1 // SPDX-License-Identifier: GPL-2.0
19 		.friendly_name = "AES-256-XTS",
27 		.friendly_name = "AES-256-CBC-CTS",
28 		.cipher_str = "cts(cbc(aes))",
34 		.friendly_name = "AES-128-CBC-ESSIV",
42 		.friendly_name = "AES-128-CBC-CTS",
43 		.cipher_str = "cts(cbc(aes))",
49 		.friendly_name = "SM4-XTS",
57 		.friendly_name = "SM4-CBC-CTS",
58 		.cipher_str = "cts(cbc(sm4))",
72 		.friendly_name = "AES-256-HCTR2",
88 	if (S_ISREG(inode->i_mode))  in select_encryption_mode()
91 	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))  in select_encryption_mode()
95 		  inode->i_ino, (inode->i_mode & S_IFMT));  in select_encryption_mode()
96 	return ERR_PTR(-EINVAL);  in select_encryption_mode()
107 	tfm = crypto_alloc_sync_skcipher(mode->cipher_str, 0,  in fscrypt_allocate_skcipher()
110 		if (PTR_ERR(tfm) == -ENOENT) {  in fscrypt_allocate_skcipher()
113 				     mode->friendly_name, mode->cipher_str);  in fscrypt_allocate_skcipher()
114 			return ERR_PTR(-ENOPKG);  in fscrypt_allocate_skcipher()
117 			    mode->cipher_str, PTR_ERR(tfm));  in fscrypt_allocate_skcipher()
120 	if (!xchg(&mode->logged_cryptoapi_impl, 1)) {  in fscrypt_allocate_skcipher()
124 		 * performance problems by logging the ->cra_driver_name the  in fscrypt_allocate_skcipher()
128 			mode->friendly_name,  in fscrypt_allocate_skcipher()
129 			crypto_skcipher_driver_name(&tfm->base));  in fscrypt_allocate_skcipher()
131 	if (WARN_ON_ONCE(crypto_sync_skcipher_ivsize(tfm) != mode->ivsize)) {  in fscrypt_allocate_skcipher()
132 		err = -EINVAL;  in fscrypt_allocate_skcipher()
136 	err = crypto_sync_skcipher_setkey(tfm, raw_key, mode->keysize);  in fscrypt_allocate_skcipher()
148  * Prepare the crypto transform object or blk-crypto key in @prep_key, given the
149  * raw key, encryption mode (@ci->ci_mode), flag indicating which encryption
150  * implementation (fs-layer or blk-crypto) will be used (@ci->ci_inlinecrypt),
151  * and IV generation method (@ci->ci_policy.flags).
160 							ci->ci_mode->keysize,  in fscrypt_prepare_key()
163 	tfm = fscrypt_allocate_skcipher(ci->ci_mode, raw_key, ci->ci_inode);  in fscrypt_prepare_key()
168 	 * I.e., here we publish ->tfm with a RELEASE barrier so that  in fscrypt_prepare_key()
170 	 * possible for per-mode keys, not for per-file keys.  in fscrypt_prepare_key()
172 	smp_store_release(&prep_key->tfm, tfm);  in fscrypt_prepare_key()
176 /* Destroy a crypto transform object and/or blk-crypto key. */
180 	crypto_free_sync_skcipher(prep_key->tfm);  in fscrypt_destroy_prepared_key()
185 /* Given a per-file encryption key, set up the file's crypto transform object */
189 	ci->ci_owns_key = true;  in fscrypt_set_per_file_enc_key()
190 	return fscrypt_prepare_key(&ci->ci_enc_key, raw_key, ci);  in fscrypt_set_per_file_enc_key()
198 	const struct inode *inode = ci->ci_inode;  in setup_per_mode_enc_key()
199 	const struct super_block *sb = inode->i_sb;  in setup_per_mode_enc_key()
200 	struct fscrypt_mode *mode = ci->ci_mode;  in setup_per_mode_enc_key()
201 	const u8 mode_num = mode - fscrypt_modes;  in setup_per_mode_enc_key()
204 	u8 hkdf_info[sizeof(mode_num) + sizeof(sb->s_uuid)];  in setup_per_mode_enc_key()
210 		return -EINVAL;  in setup_per_mode_enc_key()
