From a828daabb2ae917c12f4dc617c04db1185e6221f Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Sun, 4 Aug 2019 19:35:45 -0700 Subject: fscrypt: rename fscrypt_master_key to fscrypt_direct_key In preparation for introducing a filesystem-level keyring which will contain fscrypt master keys, rename the existing 'struct fscrypt_master_key' to 'struct fscrypt_direct_key'. This is the structure in the existing table of master keys that's maintained to deduplicate the crypto transforms for v1 DIRECT_KEY policies. I've chosen to keep this table as-is rather than make it automagically add/remove the keys to/from the filesystem-level keyring, since that would add a lot of extra complexity to the filesystem-level keyring. Reviewed-by: Theodore Ts'o Signed-off-by: Eric Biggers --- fs/crypto/fscrypt_private.h | 7 +-- fs/crypto/keyinfo.c | 130 ++++++++++++++++++++++---------------------- 2 files changed, 68 insertions(+), 69 deletions(-) (limited to 'fs/crypto') diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index d345a7d28df8..80d15a1bf606 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -77,11 +77,10 @@ struct fscrypt_info { struct inode *ci_inode; /* - * If non-NULL, then this inode uses a master key directly rather than a - * derived key, and ci_ctfm will equal ci_master_key->mk_ctfm. - * Otherwise, this inode uses a derived key. + * If non-NULL, then encryption is done using the master key directly + * and ci_ctfm will equal ci_direct_key->dk_ctfm. */ - struct fscrypt_master_key *ci_master_key; + struct fscrypt_direct_key *ci_direct_key; /* fields from the fscrypt_context */ u8 ci_data_mode; diff --git a/fs/crypto/keyinfo.c b/fs/crypto/keyinfo.c index 2d45a86f09db..c4650071df27 100644 --- a/fs/crypto/keyinfo.c +++ b/fs/crypto/keyinfo.c @@ -21,8 +21,8 @@ static struct crypto_shash *essiv_hash_tfm; /* Table of keys referenced by DIRECT_KEY policies */ -static DEFINE_HASHTABLE(fscrypt_master_keys, 6); /* 6 bits = 64 buckets */ -static DEFINE_SPINLOCK(fscrypt_master_keys_lock); +static DEFINE_HASHTABLE(fscrypt_direct_keys, 6); /* 6 bits = 64 buckets */ +static DEFINE_SPINLOCK(fscrypt_direct_keys_lock); /* * Key derivation function. This generates the derived key by encrypting the @@ -273,46 +273,46 @@ err_free_tfm: } /* Master key referenced by DIRECT_KEY policy */ -struct fscrypt_master_key { - struct hlist_node mk_node; - refcount_t mk_refcount; - const struct fscrypt_mode *mk_mode; - struct crypto_skcipher *mk_ctfm; - u8 mk_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE]; - u8 mk_raw[FSCRYPT_MAX_KEY_SIZE]; +struct fscrypt_direct_key { + struct hlist_node dk_node; + refcount_t dk_refcount; + const struct fscrypt_mode *dk_mode; + struct crypto_skcipher *dk_ctfm; + u8 dk_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE]; + u8 dk_raw[FSCRYPT_MAX_KEY_SIZE]; }; -static void free_master_key(struct fscrypt_master_key *mk) +static void free_direct_key(struct fscrypt_direct_key *dk) { - if (mk) { - crypto_free_skcipher(mk->mk_ctfm); - kzfree(mk); + if (dk) { + crypto_free_skcipher(dk->dk_ctfm); + kzfree(dk); } } -static void put_master_key(struct fscrypt_master_key *mk) +static void put_direct_key(struct fscrypt_direct_key *dk) { - if (!refcount_dec_and_lock(&mk->mk_refcount, &fscrypt_master_keys_lock)) + if (!refcount_dec_and_lock(&dk->dk_refcount, &fscrypt_direct_keys_lock)) return; - hash_del(&mk->mk_node); - spin_unlock(&fscrypt_master_keys_lock); + hash_del(&dk->dk_node); + spin_unlock(&fscrypt_direct_keys_lock); - free_master_key(mk); + free_direct_key(dk); } /* - * Find/insert the given master key into the fscrypt_master_keys table. If - * found, it is returned with elevated refcount, and 'to_insert' is freed if - * non-NULL. If not found, 'to_insert' is inserted and returned if it's - * non-NULL; otherwise NULL is returned. + * Find/insert the given key into the fscrypt_direct_keys table. If found, it + * is returned with elevated refcount, and 'to_insert' is freed if non-NULL. If + * not found, 'to_insert' is inserted and returned if it's non-NULL; otherwise + * NULL is returned. */ -static struct fscrypt_master_key * -find_or_insert_master_key(struct fscrypt_master_key *to_insert, +static struct fscrypt_direct_key * +find_or_insert_direct_key(struct fscrypt_direct_key *to_insert, const u8 *raw_key, const struct fscrypt_mode *mode, const