1 // SPDX-License-Identifier: GPL-2.0
19 		.friendly_name = "AES-256-XTS",
26 		.friendly_name = "AES-256-CTS-CBC",
27 		.cipher_str = "cts(cbc(aes))",
32 		.friendly_name = "AES-128-CBC-ESSIV",
39 		.friendly_name = "AES-128-CTS-CBC",
40 		.cipher_str = "cts(cbc(aes))",
61 	if (S_ISREG(inode->i_mode))  in select_encryption_mode()
64 	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))  in select_encryption_mode()
68 		  inode->i_ino, (inode->i_mode & S_IFMT));  in select_encryption_mode()
69 	return ERR_PTR(-EINVAL);  in select_encryption_mode()
80 	tfm = crypto_alloc_skcipher(mode->cipher_str, 0, 0);  in fscrypt_allocate_skcipher()
82 		if (PTR_ERR(tfm) == -ENOENT) {  in fscrypt_allocate_skcipher()
85 				     mode->friendly_name, mode->cipher_str);  in fscrypt_allocate_skcipher()
86 			return ERR_PTR(-ENOPKG);  in fscrypt_allocate_skcipher()
89 			    mode->cipher_str, PTR_ERR(tfm));  in fscrypt_allocate_skcipher()
92 	if (!xchg(&mode->logged_impl_name, 1)) {  in fscrypt_allocate_skcipher()
96 		 * performance problems by logging the ->cra_driver_name the  in fscrypt_allocate_skcipher()
100 			mode->friendly_name, crypto_skcipher_driver_name(tfm));  in fscrypt_allocate_skcipher()
102 	if (WARN_ON(crypto_skcipher_ivsize(tfm) != mode->ivsize)) {  in fscrypt_allocate_skcipher()
103 		err = -EINVAL;  in fscrypt_allocate_skcipher()
107 	err = crypto_skcipher_setkey(tfm, raw_key, mode->keysize);  in fscrypt_allocate_skcipher()
119  * Prepare the crypto transform object or blk-crypto key in @prep_key, given the
121  * (fs-layer or blk-crypto) will be used.
131 	tfm = fscrypt_allocate_skcipher(ci->ci_mode, raw_key, ci->ci_inode);  in fscrypt_prepare_key()
136 	 * I.e., here we publish ->tfm with a RELEASE barrier so that  in fscrypt_prepare_key()
138 	 * possible for per-mode keys, not for per-file keys.  in fscrypt_prepare_key()
140 	smp_store_release(&prep_key->tfm, tfm);  in fscrypt_prepare_key()
144 /* Destroy a crypto transform object and/or blk-crypto key. */
147 	crypto_free_skcipher(prep_key->tfm);  in fscrypt_destroy_prepared_key()
151 /* Given a per-file encryption key, set up the file's crypto transform object */
154 	ci->ci_owns_key = true;  in fscrypt_set_per_file_enc_key()
155 	return fscrypt_prepare_key(&ci->ci_enc_key, raw_key, ci);  in fscrypt_set_per_file_enc_key()
163 	const struct inode *inode = ci->ci_inode;  in setup_per_mode_enc_key()
164 	const struct super_block *sb = inode->i_sb;  in setup_per_mode_enc_key()
165 	struct fscrypt_mode *mode = ci->ci_mode;  in setup_per_mode_enc_key()
166 	const u8 mode_num = mode - fscrypt_modes;  in setup_per_mode_enc_key()
169 	u8 hkdf_info[sizeof(mode_num) + sizeof(sb->s_uuid)];  in setup_per_mode_enc_key()
174 		return -EINVAL;  in setup_per_mode_enc_key()
178 		ci->ci_enc_key = *prep_key;  in setup_per_mode_enc_key()
188 	BUILD_BUG_ON(sizeof(sb->s_uuid) != 16);  in setup_per_mode_enc_key()
192 		memcpy(&hkdf_info[hkdf_infolen], &sb->s_uuid,  in setup_per_mode_enc_key()
193 		       sizeof(sb->s_uuid));  in setup_per_mode_enc_key()
194 		hkdf_infolen += sizeof(sb->s_uuid);  in setup_per_mode_enc_key()
196 	err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf,  in setup_per_mode_enc_key()
198 				  mode_key, mode->keysize);  in setup_per_mode_enc_key()
202 	memzero_explicit(mode_key, mode->keysize);  in setup_per_mode_enc_key()
206 	ci->ci_enc_key = *prep_key;  in setup_per_mode_enc_key()
215  * application-specific information string.
