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))",
59 	if (S_ISREG(inode->i_mode))  in select_encryption_mode()
62 	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))  in select_encryption_mode()
66 		  inode->i_ino, (inode->i_mode & S_IFMT));  in select_encryption_mode()
67 	return ERR_PTR(-EINVAL);  in select_encryption_mode()
78 	tfm = crypto_alloc_skcipher(mode->cipher_str, 0, 0);  in fscrypt_allocate_skcipher()
80 		if (PTR_ERR(tfm) == -ENOENT) {  in fscrypt_allocate_skcipher()
83 				     mode->friendly_name, mode->cipher_str);  in fscrypt_allocate_skcipher()
84 			return ERR_PTR(-ENOPKG);  in fscrypt_allocate_skcipher()
87 			    mode->cipher_str, PTR_ERR(tfm));  in fscrypt_allocate_skcipher()
90 	if (!xchg(&mode->logged_impl_name, 1)) {  in fscrypt_allocate_skcipher()
94 		 * performance problems by logging the ->cra_driver_name the  in fscrypt_allocate_skcipher()
98 			mode->friendly_name, crypto_skcipher_driver_name(tfm));  in fscrypt_allocate_skcipher()
100 	if (WARN_ON(crypto_skcipher_ivsize(tfm) != mode->ivsize)) {  in fscrypt_allocate_skcipher()
101 		err = -EINVAL;  in fscrypt_allocate_skcipher()
105 	err = crypto_skcipher_setkey(tfm, raw_key, mode->keysize);  in fscrypt_allocate_skcipher()
117  * Prepare the crypto transform object or blk-crypto key in @prep_key, given the
119  * (fs-layer or blk-crypto) will be used.
129 	tfm = fscrypt_allocate_skcipher(ci->ci_mode, raw_key, ci->ci_inode);  in fscrypt_prepare_key()
134 	 * I.e., here we publish ->tfm with a RELEASE barrier so that  in fscrypt_prepare_key()
136 	 * possible for per-mode keys, not for per-file keys.  in fscrypt_prepare_key()
138 	smp_store_release(&prep_key->tfm, tfm);  in fscrypt_prepare_key()
142 /* Destroy a crypto transform object and/or blk-crypto key. */
145 	crypto_free_skcipher(prep_key->tfm);  in fscrypt_destroy_prepared_key()
149 /* Given a per-file encryption key, set up the file's crypto transform object */
152 	ci->ci_owns_key = true;  in fscrypt_set_per_file_enc_key()
153 	return fscrypt_prepare_key(&ci->ci_enc_key, raw_key, ci);  in fscrypt_set_per_file_enc_key()
161 	const struct inode *inode = ci->ci_inode;  in setup_per_mode_enc_key()
162 	const struct super_block *sb = inode->i_sb;  in setup_per_mode_enc_key()
163 	struct fscrypt_mode *mode = ci->ci_mode;  in setup_per_mode_enc_key()
164 	const u8 mode_num = mode - fscrypt_modes;  in setup_per_mode_enc_key()
167 	u8 hkdf_info[sizeof(mode_num) + sizeof(sb->s_uuid)];  in setup_per_mode_enc_key()
172 		return -EINVAL;  in setup_per_mode_enc_key()
176 		ci->ci_enc_key = *prep_key;  in setup_per_mode_enc_key()
186 	BUILD_BUG_ON(sizeof(sb->s_uuid) != 16);  in setup_per_mode_enc_key()
190 		memcpy(&hkdf_info[hkdf_infolen], &sb->s_uuid,  in setup_per_mode_enc_key()
191 		       sizeof(sb->s_uuid));  in setup_per_mode_enc_key()
192 		hkdf_infolen += sizeof(sb->s_uuid);  in setup_per_mode_enc_key()
194 	err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf,  in setup_per_mode_enc_key()
196 				  mode_key, mode->keysize);  in setup_per_mode_enc_key()
200 	memzero_explicit(mode_key, mode->keysize);  in setup_per_mode_enc_key()
204 	ci->ci_enc_key = *prep_key;  in setup_per_mode_enc_key()
216 	err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf, HKDF_CONTEXT_DIRHASH_KEY,  in fscrypt_derive_dirhash_key()
217 				  ci->ci_nonce, FSCRYPT_FILE_NONCE_SIZE,  in fscrypt_derive_dirhash_key()
