diff options
| -rw-r--r-- | Documentation/filesystems/fscrypt.rst | 68 | ||||
| -rw-r--r-- | Documentation/ioctl/ioctl-number.rst | 1 | ||||
| -rw-r--r-- | fs/crypto/bio.c | 29 | ||||
| -rw-r--r-- | fs/crypto/crypto.c | 124 | ||||
| -rw-r--r-- | fs/crypto/fscrypt_private.h | 25 | ||||
| -rw-r--r-- | fs/crypto/keyring.c | 6 | ||||
| -rw-r--r-- | fs/crypto/keysetup.c | 158 | ||||
| -rw-r--r-- | fs/crypto/keysetup_v1.c | 4 | ||||
| -rw-r--r-- | fs/crypto/policy.c | 41 | ||||
| -rw-r--r-- | fs/ext4/ext4.h | 2 | ||||
| -rw-r--r-- | fs/ext4/super.c | 14 | ||||
| -rw-r--r-- | fs/f2fs/super.c | 26 | ||||
| -rw-r--r-- | include/linux/fscrypt.h | 35 | ||||
| -rw-r--r-- | include/uapi/linux/fscrypt.h | 3 |
14 files changed, 208 insertions, 328 deletions
diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst index 8a0700af9596..471a511c7508 100644 --- a/Documentation/filesystems/fscrypt.rst +++ b/Documentation/filesystems/fscrypt.rst @@ -256,13 +256,8 @@ alternative master keys or to support rotating master keys. Instead, the master keys may be wrapped in userspace, e.g. as is done by the `fscrypt <https://github.com/google/fscrypt>`_ tool. -Including the inode number in the IVs was considered. However, it was -rejected as it would have prevented ext4 filesystems from being -resized, and by itself still wouldn't have been sufficient to prevent -the same key from being directly reused for both XTS and CTS-CBC. - -DIRECT_KEY and per-mode keys ----------------------------- +DIRECT_KEY policies +------------------- The Adiantum encryption mode (see `Encryption modes and usage`_) is suitable for both contents and filenames encryption, and it accepts @@ -285,6 +280,21 @@ IV. Moreover: key derived using the KDF. Users may use the same master key for other v2 encryption policies. +IV_INO_LBLK_64 policies +----------------------- + +When FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 is set in the fscrypt policy, +the encryption keys are derived from the master key, encryption mode +number, and filesystem UUID. This normally results in all files +protected by the same master key sharing a single contents encryption +key and a single filenames encryption key. To still encrypt different +files' data differently, inode numbers are included in the IVs. +Consequently, shrinking the filesystem may not be allowed. + +This format is optimized for use with inline encryption hardware +compliant with the UFS or eMMC standards, which support only 64 IV +bits per I/O request and may have only a small number of keyslots. + Key identifiers --------------- @@ -308,8 +318,9 @@ If unsure, you should use the (AES-256-XTS, AES-256-CTS-CBC) pair. AES-128-CBC was added only for low-powered embedded devices with crypto accelerators such as CAAM or CESA that do not support XTS. To -use AES-128-CBC, CONFIG_CRYPTO_SHA256 (or another SHA-256 -implementation) must be enabled so that ESSIV can be used. +use AES-128-CBC, CONFIG_CRYPTO_ESSIV and CONFIG_CRYPTO_SHA256 (or +another SHA-256 implementation) must be enabled so that ESSIV can be +used. Adiantum is a (primarily) stream cipher-based mode that is fast even on CPUs without dedicated crypto instructions. It's also a true @@ -341,10 +352,16 @@ a little endian number, except that: is encrypted with AES-256 where the AES-256 key is the SHA-256 hash of the file's data encryption key. -- In the "direct key" configuration (FSCRYPT_POLICY_FLAG_DIRECT_KEY - set in the fscrypt_policy), the file's nonce is also appended to the - IV. Currently this is only allowed with the Adiantum encryption - mode. +- 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. + +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". Filenames encryption -------------------- @@ -354,10 +371,10 @@ the requirements to retain support for efficient directory lookups and filenames of up to 255 bytes, the same IV is used for every filename in a directory. -However, each