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Diffstat (limited to 'fs/crypto/fscrypt_private.h')
| -rw-r--r-- | fs/crypto/fscrypt_private.h | 787 |
1 files changed, 787 insertions, 0 deletions
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h new file mode 100644 index 000000000000..4e8e82a9ccf9 --- /dev/null +++ b/fs/crypto/fscrypt_private.h @@ -0,0 +1,787 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * fscrypt_private.h + * + * Copyright (C) 2015, Google, Inc. + * + * Originally written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar. + * Heavily modified since then. + */ + +#ifndef _FSCRYPT_PRIVATE_H +#define _FSCRYPT_PRIVATE_H + +#include <crypto/sha2.h> +#include <linux/fscrypt.h> +#include <linux/minmax.h> +#include <linux/siphash.h> +#include <linux/blk-crypto.h> + +#define CONST_STRLEN(str) (sizeof(str) - 1) + +#define FSCRYPT_FILE_NONCE_SIZE 16 + +/* + * Minimum size of an fscrypt master key. Note: a longer key will be required + * if ciphers with a 256-bit security strength are used. This is just the + * absolute minimum, which applies when only 128-bit encryption is used. + */ +#define FSCRYPT_MIN_KEY_SIZE 16 + +/* Maximum size of a raw fscrypt master key */ +#define FSCRYPT_MAX_RAW_KEY_SIZE 64 + +/* Maximum size of a hardware-wrapped fscrypt master key */ +#define FSCRYPT_MAX_HW_WRAPPED_KEY_SIZE BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE + +/* Maximum size of an fscrypt master key across both key types */ +#define FSCRYPT_MAX_ANY_KEY_SIZE \ + MAX(FSCRYPT_MAX_RAW_KEY_SIZE, FSCRYPT_MAX_HW_WRAPPED_KEY_SIZE) + +/* + * FSCRYPT_MAX_KEY_SIZE is defined in the UAPI header, but the addition of + * hardware-wrapped keys has made it misleading as it's only for raw keys. + * Don't use it in kernel code; use one of the above constants instead. + */ +#undef FSCRYPT_MAX_KEY_SIZE + +/* + * This mask is passed as the third argument to the crypto_alloc_*() functions + * to prevent fscrypt from using the Crypto API drivers for non-inline crypto + * engines. Those drivers have been problematic for fscrypt. fscrypt users + * have reported hangs and even incorrect en/decryption with these drivers. + * Since going to the driver, off CPU, and back again is really slow, such + * drivers can be over 50 times slower than the CPU-based code for fscrypt's + * workload. Even on platforms that lack AES instructions on the CPU, using the + * offloads has been shown to be slower, even staying with AES. (Of course, + * Adiantum is faster still, and is the recommended option on such platforms...) + * + * Note that fscrypt also supports inline crypto engines. Those don't use the + * Crypto API and work much better than the old-style (non-inline) engines. + */ +#define FSCRYPT_CRYPTOAPI_MASK \ + (CRYPTO_ALG_ASYNC | CRYPTO_ALG_ALLOCATES_MEMORY | \ + CRYPTO_ALG_KERN_DRIVER_ONLY) + +#define FSCRYPT_CONTEXT_V1 1 +#define FSCRYPT_CONTEXT_V2 2 + +/* Keep this in sync with include/uapi/linux/fscrypt.h */ +#define FSCRYPT_MODE_MAX FSCRYPT_MODE_AES_256_HCTR2 + +struct fscrypt_context_v1 { + u8 version; /* FSCRYPT_CONTEXT_V1 */ + u8 contents_encryption_mode; + u8 filenames_encryption_mode; + u8 flags; + u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE]; + u8 nonce[FSCRYPT_FILE_NONCE_SIZE]; +}; + +struct fscrypt_context_v2 { + u8 version; /* FSCRYPT_CONTEXT_V2 */ + u8 contents_encryption_mode; + u8 filenames_encryption_mode; + u8 flags; + u8 log2_data_unit_size; + u8 __reserved[3]; + u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE]; + u8 nonce[FSCRYPT_FILE_NONCE_SIZE]; +}; + +/* + * fscrypt_context - the encryption