 2019 07:20:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B340F21783 for ; Mon, 28 Oct 2019 07:20:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="nEBXpJ+Z" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732780AbfJ1HU5 (ORCPT ); Mon, 28 Oct 2019 03:20:57 -0400 Received: from mail-pf1-f202.google.com ([209.85.210.202]:42018 "EHLO mail-pf1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732748AbfJ1HU5 (ORCPT ); Mon, 28 Oct 2019 03:20:57 -0400 Received: by mail-pf1-f202.google.com with SMTP id c8so2281697pfo.9 for ; Mon, 28 Oct 2019 00:20:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=ZjHDwu3nbLW0lBmNY/DJlc3OwujKLVw8JCEXI/TvS+E=; b=nEBXpJ+Z5XzOh8CTC+gXI+CzvCbzSbJt8B3elgfBtzas2SSG6th6AH3E5NttD2fC4T Td3Qvqo1gllIc+8V2GO8PRFMC7b+vhrArLgz+pNBFmcInNbDypppChwQmDJ6NOD+DGCq MmrC0ocCfZBwprig+N8C7iS7gI8J1T1FhTmc0lYD+u9Ozs0tQsAUcG3BCv6zf8ZnDhY0 qNjLu4rAkz3BO8sr5bKGKN/wRajFrWAX9HkFsppmK9+GyUUKtsV60V5Vxm3yPaOdPyzy xHnJ3KVD9Ht7IwetNl543B/mry0v+ZZcM5rbL9KtC2RUSUaDcMD+xKD/jvMTVOCZPJKo s2PA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=ZjHDwu3nbLW0lBmNY/DJlc3OwujKLVw8JCEXI/TvS+E=; b=qK5n42wBqqB+ntSMMUlHT6CCE8pJiPZ9N2gxDwdb3iS/yC4hTQuX3rdrND9yYiMgcP tHyiUi1YKZnMbA9Ai/H592uCvkY4tdrTz/Ey5uMAAIkPwjtL+5w/qpbqKi/i2yTNJmhc LAqVLaBbzP8KshOxrbKiLdkLTow9KAdZ37LBotONLOoOta8cCuJOKenqhZDWcO2w9TvC EOJyjUdGAHeSd2UMiT8gH07dU4UYl63ScNDkDrDWpg5aJRr6aQ6ewfNlxOyTBYJMvxsz Uo+kNYjXKYL/d2lTUhx8iT0twTtmfqk3RCSH7QigClsRaILtPKNn7gSSVLZTrL9zZGP3 9acQ== X-Gm-Message-State: APjAAAUEL3uL7E7oIsQzVFhlcfrEgGJfy9sT8MuUxNA0P7RYF1nowsjO rJdd5ren+wBE/gby0BMEO7IJmQdvFSU= X-Google-Smtp-Source: APXvYqzzPcupWdzlWmHtet9wHutTkhOG5C1OoxvfJmMimROu+MWXa97sI5lwCbMBsDzQUKxrgrEbZ1m5Ano= X-Received: by 2002:a63:200e:: with SMTP id g14mr19326954pgg.91.1572247255970; Mon, 28 Oct 2019 00:20:55 -0700 (PDT) Date: Mon, 28 Oct 2019 00:20:30 -0700 In-Reply-To: <20191028072032.6911-1-satyat@google.com> Message-Id: <20191028072032.6911-8-satyat@google.com> Mime-Version: 1.0 References: <20191028072032.6911-1-satyat@google.com> X-Mailer: git-send-email 2.24.0.rc0.303.g954a862665-goog Subject: [PATCH v5 7/9] fscrypt: add inline encryption support From: Satya Tangirala To: linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Cc: Barani Muthukumaran , Kuohong Wang , Kim Boojin , Satya Tangirala , Eric Biggers Sender: linux-fscrypt-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org Add support for inline encryption to fs/crypto/. With "inline encryption", the block layer handles the decryption/encryption as part of the bio, instead of the filesystem doing the crypto itself via Linux's crypto API. This model is needed in order to take advantage of the inline encryption hardware present on most modern mobile SoCs. To use inline encryption, the filesystem needs to be mounted with '-o inlinecrypt'. The contents of any AES-256-XTS encrypted files will then be encrypted using blk-crypto, instead of using the traditional filesystem-layer crypto. fscrypt still provides the key and IV to use, and the actual ciphertext on-disk is still the same; therefore it's testable using the existing fscrypt ciphertext verification tests. Note that since blk-crypto has a fallack to Linux's crypto API, this feature is usable and testable even without actual inline encryption hardware. Per-filesystem changes will be needed to set encryption contexts