encrypted directory still uses a unique key; or -alternatively (for the "direct key" configuration) has the file's -nonce included in the IVs. Thus, IV reuse is limited to within a -single directory. +However, each encrypted directory still uses a unique key, or +alternatively has the file's nonce (for `DIRECT_KEY policies`_) or +inode number (for `IV_INO_LBLK_64 policies`_) included in the IVs. +Thus, IV reuse is limited to within a single directory. With CTS-CBC, the IV reuse means that when the plaintext filenames share a common prefix at least as long as the cipher block size (16 @@ -431,12 +448,15 @@ This structure must be initialized as follows: (1) for ``contents_encryption_mode`` and FSCRYPT_MODE_AES_256_CTS (4) for ``filenames_encryption_mode``. -- ``flags`` must contain a value from ``<linux/fscrypt.h>`` which - identifies the amount of NUL-padding to use when encrypting - filenames. If unsure, use FSCRYPT_POLICY_FLAGS_PAD_32 (0x3). - Additionally, if the encryption modes are both - FSCRYPT_MODE_ADIANTUM, this can contain - FSCRYPT_POLICY_FLAG_DIRECT_KEY; see `DIRECT_KEY and per-mode keys`_. +- ``flags`` contains optional flags from ``<linux/fscrypt.h>``: + + - FSCRYPT_POLICY_FLAGS_PAD_*: The amount of NUL padding to use when + encrypting filenames. If unsure, use FSCRYPT_POLICY_FLAGS_PAD_32 + (0x3). + - FSCRYPT_POLICY_FLAG_DIRECT_KEY: See `DIRECT_KEY policies`_. + - FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64: See `IV_INO_LBLK_64 + policies`_. This is mutually exclusive with DIRECT_KEY and is not + supported on v1 policies. - For v2 encryption policies, ``__reserved`` must be zeroed. @@ -1089,7 +1109,7 @@ policy structs (see `Setting an encryption policy`_), except that the context structs also contain a nonce. The nonce is randomly generated by the kernel and is used as KDF input or as a tweak to cause different files to be encrypted differently; see `Per-file keys`_ and -`DIRECT_KEY and per-mode keys`_. +`DIRECT_KEY policies`_. Data path changes ----------------- diff --git a/Documentation/ioctl/ioctl-number.rst b/Documentation/ioctl/ioctl-number.rst index bef79cd4c6b4..4ef86433bd67 100644 --- a/Documentation/ioctl/ioctl-number.rst +++ b/Documentation/ioctl/ioctl-number.rst @@ -233,6 +233,7 @@ Code Seq# Include File Comments 'f' 00-0F fs/ext4/ext4.h conflict! 'f' 00-0F linux/fs.h conflict! 'f' 00-0F fs/ocfs2/ocfs2_fs.h conflict! +'f' 13-27 linux/fscrypt.h 'f' 81-8F linux/fsverity.h 'g' 00-0F linux/usb/gadgetfs.h 'g' 20-2F linux/usb/g_printer.h diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c index 82da2510721f..1f4b8a277060 100644 --- a/fs/crypto/bio.c +++ b/fs/crypto/bio.c @@ -26,7 +26,7 @@ #include <linux/namei.h> #include "fscrypt_private.h" -static void __fscrypt_decrypt_bio(struct bio *bio, bool done) +void fscrypt_decrypt_bio(struct bio *bio) { struct bio_vec *bv; struct bvec_iter_all iter_all; @@ -37,37 +37,10 @@ static void __fscrypt_decrypt_bio(struct bio *bio, bool done) bv->bv_offset); if (ret) SetPageError(page); - else if (done) - SetPageUptodate(page); - if (done) - unlock_page(page); } } - -void fscrypt_decrypt_bio(struct bio *bio) -{ - __fscrypt_decrypt_bio(bio, false); -} EXPORT_SYMBOL(fscrypt_decrypt_bio); -static void completion_pages(struct work_struct *work) -{ - struct fscrypt_ctx *ctx = container_of(work, struct fscrypt_ctx, work); - struct bio *bio = ctx->bio; - - __fscrypt_decrypt_bio(bio, true); - fscrypt_release_ctx(ctx); - bio_put(bio); -} - -void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx, struct bio *bio) -{ - INIT_WORK(&ctx->work, completion_pages); - ctx->bio = bio; - fscrypt_enqueue_decrypt_work(&ctx->work); -} -EXPORT_SYMBOL(fscrypt_enqueue_decrypt_bio); - int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, sector_t pblk, unsigned int len) { diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c index 32a7ad0098cc..3719efa546c6 100644 --- a/fs/crypto/crypto.c +++ b/fs/crypto/crypto.c @@ -27,29 +27,20 @@ #include <linux/ratelimit.h> #include <linux/dcache.h> #include <linux/namei.h> -#include <crypto/aes.h> #include <crypto/skcipher.h> #include "fscrypt_private.h" static unsigned int num_prealloc_crypto_pages = 32; -static unsigned int num_prealloc_crypto_ctxs = 128; module_param(num_prealloc_crypto_pages, uint, 0444); MODULE_PARM_DESC(num_prealloc_crypto_pages, "Number of crypto pages to preallocate"); -module_param(num_prealloc_crypto_ctxs, uint, 0444); -MODULE_PARM_DESC(num_prealloc_crypto_ctxs, - "Number of crypto contexts to preallocate"); static mempool_t *fscrypt_bounce_page_pool = NULL; -static LIST_HEAD(fscrypt_free_ctxs); -static DEFINE_SPINLOCK(fscrypt_ctx_lock); - static struct workqueue_struct *fscrypt_read_workqueue; static DEFINE_MUTEX(fscrypt_init_mutex); -static struct kmem_cache *fscrypt_ctx_cachep; struct kmem_cache *fscrypt_info_cachep; void fscrypt_enqueue_decrypt_work(struct work_struct *work) @@ -58,62 +49,6 @@ void fscrypt_enqueue_decrypt_work(struct work_struct *work) } EXPORT_SYMBOL(fscrypt_enqueue_decrypt_work); -/** - * fscrypt_release_ctx() - Release a decryption context - * @ctx: The decryption context to release. - * - * If the decryption context was allocated from the pre-allocated pool, return - * it to that pool. Else, free it. - */ -void fscrypt_release_ctx(struct fscrypt_ctx *ctx) -{ - unsigned long flags; - - if (ctx->flags & FS_CTX_REQUIRES_FREE_ENCRYPT_FL) { - kmem_cache_free(fscrypt_ctx_cachep, ctx); - } else { - spin_lock_irqsave(&fscrypt_ctx_lock, flags); - list_add(&ctx->free_list, &fscrypt_free_ctxs); - spin_unlock_irqrestore(&fscrypt_ctx_lock, flags); - } -} -EXPORT_SYMBOL(fscrypt_release_ctx); - -/** - * fscrypt_get_ctx() - Get a decryption context - * @gfp_flags: The gfp flag for memory allocation - * - * Allocate and initialize a decryption context. - * - * Return: A new decryption context on success; an ERR_PTR() otherwise. - */ -struct fscrypt_ctx *fscrypt_get_ctx(gfp_t gfp_flags) -{ - struct fscrypt_ctx *ctx; - unsigned long flags; - - /* - * First try getting a ctx from the free list so that we don't have to - * call into the slab allocator. - */ - spin_lock_irqsave(&fscrypt_ctx_lock, flags); - ctx = list_first_entry_or_null(&fscrypt_free_ctxs, - struct fscrypt_ctx, free_list); - if (ctx) - list_del(&ctx->free_list); - spin_unlock_irqrestore(&fscrypt_ctx_lock, flags); - if (!ctx) { - ctx = kmem_cache_zalloc(fscrypt_ctx_cachep, gfp_flags); - if (!ctx) - return ERR_PTR(-ENOMEM); - ctx->flags |= FS_CTX_REQUIRES_FREE_ENCRYPT_FL; - } else { - ctx->flags &= ~FS_CTX_REQUIRES_FREE_ENCRYPT_FL; - } - return ctx; -} -EXPORT_SYMBOL(fscrypt_get_ctx); - struct page *fscrypt_alloc_bounce_page(gfp_t gfp_flags) { return mempool_alloc(fscrypt_bounce_page_pool, gfp_flags); @@ -138,14 +73,17 @@ EXPORT_SYMBOL(fscrypt_free_bounce_page); void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num, const struct fscrypt_info *ci) { + u8 flags = fscrypt_policy_flags(&ci->ci_policy); + memset(iv, 0, ci->ci_mode->ivsize); - iv->lblk_num = cpu_to_le64(lblk_num); - if (fscrypt_is_direct_key_policy(&ci->ci_policy)) + if (flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) { + WARN_ON_ONCE((u32)lblk_num != lblk_num); + lblk_num |= (u64)ci->ci_inode->i_ino << 32; + } else if (flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) { memcpy(iv->nonce, ci->ci_nonce, FS_KEY_DERIVATION_NONCE_SIZE); - - if (ci->ci_essiv_tfm != NULL) - crypto_cipher_encrypt_one(ci->ci_essiv_tfm, iv->raw, iv->raw); + } + iv->lblk_num = cpu_to_le64(lblk_num); } /* Encrypt or decrypt a single filesystem block of file contents */ @@ -396,17 +334,6 @@ const struct dentry_operations fscrypt_d_ops = { .d_revalidate = fscrypt_d_revalidate, }; -static void fscrypt_destroy(void) -{ - struct fscrypt_ctx *pos, *n; - - list_for_each_entry_safe(pos, n, &fscrypt_free_ctxs, free_list) - kmem_cache_free(fscrypt_ctx_cachep, pos); - INIT_LIST_HEAD(&fscrypt_free_ctxs); - mempool_destroy(fscrypt_bounce_page_pool); - fscrypt_bounce_page_pool = NULL; -} - /** * fscrypt_initialize() - allocate major buffers for fs encryption. * @cop_flags: fscrypt operations flags @@ -414,11 +341,11 @@ static void fscrypt_destroy(void) * We only call this when we start accessing encrypted files, since it * results in memory getting allocated that wouldn't otherwise be used. * - * Return: Zero on success, non-zero otherwise. + * Return: 0 on success; -errno on failure */ int fscrypt_initialize(unsigned int cop_flags) { - int i, res = -ENOMEM; + int err = 0; /* No need to allocate a bounce page pool if this FS won't use it. */ if (cop_flags & FS_CFLG_OWN_PAGES) @@ -426,29 +353,18 @@ int fscrypt_initialize(unsigned int cop_flags) mutex_lock(&fscrypt_init_mutex); if (fscrypt_bounce_page_pool) - goto already_initialized; - - for (i = 0; i < num_prealloc_crypto_ctxs; i++) { - struct fscrypt_ctx *ctx; - - ctx = kmem_cache_zalloc(fscrypt_ctx_cachep, GFP_NOFS); - if (!ctx) - goto fail; - list_add(&ctx->free_list, &fscrypt_free_ctxs); - } + goto out_unlock; + err = -ENOMEM; fscrypt_bounce_page_pool = mempool_create_page_pool(num_prealloc_crypto_pages, 0); if (!fscrypt_bounce_page_pool) - goto fail; + goto out_unlock; -already_initialized: - mutex_unlock(&fscrypt_init_mutex); - return 0; -fail: - fscrypt_destroy(); + err = 0; +out_unlock: mutex_unlock(&fscrypt_init_mutex); - return res; + return err; } void fscrypt_msg(const struct inode *inode, const char *level, @@ -494,13 +410,9 @@ static int __init fscrypt_init(void) if (!fscrypt_read_workqueue) goto fail; - fscrypt_ctx_cachep = KMEM_CACHE(fscrypt_ctx, SLAB_RECLAIM_ACCOUNT); - if (!fscrypt_ctx_cachep) - goto fail_free_queue; - fscrypt_info_cachep = KMEM_CACHE(fscrypt_info, SLAB_RECLAIM_ACCOUNT); if (!fscrypt_info_cachep) - goto fail_free_ctx; + goto fail_free_queue; err = fscrypt_init_keyring(); if (err) @@ -510,8 +422,6 @@ static int __init fscrypt_init(void) fail_free_info: kmem_cache_destroy(fscrypt_info_cachep); -fail_free_ctx: - kmem_cache_destroy(fscrypt_ctx_cachep); fail_free_queue: destroy_workqueue(fscrypt_read_workqueue); fail: diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index e84efc01512e..130b50e5a011 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -163,11 +163,8 @@ struct fscrypt_info { /* The actual crypto transform used for encryption and decryption */ struct crypto_skcipher *ci_ctfm; - /* - * Cipher for ESSIV IV generation. Only set for CBC contents - * encryption, otherwise is NULL. - */ - struct crypto_cipher *ci_essiv_tfm; + /* True if the key should be freed when this fscrypt_info is freed */ + bool ci_owns_key; /* * Encryption mode used for this inode. It corresponds to either the @@ -209,8 +206,6 @@ typedef enum { FS_ENCRYPT, } fscrypt_direction_t; -#define FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001 - static inline bool fscrypt_valid_enc_modes(u32 contents_mode, u32 filenames_mode) { @@ -289,7 +284,8 @@ extern int fscrypt_init_hkdf(struct fscrypt_hkdf *hkdf, const u8 *master_key, */ #define HKDF_CONTEXT_KEY_IDENTIFIER 1 #define HKDF_CONTEXT_PER_FILE_KEY 2 -#define HKDF_CONTEXT_PER_MODE_KEY 3 +#define HKDF_CONTEXT_DIRECT_KEY 3 +#define HKDF_CONTEXT_IV_INO_LBLK_64_KEY 4 extern int fscrypt_hkdf_expand(struct fscrypt_hkdf *hkdf, u8 context, const u8 *info, unsigned int infolen, @@ -386,8 +382,14 @@ struct fscrypt_master_key { struct list_head mk_decrypted_inodes; spinlock_t mk_decrypted_inodes_lock; - /* Per-mode tfms for DIRECT_KEY policies, allocated on-demand */ - struct crypto_skcipher *mk_mode_keys[__FSCRYPT_MODE_MAX + 1]; + /* Crypto API transforms for DIRECT_KEY policies, allocated on-demand */ + struct crypto_skcipher *mk_direct_tfms[__FSCRYPT_MODE_MAX + 1]; + + /* + * Crypto API transforms for filesystem-layer implementation of + * IV_INO_LBLK_64 