212 	if (mk->mk_secret.is_hw_wrapped && S_ISREG(inode->i_mode)) {  in setup_per_mode_enc_key()
213 		/* Using a hardware-wrapped key for file contents encryption */  in setup_per_mode_enc_key()
215 			if (sb->s_flags & SB_INLINECRYPT)  in setup_per_mode_enc_key()
216 				fscrypt_warn(ci->ci_inode,  in setup_per_mode_enc_key()
217 …    "Hardware-wrapped key required, but no suitable inline encryption capabilities are available");  in setup_per_mode_enc_key()
219 				fscrypt_warn(ci->ci_inode,  in setup_per_mode_enc_key()
220 					     "Hardware-wrapped keys require inline encryption (-o inlinecrypt)");  in setup_per_mode_enc_key()
221 			return -EINVAL;  in setup_per_mode_enc_key()
228 		ci->ci_enc_key = *prep_key;  in setup_per_mode_enc_key()
239 						       mk->mk_secret.bytes,  in setup_per_mode_enc_key()
240 						       mk->mk_secret.size, true,  in setup_per_mode_enc_key()
248 	BUILD_BUG_ON(sizeof(sb->s_uuid) != 16);  in setup_per_mode_enc_key()
252 		memcpy(&hkdf_info[hkdf_infolen], &sb->s_uuid,  in setup_per_mode_enc_key()
253 		       sizeof(sb->s_uuid));  in setup_per_mode_enc_key()
254 		hkdf_infolen += sizeof(sb->s_uuid);  in setup_per_mode_enc_key()
256 	fscrypt_hkdf_expand(&mk->mk_secret.hkdf, hkdf_context, hkdf_info,  in setup_per_mode_enc_key()
257 			    hkdf_infolen, mode_key, mode->keysize);  in setup_per_mode_enc_key()
259 	memzero_explicit(mode_key, mode->keysize);  in setup_per_mode_enc_key()
263 	ci->ci_enc_key = *prep_key;  in setup_per_mode_enc_key()
272  * application-specific information string.
275  * as a pair of 64-bit words.  Therefore, on big endian CPUs we have to do an
282 	fscrypt_hkdf_expand(&mk->mk_secret.hkdf, context, info, infolen,  in fscrypt_derive_siphash_key()
285 	BUILD_BUG_ON(ARRAY_SIZE(key->key) != 2);  in fscrypt_derive_siphash_key()
286 	le64_to_cpus(&key->key[0]);  in fscrypt_derive_siphash_key()
287 	le64_to_cpus(&key->key[1]);  in fscrypt_derive_siphash_key()
294 				   ci->ci_nonce, FSCRYPT_FILE_NONCE_SIZE,  in fscrypt_derive_dirhash_key()
295 				   &ci->ci_dirhash_key);  in fscrypt_derive_dirhash_key()
296 	ci->ci_dirhash_key_initialized = true;  in fscrypt_derive_dirhash_key()
302 	WARN_ON_ONCE(ci->ci_inode->i_ino == 0);  in fscrypt_hash_inode_number()
303 	WARN_ON_ONCE(!mk->mk_ino_hash_key_initialized);  in fscrypt_hash_inode_number()
305 	ci->ci_hashed_ino = (u32)siphash_1u64(ci->ci_inode->i_ino,  in fscrypt_hash_inode_number()
306 					      &mk->mk_ino_hash_key);  in fscrypt_hash_inode_number()
314 	err = setup_per_mode_enc_key(ci, mk, mk->mk_iv_ino_lblk_32_keys,  in fscrypt_setup_iv_ino_lblk_32_key()
320 	if (!smp_load_acquire(&mk->mk_ino_hash_key_initialized)) {  in fscrypt_setup_iv_ino_lblk_32_key()
324 		if (mk->mk_ino_hash_key_initialized)  in fscrypt_setup_iv_ino_lblk_32_key()
328 					   NULL, 0, &mk->mk_ino_hash_key);  in fscrypt_setup_iv_ino_lblk_32_key()
330 		smp_store_release(&mk->mk_ino_hash_key_initialized, true);  in fscrypt_setup_iv_ino_lblk_32_key()
339 	if (ci->ci_inode->i_ino)  in fscrypt_setup_iv_ino_lblk_32_key()
350 	if (mk->mk_secret.is_hw_wrapped &&  in fscrypt_setup_v2_file_key()
351 	    !(ci->ci_policy.v2.flags & (FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 |  in fscrypt_setup_v2_file_key()
353 		fscrypt_warn(ci->ci_inode,  in fscrypt_setup_v2_file_key()