218  * as a pair of 64-bit words.  Therefore, on big endian CPUs we have to do an
227 	err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf, context, info, infolen,  in fscrypt_derive_siphash_key()
233 	BUILD_BUG_ON(ARRAY_SIZE(key->key) != 2);  in fscrypt_derive_siphash_key()
234 	le64_to_cpus(&key->key[0]);  in fscrypt_derive_siphash_key()
235 	le64_to_cpus(&key->key[1]);  in fscrypt_derive_siphash_key()
245 					 ci->ci_nonce, FSCRYPT_FILE_NONCE_SIZE,  in fscrypt_derive_dirhash_key()
246 					 &ci->ci_dirhash_key);  in fscrypt_derive_dirhash_key()
249 	ci->ci_dirhash_key_initialized = true;  in fscrypt_derive_dirhash_key()
256 	WARN_ON(ci->ci_inode->i_ino == 0);  in fscrypt_hash_inode_number()
257 	WARN_ON(!mk->mk_ino_hash_key_initialized);  in fscrypt_hash_inode_number()
259 	ci->ci_hashed_ino = (u32)siphash_1u64(ci->ci_inode->i_ino,  in fscrypt_hash_inode_number()
260 					      &mk->mk_ino_hash_key);  in fscrypt_hash_inode_number()
268 	err = setup_per_mode_enc_key(ci, mk, mk->mk_iv_ino_lblk_32_keys,  in fscrypt_setup_iv_ino_lblk_32_key()
274 	if (!smp_load_acquire(&mk->mk_ino_hash_key_initialized)) {  in fscrypt_setup_iv_ino_lblk_32_key()
278 		if (mk->mk_ino_hash_key_initialized)  in fscrypt_setup_iv_ino_lblk_32_key()
283 						 NULL, 0, &mk->mk_ino_hash_key);  in fscrypt_setup_iv_ino_lblk_32_key()
287 		smp_store_release(&mk->mk_ino_hash_key_initialized, true);  in fscrypt_setup_iv_ino_lblk_32_key()
298 	if (ci->ci_inode->i_ino)  in fscrypt_setup_iv_ino_lblk_32_key()
309 	if (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) {  in fscrypt_setup_v2_file_key()
311 		 * DIRECT_KEY: instead of deriving per-file encryption keys, the  in fscrypt_setup_v2_file_key()
312 		 * per-file nonce will be included in all the IVs.  But unlike  in fscrypt_setup_v2_file_key()
314 		 * with the master key directly but rather derive a per-mode  in fscrypt_setup_v2_file_key()
318 		err = setup_per_mode_enc_key(ci, mk, mk->mk_direct_keys,  in fscrypt_setup_v2_file_key()
320 	} else if (ci->ci_policy.v2.flags &  in fscrypt_setup_v2_file_key()
328 		err = setup_per_mode_enc_key(ci, mk, mk->mk_iv_ino_lblk_64_keys,  in fscrypt_setup_v2_file_key()
331 	} else if (ci->ci_policy.v2.flags &  in fscrypt_setup_v2_file_key()
337 		err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf,  in fscrypt_setup_v2_file_key()
339 					  ci->ci_nonce, FSCRYPT_FILE_NONCE_SIZE,  in fscrypt_setup_v2_file_key()
340 					  derived_key, ci->ci_mode->keysize);  in fscrypt_setup_v2_file_key()
345 		memzero_explicit(derived_key, ci->ci_mode->keysize);  in fscrypt_setup_v2_file_key()
363  * If the master key is found in the filesystem-level keyring, then the
365  * read-locked.  This is needed to ensure that only one task links the
366  * fscrypt_info into ->mk_decrypted_inodes (as multiple tasks may race to create
383 	switch (ci->ci_policy.version) {  in setup_file_encryption_key()
387 		       ci->ci_policy.v1.master_key_descriptor,  in setup_file_encryption_key()
393 		       ci->ci_policy.v2.master_key_identifier,  in setup_file_encryption_key()
398 		return -EINVAL;  in setup_file_encryption_key()
401 	key = fscrypt_find_master_key(ci->ci_inode->i_sb, &mk_spec);  in setup_file_encryption_key()
403 		if (key != ERR_PTR(-ENOKEY) ||  in setup_file_encryption_key()
404 		    ci->ci_policy.version != FSCRYPT_POLICY_V1)  in setup_file_encryption_key()
410 		 * to before the search of ->s_master_keys, since users  in setup_file_encryption_key()