policies, allocated on-demand. + */ + struct crypto_skcipher *mk_iv_ino_lblk_64_tfms[__FSCRYPT_MODE_MAX + 1]; } __randomize_layout; @@ -443,8 +445,7 @@ struct fscrypt_mode { const char *cipher_str; int keysize; int ivsize; - bool logged_impl_name; - bool needs_essiv; + int logged_impl_name; }; static inline bool diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c index c34fa7c61b43..040df1f5e1c8 100644 --- a/fs/crypto/keyring.c +++ b/fs/crypto/keyring.c @@ -43,8 +43,10 @@ static void free_master_key(struct fscrypt_master_key *mk) wipe_master_key_secret(&mk->mk_secret); - for (i = 0; i < ARRAY_SIZE(mk->mk_mode_keys); i++) - crypto_free_skcipher(mk->mk_mode_keys[i]); + for (i = 0; i <= __FSCRYPT_MODE_MAX; i++) { + crypto_free_skcipher(mk->mk_direct_tfms[i]); + crypto_free_skcipher(mk->mk_iv_ino_lblk_64_tfms[i]); + } key_put(mk->mk_users); kzfree(mk); diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index d71c2d6dd162..f577bb6613f9 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -8,15 +8,11 @@ * Heavily modified since then. */ -#include <crypto/aes.h> -#include <crypto/sha.h> #include <crypto/skcipher.h> #include <linux/key.h> #include "fscrypt_private.h" -static struct crypto_shash *essiv_hash_tfm; - static struct fscrypt_mode available_modes[] = { [FSCRYPT_MODE_AES_256_XTS] = { .friendly_name = "AES-256-XTS", @@ -31,11 +27,10 @@ static struct fscrypt_mode available_modes[] = { .ivsize = 16, }, [FSCRYPT_MODE_AES_128_CBC] = { - .friendly_name = "AES-128-CBC", - .cipher_str = "cbc(aes)", + .friendly_name = "AES-128-CBC-ESSIV", + .cipher_str = "essiv(cbc(aes),sha256)", .keysize = 16, .ivsize = 16, - .needs_essiv = true, }, [FSCRYPT_MODE_AES_128_CTS] = { .friendly_name = "AES-128-CTS-CBC", @@ -86,15 +81,13 @@ struct crypto_skcipher *fscrypt_allocate_skcipher(struct fscrypt_mode *mode, mode->cipher_str, PTR_ERR(tfm)); return tfm; } - if (unlikely(!mode->logged_impl_name)) { + if (!xchg(&mode->logged_impl_name, 1)) { /* * fscrypt performance can vary greatly depending on which * crypto algorithm implementation is used. Help people debug * performance problems by logging the ->cra_driver_name the - * first time a mode is used. Note that multiple threads can - * race here, but it doesn't really matter. + * first time a mode is used. */ - mode->logged_impl_name = true; pr_info("fscrypt: %s using implementation \"%s\"\n", mode->friendly_name, crypto_skcipher_alg(tfm)->base.cra_driver_name); @@ -111,131 +104,64 @@ err_free_tfm: return ERR_PTR(err); } -static int derive_essiv_salt(const u8 *key, int keysize, u8 *salt) -{ - struct crypto_shash *tfm = READ_ONCE(essiv_hash_tfm); - - /* init hash transform on demand */ - if (unlikely(!tfm)) { - struct crypto_shash *prev_tfm; - - tfm = crypto_alloc_shash("sha256", 0, 0); - if (IS_ERR(tfm)) { - if (PTR_ERR(tfm) == -ENOENT) { - fscrypt_warn(NULL, - "Missing crypto API support for SHA-256"); - return -ENOPKG; - } - fscrypt_err(NULL, - "Error allocating SHA-256 transform: %ld", - PTR_ERR(tfm)); - return PTR_ERR(tfm); - } - prev_tfm = cmpxchg(&essiv_hash_tfm, NULL, tfm); - if (prev_tfm) { - crypto_free_shash(tfm); - tfm = prev_tfm; - } - } - - { - SHASH_DESC_ON_STACK(desc, tfm); - desc->tfm = tfm; - - return crypto_shash_digest(desc, key, keysize, salt); - } -} - -static int init_essiv_generator(struct fscrypt_info *ci, const u8 *raw_key, - int keysize) -{ - int err; - struct crypto_cipher *essiv_tfm; - u8 salt[SHA256_DIGEST_SIZE]; - - if (WARN_ON(ci->ci_mode->ivsize != AES_BLOCK_SIZE)) - return -EINVAL; - - essiv_tfm = crypto_alloc_cipher("aes", 0, 0); - if (IS_ERR(essiv_tfm)) - return PTR_ERR(essiv_tfm); - - ci->ci_essiv_tfm = essiv_tfm; - - err = derive_essiv_salt(raw_key, keysize, salt); - if (err) - goto out; - - /* - * Using SHA256 to derive the salt/key will result in AES-256 being - * used for IV generation. File contents encryption will still use the - * configured keysize (AES-128) nevertheless. - */ - err = crypto_cipher_setkey(essiv_tfm, salt, sizeof(salt)); - if (err) - goto out; - -out: - memzero_explicit(salt, sizeof(salt)); - return err; -} - -/* Given the per-file key, set up the file's crypto transform object(s) */ +/* Given the per-file key, set up the file's crypto transform object */ int fscrypt_set_derived_key(struct fscrypt_info *ci, const u8 *derived_key) { - struct fscrypt_mode *mode = ci->ci_mode; - struct crypto_skcipher *ctfm; - int err; - - ctfm = fscrypt_allocate_skcipher(mode, derived_key, ci->ci_inode); - if (IS_ERR(ctfm)) - return PTR_ERR(ctfm); + struct crypto_skcipher *tfm; - ci->ci_ctfm = ctfm; + tfm = fscrypt_allocate_skcipher(ci->ci_mode, derived_key, ci->ci_inode); + if (IS_ERR(tfm)) + return PTR_ERR(tfm); - if (mode->needs_essiv) { - err = init_essiv_generator(ci, derived_key, mode->keysize); - if (err) { - fscrypt_warn(ci->ci_inode, - "Error initializing ESSIV generator: %d", - err); - return err; - } - } + ci->ci_ctfm = tfm; + ci->ci_owns_key = true; return 0; } static int setup_per_mode_key(struct fscrypt_info *ci, - struct fscrypt_master_key *mk) + struct fscrypt_master_key *mk, + struct crypto_skcipher **tfms, + u8 hkdf_context, bool include_fs_uuid) { + 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; struct crypto_skcipher *tfm, *prev_tfm; u8 mode_key[FSCRYPT_MAX_KEY_SIZE]; + u8 hkdf_info[sizeof(mode_num) + sizeof(sb->s_uuid)]; + unsigned int hkdf_infolen = 0; int err; - if (WARN_ON(mode_num >= ARRAY_SIZE(mk->mk_mode_keys))) + if (WARN_ON(mode_num > __FSCRYPT_MODE_MAX)) return -EINVAL; /* pairs with cmpxchg() below */ - tfm = READ_ONCE(mk->mk_mode_keys[mode_num]); + tfm = READ_ONCE(tfms[mode_num]); if (likely(tfm != NULL)) goto done; BUILD_BUG_ON(sizeof(mode_num) != 1); + BUILD_BUG_ON(sizeof(sb->s_uuid) != 16); + BUILD_BUG_ON(sizeof(hkdf_info) != 17); + hkdf_info[hkdf_infolen++] = mode_num; + if (include_fs_uuid) { + memcpy(&hkdf_info[hkdf_infolen], &sb->s_uuid, + sizeof(sb->s_uuid)); + hkdf_infolen += sizeof(sb->s_uuid); + } err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf, - HKDF_CONTEXT_PER_MODE_KEY, - &mode_num, sizeof(mode_num), + hkdf_context, hkdf_info, hkdf_infolen, mode_key, mode->keysize); if (err) return err; - tfm = fscrypt_allocate_skcipher(mode, mode_key, ci->ci_inode); + tfm = fscrypt_allocate_skcipher(mode, mode_key, inode); memzero_explicit(mode_key, mode->keysize); if (IS_ERR(tfm)) return PTR_ERR(tfm); /* pairs with READ_ONCE() above */ - prev_tfm = cmpxchg(&mk->mk_mode_keys[mode_num], NULL, tfm); + prev_tfm = cmpxchg(&tfms[mode_num], NULL, tfm); if (prev_tfm != NULL) { crypto_free_skcipher(tfm); tfm = prev_tfm; @@ -266,7 +192,19 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, ci->ci_mode->friendly_name); return -EINVAL; } - return setup_per_mode_key(ci, mk); + return setup_per_mode_key(ci, mk, mk->mk_direct_tfms, + HKDF_CONTEXT_DIRECT_KEY, false); + } else if (ci->ci_policy.v2.flags & + FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) { + /* + * IV_INO_LBLK_64: encryption keys are derived from (master_key, + * mode_num, filesystem_uuid), and inode number is included in + * the IVs. This format is optimized for use with inline + * encryption hardware compliant with the UFS or eMMC standards. + */ + return setup_per_mode_key(ci, mk, mk->mk_iv_ino_lblk_64_tfms, + HKDF_CONTEXT_IV_INO_LBLK_64_KEY, + true); } err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf, @@ -388,13 +326,10 @@ static void put_crypt_info(struct fscrypt_info *ci) if (!ci) return; - if (ci->ci_direct_key) { + if (ci->ci_direct_key) fscrypt_put_direct_key(ci->ci_direct_key); - } else if ((ci->ci_ctfm != NULL || ci->ci_essiv_tfm != NULL) && - !fscrypt_is_direct_key_policy(&ci->ci_policy)) { + else if (ci->ci_owns_key) crypto_free_skcipher(ci->ci_ctfm); - crypto_free_cipher(ci->ci_essiv_tfm); - } key = ci->ci_master_key; if (key) { @@ -415,6 +350,7 @@ static void