354 			     "Hardware-wrapped keys are only supported with IV_INO_LBLK policies");  in fscrypt_setup_v2_file_key()
355 		return -EINVAL;  in fscrypt_setup_v2_file_key()
358 	if (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) {  in fscrypt_setup_v2_file_key()
360 		 * DIRECT_KEY: instead of deriving per-file encryption keys, the  in fscrypt_setup_v2_file_key()
361 		 * per-file nonce will be included in all the IVs.  But unlike  in fscrypt_setup_v2_file_key()
363 		 * with the master key directly but rather derive a per-mode  in fscrypt_setup_v2_file_key()
367 		err = setup_per_mode_enc_key(ci, mk, mk->mk_direct_keys,  in fscrypt_setup_v2_file_key()
369 	} else if (ci->ci_policy.v2.flags &  in fscrypt_setup_v2_file_key()
377 		err = setup_per_mode_enc_key(ci, mk, mk->mk_iv_ino_lblk_64_keys,  in fscrypt_setup_v2_file_key()
380 	} else if (ci->ci_policy.v2.flags &  in fscrypt_setup_v2_file_key()
386 		fscrypt_hkdf_expand(&mk->mk_secret.hkdf,  in fscrypt_setup_v2_file_key()
388 				    ci->ci_nonce, FSCRYPT_FILE_NONCE_SIZE,  in fscrypt_setup_v2_file_key()
389 				    derived_key, ci->ci_mode->keysize);  in fscrypt_setup_v2_file_key()
391 		memzero_explicit(derived_key, ci->ci_mode->keysize);  in fscrypt_setup_v2_file_key()
413  * (but in practice we only need to consider @ci->ci_mode, since any other
415  * required key size over @ci->ci_mode).  This allows AES-256-XTS keys to be
416  * derived from a 256-bit master key, which is cryptographically sufficient,
417  * rather than requiring a 512-bit master key which is unnecessarily long.  (We
418  * still allow 512-bit master keys if the user chooses to use them, though.)
425 	if (ci->ci_policy.version == FSCRYPT_POLICY_V1)  in fscrypt_valid_master_key_size()
426 		min_keysize = ci->ci_mode->keysize;  in fscrypt_valid_master_key_size()
428 		min_keysize = ci->ci_mode->security_strength;  in fscrypt_valid_master_key_size()
430 	if (mk->mk_secret.size < min_keysize) {  in fscrypt_valid_master_key_size()
433 			     master_key_spec_type(&mk->mk_spec),  in fscrypt_valid_master_key_size()
434 			     master_key_spec_len(&mk->mk_spec),  in fscrypt_valid_master_key_size()
435 			     (u8 *)&mk->mk_spec.u,  in fscrypt_valid_master_key_size()
436 			     mk->mk_secret.size, min_keysize);  in fscrypt_valid_master_key_size()
445  * If the master key is found in the filesystem-level keyring, then it is
446  * returned in *mk_ret with its semaphore read-locked.  This is needed to ensure
447  * that only one task links the fscrypt_inode_info into ->mk_decrypted_inodes
456 	struct super_block *sb = ci->ci_inode->i_sb;  in setup_file_encryption_key()
461 	err = fscrypt_policy_to_key_spec(&ci->ci_policy, &mk_spec);  in setup_file_encryption_key()
471 		 * Add the test_dummy_encryption key on-demand.  In principle,  in setup_file_encryption_key()
477 		    fscrypt_policies_equal(dummy_policy, &ci->ci_policy)) {  in setup_file_encryption_key()
485 		if (ci->ci_policy.version != FSCRYPT_POLICY_V1)  in setup_file_encryption_key()
486 			return -ENOKEY;  in setup_file_encryption_key()
495 		 * to before the search of ->s_master_keys, since users  in setup_file_encryption_key()
496 		 * shouldn't be able to override filesystem-level keys.  in setup_file_encryption_key()