when submitting bios and to implement the 'inlinecrypt' mount option. This patch just adds the common code. Co-developed-by: Eric Biggers Signed-off-by: Eric Biggers Signed-off-by: Satya Tangirala --- fs/crypto/Kconfig | 6 + fs/crypto/Makefile | 1 + fs/crypto/bio.c | 31 ++- fs/crypto/fscrypt_private.h | 72 +++++++ fs/crypto/inline_crypt.c | 390 ++++++++++++++++++++++++++++++++++++ fs/crypto/keyring.c | 2 + fs/crypto/keysetup.c | 18 +- include/linux/fscrypt.h | 60 ++++++ 8 files changed, 566 insertions(+), 14 deletions(-) create mode 100644 fs/crypto/inline_crypt.c diff --git a/fs/crypto/Kconfig b/fs/crypto/Kconfig index ff5a1746cbae..5061aa546202 100644 --- a/fs/crypto/Kconfig +++ b/fs/crypto/Kconfig @@ -16,3 +16,9 @@ config FS_ENCRYPTION efficient since it avoids caching the encrypted and decrypted pages in the page cache. Currently Ext4, F2FS and UBIFS make use of this feature. + +config FS_ENCRYPTION_INLINE_CRYPT + bool "Enable fscrypt to use inline crypto" + depends on FS_ENCRYPTION && BLK_INLINE_ENCRYPTION + help + Enable fscrypt to use inline encryption hardware if available. diff --git a/fs/crypto/Makefile b/fs/crypto/Makefile index 232e2bb5a337..652c7180ec6d 100644 --- a/fs/crypto/Makefile +++ b/fs/crypto/Makefile @@ -11,3 +11,4 @@ fscrypto-y := crypto.o \ policy.o fscrypto-$(CONFIG_BLOCK) += bio.o +fscrypto-$(CONFIG_FS_ENCRYPTION_INLINE_CRYPT) += inline_crypt.o diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c index 1f4b8a277060..956798debf71 100644 --- a/fs/crypto/bio.c +++ b/fs/crypto/bio.c @@ -46,26 +46,38 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, { const unsigned int blockbits = inode->i_blkbits; const unsigned int blocksize = 1 << blockbits; + const bool inlinecrypt = fscrypt_inode_uses_inline_crypto(inode); struct page *ciphertext_page; struct bio *bio; int ret, err = 0; - ciphertext_page = fscrypt_alloc_bounce_page(GFP_NOWAIT); - if (!ciphertext_page) - return -ENOMEM; + if (inlinecrypt) { + ciphertext_page = ZERO_PAGE(0); + } else { + ciphertext_page = fscrypt_alloc_bounce_page(GFP_NOWAIT); + if (!ciphertext_page) + return -ENOMEM; + } while (len--) { - err = fscrypt_crypt_block(inode, FS_ENCRYPT, lblk, - ZERO_PAGE(0), ciphertext_page, - blocksize, 0, GFP_NOFS); - if (err) - goto errout; + if (!inlinecrypt) { + err = fscrypt_crypt_block(inode, FS_ENCRYPT, lblk, + ZERO_PAGE(0), ciphertext_page, + blocksize, 0, GFP_NOFS); + if (err) + goto errout; + } bio = bio_alloc(GFP_NOWAIT, 1); if (!bio) { err = -ENOMEM; goto errout; } + err = fscrypt_set_bio_crypt_ctx(bio, inode, lblk, GFP_NOIO); + if (err) { + bio_put(bio); + goto errout; + } bio_set_dev(bio, inode->i_sb->s_bdev); bio->bi_iter.bi_sector = pblk << (blockbits - 9); bio_set_op_attrs(bio, REQ_OP_WRITE, 0); @@ -87,7 +99,8 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, } err = 0; errout: - fscrypt_free_bounce_page(ciphertext_page); + if (!inlinecrypt) + fscrypt_free_bounce_page(ciphertext_page); return err; } EXPORT_SYMBOL(fscrypt_zeroout_range); diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index b44e445b43a8..c731bd4245c5 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -13,6 +13,9 @@ #include #include +#include + +struct fscrypt_master_key; #define CONST_STRLEN(str) (sizeof(str) - 1) @@ -163,6 +166,14 @@ struct fscrypt_info { /* The actual crypto transform used for encryption