context of an inode + * + * This is the on-disk equivalent of an fscrypt_policy, stored alongside each + * encrypted file usually in a hidden extended attribute. It contains the + * fields from the fscrypt_policy, in order to identify the encryption algorithm + * and key with which the file is encrypted. It also contains a nonce that was + * randomly generated by fscrypt itself; this is used as KDF input or as a tweak + * to cause different files to be encrypted differently. + */ +union fscrypt_context { + u8 version; + struct fscrypt_context_v1 v1; + struct fscrypt_context_v2 v2; +}; + +/* + * Return the size expected for the given fscrypt_context based on its version + * number, or 0 if the context version is unrecognized. + */ +static inline int fscrypt_context_size(const union fscrypt_context *ctx) +{ + switch (ctx->version) { + case FSCRYPT_CONTEXT_V1: + BUILD_BUG_ON(sizeof(ctx->v1) != 28); + return sizeof(ctx->v1); + case FSCRYPT_CONTEXT_V2: + BUILD_BUG_ON(sizeof(ctx->v2) != 40); + return sizeof(ctx->v2); + } + return 0; +} + +/* Check whether an fscrypt_context has a recognized version number and size */ +static inline bool fscrypt_context_is_valid(const union fscrypt_context *ctx, + int ctx_size) +{ + return ctx_size >= 1 && ctx_size == fscrypt_context_size(ctx); +} + +/* Retrieve the context's nonce, assuming the context was already validated */ +static inline const u8 *fscrypt_context_nonce(const union fscrypt_context *ctx) +{ + switch (ctx->version) { + case FSCRYPT_CONTEXT_V1: + return ctx->v1.nonce; + case FSCRYPT_CONTEXT_V2: + return ctx->v2.nonce; + } + WARN_ON_ONCE(1); + return NULL; +} + +union fscrypt_policy { + u8 version; + struct fscrypt_policy_v1 v1; + struct fscrypt_policy_v2 v2; +}; + +/* + * Return the size expected for the given fscrypt_policy based on its version + * number, or 0 if the policy version is unrecognized. + */ +static inline int fscrypt_policy_size(const union fscrypt_policy *policy) +{ + switch (policy->version) { + case FSCRYPT_POLICY_V1: + return sizeof(policy->v1); + case FSCRYPT_POLICY_V2: + return sizeof(policy->v2); + } + return 0; +} + +/* Return the contents encryption mode of a valid encryption policy */ +static inline u8 +fscrypt_policy_contents_mode(const union fscrypt_policy *policy) +{ + switch (policy->version) { + case FSCRYPT_POLICY_V1: + return policy->v1.contents_encryption_mode; + case FSCRYPT_POLICY_V2: + return policy->v2.contents_encryption_mode; + } + BUG(); +} + +/* Return the filenames encryption mode of a valid encryption policy */ +static inline u8 +fscrypt_policy_fnames_mode(const union fscrypt_policy *policy) +{ + switch (policy->version) { + case FSCRYPT_POLICY_V1: + return policy->v1.filenames_encryption_mode; + case FSCRYPT_POLICY_V2: + return policy->v2.filenames_encryption_mode; + } + BUG(); +} + +/* Return the flags (FSCRYPT_POLICY_FLAG*) of a valid encryption policy */ +static inline u8 +fscrypt_policy_flags(const union fscrypt_policy *policy) +{ + switch (policy->version) { + case FSCRYPT_POLICY_V1: + return policy->v1.flags; + case FSCRYPT_POLICY_V2: + return policy->v2.flags; + } + 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. + */ +struct fscrypt_symlink_data { + __le16 len; + char encrypted_path[]; +} __packed; + +/** + * struct fscrypt_prepared_key - a key prepared for actual encryption/decryption + * @tfm: crypto API transform object + * @blk_key: key for blk-crypto + * + * Normally only one of the fields will be non-NULL. + */ +struct fscrypt_prepared_key { + struct crypto_sync_skcipher *tfm; +#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT + struct blk_crypto_key *blk_key; +#endif +}; + +/* + * fscrypt_inode_info - the "encryption key" for an inode + * + * When an encrypted file's key is made available, an instance of this struct is + * allocated and a pointer to it is stored in the file's in-memory inode. Once + * created, it remains until the inode is evicted. + */ +struct fscrypt_inode_info { + + /* The key in a form prepared for actual encryption/decryption */ + struct fscrypt_prepared_key ci_enc_key; + + /* True if ci_enc_key should be freed when this struct is freed */ + u8 ci_owns_key : 1; + +#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT + /* + * True if this inode will use inline encryption (blk-crypto) instead of + * the traditional filesystem-layer encryption. + */ + u8 ci_inlinecrypt : 1; +#endif + + /* True if ci_dirhash_key is initialized */ + u8 ci_dirhash_key_initialized : 1; + + /* + * 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; + + /* Cached value: log2 of number of data units per FS block */ + u8 ci_data_units_per_block_bits; + + /* Hashed inode number. Only set for IV_INO_LBLK_32 */ + u32 ci_hashed_ino; + + /* + * Encryption mode used for this inode. It corresponds to either the + * contents or filenames encryption mode, depending on the inode type. + */ + struct fscrypt_mode *ci_mode; + + /* Back-pointer to the inode */ + struct inode *ci_inode; + + /* + * The master key with which this inode was unlocked (decrypted). This + * will be NULL if the master key was found in a process-subscribed + * keyring rather than in the filesystem-level keyring. + */ + struct fscrypt_master_key *ci_master_key; + + /* + * Link in list of inodes that were unlocked with the master key. + * Only used when ->ci_master_key is set. + */ + struct list_head ci_master_key_link; + + /* + * If non-NULL, then encryption is done using the master key directly + * and ci_enc_key will equal ci_direct_key->dk_key. + */ + struct fscrypt_direct_key *ci_direct_key; + + /* + * This inode's hash key for filenames. This is a 128-bit SipHash-2-4 + * key. This is only set for directories that use a keyed dirhash over + * the plaintext filenames -- currently just casefolded directories. + */ + siphash_key_t ci_dirhash_key; + + /* The encryption policy used by this inode */ + union fscrypt_policy ci_policy; + + /* This inode's nonce, copied from the fscrypt_context */ + u8 ci_nonce[FSCRYPT_FILE_NONCE_SIZE]; +}; + +typedef enum { + FS_DECRYPT = 0, + FS_ENCRYPT, +} fscrypt_direction_t; + +/* crypto.c */ +extern struct kmem_cache *fscrypt_inode_info_cachep; +int fscrypt_initialize(struct super_block *sb); +int fscrypt_crypt_data_unit(const struct fscrypt_inode_info *ci, + fscrypt_direction_t rw, u64 index, + struct page *src_page, struct page *dest_page, + unsigned int len, unsigned int offs); +struct page *fscrypt_alloc_bounce_page(gfp_t gfp_flags); + +void __printf(3, 4) __cold +fscrypt_msg(const struct inode *inode, const char *level, const char *fmt, ...); + +#define fscrypt_warn(inode, fmt, ...) \ + fscrypt_msg((inode), KERN_WARNING, fmt, ##__VA_ARGS__) +#define fscrypt_err(inode, fmt, ...) \ + fscrypt_msg((inode), KERN_ERR, fmt, ##__VA_ARGS__) + +#define FSCRYPT_MAX_IV_SIZE 32 + +union fscrypt_iv { + struct { + /* 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]; + }; + u8 raw[FSCRYPT_MAX_IV_SIZE]; + __le64 dun[FSCRYPT_MAX_IV_SIZE / sizeof(__le64)]; +}; + +void fscrypt_generate_iv(union fscrypt_iv *iv, u64 index, + const struct fscrypt_inode_info *ci); + +/* + * Return the number of bits used by the maximum file data unit index that is + * possible