[linux-block.git] / fs / crypto / keysetup_v1.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Key setup for v1 encryption policies
 *
 * Copyright 2015, 2019 Google LLC
 */

/*
 * This file implements compatibility functions for the original encryption
 * policy version ("v1"), including:
 *
 * - Deriving per-file encryption keys using the AES-128-ECB based KDF
 *   (rather than the new method of using HKDF-SHA512)
 *
 * - Retrieving fscrypt master keys from process-subscribed keyrings
 *   (rather than the new method of using a filesystem-level keyring)
 *
 * - Handling policies with the DIRECT_KEY flag set using a master key table
 *   (rather than the new method of implementing DIRECT_KEY with per-mode keys
 *    managed alongside the master keys in the filesystem-level keyring)
 */

#include <crypto/algapi.h>
#include <crypto/skcipher.h>
#include <keys/user-type.h>
#include <linux/hashtable.h>
#include <linux/scatterlist.h>

#include "fscrypt_private.h"

/* Table of keys referenced by DIRECT_KEY policies */
static DEFINE_HASHTABLE(fscrypt_direct_keys, 6); /* 6 bits = 64 buckets */
static DEFINE_SPINLOCK(fscrypt_direct_keys_lock);

/*
 * v1 key derivation function.  This generates the derived key by encrypting the
 * master key with AES-128-ECB using the nonce as the AES key.  This provides a
 * unique derived key with sufficient entropy for each inode.  However, it's
 * nonstandard, non-extensible, doesn't evenly distribute the entropy from the
 * master key, and is trivially reversible: an attacker who compromises a
 * derived key can "decrypt" it to get back to the master key, then derive any
 * other key.  For all new code, use HKDF instead.
 *
 * The master key must be at least as long as the derived key.  If the master
 * key is longer, then only the first 'derived_keysize' bytes are used.
 */
static int derive_key_aes(const u8 *master_key,
			  const u8 nonce[FSCRYPT_FILE_NONCE_SIZE],
			  u8 *derived_key, unsigned int derived_keysize)
{
	int res = 0;
	struct skcipher_request *req = NULL;
	DECLARE_CRYPTO_WAIT(wait);
	struct scatterlist src_sg, dst_sg;
	struct crypto_skcipher *tfm = crypto_alloc_skcipher("ecb(aes)", 0, 0);

	if (IS_ERR(tfm)) {
		res = PTR_ERR(tfm);
		tfm = NULL;
		goto out;
	}
	crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
	req = skcipher_request_alloc(tfm, GFP_KERNEL);
	if (!req) {
		res = -ENOMEM;
		goto out;
	}
	skcipher_request_set_callback(req,
			CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
			crypto_req_done, &wait);
	res = crypto_skcipher_setkey(tfm, nonce, FSCRYPT_FILE_NONCE_SIZE);
	if (res < 0)
		goto out;

	sg_init_one(&src_sg, master_key, derived_keysize);
	sg_init_one(&dst_sg, derived_key, derived_keysize);
	skcipher_request_set_crypt(req, &src_sg, &dst_sg, derived_keysize,
				   NULL);
	res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);
out:
	skcipher_request_free(req);
	crypto_free_skcipher(tfm);
	return res;
}

/*
 * Search the current task's subscribed keyrings for a "logon" key with
 * description prefix:descriptor, and if found acquire a read lock on it and
 * return a pointer to its validated payload in *payload_ret.
 */
static struct key *
find_and_lock_process_key(const char *prefix,
			  const u8 descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE],
			  unsigned int min_keysize,
			  const struct fscrypt_key **payload_ret)
{
	char *description;
	struct key *key;
	const struct user_key_payload *ukp;
	const struct fscrypt_key *payload;

	description = kasprintf(GFP_KERNEL, "%s%*phN", prefix,
				FSCRYPT_KEY_DESCRIPTOR_SIZE, descriptor);
	if (!description)
		return ERR_PTR(-ENOMEM);

	key = request_key(&key_type_logon, description, NULL);
	kfree(description);
	if (IS_ERR(key))
		return key;

	down_read(&key->sem);
	ukp = user_key_payload_locked(key);

	if (!ukp) /* was the key revoked before we acquired its semaphore? */
		goto invalid;

	payload = (const struct fscrypt_key *)ukp->data;

	if (ukp->datalen != sizeof(struct fscrypt_key) ||
	    payload->size < 1 || payload->size > FSCRYPT_MAX_KEY_SIZE) {
		fscrypt_warn(NULL,
			     "key with description '%s' has invalid payload",
			     key->description);
		goto invalid;
	}

	if (payload->size < min_keysize) {
		fscrypt_warn(NULL,
			     "key with description '%s' is too short (got %u bytes, need %u+ bytes)",
			     key->description, payload->size, min_keysize);
		goto invalid;
	}