218 				  (u8 *)&ci->ci_dirhash_key,  in fscrypt_derive_dirhash_key()
219 				  sizeof(ci->ci_dirhash_key));  in fscrypt_derive_dirhash_key()
222 	ci->ci_dirhash_key_initialized = true;  in fscrypt_derive_dirhash_key()
229 	WARN_ON(ci->ci_inode->i_ino == 0);  in fscrypt_hash_inode_number()
230 	WARN_ON(!mk->mk_ino_hash_key_initialized);  in fscrypt_hash_inode_number()
232 	ci->ci_hashed_ino = (u32)siphash_1u64(ci->ci_inode->i_ino,  in fscrypt_hash_inode_number()
233 					      &mk->mk_ino_hash_key);  in fscrypt_hash_inode_number()
241 	err = setup_per_mode_enc_key(ci, mk, mk->mk_iv_ino_lblk_32_keys,  in fscrypt_setup_iv_ino_lblk_32_key()
247 	if (!smp_load_acquire(&mk->mk_ino_hash_key_initialized)) {  in fscrypt_setup_iv_ino_lblk_32_key()
251 		if (mk->mk_ino_hash_key_initialized)  in fscrypt_setup_iv_ino_lblk_32_key()
254 		err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf,  in fscrypt_setup_iv_ino_lblk_32_key()
256 					  (u8 *)&mk->mk_ino_hash_key,  in fscrypt_setup_iv_ino_lblk_32_key()
257 					  sizeof(mk->mk_ino_hash_key));  in fscrypt_setup_iv_ino_lblk_32_key()
261 		smp_store_release(&mk->mk_ino_hash_key_initialized, true);  in fscrypt_setup_iv_ino_lblk_32_key()
272 	if (ci->ci_inode->i_ino)  in fscrypt_setup_iv_ino_lblk_32_key()
283 	if (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) {  in fscrypt_setup_v2_file_key()
285 		 * DIRECT_KEY: instead of deriving per-file encryption keys, the  in fscrypt_setup_v2_file_key()
286 		 * per-file nonce will be included in all the IVs.  But unlike  in fscrypt_setup_v2_file_key()
288 		 * with the master key directly but rather derive a per-mode  in fscrypt_setup_v2_file_key()
292 		err = setup_per_mode_enc_key(ci, mk, mk->mk_direct_keys,  in fscrypt_setup_v2_file_key()
294 	} else if (ci->ci_policy.v2.flags &  in fscrypt_setup_v2_file_key()
302 		err = setup_per_mode_enc_key(ci, mk, mk->mk_iv_ino_lblk_64_keys,  in fscrypt_setup_v2_file_key()
305 	} else if (ci->ci_policy.v2.flags &  in fscrypt_setup_v2_file_key()
311 		err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf,  in fscrypt_setup_v2_file_key()
313 					  ci->ci_nonce, FSCRYPT_FILE_NONCE_SIZE,  in fscrypt_setup_v2_file_key()
314 					  derived_key, ci->ci_mode->keysize);  in fscrypt_setup_v2_file_key()
319 		memzero_explicit(derived_key, ci->ci_mode->keysize);  in fscrypt_setup_v2_file_key()
337  * If the master key is found in the filesystem-level keyring, then the
339  * ->mk_secret_sem read-locked.  This is needed to ensure that only one task
340  * links the fscrypt_info into ->mk_decrypted_inodes (as multiple tasks may race
357 	switch (ci->ci_policy.version) {  in setup_file_encryption_key()
361 		       ci->ci_policy.v1.master_key_descriptor,  in setup_file_encryption_key()
367 		       ci->ci_policy.v2.master_key_identifier,  in setup_file_encryption_key()
372 		return -EINVAL;  in setup_file_encryption_key()
375 	key = fscrypt_find_master_key(ci->ci_inode->i_sb, &mk_spec);  in setup_file_encryption_key()
377 		if (key != ERR_PTR(-ENOKEY) ||  in setup_file_encryption_key()
378 		    ci->ci_policy.version != FSCRYPT_POLICY_V1)  in setup_file_encryption_key()
384 		 * to before the search of ->s_master_keys, since users  in setup_file_encryption_key()
385 		 * shouldn't be able to override filesystem-level keys.  in setup_file_encryption_key()
390 	mk = key->payload.data[0];  in setup_file_encryption_key()
