[mirror_ubuntu-artful-kernel.git] / fs / crypto / keyinfo.c

/*
 * key management facility for FS encryption support.
 *
 * Copyright (C) 2015, Google, Inc.
 *
 * This contains encryption key functions.
 *
 * Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
 */

#include <keys/user-type.h>
#include <linux/scatterlist.h>
#include "fscrypt_private.h"

static void derive_crypt_complete(struct crypto_async_request *req, int rc)
{
	struct fscrypt_completion_result *ecr = req->data;

	if (rc == -EINPROGRESS)
		return;

	ecr->res = rc;
	complete(&ecr->completion);
}

/**
 * derive_key_aes() - Derive a key using AES-128-ECB
 * @deriving_key: Encryption key used for derivation.
 * @source_key:   Source key to which to apply derivation.
 * @derived_key:  Derived key.
 *
 * Return: Zero on success; non-zero otherwise.
 */
static int derive_key_aes(u8 deriving_key[FS_AES_128_ECB_KEY_SIZE],
				u8 source_key[FS_AES_256_XTS_KEY_SIZE],
				u8 derived_key[FS_AES_256_XTS_KEY_SIZE])
{
	int res = 0;
	struct skcipher_request *req = NULL;
	DECLARE_FS_COMPLETION_RESULT(ecr);
	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_WEAK_KEY);
	req = skcipher_request_alloc(tfm, GFP_NOFS);
	if (!req) {
		res = -ENOMEM;
		goto out;
	}
	skcipher_request_set_callback(req,
			CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
			derive_crypt_complete, &ecr);
	res = crypto_skcipher_setkey(tfm, deriving_key,
					FS_AES_128_ECB_KEY_SIZE);
	if (res < 0)
		goto out;

	sg_init_one(&src_sg, source_key, FS_AES_256_XTS_KEY_SIZE);
	sg_init_one(&dst_sg, derived_key, FS_AES_256_XTS_KEY_SIZE);
	skcipher_request_set_crypt(req, &src_sg, &dst_sg,
					FS_AES_256_XTS_KEY_SIZE, NULL);
	res = crypto_skcipher_encrypt(req);
	if (res == -EINPROGRESS || res == -EBUSY) {
		wait_for_completion(&ecr.completion);
		res = ecr.res;
	}
out:
	skcipher_request_free(req);
	crypto_free_skcipher(tfm);
	return res;
}

static int validate_user_key(struct fscrypt_info *crypt_info,
			struct fscrypt_context *ctx, u8 *raw_key,
			u8 *prefix, int prefix_size)
{
	u8 *full_key_descriptor;
	struct key *keyring_key;
	struct fscrypt_key *master_key;
	const struct user_key_payload *ukp;
	int full_key_len = prefix_size + (FS_KEY_DESCRIPTOR_SIZE * 2) + 1;
	int res;

	full_key_descriptor = kmalloc(full_key_len, GFP_NOFS);
	if (!full_key_descriptor)
		return -ENOMEM;

	memcpy(full_key_descriptor, prefix, prefix_size);
	sprintf(full_key_descriptor + prefix_size,
			"%*phN", FS_KEY_DESCRIPTOR_SIZE,
			ctx->master_key_descriptor);
	full_key_descriptor[full_key_len - 1] = '\0';
	keyring_key = request_key(&key_type_logon, full_key_descriptor, NULL);
	kfree(full_key_descriptor);
	if (IS_ERR(keyring_key))
		return PTR_ERR(keyring_key);

	if (keyring_key->type != &key_type_logon) {
		printk_once(KERN_WARNING
				"%s: key type must be logon\n", __func__);
		res = -ENOKEY;
		goto out;
	}
	down_read(&keyring_key->sem);
	ukp = user_key_payload(keyring_key);
	if (ukp->datalen != sizeof(struct fscrypt_key)) {
		res = -EINVAL;
		up_read(&keyring_key->sem);
		goto out;
	}
	master_key = (struct fscrypt_key *)ukp->data;
	BUILD_BUG_ON(FS_AES_128_ECB_KEY_SIZE != FS_KEY_DERIVATION_NONCE_SIZE);

	if (master_key->size != FS_AES_256_XTS_KEY_SIZE) {
		printk_once(KERN_WARNING
				"%s: key size incorrect: %d\n",
				__func__, master_key->size);
		res = -ENOKEY;
		up_read(&keyring_key->sem);
		goto out;
	}
	res = derive_key_aes(ctx->nonce, master_key->raw, raw_key);
	up_read(&keyring_key->sem);
	if (res)
		goto out;