411 		 * shouldn't be able to override filesystem-level keys.  in setup_file_encryption_key()
416 	mk = key->payload.data[0];  in setup_file_encryption_key()
417 	down_read(&key->sem);  in setup_file_encryption_key()
420 	if (!is_master_key_secret_present(&mk->mk_secret)) {  in setup_file_encryption_key()
421 		err = -ENOKEY;  in setup_file_encryption_key()
431 	if (mk->mk_secret.size < ci->ci_mode->keysize) {  in setup_file_encryption_key()
436 			     mk->mk_secret.size, ci->ci_mode->keysize);  in setup_file_encryption_key()
437 		err = -ENOKEY;  in setup_file_encryption_key()
441 	switch (ci->ci_policy.version) {  in setup_file_encryption_key()
443 		err = fscrypt_setup_v1_file_key(ci, mk->mk_secret.raw);  in setup_file_encryption_key()
450 		err = -EINVAL;  in setup_file_encryption_key()
460 	up_read(&key->sem);  in setup_file_encryption_key()
472 	if (ci->ci_direct_key)  in put_crypt_info()
473 		fscrypt_put_direct_key(ci->ci_direct_key);  in put_crypt_info()
474 	else if (ci->ci_owns_key)  in put_crypt_info()
475 		fscrypt_destroy_prepared_key(&ci->ci_enc_key);  in put_crypt_info()
477 	key = ci->ci_master_key;  in put_crypt_info()
479 		struct fscrypt_master_key *mk = key->payload.data[0];  in put_crypt_info()
487 		 * gets removed from ->s_master_keys.  in put_crypt_info()
489 		spin_lock(&mk->mk_decrypted_inodes_lock);  in put_crypt_info()
490 		list_del(&ci->ci_master_key_link);  in put_crypt_info()
491 		spin_unlock(&mk->mk_decrypted_inodes_lock);  in put_crypt_info()
492 		if (refcount_dec_and_test(&mk->mk_refcount))  in put_crypt_info()
511 	res = fscrypt_initialize(inode->i_sb->s_cop->flags);  in fscrypt_setup_encryption_info()
517 		return -ENOMEM;  in fscrypt_setup_encryption_info()
519 	crypt_info->ci_inode = inode;  in fscrypt_setup_encryption_info()
520 	crypt_info->ci_policy = *policy;  in fscrypt_setup_encryption_info()
521 	memcpy(crypt_info->ci_nonce, nonce, FSCRYPT_FILE_NONCE_SIZE);  in fscrypt_setup_encryption_info()
523 	mode = select_encryption_mode(&crypt_info->ci_policy, inode);  in fscrypt_setup_encryption_info()
528 	WARN_ON(mode->ivsize > FSCRYPT_MAX_IV_SIZE);  in fscrypt_setup_encryption_info()
529 	crypt_info->ci_mode = mode;  in fscrypt_setup_encryption_info()
537 	 * For existing inodes, multiple tasks may race to set ->i_crypt_info.  in fscrypt_setup_encryption_info()
539 	 * fscrypt_get_info().  I.e., here we publish ->i_crypt_info with a  in fscrypt_setup_encryption_info()
542 	if (cmpxchg_release(&inode->i_crypt_info, NULL, crypt_info) == NULL) {  in fscrypt_setup_encryption_info()
544 		 * We won the race and set ->i_crypt_info to our crypt_info.  in fscrypt_setup_encryption_info()
549 				master_key->payload.data[0];  in fscrypt_setup_encryption_info()
551 			refcount_inc(&mk->mk_refcount);  in fscrypt_setup_encryption_info()
552 			crypt_info->ci_master_key = key_get(master_key);  in fscrypt_setup_encryption_info()
553 			spin_lock(&mk->mk_decrypted_inodes_lock);  in fscrypt_setup_encryption_info()
554 			list_add(&crypt_info->ci_master_key_link,  in fscrypt_setup_encryption_info()
555 				 &mk->mk_decrypted_inodes);  in fscrypt_setup_encryption_info()
556 			spin_unlock(&mk->mk_decrypted_inodes_lock);  in fscrypt_setup_encryption_info()
563 		up_read(&master_key->sem);  in fscrypt_setup_encryption_info()
571  * fscrypt_get_encryption_info() - set up an inode's encryption key
579  * Set up ->i_crypt_info, if it hasn't already been done.