391 	down_read(&mk->mk_secret_sem);  in setup_file_encryption_key()
394 	if (!is_master_key_secret_present(&mk->mk_secret)) {  in setup_file_encryption_key()
395 		err = -ENOKEY;  in setup_file_encryption_key()
405 	if (mk->mk_secret.size < ci->ci_mode->keysize) {  in setup_file_encryption_key()
410 			     mk->mk_secret.size, ci->ci_mode->keysize);  in setup_file_encryption_key()
411 		err = -ENOKEY;  in setup_file_encryption_key()
415 	switch (ci->ci_policy.version) {  in setup_file_encryption_key()
417 		err = fscrypt_setup_v1_file_key(ci, mk->mk_secret.raw);  in setup_file_encryption_key()
424 		err = -EINVAL;  in setup_file_encryption_key()
434 	up_read(&mk->mk_secret_sem);  in setup_file_encryption_key()
446 	if (ci->ci_direct_key)  in put_crypt_info()
447 		fscrypt_put_direct_key(ci->ci_direct_key);  in put_crypt_info()
448 	else if (ci->ci_owns_key)  in put_crypt_info()
449 		fscrypt_destroy_prepared_key(&ci->ci_enc_key);  in put_crypt_info()
451 	key = ci->ci_master_key;  in put_crypt_info()
453 		struct fscrypt_master_key *mk = key->payload.data[0];  in put_crypt_info()
461 		 * gets removed from ->s_master_keys.  in put_crypt_info()
463 		spin_lock(&mk->mk_decrypted_inodes_lock);  in put_crypt_info()
464 		list_del(&ci->ci_master_key_link);  in put_crypt_info()
465 		spin_unlock(&mk->mk_decrypted_inodes_lock);  in put_crypt_info()
466 		if (refcount_dec_and_test(&mk->mk_refcount))  in put_crypt_info()
485 	res = fscrypt_initialize(inode->i_sb->s_cop->flags);  in fscrypt_setup_encryption_info()
491 		return -ENOMEM;  in fscrypt_setup_encryption_info()
493 	crypt_info->ci_inode = inode;  in fscrypt_setup_encryption_info()
494 	crypt_info->ci_policy = *policy;  in fscrypt_setup_encryption_info()
495 	memcpy(crypt_info->ci_nonce, nonce, FSCRYPT_FILE_NONCE_SIZE);  in fscrypt_setup_encryption_info()
497 	mode = select_encryption_mode(&crypt_info->ci_policy, inode);  in fscrypt_setup_encryption_info()
502 	WARN_ON(mode->ivsize > FSCRYPT_MAX_IV_SIZE);  in fscrypt_setup_encryption_info()
503 	crypt_info->ci_mode = mode;  in fscrypt_setup_encryption_info()
511 	 * For existing inodes, multiple tasks may race to set ->i_crypt_info.  in fscrypt_setup_encryption_info()
513 	 * fscrypt_get_info().  I.e., here we publish ->i_crypt_info with a  in fscrypt_setup_encryption_info()
516 	if (cmpxchg_release(&inode->i_crypt_info, NULL, crypt_info) == NULL) {  in fscrypt_setup_encryption_info()
518 		 * We won the race and set ->i_crypt_info to our crypt_info.  in fscrypt_setup_encryption_info()
523 				master_key->payload.data[0];  in fscrypt_setup_encryption_info()
525 			refcount_inc(&mk->mk_refcount);  in fscrypt_setup_encryption_info()
526 			crypt_info->ci_master_key = key_get(master_key);  in fscrypt_setup_encryption_info()
527 			spin_lock(&mk->mk_decrypted_inodes_lock);  in fscrypt_setup_encryption_info()
528 			list_add(&crypt_info->ci_master_key_link,  in fscrypt_setup_encryption_info()
529 				 &mk->mk_decrypted_inodes);  in fscrypt_setup_encryption_info()
530 			spin_unlock(&mk->mk_decrypted_inodes_lock);  in fscrypt_setup_encryption_info()
537 		struct fscrypt_master_key *mk = master_key->payload.data[0];  in fscrypt_setup_encryption_info()
539 		up_read(&mk->mk_secret_sem);  in fscrypt_setup_encryption_info()
547  * fscrypt_get_encryption_info() - set up an inode's encryption key
550  * Set up ->i_crypt_info, if it hasn't already been done.