	*payload_ret = payload;
	return key;

invalid:
	up_read(&key->sem);
	key_put(key);
	return ERR_PTR(-ENOKEY);
}

/* Master key referenced by DIRECT_KEY policy */
struct fscrypt_direct_key {
	struct hlist_node		dk_node;
	refcount_t			dk_refcount;
	const struct fscrypt_mode	*dk_mode;
	struct fscrypt_prepared_key	dk_key;
	u8				dk_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
	u8				dk_raw[FSCRYPT_MAX_KEY_SIZE];
};

static void free_direct_key(struct fscrypt_direct_key *dk)
{
	if (dk) {
		fscrypt_destroy_prepared_key(&dk->dk_key);
		kfree_sensitive(dk);
	}
}

void fscrypt_put_direct_key(struct fscrypt_direct_key *dk)
{
	if (!refcount_dec_and_lock(&dk->dk_refcount, &fscrypt_direct_keys_lock))
		return;
	hash_del(&dk->dk_node);
	spin_unlock(&fscrypt_direct_keys_lock);

	free_direct_key(dk);
}

/*
 * 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_direct_key *
find_or_insert_direct_key(struct fscrypt_direct_key *to_insert,
			  const u8 *raw_key, const struct fscrypt_info *ci)
{
	unsigned long hash_key;
	struct fscrypt_direct_key *dk;

	/*
	 * Careful: to avoid potentially leaking secret key bytes via timing
	 * information, we must key the hash table by descriptor rather than by
	 * raw key, and use crypto_memneq() when comparing raw keys.
	 */

	BUILD_BUG_ON(sizeof(hash_key) > FSCRYPT_KEY_DESCRIPTOR_SIZE);
	memcpy(&hash_key, ci->ci_policy.v1.master_key_descriptor,
	       sizeof(hash_key));

	spin_lock(&fscrypt_direct_keys_lock);
	hash_for_each_possible(fscrypt_direct_keys, dk, dk_node, hash_key) {
		if (memcmp(ci->ci_policy.v1.master_key_descriptor,
			   dk->dk_descriptor, FSCRYPT_KEY_DESCRIPTOR_SIZE) != 0)
			continue;
		if (ci->ci_mode != dk->dk_mode)
			continue;
		if (!fscrypt_is_key_prepared(&dk->dk_key, ci))
			continue;
		if (crypto_memneq(raw_key, dk->dk_raw, ci->ci_mode->keysize))
			continue;
		/* using existing tfm with same (descriptor, mode, raw_key) */
		refcount_inc(&dk->dk_refcount);
		spin_unlock(&fscrypt_direct_keys_lock);
		free_direct_key(to_insert);
		return dk;
	}
	if (to_insert)
		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_direct_key *
fscrypt_get_direct_key(const struct fscrypt_info *ci, const u8 *raw_key)
{
	struct fscrypt_direct_key *dk;
	int err;

	/* Is there already a tfm for this key? */
	dk = find_or_insert_direct_key(NULL, raw_key, ci);
	if (dk)
		return dk;

	/* Nope, allocate one. */
	dk = kzalloc(sizeof(*dk), GFP_KERNEL);
	if (!dk)
		return ERR_PTR(-ENOMEM);
	refcount_set(&dk->dk_refcount, 1);
	dk->dk_mode = ci->ci_mode;
	err = fscrypt_prepare_key(&dk->dk_key, raw_key, ci);
	if (err)
		goto err_free_dk;
	memcpy(dk->dk_descriptor, ci->ci_policy.v1.master_key_descriptor,
	       FSCRYPT_KEY_DESCRIPTOR_SIZE);
	memcpy(dk->dk_raw, raw_key, ci->ci_mode->keysize);

	return find_or_insert_direct_key(dk, raw_key, ci);

err_free_dk:
	free_direct_key(dk);
	return ERR_PTR(err);
}

/* v1 policy, DIRECT_KEY: use the master key directly */
static int setup_v1_file_key_direct(struct fscrypt_info *ci,
				    const u8 *raw_master_key)
{
	struct fscrypt_direct_key *dk;

	dk = fscrypt_get_direct_key(ci, raw_master_key);
	if (IS_ERR(dk))
		return PTR_ERR(dk);
	ci->ci_direct_key = dk;
	ci->ci_enc_key = dk->dk_key;
	return 0;
}