and decryption */ struct crypto_skcipher *ci_ctfm; +#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT + /* + * The raw key for inline encryption, if this file is using inline + * encryption rather than the traditional filesystem layer encryption. + */ + const u8 *ci_inline_crypt_key; +#endif + /* True if the key should be freed when this fscrypt_info is freed */ bool ci_owns_key; @@ -293,6 +304,54 @@ extern int fscrypt_hkdf_expand(struct fscrypt_hkdf *hkdf, u8 context, extern void fscrypt_destroy_hkdf(struct fscrypt_hkdf *hkdf); +/* inline_crypt.c */ +#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT +extern bool fscrypt_should_use_inline_encryption(const struct fscrypt_info *ci); + +extern int fscrypt_set_inline_crypt_key(struct fscrypt_info *ci, + const u8 *derived_key); + +extern void fscrypt_free_inline_crypt_key(struct fscrypt_info *ci); + +extern int fscrypt_setup_per_mode_inline_crypt_key( + struct fscrypt_info *ci, + struct fscrypt_master_key *mk); + +extern void fscrypt_evict_inline_crypt_keys(struct fscrypt_master_key *mk); + +#else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */ + +static inline bool fscrypt_should_use_inline_encryption( + const struct fscrypt_info *ci) +{ + return false; +} + +static inline int fscrypt_set_inline_crypt_key(struct fscrypt_info *ci, + const u8 *derived_key) +{ + WARN_ON(1); + return -EOPNOTSUPP; +} + +static inline void fscrypt_free_inline_crypt_key(struct fscrypt_info *ci) +{ +} + +static inline int fscrypt_setup_per_mode_inline_crypt_key( + struct fscrypt_info *ci, + struct fscrypt_master_key *mk) +{ + WARN_ON(1); + return -EOPNOTSUPP; +} + +static inline void fscrypt_evict_inline_crypt_keys( + struct fscrypt_master_key *mk) +{ +} +#endif /* !CONFIG_FS_ENCRYPTION_INLINE_CRYPT */ + /* keyring.c */ /* @@ -391,6 +450,16 @@ struct fscrypt_master_key { */ struct crypto_skcipher *mk_iv_ino_lblk_64_tfms[__FSCRYPT_MODE_MAX + 1]; +#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT + /* Raw keys for IV_INO_LBLK_64 policies, allocated on-demand */ + u8 *mk_iv_ino_lblk_64_raw_keys[__FSCRYPT_MODE_MAX + 1]; + + /* The data unit size being used for inline encryption */ + unsigned int mk_data_unit_size; + + /* The filesystem's block device */ + struct block_device *mk_bdev; +#endif } __randomize_layout; static inline bool @@ -445,9 +514,12 @@ struct fscrypt_mode { const char *cipher_str; int keysize; int ivsize; + enum blk_crypto_mode_num blk_crypto_mode; bool logged_impl_name; }; +extern struct fscrypt_mode fscrypt_modes[]; + static inline bool fscrypt_mode_supports_direct_key(const struct fscrypt_mode *mode) { diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c new file mode 100644 index 000000000000..e41c6d66ff0d --- /dev/null +++ b/fs/crypto/inline_crypt.c @@ -0,0 +1,390 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Inline encryption support for fscrypt + * + * Copyright 2019 Google LLC + */ + +/* + * With "inline encryption", the block layer handles the decryption/encryption + * as part of the bio, instead of the filesystem doing the crypto itself via + * crypto API. See Documentation/block/inline-encryption.rst. fscrypt still + * provides the key and IV to use. + */ + +#include +#include +#include +#include + +#include "fscrypt_private.h" + +/* Return true iff inline encryption should be used for this file */ +bool fscrypt_should_use_inline_encryption(const struct fscrypt_info *ci) +{ + const struct inode *inode = ci->ci_inode; + struct super_block *sb = inode->i_sb; + + /* The file must need contents encryption, not filenames encryption */ + if (!S_ISREG(inode->i_mode)) + return false; + + /* blk-crypto must implement the needed encryption algorithm */ + if (ci->ci_mode->blk_crypto_mode == BLK_ENCRYPTION_MODE_INVALID) + return false; + + /* DIRECT_KEY needs a 24+ byte IV, so it can't work with 8-byte DUNs */ + if (fscrypt_is_direct_key_policy(&ci->ci_policy)) + return false; + + /* The filesystem must be mounted with -o inlinecrypt */ + if (!sb->s_cop->inline_crypt_enabled || + !sb->s_cop->inline_crypt_enabled(sb)) + return false; + + return true; +} + +/* Set a per-file inline encryption key (for passing to blk-crypto) */ +int fscrypt_set_inline_crypt_key(struct fscrypt_info *ci, const u8 *derived_key) +{ + const struct fscrypt_mode *mode = ci->ci_mode; + const struct super_block *sb = ci->ci_inode->i_sb; + + ci->ci_inline_crypt_key = kmemdup(derived_key, mode->keysize, GFP_NOFS); + if (!ci->ci_inline_crypt_key) + return -ENOMEM; + ci->ci_owns_key = true; + + return blk_crypto_start_using_mode(mode->blk_crypto_mode, + sb->s_blocksize, + sb->s_bdev->bd_queue); +} + +/* Free a per-file inline encryption key and evict it from blk-crypto */ +void fscrypt_free_inline_crypt_key(struct fscrypt_info *ci) +{ + if (ci->ci_inline_crypt_key != NULL) { + const struct fscrypt_mode *mode = ci->ci_mode; + const struct super_block *sb = ci->ci_inode->i_sb; + + blk_crypto_evict_key(sb->s_bdev->bd_queue, + ci->ci_inline_crypt_key, + mode->blk_crypto_mode, sb->s_blocksize); + kzfree(ci->ci_inline_crypt_key); + } +} + +/* + * Set up ->inline_crypt_key (for passing to blk-crypto) for inodes which use an + * IV_INO_LBLK_64 encryption policy. + * + * Return: 0 on success, -errno on failure + */ +int fscrypt_setup_per_mode_inline_crypt_key(struct fscrypt_info *ci, + struct fscrypt_master_key *mk) +{ + static DEFINE_MUTEX(inline_crypt_setup_mutex); + const struct super_block *sb = ci->ci_inode->i_sb; + struct block_device *bdev = sb->s_bdev; + const struct fscrypt_mode *mode = ci->ci_mode; + const u8 mode_num = mode - fscrypt_modes; + u8 *raw_key; + u8 hkdf_info[sizeof(mode_num) + sizeof(sb->s_uuid)]; + int err; + + if (WARN_ON(mode_num > __FSCRYPT_MODE_MAX)) + return -EINVAL; + + /* pairs with smp_store_release() below */ + raw_key = smp_load_acquire(&mk->mk_iv_ino_lblk_64_raw_keys[mode_num]); + if (raw_key) { + err = 0; + goto out; + } + + mutex_lock(&inline_crypt_setup_mutex); + + raw_key = mk->mk_iv_ino_lblk_64_raw_keys[mode_num]; + if (raw_key) { + err = 0; + goto out_unlock; + } + + raw_key = kmalloc(mode->keysize, GFP_NOFS); + if (!raw_key) { + err = -ENOMEM; + goto out_unlock; + } + + BUILD_BUG_ON(sizeof(mode_num) != 1); + BUILD_BUG_ON(sizeof(sb->s_uuid) != 16); + BUILD_BUG_ON(sizeof(hkdf_info) != 17); + hkdf_info[0] = mode_num; + memcpy(&hkdf_info[1], &sb->s_uuid, sizeof(sb->s_uuid)); + + err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf, + HKDF_CONTEXT_IV_INO_LBLK_64_KEY, + hkdf_info, sizeof(hkdf_info), + raw_key, mode->keysize); + if (err) + goto out_unlock; + + err = blk_crypto_start_using_mode(mode->blk_crypto_mode, + sb->s_blocksize, bdev->bd_queue); + if (err) + goto out_unlock; + + /* + * When