	crypt_info->ci_keyring_key = keyring_key;
	return 0;
out:
	key_put(keyring_key);
	return res;
}

static int determine_cipher_type(struct fscrypt_info *ci, struct inode *inode,
				 const char **cipher_str_ret, int *keysize_ret)
{
	if (S_ISREG(inode->i_mode)) {
		if (ci->ci_data_mode == FS_ENCRYPTION_MODE_AES_256_XTS) {
			*cipher_str_ret = "xts(aes)";
			*keysize_ret = FS_AES_256_XTS_KEY_SIZE;
			return 0;
		}
		pr_warn_once("fscrypto: unsupported contents encryption mode "
			     "%d for inode %lu\n",
			     ci->ci_data_mode, inode->i_ino);
		return -ENOKEY;
	}

	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) {
		if (ci->ci_filename_mode == FS_ENCRYPTION_MODE_AES_256_CTS) {
			*cipher_str_ret = "cts(cbc(aes))";
			*keysize_ret = FS_AES_256_CTS_KEY_SIZE;
			return 0;
		}
		pr_warn_once("fscrypto: unsupported filenames encryption mode "
			     "%d for inode %lu\n",
			     ci->ci_filename_mode, inode->i_ino);
		return -ENOKEY;
	}

	pr_warn_once("fscrypto: unsupported file type %d for inode %lu\n",
		     (inode->i_mode & S_IFMT), inode->i_ino);
	return -ENOKEY;
}

static void put_crypt_info(struct fscrypt_info *ci)
{
	if (!ci)
		return;

	key_put(ci->ci_keyring_key);
	crypto_free_skcipher(ci->ci_ctfm);
	kmem_cache_free(fscrypt_info_cachep, ci);
}

int fscrypt_get_crypt_info(struct inode *inode)
{
	struct fscrypt_info *crypt_info;
	struct fscrypt_context ctx;
	struct crypto_skcipher *ctfm;
	const char *cipher_str;
	int keysize;
	u8 *raw_key = NULL;
	int res;

	res = fscrypt_initialize(inode->i_sb->s_cop->flags);
	if (res)
		return res;

	if (!inode->i_sb->s_cop->get_context)
		return -EOPNOTSUPP;
retry:
	crypt_info = ACCESS_ONCE(inode->i_crypt_info);
	if (crypt_info) {
		if (!crypt_info->ci_keyring_key ||
				key_validate(crypt_info->ci_keyring_key) == 0)
			return 0;
		fscrypt_put_encryption_info(inode, crypt_info);
		goto retry;
	}

	res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
	if (res < 0) {
		if (!fscrypt_dummy_context_enabled(inode))
			return res;
		ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
		ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
		ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
		ctx.flags = 0;
	} else if (res != sizeof(ctx)) {
		return -EINVAL;
	}

	if (ctx.format != FS_ENCRYPTION_CONTEXT_FORMAT_V1)
		return -EINVAL;

	if (ctx.flags & ~FS_POLICY_FLAGS_VALID)
		return -EINVAL;

	crypt_info = kmem_cache_alloc(fscrypt_info_cachep, GFP_NOFS);
	if (!crypt_info)
		return -ENOMEM;

	crypt_info->ci_flags = ctx.flags;
	crypt_info->ci_data_mode = ctx.contents_encryption_mode;
	crypt_info->ci_filename_mode = ctx.filenames_encryption_mode;
	crypt_info->ci_ctfm = NULL;
	crypt_info->ci_keyring_key = NULL;
	memcpy(crypt_info->ci_master_key, ctx.master_key_descriptor,
				sizeof(crypt_info->ci_master_key));

	res = determine_cipher_type(crypt_info, inode, &cipher_str, &keysize);
	if (res)
		goto out;