/* v1 policy, !DIRECT_KEY: derive the file's encryption key */
static int setup_v1_file_key_derived(struct fscrypt_info *ci,
				     const u8 *raw_master_key)
{
	u8 *derived_key;
	int err;

	/*
	 * This cannot be a stack buffer because it will be passed to the
	 * scatterlist crypto API during derive_key_aes().
	 */
	derived_key = kmalloc(ci->ci_mode->keysize, GFP_KERNEL);
	if (!derived_key)
		return -ENOMEM;

	err = derive_key_aes(raw_master_key, ci->ci_nonce,
			     derived_key, ci->ci_mode->keysize);
	if (err)
		goto out;

	err = fscrypt_set_per_file_enc_key(ci, derived_key);
out:
	kfree_sensitive(derived_key);
	return err;
}

int fscrypt_setup_v1_file_key(struct fscrypt_info *ci, const u8 *raw_master_key)
{
	if (ci->ci_policy.v1.flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY)
		return setup_v1_file_key_direct(ci, raw_master_key);
	else
		return setup_v1_file_key_derived(ci, raw_master_key);
}

int fscrypt_setup_v1_file_key_via_subscribed_keyrings(struct fscrypt_info *ci)
{
	struct key *key;
	const struct fscrypt_key *payload;
	int err;

	key = find_and_lock_process_key(FSCRYPT_KEY_DESC_PREFIX,
					ci->ci_policy.v1.master_key_descriptor,
					ci->ci_mode->keysize, &payload);
	if (key == ERR_PTR(-ENOKEY) && ci->ci_inode->i_sb->s_cop->key_prefix) {
		key = find_and_lock_process_key(ci->ci_inode->i_sb->s_cop->key_prefix,
						ci->ci_policy.v1.master_key_descriptor,
						ci->ci_mode->keysize, &payload);
	}
	if (IS_ERR(key))
		return PTR_ERR(key);