put_crypt_info(struct fscrypt_info *ci) key_invalidate(key); key_put(key); } + memzero_explicit(ci, sizeof(*ci)); kmem_cache_free(fscrypt_info_cachep, ci); } diff --git a/fs/crypto/keysetup_v1.c b/fs/crypto/keysetup_v1.c index ad1a36c370c3..5298ef22aa85 100644 --- a/fs/crypto/keysetup_v1.c +++ b/fs/crypto/keysetup_v1.c @@ -270,10 +270,6 @@ static int setup_v1_file_key_direct(struct fscrypt_info *ci, return -EINVAL; } - /* ESSIV implies 16-byte IVs which implies !DIRECT_KEY */ - if (WARN_ON(mode->needs_essiv)) - return -EINVAL; - dk = fscrypt_get_direct_key(ci, raw_master_key); if (IS_ERR(dk)) return PTR_ERR(dk); diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c index 4072ba644595..96f528071bed 100644 --- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -29,6 +29,40 @@ bool fscrypt_policies_equal(const union fscrypt_policy *policy1, return !memcmp(policy1, policy2, fscrypt_policy_size(policy1)); } +static bool supported_iv_ino_lblk_64_policy( + const struct fscrypt_policy_v2 *policy, + const struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + int ino_bits = 64, lblk_bits = 64; + + if (policy->flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) { + fscrypt_warn(inode, + "The DIRECT_KEY and IV_INO_LBLK_64 flags are mutually exclusive"); + return false; + } + /* + * It's unsafe to include inode numbers in the IVs if the filesystem can + * potentially renumber inodes, e.g. via filesystem shrinking. + */ + if (!sb->s_cop->has_stable_inodes || + !sb->s_cop->has_stable_inodes(sb)) { + fscrypt_warn(inode, + "Can't use IV_INO_LBLK_64 policy on filesystem '%s' because it doesn't have stable inode numbers", + 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 > 32 || lblk_bits > 32) { + fscrypt_warn(inode, + "Can't use IV_INO_LBLK_64 policy on filesystem '%s' because it doesn't use 32-bit inode and block numbers", + sb->s_id); + return false; + } + return true; +} + /** * fscrypt_supported_policy - check whether an encryption policy is supported * @@ -55,7 +89,8 @@ bool fscrypt_supported_policy(const union fscrypt_policy *policy_u, return false; } - if (policy->flags & ~FSCRYPT_POLICY_FLAGS_VALID) { + if (policy->flags & ~(FSCRYPT_POLICY_FLAGS_PAD_MASK | + FSCRYPT_POLICY_FLAG_DIRECT_KEY)) { fscrypt_warn(inode, "Unsupported encryption flags (0x%02x)", policy->flags); @@ -83,6 +118,10 @@ bool fscrypt_supported_policy(const union fscrypt_policy *policy_u, return false; } + if ((policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) && + !supported_iv_ino_lblk_64_policy(policy, inode)) + return false; + if (memchr_inv(policy->__reserved, 0, sizeof(policy->__reserved))) { fscrypt_warn(inode, diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 03db3e71676c..b3a2cc7c0252 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1678,6 +1678,7 @@ static inline bool ext4_verity_in_progress(struct inode *inode) #define EXT4_FEATURE_COMPAT_RESIZE_INODE 0x0010 #define EXT4_FEATURE_COMPAT_DIR_INDEX 0x0020 #define EXT4_FEATURE_COMPAT_SPARSE_SUPER2 0x0200 +#define EXT4_FEATURE_COMPAT_STABLE_INODES 0x0800 #define EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER 0x0001 #define EXT4_FEATURE_RO_COMPAT_LARGE_FILE 0x0002 @@ -1779,6 +1780,7 @@ EXT4_FEATURE_COMPAT_FUNCS(xattr, EXT_ATTR) EXT4_FEATURE_COMPAT_FUNCS(resize_inode, RESIZE_INODE) EXT4_FEATURE_COMPAT_FUNCS(dir_index, DIR_INDEX) EXT4_FEATURE_COMPAT_FUNCS(sparse_super2, SPARSE_SUPER2) +EXT4_FEATURE_COMPAT_FUNCS(stable_inodes, STABLE_INODES) EXT4_FEATURE_RO_COMPAT_FUNCS(sparse_super, SPARSE_SUPER) EXT4_FEATURE_RO_COMPAT_FUNCS(large_file, LARGE_FILE) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index dd654e53ba3d..b3cbf8622eab 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1345,6 +1345,18 @@ static bool ext4_dummy_context(struct inode *inode) return DUMMY_ENCRYPTION_ENABLED(EXT4_SB(inode->i_sb)); } +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); +} + static const