a master key's first inline encryption key is set up, save a + * reference to the filesystem's block device so that the inline + * encryption keys can be evicted when the master key is destroyed. + */ + if (!mk->mk_bdev) { + mk->mk_bdev = bdgrab(bdev); + mk->mk_data_unit_size = sb->s_blocksize; + } + + /* pairs with smp_load_acquire() above */ + smp_store_release(&mk->mk_iv_ino_lblk_64_raw_keys[mode_num], raw_key); + err = 0; +out_unlock: + mutex_unlock(&inline_crypt_setup_mutex); +out: + if (err == 0) { + ci->ci_inline_crypt_key = raw_key; + /* + * Since each struct fscrypt_master_key belongs to a particular + * filesystem (a struct super_block), there should be only one + * block device, and only one data unit size as it should equal + * the filesystem's blocksize (i.e. s_blocksize). + */ + if (WARN_ON(mk->mk_bdev != bdev)) + err = -EINVAL; + if (WARN_ON(mk->mk_data_unit_size != sb->s_blocksize)) + err = -EINVAL; + } else { + kzfree(raw_key); + } + return err; +} + +/* + * Evict per-mode inline encryption keys from blk-crypto when a master key is + * destroyed. + */ +void fscrypt_evict_inline_crypt_keys(struct fscrypt_master_key *mk) +{ + struct block_device *bdev = mk->mk_bdev; + size_t i; + + if (!bdev) /* No inline encryption keys? */ + return; + + for (i = 0; i < ARRAY_SIZE(mk->mk_iv_ino_lblk_64_raw_keys); i++) { + u8 *raw_key = mk->mk_iv_ino_lblk_64_raw_keys[i]; + + if (raw_key != NULL) { + blk_crypto_evict_key(bdev->bd_queue, raw_key, + fscrypt_modes[i].blk_crypto_mode, + mk->mk_data_unit_size); + kzfree(raw_key); + } + } + bdput(bdev); +} + +/** + * fscrypt_inode_uses_inline_crypto - test whether an inode uses inline encryption + * @inode: an inode + * + * Return: true if the inode requires file contents encryption and if the + * encryption should be done in the block layer via blk-crypto rather + * than in the filesystem layer. + */ +bool fscrypt_inode_uses_inline_crypto(const struct inode *inode) +{ + return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode) && + inode->i_crypt_info->ci_inline_crypt_key != NULL; +} +EXPORT_SYMBOL_GPL(fscrypt_inode_uses_inline_crypto); + +/** + * fscrypt_inode_uses_fs_layer_crypto - test whether an inode uses fs-layer encryption + * @inode: an inode + * + * Return: true if the inode requires file contents encryption and if the + * encryption should be done in the filesystem layer rather than in the + * block layer via blk-crypto. + */ +bool fscrypt_inode_uses_fs_layer_crypto(const struct inode *inode) +{ + return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode) && + inode->i_crypt_info->ci_inline_crypt_key == NULL; +} +EXPORT_SYMBOL_GPL(fscrypt_inode_uses_fs_layer_crypto); + +static inline u64 fscrypt_generate_dun(const struct fscrypt_info *ci, + u64 lblk_num) +{ + union fscrypt_iv iv; + + fscrypt_generate_iv(&iv, lblk_num, ci); + /* + * fscrypt_should_use_inline_encryption() ensures we never get here if + * more than the first 8 bytes of the IV are nonzero. + */ + BUG_ON(memchr_inv(&iv.raw[8], 0, ci->ci_mode->ivsize - 8)); + return le64_to_cpu(iv.lblk_num); +} + +/** + * fscrypt_set_bio_crypt_ctx - prepare a file contents bio for inline encryption + * @bio: a bio which will eventually be submitted to the file + * @inode: the file's inode + * @first_lblk: the first file logical block number in the I/O + * @gfp_mask: memory