	err = fscrypt_setup_v1_file_key(ci, payload->raw);
	up_read(&key->sem);
	key_put(key);
	return err;
}
Commit	Line	Data
0109ce76 EB	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* Key setup for v1 encryption policies
	4	*
	5	* Copyright 2015, 2019 Google LLC
	6	*/
	7
	8	/*
	9	* This file implements compatibility functions for the original encryption
	10	* policy version ("v1"), including:
	11	*
f592efe7	12	* - Deriving per-file encryption keys using the AES-128-ECB based KDF
0109ce76 EB	13	* (rather than the new method of using HKDF-SHA512)
	14	*
	15	* - Retrieving fscrypt master keys from process-subscribed keyrings
	16	* (rather than the new method of using a filesystem-level keyring)
	17	*
	18	* - Handling policies with the DIRECT_KEY flag set using a master key table
	19	* (rather than the new method of implementing DIRECT_KEY with per-mode keys
	20	* managed alongside the master keys in the filesystem-level keyring)
	21	*/
	22
	23	#include <crypto/algapi.h>
	24	#include <crypto/skcipher.h>
	25	#include <keys/user-type.h>
	26	#include <linux/hashtable.h>
	27	#include <linux/scatterlist.h>
	28
	29	#include "fscrypt_private.h"
	30
	31	/* Table of keys referenced by DIRECT_KEY policies */
	32	static DEFINE_HASHTABLE(fscrypt_direct_keys, 6); /* 6 bits = 64 buckets */
	33	static DEFINE_SPINLOCK(fscrypt_direct_keys_lock);
	34
	35	/*
	36	* v1 key derivation function. This generates the derived key by encrypting the
	37	* master key with AES-128-ECB using the nonce as the AES key. This provides a
	38	* unique derived key with sufficient entropy for each inode. However, it's
	39	* nonstandard, non-extensible, doesn't evenly distribute the entropy from the
	40	* master key, and is trivially reversible: an attacker who compromises a
	41	* derived key can "decrypt" it to get back to the master key, then derive any
	42	* other key. For all new code, use HKDF instead.
	43	*
	44	* The master key must be at least as long as the derived key. If the master
	45	* key is longer, then only the first 'derived_keysize' bytes are used.
	46	*/
	47	static int derive_key_aes(const u8 *master_key,
1d6217a4	48	const u8 nonce[FSCRYPT_FILE_NONCE_SIZE],
0109ce76 EB	49	u8 *derived_key, unsigned int derived_keysize)
	50	{
	51	int res = 0;
	52	struct skcipher_request *req = NULL;
	53	DECLARE_CRYPTO_WAIT(wait);
	54	struct scatterlist src_sg, dst_sg;
	55	struct crypto_skcipher *tfm = crypto_alloc_skcipher("ecb(aes)", 0, 0);
	56
	57	if (IS_ERR(tfm)) {
	58	res = PTR_ERR(tfm);
	59	tfm = NULL;
	60	goto out;
	61	}
	62	crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
9dad5feb	63	req = skcipher_request_alloc(tfm, GFP_KERNEL);
0109ce76 EB	64	if (!req) {
	65	res = -ENOMEM;
	66	goto out;
	67	}
	68	skcipher_request_set_callback(req,
	69	CRYPTO_TFM_REQ_MAY_BACKLOG \| CRYPTO_TFM_REQ_MAY_SLEEP,
	70	crypto_req_done, &wait);
1d6217a4	71	res = crypto_skcipher_setkey(tfm, nonce, FSCRYPT_FILE_NONCE_SIZE);
0109ce76 EB	72	if (res < 0)
	73	goto out;
	74
	75	sg_init_one(&src_sg, master_key, derived_keysize);
	76	sg_init_one(&dst_sg, derived_key, derived_keysize);
	77	skcipher_request_set_crypt(req, &src_sg, &dst_sg, derived_keysize,
	78	NULL);
	79	res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);
	80	out:
	81	skcipher_request_free(req);
	82	crypto_free_skcipher(tfm);
	83	return res;
	84	}
	85
	86	/*
	87	* Search the current task's subscribed keyrings for a "logon" key with
	88	* description prefix:descriptor, and if found acquire a read lock on it and
	89	* return a pointer to its validated payload in *payload_ret.
	90	*/
	91	static struct key *
	92	find_and_lock_process_key(const char *prefix,
	93	const u8 descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE],
	94	unsigned int min_keysize,