581  * Note: unless ->i_crypt_info is already set, this isn't %GFP_NOFS-safe.  So
584  * Return: 0 if ->i_crypt_info was set or was already set, *or* if the
586  *	   distinguish these cases.)  Also can return another -errno code.
597 	res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));  in fscrypt_get_encryption_info()
599 		if (res == -ERANGE && allow_unsupported)  in fscrypt_get_encryption_info()
617 		return -EINVAL;  in fscrypt_get_encryption_info()
623 					    S_ISDIR(inode->i_mode));  in fscrypt_get_encryption_info()
625 	if (res == -ENOPKG && allow_unsupported) /* Algorithm unavailable? */  in fscrypt_get_encryption_info()
627 	if (res == -ENOKEY)  in fscrypt_get_encryption_info()
633  * fscrypt_prepare_new_inode() - prepare to create a new inode in a directory
634  * @dir: a possibly-encrypted directory
635  * @inode: the new inode.  ->i_mode must be set already.
636  *	   ->i_ino doesn't need to be set yet.
639  * If the directory is encrypted, set up its ->i_crypt_info in preparation for
641  * encrypted, set up its ->i_crypt_info and set *encrypt_ret=true.
643  * This isn't %GFP_NOFS-safe, and therefore it should be called before starting
644  * any filesystem transaction to create the inode.  For this reason, ->i_ino
650  * Return: 0 on success, -ENOKEY if the encryption key is missing, or another
651  *	   -errno code
665 	if (WARN_ON_ONCE(inode->i_mode == 0))  in fscrypt_prepare_new_inode()
666 		return -EINVAL;  in fscrypt_prepare_new_inode()
672 	if (!S_ISREG(inode->i_mode) &&  in fscrypt_prepare_new_inode()
673 	    !S_ISDIR(inode->i_mode) &&  in fscrypt_prepare_new_inode()
674 	    !S_ISLNK(inode->i_mode))  in fscrypt_prepare_new_inode()
682 					     S_ISDIR(inode->i_mode));  in fscrypt_prepare_new_inode()
687  * fscrypt_put_encryption_info() - free most of an inode's fscrypt data
695 	put_crypt_info(inode->i_crypt_info);  in fscrypt_put_encryption_info()
696 	inode->i_crypt_info = NULL;  in fscrypt_put_encryption_info()
701  * fscrypt_free_inode() - free an inode's fscrypt data requiring RCU delay
709 	if (IS_ENCRYPTED(inode) && S_ISLNK(inode->i_mode)) {  in fscrypt_free_inode()
710 		kfree(inode->i_link);  in fscrypt_free_inode()
711 		inode->i_link = NULL;  in fscrypt_free_inode()
717  * fscrypt_drop_inode() - check whether the inode's master key has been removed
720  * Filesystems supporting fscrypt must call this from their ->drop_inode()
734 	 * was provided via the legacy mechanism of the process-subscribed  in fscrypt_drop_inode()
737 	if (!ci || !ci->ci_master_key)  in fscrypt_drop_inode()
739 	mk = ci->ci_master_key->payload.data[0];  in fscrypt_drop_inode()
742 	 * With proper, non-racy use of FS_IOC_REMOVE_ENCRYPTION_KEY, all inodes  in fscrypt_drop_inode()
747 	if (inode->i_state & I_DIRTY_ALL)  in fscrypt_drop_inode()
758 	return !is_master_key_secret_present(&mk->mk_secret);  in fscrypt_drop_inode()