552  * Note: unless ->i_crypt_info is already set, this isn't %GFP_NOFS-safe.  So
555  * Return: 0 if ->i_crypt_info was set or was already set, *or* if the
557  *	   distinguish these cases.)  Also can return another -errno code.
568 	res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));  in fscrypt_get_encryption_info()
582 		return -EINVAL;  in fscrypt_get_encryption_info()
587 					    S_ISDIR(inode->i_mode));  in fscrypt_get_encryption_info()
588 	if (res == -ENOKEY)  in fscrypt_get_encryption_info()
595  * fscrypt_prepare_new_inode() - prepare to create a new inode in a directory
596  * @dir: a possibly-encrypted directory
597  * @inode: the new inode.  ->i_mode must be set already.
598  *	   ->i_ino doesn't need to be set yet.
601  * If the directory is encrypted, set up its ->i_crypt_info in preparation for
603  * encrypted, set up its ->i_crypt_info and set *encrypt_ret=true.
605  * This isn't %GFP_NOFS-safe, and therefore it should be called before starting
606  * any filesystem transaction to create the inode.  For this reason, ->i_ino
612  * Return: 0 on success, -ENOKEY if the encryption key is missing, or another
613  *	   -errno code
627 	if (WARN_ON_ONCE(inode->i_mode == 0))  in fscrypt_prepare_new_inode()
628 		return -EINVAL;  in fscrypt_prepare_new_inode()
634 	if (!S_ISREG(inode->i_mode) &&  in fscrypt_prepare_new_inode()
635 	    !S_ISDIR(inode->i_mode) &&  in fscrypt_prepare_new_inode()
636 	    !S_ISLNK(inode->i_mode))  in fscrypt_prepare_new_inode()
644 					     S_ISDIR(inode->i_mode));  in fscrypt_prepare_new_inode()
649  * fscrypt_put_encryption_info() - free most of an inode's fscrypt data
657 	put_crypt_info(inode->i_crypt_info);  in fscrypt_put_encryption_info()
658 	inode->i_crypt_info = NULL;  in fscrypt_put_encryption_info()
663  * fscrypt_free_inode() - free an inode's fscrypt data requiring RCU delay
671 	if (IS_ENCRYPTED(inode) && S_ISLNK(inode->i_mode)) {  in fscrypt_free_inode()
672 		kfree(inode->i_link);  in fscrypt_free_inode()
673 		inode->i_link = NULL;  in fscrypt_free_inode()
679  * fscrypt_drop_inode() - check whether the inode's master key has been removed
682  * Filesystems supporting fscrypt must call this from their ->drop_inode()
696 	 * was provided via the legacy mechanism of the process-subscribed  in fscrypt_drop_inode()
699 	if (!ci || !ci->ci_master_key)  in fscrypt_drop_inode()
701 	mk = ci->ci_master_key->payload.data[0];  in fscrypt_drop_inode()
704 	 * With proper, non-racy use of FS_IOC_REMOVE_ENCRYPTION_KEY, all inodes  in fscrypt_drop_inode()
709 	if (inode->i_state & I_DIRTY_ALL)  in fscrypt_drop_inode()
713 	 * Note: since we aren't holding ->mk_secret_sem, the result here can  in fscrypt_drop_inode()
720 	return !is_master_key_secret_present(&mk->mk_secret);  in fscrypt_drop_inode()