	/*
	 * This cannot be a stack buffer because it is passed to the scatterlist
	 * crypto API as part of key derivation.
	 */
	res = -ENOMEM;
	raw_key = kmalloc(FS_MAX_KEY_SIZE, GFP_NOFS);
	if (!raw_key)
		goto out;

	if (fscrypt_dummy_context_enabled(inode)) {
		memset(raw_key, 0x42, keysize/2);
		memset(raw_key+keysize/2, 0x24, keysize - (keysize/2));
		goto got_key;
	}

	res = validate_user_key(crypt_info, &ctx, raw_key,
			FS_KEY_DESC_PREFIX, FS_KEY_DESC_PREFIX_SIZE);
	if (res && inode->i_sb->s_cop->key_prefix) {
		u8 *prefix = NULL;
		int prefix_size, res2;

		prefix_size = inode->i_sb->s_cop->key_prefix(inode, &prefix);
		res2 = validate_user_key(crypt_info, &ctx, raw_key,
							prefix, prefix_size);
		if (res2) {
			if (res2 == -ENOKEY)
				res = -ENOKEY;
			goto out;
		}
	} else if (res) {
		goto out;
	}
got_key:
	ctfm = crypto_alloc_skcipher(cipher_str, 0, 0);
	if (!ctfm || IS_ERR(ctfm)) {
		res = ctfm ? PTR_ERR(ctfm) : -ENOMEM;
		printk(KERN_DEBUG
		       "%s: error %d (inode %u) allocating crypto tfm\n",
		       __func__, res, (unsigned) inode->i_ino);
		goto out;
	}
	crypt_info->ci_ctfm = ctfm;
	crypto_skcipher_clear_flags(ctfm, ~0);
	crypto_skcipher_set_flags(ctfm, CRYPTO_TFM_REQ_WEAK_KEY);
	res = crypto_skcipher_setkey(ctfm, raw_key, keysize);
	if (res)
		goto out;

	kzfree(raw_key);
	raw_key = NULL;
	if (cmpxchg(&inode->i_crypt_info, NULL, crypt_info) != NULL) {
		put_crypt_info(crypt_info);
		goto retry;
	}
	return 0;

out:
	if (res == -ENOKEY)
		res = 0;
	put_crypt_info(crypt_info);
	kzfree(raw_key);
	return res;
}

void fscrypt_put_encryption_info(struct inode *inode, struct fscrypt_info *ci)
{
	struct fscrypt_info *prev;

	if (ci == NULL)
		ci = ACCESS_ONCE(inode->i_crypt_info);
	if (ci == NULL)
		return;

	prev = cmpxchg(&inode->i_crypt_info, ci, NULL);
	if (prev != ci)
		return;

	put_crypt_info(ci);
}
EXPORT_SYMBOL(fscrypt_put_encryption_info);

int fscrypt_get_encryption_info(struct inode *inode)
{
	struct fscrypt_info *ci = inode->i_crypt_info;