on the given filesystem, using the given log2 data unit size. + */ +static inline int +fscrypt_max_file_dun_bits(const struct super_block *sb, int du_bits) +{ + return fls64(sb->s_maxbytes - 1) - du_bits; +} + +/* fname.c */ +bool __fscrypt_fname_encrypted_size(const union fscrypt_policy *policy, + u32 orig_len, u32 max_len, + u32 *encrypted_len_ret); + +/* hkdf.c */ +void fscrypt_init_hkdf(struct hmac_sha512_key *hkdf, const u8 *master_key, + unsigned int master_key_size); + +/* + * The list of contexts in which fscrypt uses HKDF. These values are used as + * the first byte of the HKDF application-specific info string to guarantee that + * info strings are never repeated between contexts. This ensures that all HKDF + * outputs are unique and cryptographically isolated, i.e. knowledge of one + * output doesn't reveal another. + */ +#define HKDF_CONTEXT_KEY_IDENTIFIER_FOR_RAW_KEY 1 /* info=<empty> */ +#define HKDF_CONTEXT_PER_FILE_ENC_KEY 2 /* info=file_nonce */ +#define HKDF_CONTEXT_DIRECT_KEY 3 /* info=mode_num */ +#define HKDF_CONTEXT_IV_INO_LBLK_64_KEY 4 /* info=mode_num||fs_uuid */ +#define HKDF_CONTEXT_DIRHASH_KEY 5 /* info=file_nonce */ +#define HKDF_CONTEXT_IV_INO_LBLK_32_KEY 6 /* info=mode_num||fs_uuid */ +#define HKDF_CONTEXT_INODE_HASH_KEY 7 /* info=<empty> */ +#define HKDF_CONTEXT_KEY_IDENTIFIER_FOR_HW_WRAPPED_KEY \ + 8 /* info=<empty> */ + +void fscrypt_hkdf_expand(const struct hmac_sha512_key *hkdf, u8 context, + const u8 *info, unsigned int infolen, + u8 *okm, unsigned int okmlen); + +/* inline_crypt.c */ +#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT +int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci, + bool is_hw_wrapped_key); + +static inline bool +fscrypt_using_inline_encryption(const struct fscrypt_inode_info *ci) +{ + return ci->ci_inlinecrypt; +} + +int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, + const u8 *key_bytes, size_t key_size, + bool is_hw_wrapped, + const struct fscrypt_inode_info *ci); + +void fscrypt_destroy_inline_crypt_key(struct super_block *sb, + struct fscrypt_prepared_key *prep_key); + +int fscrypt_derive_sw_secret(struct super_block *sb, + const u8 *wrapped_key, size_t wrapped_key_size, + u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE]); + +/* + * Check whether the crypto transform or blk-crypto key has been allocated in + * @prep_key, depending on which encryption implementation the file will use. + */ +static inline bool +fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key, + const struct fscrypt_inode_info *ci) +{ + /* + * The two smp_load_acquire()'s here pair with the smp_store_release()'s + * in fscrypt_prepare_inline_crypt_key() and fscrypt_prepare_key(). + * I.e., in some cases (namely, if this prep_key is a per-mode + * encryption key) another task can publish blk_key or tfm concurrently, + * executing a RELEASE barrier. We need to use smp_load_acquire() here + * to safely ACQUIRE the memory the other task published. + */ + if (fscrypt_using_inline_encryption(ci)) + return smp_load_acquire(&prep_key->blk_key) != NULL; + return smp_load_acquire(&prep_key->tfm) != NULL; +} + +#else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */ + +static inline int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci, + bool is_hw_wrapped_key) +{ + return 0; +} + +static inline bool +fscrypt_using_inline_encryption(const struct fscrypt_inode_info *ci) +{ + return false; +} + +static inline int +fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, + const u8 *key_bytes, size_t key_size, + bool is_hw_wrapped, + const struct fscrypt_inode_info *ci) +{ + WARN_ON_ONCE(1); + return -EOPNOTSUPP; +} + +static inline void +fscrypt_destroy_inline_crypt_key(struct super_block *sb, + struct fscrypt_prepared_key *prep_key) +{ +} + +static inline int +fscrypt_derive_sw_secret(struct super_block *sb, + const u8 *wrapped_key, size_t wrapped_key_size, + u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE]) +{ + fscrypt_warn(NULL, "kernel doesn't support hardware-wrapped keys"); + return -EOPNOTSUPP; +} + +static inline bool +fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key, + const struct fscrypt_inode_info *ci) +{ + return smp_load_acquire(&prep_key->tfm) != NULL; +} +#endif /* !CONFIG_FS_ENCRYPTION_INLINE_CRYPT */ + +/* keyring.c */ + +/* + * fscrypt_master_key_secret - secret key material of an in-use master key + */ +struct fscrypt_master_key_secret { + + /* + * The KDF with which subkeys of this key can be derived. + * + * For v1 policy keys, this isn't applicable and won't be set. + * Otherwise, this KDF will be keyed by this master key if + * ->is_hw_wrapped=false, or by the "software secret" that hardware + * derived from this master key if ->is_hw_wrapped=true. + */ + struct hmac_sha512_key hkdf; + + /* + * True if this key is a hardware-wrapped key; false if this key is a + * raw key (i.e. a "software key"). For v1 policy keys this will always + * be false, as v1 policy support is a legacy feature which doesn't + * support newer functionality such as hardware-wrapped keys. + */ + bool is_hw_wrapped; + + /* + * Size of the key in bytes. This remains set even if ->bytes was + * zeroized due to no longer being needed. I.e. we still remember the + * size of the key even if we don't need to remember the key itself. + */ + u32 size; + + /* + * The bytes of the key, when still needed. This can be either a raw + * key or a hardware-wrapped key, as indicated by ->is_hw_wrapped. In + * the case of a raw, v2 policy key, there is no need to remember the + * actual key separately from ->hkdf so this field will be zeroized as + * soon as ->hkdf is initialized. + */ + u8 bytes[FSCRYPT_MAX_ANY_KEY_SIZE]; + +} __randomize_layout; + +/* + * fscrypt_master_key - an in-use master key + * + * This represents a master encryption key which has been added to the + * filesystem. There are three high-level states that a key can be in: + * + * FSCRYPT_KEY_STATUS_PRESENT + * Key is fully usable; it can be used to unlock inodes that are encrypted + * with it (this includes being able to create new inodes). ->mk_present + * indicates whether the key is in this state. ->mk_secret exists, the key + * is in the keyring, and ->mk_active_refs > 0 due to ->mk_present. + * + * FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED + * Removal of this key has been initiated, but some inodes that were + * unlocked with it are still in-use. Like ABSENT, ->mk_secret is wiped, + * and the key can no longer be used to unlock inodes. Unlike ABSENT, the + * key is still in the keyring; ->mk_decrypted_inodes is nonempty; and + * ->mk_active_refs > 0, being equal to the size of ->mk_decrypted_inodes. + * + * This state transitions to ABSENT if ->mk_decrypted_inodes becomes empty, + * or to PRESENT if FS_IOC_ADD_ENCRYPTION_KEY is called again for this key. + * + * FSCRYPT_KEY_STATUS_ABSENT + * Key is fully removed. The key is no longer in the keyring, + * ->mk_decrypted_inodes is empty, ->mk_active_refs == 0, ->mk_secret is + * wiped, and the key can no longer be used to unlock inodes. + */ +struct fscrypt_master_key { + + /* + * Link in ->s_master_keys->key_hashtable. + * Only valid if ->mk_active_refs > 