allocation flags + * + * If the contents of the file should be encrypted (or decrypted) with inline + * encryption, then assign the appropriate encryption context to the bio. + * + * Normally the bio should be newly allocated (i.e. no pages added yet), as + * otherwise fscrypt_mergeable_bio() won't work as intended. + * + * The encryption context will be freed automatically when the bio is freed. + * + * Return: 0 on success, -errno on failure. If __GFP_NOFAIL is specified, this + * is guaranteed to succeed. + */ +int fscrypt_set_bio_crypt_ctx(struct bio *bio, const struct inode *inode, + u64 first_lblk, gfp_t gfp_mask) +{ + const struct fscrypt_info *ci = inode->i_crypt_info; + u64 dun; + + if (!fscrypt_inode_uses_inline_crypto(inode)) + return 0; + + dun = fscrypt_generate_dun(ci, first_lblk); + + return bio_crypt_set_ctx(bio, ci->ci_inline_crypt_key, + ci->ci_mode->blk_crypto_mode, + dun, inode->i_blkbits, gfp_mask); +} +EXPORT_SYMBOL_GPL(fscrypt_set_bio_crypt_ctx); + +/* Extract the inode and logical block number from a buffer_head. */ +static bool bh_get_inode_and_lblk_num(const struct buffer_head *bh, + const struct inode **inode_ret, + u64 *lblk_num_ret) +{ + struct page *page = bh->b_page; + const struct address_space *mapping; + const struct inode *inode; + + /* + * The ext4 journal (jbd2) can submit a buffer_head it directly created + * for a non-pagecache page. fscrypt doesn't care about these. + */ + mapping = page_mapping(page); + if (!mapping) + return false; + inode = mapping->host; + + *inode_ret = inode; + *lblk_num_ret = ((u64)page->index << (PAGE_SHIFT - inode->i_blkbits)) + + (bh_offset(bh) >> inode->i_blkbits); + return true; +} + +/** + * fscrypt_set_bio_crypt_ctx_bh - prepare a file contents bio for inline encryption + * @bio: a bio which will eventually be submitted to the file + * @first_bh: the first buffer_head for which I/O will be submitted + * @gfp_mask: memory allocation flags + * + * Same as fscrypt_set_bio_crypt_ctx(), except this takes a buffer_head instead + * of an inode and block number directly. + * + * Return: 0 on success, -errno on failure + */ +int fscrypt_set_bio_crypt_ctx_bh(struct bio *bio, + const struct buffer_head *first_bh, + gfp_t gfp_mask) +{ + const struct inode *inode; + u64 first_lblk; + + if (!bh_get_inode_and_lblk_num(first_bh, &inode, &first_lblk)) + return 0; + + return fscrypt_set_bio_crypt_ctx(bio, inode, first_lblk, gfp_mask); +} +EXPORT_SYMBOL_GPL(fscrypt_set_bio_crypt_ctx_bh); + +/** + * fscrypt_mergeable_bio - test whether data can be added to a bio + * @bio: the bio being built up + * @inode: the inode for the next part of the I/O + * @next_lblk: the next file logical block number in the I/O + * + * When building a bio which may contain data which should undergo inline + * encryption (or decryption) via fscrypt, filesystems should call this function + * to ensure that the resulting bio contains only logically contiguous data. + * This will return false if the next part of the I/O cannot be merged with the + * bio because either the encryption key would be different or the encryption + * data unit numbers would be discontiguous. + * + * fscrypt_set_bio_crypt_ctx() must have already been called on the bio. + * + * Return: true iff the I/O is mergeable + */ +bool fscrypt_mergeable_bio(struct bio *bio, const struct inode *inode, + u64 next_lblk) +{ + const struct bio_crypt_ctx *bc; + const u8 *next_key; + u64 next_dun; + + if (bio_has_crypt_ctx(bio) != fscrypt_inode_uses_inline_crypto(inode)) + return false; + if (!bio_has_crypt_ctx(bio)) + return true; + bc = bio->bi_crypt_context; + next_key = inode->i_crypt_info->ci_inline_crypt_key; + next_dun = fscrypt_generate_dun(inode->i_crypt_info, next_lblk); + + /* + * Comparing the key pointers is good enough, as all I/O for each key + * uses the same pointer. I.e., there's currently no need to support + * merging requests where the keys are the same but the pointers differ. + */ + return next_key == bc->raw_key && + next_dun == bc->data_unit_num + + (bio_sectors(bio) >> + (bc->data_unit_size_bits - SECTOR_SHIFT)); +} +EXPORT_SYMBOL_GPL(fscrypt_mergeable_bio); + +/** + * fscrypt_mergeable_bio_bh - test whether data can be added to a bio + * @bio: the bio being built up + * @next_bh: the next buffer_head for which I/O will be submitted + * + * Same as fscrypt_mergeable_bio(), except this takes a buffer_head instead of + * an inode and block number directly. + * + * Return: true iff the I/O is mergeable + */ +bool fscrypt_mergeable_bio_bh(struct bio *bio, + const struct buffer_head *next_bh) +{ + const struct inode *inode; + u64 next_lblk; + + if (!bh_get_inode_and_lblk_num(next_bh, &inode, &next_lblk)) + return !bio_has_crypt_ctx(bio); + + return fscrypt_mergeable_bio(bio, inode, next_lblk); +} +EXPORT_SYMBOL_GPL(fscrypt_mergeable_bio_bh); diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c index 040df1f5e1c8..7788adfa2dc4 100644 --- a/fs/crypto/keyring.c +++ b/fs/crypto/keyring.c @@ -48,6 +48,8 @@ static void free_master_key(struct fscrypt_master_key *mk) crypto_free_skcipher(mk->mk_iv_ino_lblk_64_tfms[i]); } + fscrypt_evict_inline_crypt_keys(mk); + key_put(mk->mk_users); kzfree(mk); } diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index f87ab930b92a..8070dad9a541 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -13,12 +13,13 @@ #include "fscrypt_private.h" -static struct fscrypt_mode available_modes[] = { +struct fscrypt_mode fscrypt_modes[] = { [FSCRYPT_MODE_AES_256_XTS] = { .friendly_name = "AES-256-XTS", .cipher_str = "xts(aes)", .keysize = 64, .ivsize = 16, + .blk_crypto_mode = BLK_ENCRYPTION_MODE_AES_256_XTS, }, [FSCRYPT_MODE_AES_256_CTS] = { .friendly_name = "AES-256-CTS-CBC", @@ -51,10 +52,10 @@ select_encryption_mode(const union fscrypt_policy *policy, const struct inode *inode) { if (S_ISREG(inode->i_mode)) - return &available_modes[fscrypt_policy_contents_mode(policy)]; + return &fscrypt_modes[fscrypt_policy_contents_mode(policy)]; if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) - return &available_modes[fscrypt_policy_fnames_mode(policy)]; + return &fscrypt_modes[fscrypt_policy_fnames_mode(policy)]; WARN_ONCE(1, "fscrypt: filesystem tried to load encryption info for inode %lu, which is not encryptable (file type %d)\n", inode->i_ino, (inode->i_mode & S_IFMT)); @@ -111,6 +112,9 @@ int fscrypt_set_derived_key(struct fscrypt_info *ci, const u8 *derived_key) { struct crypto_skcipher *tfm; + if (fscrypt_should_use_inline_encryption(ci)) + return fscrypt_set_inline_crypt_key(ci, derived_key); + tfm = fscrypt_allocate_skcipher(ci->ci_mode, derived_key, ci->ci_inode); if (IS_ERR(tfm)) return PTR_ERR(tfm); @@ -128,7 +132,7 @@ static