	95	const struct fscrypt_key **payload_ret)
	96	{
	97	char *description;
	98	struct key *key;
	99	const struct user_key_payload *ukp;
	100	const struct fscrypt_key *payload;
	101
9dad5feb	102	description = kasprintf(GFP_KERNEL, "%s%*phN", prefix,
0109ce76 EB	103	FSCRYPT_KEY_DESCRIPTOR_SIZE, descriptor);
	104	if (!description)
	105	return ERR_PTR(-ENOMEM);
	106
	107	key = request_key(&key_type_logon, description, NULL);
	108	kfree(description);
	109	if (IS_ERR(key))
	110	return key;
	111
	112	down_read(&key->sem);
	113	ukp = user_key_payload_locked(key);
	114
	115	if (!ukp) /* was the key revoked before we acquired its semaphore? */
	116	goto invalid;
	117
	118	payload = (const struct fscrypt_key *)ukp->data;
	119
	120	if (ukp->datalen != sizeof(struct fscrypt_key) \|\|
	121	payload->size < 1 \|\| payload->size > FSCRYPT_MAX_KEY_SIZE) {
	122	fscrypt_warn(NULL,
	123	"key with description '%s' has invalid payload",
	124	key->description);
	125	goto invalid;
	126	}
	127
	128	if (payload->size < min_keysize) {
	129	fscrypt_warn(NULL,
	130	"key with description '%s' is too short (got %u bytes, need %u+ bytes)",
	131	key->description, payload->size, min_keysize);
	132	goto invalid;
	133	}
	134
	135	*payload_ret = payload;
	136	return key;
	137
	138	invalid:
	139	up_read(&key->sem);
	140	key_put(key);
	141	return ERR_PTR(-ENOKEY);
	142	}
	143
	144	/* Master key referenced by DIRECT_KEY policy */
	145	struct fscrypt_direct_key {
	146	struct hlist_node dk_node;
	147	refcount_t dk_refcount;
	148	const struct fscrypt_mode *dk_mode;
5fee3609	149	struct fscrypt_prepared_key dk_key;
0109ce76 EB	150	u8 dk_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
	151	u8 dk_raw[FSCRYPT_MAX_KEY_SIZE];
	152	};
	153
	154	static void free_direct_key(struct fscrypt_direct_key *dk)
	155	{
	156	if (dk) {
5fee3609	157	fscrypt_destroy_prepared_key(&dk->dk_key);
453431a5	158	kfree_sensitive(dk);
0109ce76 EB	159	}
	160	}
	161
	162	void fscrypt_put_direct_key(struct fscrypt_direct_key *dk)
	163	{
	164	if (!refcount_dec_and_lock(&dk->dk_refcount, &fscrypt_direct_keys_lock))
	165	return;
	166	hash_del(&dk->dk_node);
	167	spin_unlock(&fscrypt_direct_keys_lock);
	168
	169	free_direct_key(dk);
	170	}
	171
	172	/*
	173	* Find/insert the given key into the fscrypt_direct_keys table. If found, it
	174	* is returned with elevated refcount, and 'to_insert' is freed if non-NULL. If
	175	* not found, 'to_insert' is inserted and returned if it's non-NULL; otherwise
	176	* NULL is returned.
	177	*/
	178	static struct fscrypt_direct_key *
	179	find_or_insert_direct_key(struct fscrypt_direct_key *to_insert,
	180	const u8 raw_key, const struct fscrypt_info ci)
	181	{
	182	unsigned long hash_key;
	183	struct fscrypt_direct_key *dk;
	184
	185	/*
	186	* Careful: to avoid potentially leaking secret key bytes via timing
	187	* information, we must key the hash table by descriptor rather than by
	188	* raw key, and use crypto_memneq() when comparing raw keys.
	189	*/
	190
	191	BUILD_BUG_ON(sizeof(hash_key) > FSCRYPT_KEY_DESCRIPTOR_SIZE);
5dae460c EB	192	memcpy(&hash_key, ci->ci_policy.v1.master_key_descriptor,
5dae460c EB	193	sizeof(hash_key));
0109ce76 EB	194
	195	spin_lock(&fscrypt_direct_keys_lock);
	196	hash_for_each_possible(fscrypt_direct_keys, dk, dk_node, hash_key) {
5dae460c EB	197	if (memcmp(ci->ci_policy.v1.master_key_descriptor,
5dae460c EB	198	dk->dk_descriptor, FSCRYPT_KEY_DESCRIPTOR_SIZE) != 0)
0109ce76 EB	199	continue;
	200	if (ci->ci_mode != dk->dk_mode)
	201	continue;
5fee3609 ST	202	if (!fscrypt_is_key_prepared(&dk->dk_key, ci))
5fee3609 ST	203	continue;
0109ce76 EB	204	if (crypto_memneq(raw_key, dk->dk_raw, ci->ci_mode->keysize))
	205	continue;
	206	/* using existing tfm with same (descriptor, mode, raw_key) */