0. + */ + struct hlist_node mk_node; + + /* Semaphore that protects ->mk_secret, ->mk_users, and ->mk_present */ + struct rw_semaphore mk_sem; + + /* + * Active and structural reference counts. An active ref guarantees + * that the struct continues to exist, continues to be in the keyring + * ->s_master_keys, and that any embedded subkeys (e.g. + * ->mk_direct_keys) that have been prepared continue to exist. + * A structural ref only guarantees that the struct continues to exist. + * + * There is one active ref associated with ->mk_present being true, and + * one active ref for each inode in ->mk_decrypted_inodes. + * + * There is one structural ref associated with the active refcount being + * nonzero. Finding a key in the keyring also takes a structural ref, + * which is then held temporarily while the key is operated on. + */ + refcount_t mk_active_refs; + refcount_t mk_struct_refs; + + struct rcu_head mk_rcu_head; + + /* + * The secret key material. Wiped as soon as it is no longer needed; + * for details, see the fscrypt_master_key struct comment. + * + * Locking: protected by ->mk_sem. + */ + struct fscrypt_master_key_secret mk_secret; + + /* + * For v1 policy keys: an arbitrary key descriptor which was assigned by + * userspace (->descriptor). + * + * For v2 policy keys: a cryptographic hash of this key (->identifier). + */ + struct fscrypt_key_specifier mk_spec; + + /* + * Keyring which contains a key of type 'key_type_fscrypt_user' for each + * user who has added this key. Normally each key will be added by just + * one user, but it's possible that multiple users share a key, and in + * that case we need to keep track of those users so that one user can't + * remove the key before the others want it removed too. + * + * This is NULL for v1 policy keys; those can only be added by root. + * + * Locking: protected by ->mk_sem. (We don't just rely on the keyrings + * subsystem semaphore ->mk_users->sem, as we need support for atomic + * search+insert along with proper synchronization with other fields.) + */ + struct key *mk_users; + + /* + * List of inodes that were unlocked using this key. This allows the + * inodes to be evicted efficiently if the key is removed. + */ + struct list_head mk_decrypted_inodes; + spinlock_t mk_decrypted_inodes_lock; + + /* + * Per-mode encryption keys for the various types of encryption policies + * that use them. Allocated and derived on-demand. + */ + struct fscrypt_prepared_key mk_direct_keys[FSCRYPT_MODE_MAX + 1]; + struct fscrypt_prepared_key mk_iv_ino_lblk_64_keys[FSCRYPT_MODE_MAX + 1]; + struct fscrypt_prepared_key mk_iv_ino_lblk_32_keys[FSCRYPT_MODE_MAX + 1]; + + /* Hash key for inode numbers. Initialized only when needed. */ + siphash_key_t mk_ino_hash_key; + bool mk_ino_hash_key_initialized; + + /* + * Whether this key is in the "present" state, i.e. fully usable. For + * details, see the fscrypt_master_key struct comment. + * + * Locking: protected by ->mk_sem, but can be read locklessly using + * READ_ONCE(). Writers must use WRITE_ONCE() when concurrent readers + * are possible. + */ + bool mk_present; + +} __randomize_layout; + +static inline const char *master_key_spec_type( + const struct fscrypt_key_specifier *spec) +{ + switch (spec->type) { + case FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR: + return "descriptor"; + case FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER: + return "identifier"; + } + return "[unknown]"; +} + +static inline int master_key_spec_len(const struct fscrypt_key_specifier *spec) +{ + switch (spec->type) { + case FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR: + return FSCRYPT_KEY_DESCRIPTOR_SIZE; + case FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER: + return FSCRYPT_KEY_IDENTIFIER_SIZE; + } + return 0; +} + +void fscrypt_put_master_key(struct fscrypt_master_key *mk); + +void fscrypt_put_master_key_activeref(struct super_block *sb, + struct fscrypt_master_key *mk); + +struct fscrypt_master_key * +fscrypt_find_master_key(struct super_block *sb, + const struct fscrypt_key_specifier *mk_spec); + +void fscrypt_get_test_dummy_key_identifier( + u8 key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE]); + +int fscrypt_add_test_dummy_key(struct super_block *sb, + struct fscrypt_key_specifier *key_spec); + +int fscrypt_verify_key_added(struct super_block *sb, + const u8 identifier[FSCRYPT_KEY_IDENTIFIER_SIZE]); + +int __init fscrypt_init_keyring(void); + +/* keysetup.c */ + +struct fscrypt_mode { + const char *friendly_name; + const char *cipher_str; + int keysize; /* key size in bytes */ + int security_strength; /* security strength in bytes */ + int ivsize; /* IV size in bytes */ + int logged_cryptoapi_impl; + int logged_blk_crypto_native; + int logged_blk_crypto_fallback; + enum blk_crypto_mode_num blk_crypto_mode; +}; + +extern struct fscrypt_mode fscrypt_modes[]; + +int fscrypt_prepare_key(struct fscrypt_prepared_key *prep_key, + const u8 *raw_key, const struct fscrypt_inode_info *ci); + +void fscrypt_destroy_prepared_key(struct super_block *sb, + struct fscrypt_prepared_key *prep_key); + +int fscrypt_set_per_file_enc_key(struct fscrypt_inode_info *ci, + const u8 *raw_key); + +void fscrypt_derive_dirhash_key(struct fscrypt_inode_info *ci, + const struct fscrypt_master_key *mk); + +void fscrypt_hash_inode_number(struct fscrypt_inode_info *ci, + const struct fscrypt_master_key *mk); + +int fscrypt_get_encryption_info(struct inode *inode, bool allow_unsupported); + +/** + * fscrypt_require_key() - require an inode's encryption key + * @inode: the inode we need the key for + * + * If the inode is encrypted, set up its encryption key if not already done. + * Then require that the key be present and return -ENOKEY otherwise. + * + * No locks are needed, and the key will live as long as the struct inode --- so + * it won't go away from under you. + * + * Return: 0 on success, -ENOKEY if the key is missing, or another -errno code + * if a problem occurred while setting up the encryption key. + */ +static inline int fscrypt_require_key(struct inode *inode) +{ + if (IS_ENCRYPTED(inode)) { + int err = fscrypt_get_encryption_info(inode, false); + + if (err) + return err; + if (!fscrypt_has_encryption_key(inode)) + return -ENOKEY; + } + return 0; +} + +/* keysetup_v1.c */ + +void fscrypt_put_direct_key(struct fscrypt_direct_key *dk); + +int fscrypt_setup_v1_file_key(struct fscrypt_inode_info *ci, + const u8 *raw_master_key); + +int fscrypt_setup_v1_file_key_via_subscribed_keyrings( + struct fscrypt_inode_info *ci); + +/* policy.c */ + +bool fscrypt_policies_equal(const union fscrypt_policy *policy1, + const union fscrypt_policy *policy2); +int fscrypt_policy_to_key_spec(const union fscrypt_policy *policy, + struct fscrypt_key_specifier *key_spec); +const union fscrypt_policy *fscrypt_get_dummy_policy(struct super_block *sb); +bool fscrypt_supported_policy(const union fscrypt_policy *policy_u, + const struct inode *inode); +int fscrypt_policy_from_context(union fscrypt_policy *policy_u, + const union fscrypt_context *ctx_u, + int ctx_size); +const union fscrypt_policy *fscrypt_policy_to_inherit(struct inode *dir); + +#endif /* _FSCRYPT_PRIVATE_H */ |