struct fscrypt_operations ext4_cryptops = { .key_prefix = "ext4:", .get_context = ext4_get_context, @@ -1352,6 +1364,8 @@ static const struct fscrypt_operations ext4_cryptops = { .dummy_context = ext4_dummy_context, .empty_dir = ext4_empty_dir, .max_namelen = EXT4_NAME_LEN, + .has_stable_inodes = ext4_has_stable_inodes, + .get_ino_and_lblk_bits = ext4_get_ino_and_lblk_bits, }; #endif diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 95761740cf1f..197ad6b314de 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -2308,13 +2308,27 @@ static bool f2fs_dummy_context(struct inode *inode) return DUMMY_ENCRYPTION_ENABLED(F2FS_I_SB(inode)); } +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 const struct fscrypt_operations f2fs_cryptops = { - .key_prefix = "f2fs:", - .get_context = f2fs_get_context, - .set_context = f2fs_set_context, - .dummy_context = f2fs_dummy_context, - .empty_dir = f2fs_empty_dir, - .max_namelen = F2FS_NAME_LEN, + .key_prefix = "f2fs:", + .get_context = f2fs_get_context, + .set_context = f2fs_set_context, + .dummy_context = f2fs_dummy_context, + .empty_dir = f2fs_empty_dir, + .max_namelen = F2FS_NAME_LEN, + .has_stable_inodes = f2fs_has_stable_inodes, + .get_ino_and_lblk_bits = f2fs_get_ino_and_lblk_bits, }; #endif diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index f622f7460ed8..1a7bffe78ed5 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -20,7 +20,6 @@ #define FS_CRYPTO_BLOCK_SIZE 16 -struct fscrypt_ctx; struct fscrypt_info; struct fscrypt_str { @@ -62,18 +61,9 @@ struct fscrypt_operations { bool (*dummy_context)(struct inode *); bool (*empty_dir)(struct inode *); unsigned int max_namelen; -}; - -/* Decryption work */ -struct fscrypt_ctx { - union { - struct { - struct bio *bio; - struct work_struct work; - }; - struct list_head free_list; /* Free list */ - }; - u8 flags; /* Flags */ + 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); }; static inline bool fscrypt_has_encryption_key(const struct inode *inode) @@ -102,8 +92,6 @@ static inline void fscrypt_handle_d_move(struct dentry *dentry) /* crypto.c */ extern void fscrypt_enqueue_decrypt_work(struct work_struct *); -extern struct fscrypt_ctx *fscrypt_get_ctx(gfp_t); -extern void fscrypt_release_ctx(struct fscrypt_ctx *); extern struct page *fscrypt_encrypt_pagecache_blocks(struct page *page, unsigned int len, @@ -244,8 +232,6 @@ static inline bool fscrypt_match_name(const struct fscrypt_name *fname, /* bio.c */ extern void fscrypt_decrypt_bio(struct bio *); -extern void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx, - struct bio *bio); extern int fscrypt_zeroout_range(const struct inode *, pgoff_t, sector_t, unsigned int); @@ -295,16 +281,6 @@ static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work) { } -static inline struct fscrypt_ctx *fscrypt_get_ctx(gfp_t gfp_flags) -{ - return ERR_PTR(-EOPNOTSUPP); -} - -static inline void fscrypt_release_ctx(struct fscrypt_ctx *ctx) -{ - return; -} - static inline struct page *fscrypt_encrypt_pagecache_blocks(struct page *page, unsigned int len, unsigned int offs, @@ -484,11 +460,6 @@ static inline void fscrypt_decrypt_bio(struct bio *bio) { } -static inline void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx, - struct bio *bio) -{ -} - static inline int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, sector_t pblk, unsigned int len) { diff --git a/include/uapi/linux/fscrypt.h b/include/uapi/linux/fscrypt.h index 39ccfe9311c3..1beb174ad950 100644 --- a/include/uapi/linux/fscrypt.h +++ b/include/uapi/linux/fscrypt.h @@ -17,7 +17,8 @@ #define FSCRYPT_POLICY_FLAGS_PAD_32 0x03 #define FSCRYPT_POLICY_FLAGS_PAD_MASK 0x03 #define FSCRYPT_POLICY_FLAG_DIRECT_KEY 0x04 -#define FSCRYPT_POLICY_FLAGS_VALID 0x07 +#define FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 0x08 +#define FSCRYPT_POLICY_FLAGS_VALID 0x0F /* Encryption algorithms */ #define FSCRYPT_MODE_AES_256_XTS 1 |