int setup_per_mode_key(struct fscrypt_info *ci, const struct inode *inode = ci->ci_inode; const struct super_block *sb = inode->i_sb; struct fscrypt_mode *mode = ci->ci_mode; - u8 mode_num = mode - available_modes; + const u8 mode_num = mode - fscrypt_modes; struct crypto_skcipher *tfm, *prev_tfm; u8 mode_key[FSCRYPT_MAX_KEY_SIZE]; u8 hkdf_info[sizeof(mode_num) + sizeof(sb->s_uuid)]; @@ -204,6 +208,8 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, * the IVs. This format is optimized for use with inline * encryption hardware compliant with the UFS or eMMC standards. */ + if (fscrypt_should_use_inline_encryption(ci)) + return fscrypt_setup_per_mode_inline_crypt_key(ci, mk); return setup_per_mode_key(ci, mk, mk->mk_iv_ino_lblk_64_tfms, HKDF_CONTEXT_IV_INO_LBLK_64_KEY, true); @@ -330,8 +336,10 @@ static void put_crypt_info(struct fscrypt_info *ci) if (ci->ci_direct_key) fscrypt_put_direct_key(ci->ci_direct_key); - else if (ci->ci_owns_key) + else if (ci->ci_owns_key) { crypto_free_skcipher(ci->ci_ctfm); + fscrypt_free_inline_crypt_key(ci); + } key = ci->ci_master_key; if (key) { diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 1a7bffe78ed5..9583837ca37b 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -64,6 +64,7 @@ struct fscrypt_operations { bool (*has_stable_inodes)(struct super_block *sb); void (*get_ino_and_lblk_bits)(struct super_block *sb, int *ino_bits_ret, int *lblk_bits_ret); + bool (*inline_crypt_enabled)(struct super_block *sb); }; static inline bool fscrypt_has_encryption_key(const struct inode *inode) @@ -529,6 +530,65 @@ static inline void fscrypt_set_ops(struct super_block *sb, #endif /* !CONFIG_FS_ENCRYPTION */ +/* inline_crypt.c */ +#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT +extern bool fscrypt_inode_uses_inline_crypto(const struct inode *inode); + +extern bool fscrypt_inode_uses_fs_layer_crypto(const struct inode *inode); + +extern int fscrypt_set_bio_crypt_ctx(struct bio *bio, const struct inode *inode, + u64 first_lblk, gfp_t gfp_mask); + +extern int fscrypt_set_bio_crypt_ctx_bh(struct bio *bio, + const struct buffer_head *first_bh, + gfp_t gfp_mask); + +extern bool fscrypt_mergeable_bio(struct bio *bio, const struct inode *inode, + u64 next_lblk); + +extern bool fscrypt_mergeable_bio_bh(struct bio *bio, + const struct buffer_head *next_bh); + +#else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */ +static inline bool fscrypt_inode_uses_inline_crypto(const struct inode *inode) +{ + return false; +} + +static inline bool fscrypt_inode_uses_fs_layer_crypto(const struct inode *inode) +{ + return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode); +} + +static inline int fscrypt_set_bio_crypt_ctx(struct bio *bio, + const struct inode *inode, + u64 first_lblk, gfp_t gfp_mask) +{ + return 0; +} + +static inline int fscrypt_set_bio_crypt_ctx_bh( + struct bio *bio, + const struct buffer_head *first_bh, + gfp_t gfp_mask) +{ + return 0; +} + +static inline bool fscrypt_mergeable_bio(struct bio *bio, + const struct inode *inode, + u64 next_lblk) +{ + return true; +} + +static inline bool fscrypt_mergeable_bio_bh(struct bio *bio, + const struct buffer_head *next_bh) +{ + return true; +} +#endif /* !CONFIG_FS_ENCRYPTION_INLINE_CRYPT */ + /** * fscrypt_require_key - require an inode's encryption key * @inode: the inode we need the key for