500 	down_read(&mk->mk_sem);  in setup_file_encryption_key()
502 	if (!mk->mk_present) {  in setup_file_encryption_key()
504 		err = -ENOKEY;  in setup_file_encryption_key()
509 		err = -ENOKEY;  in setup_file_encryption_key()
513 	err = fscrypt_select_encryption_impl(ci, mk->mk_secret.is_hw_wrapped);  in setup_file_encryption_key()
517 	switch (ci->ci_policy.version) {  in setup_file_encryption_key()
519 		if (WARN_ON_ONCE(mk->mk_secret.is_hw_wrapped)) {  in setup_file_encryption_key()
522 			 * that is hardware-wrapped isn't allowed.  in setup_file_encryption_key()
524 			err = -EINVAL;  in setup_file_encryption_key()
527 		err = fscrypt_setup_v1_file_key(ci, mk->mk_secret.bytes);  in setup_file_encryption_key()
534 		err = -EINVAL;  in setup_file_encryption_key()
544 	up_read(&mk->mk_sem);  in setup_file_encryption_key()
556 	if (ci->ci_direct_key)  in put_crypt_info()
557 		fscrypt_put_direct_key(ci->ci_direct_key);  in put_crypt_info()
558 	else if (ci->ci_owns_key)  in put_crypt_info()
559 		fscrypt_destroy_prepared_key(ci->ci_inode->i_sb,  in put_crypt_info()
560 					     &ci->ci_enc_key);  in put_crypt_info()
562 	mk = ci->ci_master_key;  in put_crypt_info()
570 		spin_lock(&mk->mk_decrypted_inodes_lock);  in put_crypt_info()
571 		list_del(&ci->ci_master_key_link);  in put_crypt_info()
572 		spin_unlock(&mk->mk_decrypted_inodes_lock);  in put_crypt_info()
573 		fscrypt_put_master_key_activeref(ci->ci_inode->i_sb, mk);  in put_crypt_info()
590 	res = fscrypt_initialize(inode->i_sb);  in fscrypt_setup_encryption_info()
596 		return -ENOMEM;  in fscrypt_setup_encryption_info()
598 	crypt_info->ci_inode = inode;  in fscrypt_setup_encryption_info()
599 	crypt_info->ci_policy = *policy;  in fscrypt_setup_encryption_info()
600 	memcpy(crypt_info->ci_nonce, nonce, FSCRYPT_FILE_NONCE_SIZE);  in fscrypt_setup_encryption_info()
602 	mode = select_encryption_mode(&crypt_info->ci_policy, inode);  in fscrypt_setup_encryption_info()
607 	WARN_ON_ONCE(mode->ivsize > FSCRYPT_MAX_IV_SIZE);  in fscrypt_setup_encryption_info()
608 	crypt_info->ci_mode = mode;  in fscrypt_setup_encryption_info()
610 	crypt_info->ci_data_unit_bits =  in fscrypt_setup_encryption_info()
611 		fscrypt_policy_du_bits(&crypt_info->ci_policy, inode);  in fscrypt_setup_encryption_info()
612 	crypt_info->ci_data_units_per_block_bits =  in fscrypt_setup_encryption_info()
613 		inode->i_blkbits - crypt_info->ci_data_unit_bits;  in fscrypt_setup_encryption_info()
632 			crypt_info->ci_master_key = mk;  in fscrypt_setup_encryption_info()
633 			refcount_inc(&mk->mk_active_refs);  in fscrypt_setup_encryption_info()
634 			spin_lock(&mk->mk_decrypted_inodes_lock);  in fscrypt_setup_encryption_info()
635 			list_add(&crypt_info->ci_master_key_link,  in fscrypt_setup_encryption_info()
636 				 &mk->mk_decrypted_inodes);  in fscrypt_setup_encryption_info()
637 			spin_unlock(&mk->mk_decrypted_inodes_lock);  in fscrypt_setup_encryption_info()
644 		up_read(&mk->mk_sem);  in fscrypt_setup_encryption_info()
652  * fscrypt_get_encryption_info() - set up an inode's encryption key
662  * Note: unless the key setup was already done, this isn't %GFP_NOFS-safe.  So
667  *	   distinguish these cases.)  Also can return another -errno code.