struct fscrypt_info *ci) { unsigned long hash_key; - struct fscrypt_master_key *mk; + struct fscrypt_direct_key *dk; /* * Careful: to avoid potentially leaking secret key bytes via timing @@ -323,60 +323,60 @@ find_or_insert_master_key(struct fscrypt_master_key *to_insert, BUILD_BUG_ON(sizeof(hash_key) > FSCRYPT_KEY_DESCRIPTOR_SIZE); memcpy(&hash_key, ci->ci_master_key_descriptor, sizeof(hash_key)); - spin_lock(&fscrypt_master_keys_lock); - hash_for_each_possible(fscrypt_master_keys, mk, mk_node, hash_key) { - if (memcmp(ci->ci_master_key_descriptor, mk->mk_descriptor, + spin_lock(&fscrypt_direct_keys_lock); + hash_for_each_possible(fscrypt_direct_keys, dk, dk_node, hash_key) { + if (memcmp(ci->ci_master_key_descriptor, dk->dk_descriptor, FSCRYPT_KEY_DESCRIPTOR_SIZE) != 0) continue; - if (mode != mk->mk_mode) + if (mode != dk->dk_mode) continue; - if (crypto_memneq(raw_key, mk->mk_raw, mode->keysize)) + if (crypto_memneq(raw_key, dk->dk_raw, mode->keysize)) continue; /* using existing tfm with same (descriptor, mode, raw_key) */ - refcount_inc(&mk->mk_refcount); - spin_unlock(&fscrypt_master_keys_lock); - free_master_key(to_insert); - return mk; + refcount_inc(&dk->dk_refcount); + spin_unlock(&fscrypt_direct_keys_lock); + free_direct_key(to_insert); + return dk; } if (to_insert) - hash_add(fscrypt_master_keys, &to_insert->mk_node, hash_key); - spin_unlock(&fscrypt_master_keys_lock); + hash_add(fscrypt_direct_keys, &to_insert->dk_node, hash_key); + spin_unlock(&fscrypt_direct_keys_lock); return to_insert; } /* Prepare to encrypt directly using the master key in the given mode */ -static struct fscrypt_master_key * -fscrypt_get_master_key(const struct fscrypt_info *ci, struct fscrypt_mode *mode, +static struct fscrypt_direct_key * +fscrypt_get_direct_key(const struct fscrypt_info *ci, struct fscrypt_mode *mode, const u8 *raw_key, const struct inode *inode) { - struct fscrypt_master_key *mk; + struct fscrypt_direct_key *dk; int err; /* Is there already a tfm for this key? */ - mk = find_or_insert_master_key(NULL, raw_key, mode, ci); - if (mk) - return mk; + dk = find_or_insert_direct_key(NULL, raw_key, mode, ci); + if (dk) + return dk; /* Nope, allocate one. */ - mk = kzalloc(sizeof(*mk), GFP_NOFS); - if (!mk) + dk = kzalloc(sizeof(*dk), GFP_NOFS); + if (!dk) return ERR_PTR(-ENOMEM); - refcount_set(&mk->mk_refcount, 1); - mk->mk_mode = mode; - mk->mk_ctfm = allocate_skcipher_for_mode(mode, raw_key, inode); - if (IS_ERR(mk->mk_ctfm)) { - err = PTR_ERR(mk->mk_ctfm); - mk->mk_ctfm = NULL; - goto err_free_mk; + refcount_set(&dk->dk_refcount, 1); + dk->dk_mode = mode; + dk->dk_ctfm = allocate_skcipher_for_mode(mode, raw_key, inode); + if (IS_ERR(dk->dk_ctfm)) { + err = PTR_ERR(dk->dk_ctfm); + dk->dk_ctfm = NULL; + goto err_free_dk; } - memcpy(mk->mk_descriptor, ci->ci_master_key_descriptor, + memcpy(dk->dk_descriptor, ci->ci_master_key_descriptor, FSCRYPT_KEY_DESCRIPTOR_SIZE); - memcpy(mk->mk_raw, raw_key, mode->keysize); + memcpy(dk->dk_raw, raw_key, mode->keysize); - return find_or_insert_master_key(mk, raw_key, mode, ci); + return find_or_insert_direct_key(dk, raw_key, mode, ci); -err_free_mk: - free_master_key(mk); +err_free_dk: + free_direct_key(dk); return ERR_PTR(err); } @@ -455,22 +455,22 @@ static int setup_crypto_transform(struct fscrypt_info *ci, struct fscrypt_mode *mode, const u8 *raw_key, const struct inode *inode) { - struct fscrypt_master_key *mk; + struct fscrypt_direct_key *dk; struct crypto_skcipher *ctfm; int err; if (ci->ci_flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) { - mk = fscrypt_get_master_key(ci, mode, raw_key, inode); - if (IS_ERR(mk)) - return PTR_ERR(mk); - ctfm = mk->mk_ctfm; + dk = fscrypt_get_direct_key(ci, mode, raw_key, inode); + if (IS_ERR(dk)) + return PTR_ERR(dk); + ctfm = dk->dk_ctfm; } else { - mk = NULL; + dk = NULL; ctfm = allocate_skcipher_for_mode(mode, raw_key, inode); if (IS_ERR(ctfm)) return PTR_ERR(ctfm); } - ci->ci_master_key = mk; + ci->ci_direct_key = dk; ci->ci_ctfm = ctfm; if (mode->needs_essiv) { @@ -494,8 +494,8 @@ static void put_crypt_info(struct fscrypt_info *ci) if (!ci) return; - if (ci->ci_master_key) { - put_master_key(ci->ci_master_key); + if (ci->ci_direct_key) { + put_direct_key(ci->ci_direct_key); } else { crypto_free_skcipher(ci->ci_ctfm); crypto_free_cipher(ci->ci_essiv_tfm); -- cgit v1.2.3