	207	refcount_inc(&dk->dk_refcount);
	208	spin_unlock(&fscrypt_direct_keys_lock);
	209	free_direct_key(to_insert);
	210	return dk;
	211	}
	212	if (to_insert)
	213	hash_add(fscrypt_direct_keys, &to_insert->dk_node, hash_key);
	214	spin_unlock(&fscrypt_direct_keys_lock);
	215	return to_insert;
	216	}
	217
	218	/* Prepare to encrypt directly using the master key in the given mode */
	219	static struct fscrypt_direct_key *
	220	fscrypt_get_direct_key(const struct fscrypt_info ci, const u8 raw_key)
	221	{
	222	struct fscrypt_direct_key *dk;
	223	int err;
	224
	225	/* Is there already a tfm for this key? */
	226	dk = find_or_insert_direct_key(NULL, raw_key, ci);
	227	if (dk)
	228	return dk;
	229
	230	/* Nope, allocate one. */
9dad5feb	231	dk = kzalloc(sizeof(*dk), GFP_KERNEL);
0109ce76 EB	232	if (!dk)
	233	return ERR_PTR(-ENOMEM);
	234	refcount_set(&dk->dk_refcount, 1);
	235	dk->dk_mode = ci->ci_mode;
5fee3609 ST	236	err = fscrypt_prepare_key(&dk->dk_key, raw_key, ci);
5fee3609 ST	237	if (err)
0109ce76	238	goto err_free_dk;
5dae460c	239	memcpy(dk->dk_descriptor, ci->ci_policy.v1.master_key_descriptor,
0109ce76 EB	240	FSCRYPT_KEY_DESCRIPTOR_SIZE);
	241	memcpy(dk->dk_raw, raw_key, ci->ci_mode->keysize);
	242
	243	return find_or_insert_direct_key(dk, raw_key, ci);
	244
	245	err_free_dk:
	246	free_direct_key(dk);
	247	return ERR_PTR(err);
	248	}
	249
	250	/* v1 policy, DIRECT_KEY: use the master key directly */
	251	static int setup_v1_file_key_direct(struct fscrypt_info *ci,
	252	const u8 *raw_master_key)
	253	{
0109ce76 EB	254	struct fscrypt_direct_key *dk;
0109ce76 EB	255
0109ce76 EB	256	dk = fscrypt_get_direct_key(ci, raw_master_key);
	257	if (IS_ERR(dk))
	258	return PTR_ERR(dk);
	259	ci->ci_direct_key = dk;
5fee3609	260	ci->ci_enc_key = dk->dk_key;
0109ce76 EB	261	return 0;
	262	}
	263
	264	/* v1 policy, !DIRECT_KEY: derive the file's encryption key */
	265	static int setup_v1_file_key_derived(struct fscrypt_info *ci,
	266	const u8 *raw_master_key)
	267	{
	268	u8 *derived_key;
	269	int err;
	270
	271	/*
	272	* This cannot be a stack buffer because it will be passed to the
	273	* scatterlist crypto API during derive_key_aes().
	274	*/
9dad5feb	275	derived_key = kmalloc(ci->ci_mode->keysize, GFP_KERNEL);
0109ce76 EB	276	if (!derived_key)
	277	return -ENOMEM;
	278
	279	err = derive_key_aes(raw_master_key, ci->ci_nonce,
	280	derived_key, ci->ci_mode->keysize);
	281	if (err)
	282	goto out;
	283
f592efe7	284	err = fscrypt_set_per_file_enc_key(ci, derived_key);
0109ce76	285	out:
453431a5	286	kfree_sensitive(derived_key);
0109ce76 EB	287	return err;
	288	}
	289
	290	int fscrypt_setup_v1_file_key(struct fscrypt_info ci, const u8 raw_master_key)
	291	{
5dae460c	292	if (ci->ci_policy.v1.flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY)
0109ce76 EB	293	return setup_v1_file_key_direct(ci, raw_master_key);
	294	else
	295	return setup_v1_file_key_derived(ci, raw_master_key);
	296	}
	297
	298	int fscrypt_setup_v1_file_key_via_subscribed_keyrings(struct fscrypt_info *ci)
	299	{
	300	struct key *key;
	301	const struct fscrypt_key *payload;
	302	int err;
	303
	304	key = find_and_lock_process_key(FSCRYPT_KEY_DESC_PREFIX,
5dae460c	305	ci->ci_policy.v1.master_key_descriptor,
0109ce76 EB	306	ci->ci_mode->keysize, &payload);
	307	if (key == ERR_PTR(-ENOKEY) && ci->ci_inode->i_sb->s_cop->key_prefix) {
	308	key = find_and_lock_process_key(ci->ci_inode->i_sb->s_cop->key_prefix,
5dae460c	309	ci->ci_policy.v1.master_key_descriptor,
0109ce76 EB	310	ci->ci_mode->keysize, &payload);
	311	}
	312	if (IS_ERR(key))
	313	return PTR_ERR(key);
	314
	315	err = fscrypt_setup_v1_file_key(ci, payload->raw);
	316	up_read(&key->sem);
	317	key_put(key);
	318	return err;
	319	}