678 	res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));  in fscrypt_get_encryption_info()
680 		if (res == -ERANGE && allow_unsupported)  in fscrypt_get_encryption_info()
698 		return -EINVAL;  in fscrypt_get_encryption_info()
704 					    S_ISDIR(inode->i_mode));  in fscrypt_get_encryption_info()
706 	if (res == -ENOPKG && allow_unsupported) /* Algorithm unavailable? */  in fscrypt_get_encryption_info()
708 	if (res == -ENOKEY)  in fscrypt_get_encryption_info()
714  * fscrypt_prepare_new_inode() - prepare to create a new inode in a directory
715  * @dir: a possibly-encrypted directory
716  * @inode: the new inode.  ->i_mode and ->i_blkbits must be set already.
717  *	   ->i_ino doesn't need to be set yet.
724  * This isn't %GFP_NOFS-safe, and therefore it should be called before starting
725  * any filesystem transaction to create the inode.  For this reason, ->i_ino
731  * Return: 0 on success, -ENOKEY if a key needs to be set up for @dir or @inode
732  *	   but the needed master key is absent, or another -errno code
746 	if (WARN_ON_ONCE(inode->i_blkbits == 0))  in fscrypt_prepare_new_inode()
747 		return -EINVAL;  in fscrypt_prepare_new_inode()
749 	if (WARN_ON_ONCE(inode->i_mode == 0))  in fscrypt_prepare_new_inode()
750 		return -EINVAL;  in fscrypt_prepare_new_inode()
756 	if (!S_ISREG(inode->i_mode) &&  in fscrypt_prepare_new_inode()
757 	    !S_ISDIR(inode->i_mode) &&  in fscrypt_prepare_new_inode()
758 	    !S_ISLNK(inode->i_mode))  in fscrypt_prepare_new_inode()
766 					     S_ISDIR(inode->i_mode));  in fscrypt_prepare_new_inode()
771  * fscrypt_put_encryption_info() - free most of an inode's fscrypt data
793  * fscrypt_free_inode() - free an inode's fscrypt data requiring RCU delay
801 	if (IS_ENCRYPTED(inode) && S_ISLNK(inode->i_mode)) {  in fscrypt_free_inode()
802 		kfree(inode->i_link);  in fscrypt_free_inode()
803 		inode->i_link = NULL;  in fscrypt_free_inode()
809  * fscrypt_drop_inode() - check whether the inode's master key has been removed
812  * Filesystems supporting fscrypt must call this from their ->drop_inode()
825 	 * was provided via the legacy mechanism of the process-subscribed  in fscrypt_drop_inode()
828 	if (!ci || !ci->ci_master_key)  in fscrypt_drop_inode()
832 	 * With proper, non-racy use of FS_IOC_REMOVE_ENCRYPTION_KEY, all inodes  in fscrypt_drop_inode()
837 	if (inode->i_state & I_DIRTY_ALL)  in fscrypt_drop_inode()
841 	 * We can't take ->mk_sem here, since this runs in atomic context.  in fscrypt_drop_inode()
842 	 * Therefore, ->mk_present can change concurrently, and our result may  in fscrypt_drop_inode()
849 	return !READ_ONCE(ci->ci_master_key->mk_present);  in fscrypt_drop_inode()