	if (!ci ||
		(ci->ci_keyring_key &&
		 (ci->ci_keyring_key->flags & ((1 << KEY_FLAG_INVALIDATED) |
					       (1 << KEY_FLAG_REVOKED) |
					       (1 << KEY_FLAG_DEAD)))))
		return fscrypt_get_crypt_info(inode);
	return 0;
}
EXPORT_SYMBOL(fscrypt_get_encryption_info);
Commit	Line	Data
0adda907	1	/*
0b81d077	2	* key management facility for FS encryption support.
0adda907 JK	3	*
	4	* Copyright (C) 2015, Google, Inc.
	5	*
0b81d077	6	* This contains encryption key functions.
0adda907 JK	7	*
	8	* Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
	9	*/
0b81d077	10
0adda907	11	#include <keys/user-type.h>
0adda907	12	#include <linux/scatterlist.h>
3325bea5	13	#include "fscrypt_private.h"
0adda907 JK	14
	15	static void derive_crypt_complete(struct crypto_async_request *req, int rc)
	16	{
0b81d077	17	struct fscrypt_completion_result *ecr = req->data;
0adda907 JK	18
	19	if (rc == -EINPROGRESS)
	20	return;
	21
	22	ecr->res = rc;
	23	complete(&ecr->completion);
	24	}
	25
	26	/**
0b81d077	27	* derive_key_aes() - Derive a key using AES-128-ECB
0fac2d50	28	* @deriving_key: Encryption key used for derivation.
0adda907 JK	29	* @source_key: Source key to which to apply derivation.
	30	* @derived_key: Derived key.
	31	*
	32	* Return: Zero on success; non-zero otherwise.
	33	*/
0b81d077 JK	34	static int derive_key_aes(u8 deriving_key[FS_AES_128_ECB_KEY_SIZE],
	35	u8 source_key[FS_AES_256_XTS_KEY_SIZE],
	36	u8 derived_key[FS_AES_256_XTS_KEY_SIZE])
0adda907 JK	37	{
0adda907 JK	38	int res = 0;
d407574e	39	struct skcipher_request *req = NULL;
0b81d077	40	DECLARE_FS_COMPLETION_RESULT(ecr);
0adda907	41	struct scatterlist src_sg, dst_sg;
d407574e	42	struct crypto_skcipher *tfm = crypto_alloc_skcipher("ecb(aes)", 0, 0);
0adda907 JK	43
	44	if (IS_ERR(tfm)) {
	45	res = PTR_ERR(tfm);
	46	tfm = NULL;
	47	goto out;
	48	}
d407574e LT	49	crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_WEAK_KEY);
d407574e LT	50	req = skcipher_request_alloc(tfm, GFP_NOFS);
0adda907 JK	51	if (!req) {
	52	res = -ENOMEM;
	53	goto out;
	54	}
d407574e	55	skcipher_request_set_callback(req,
0adda907 JK	56	CRYPTO_TFM_REQ_MAY_BACKLOG \| CRYPTO_TFM_REQ_MAY_SLEEP,
0adda907 JK	57	derive_crypt_complete, &ecr);
d407574e	58	res = crypto_skcipher_setkey(tfm, deriving_key,
0b81d077	59	FS_AES_128_ECB_KEY_SIZE);
0adda907 JK	60	if (res < 0)
	61	goto out;
	62
0b81d077 JK	63	sg_init_one(&src_sg, source_key, FS_AES_256_XTS_KEY_SIZE);
0b81d077 JK	64	sg_init_one(&dst_sg, derived_key, FS_AES_256_XTS_KEY_SIZE);
d407574e	65	skcipher_request_set_crypt(req, &src_sg, &dst_sg,
0b81d077	66	FS_AES_256_XTS_KEY_SIZE, NULL);
d407574e	67	res = crypto_skcipher_encrypt(req);
0adda907	68	if (res == -EINPROGRESS \|\| res == -EBUSY) {
0adda907 JK	69	wait_for_completion(&ecr.completion);
	70	res = ecr.res;
	71	}
	72	out:
d407574e LT	73	skcipher_request_free(req);
d407574e LT	74	crypto_free_skcipher(tfm);
0adda907 JK	75	return res;
	76	}
	77
b5a7aef1 JK	78	static int validate_user_key(struct fscrypt_info *crypt_info,
	79	struct fscrypt_context ctx, u8 raw_key,
	80	u8 *prefix, int prefix_size)
	81	{
	82	u8 *full_key_descriptor;
	83	struct key *keyring_key;
	84	struct fscrypt_key *master_key;
	85	const struct user_key_payload *ukp;
	86	int full_key_len = prefix_size + (FS_KEY_DESCRIPTOR_SIZE * 2) + 1;
	87	int res;
	88
	89	full_key_descriptor = kmalloc(full_key_len, GFP_NOFS);
	90	if (!full_key_descriptor)
	91	return -ENOMEM;
	92
	93	memcpy(full_key_descriptor, prefix, prefix_size);
	94	sprintf(full_key_descriptor + prefix_size,
	95	"%*phN", FS_KEY_DESCRIPTOR_SIZE,
	96	ctx->master_key_descriptor);
	97	full_key_descriptor[full_key_len - 1] = '\0';
	98	keyring_key = request_key(&key_type_logon, full_key_descriptor, NULL);
	99	kfree(full_key_descriptor);
	100	if (IS_ERR(keyring_key))
	101	return PTR_ERR(keyring_key);
	102
	103	if (keyring_key->type != &key_type_logon) {
	104	printk_once(KERN_WARNING
	105	"%s: key type must be logon\n", __func__);
	106	res = -ENOKEY;
	107	goto out;
	108	}
	109	down_read(&keyring_key->sem);
	110	ukp = user_key_payload(keyring_key);
	111	if (ukp->datalen != sizeof(struct fscrypt_key)) {
	112	res = -EINVAL;
	113	up_read(&keyring_key->sem);
	114	goto out;
	115	}
	116	master_key = (struct fscrypt_key *)ukp->data;
	117	BUILD_BUG_ON(FS_AES_128_ECB_KEY_SIZE != FS_KEY_DERIVATION_NONCE_SIZE);
	118
	119	if (master_key->size != FS_AES_256_XTS_KEY_SIZE) {
	120	printk_once(KERN_WARNING
	121	"%s: key size incorrect: %d\n",
	122	__func__, master_key->size);
	123	res = -ENOKEY;
	124	up_read(&keyring_key->sem);
	125	goto out;
	126	}
	127	res = derive_key_aes(ctx->nonce, master_key->raw, raw_key);
	128	up_read(&keyring_key->sem);
	129	if (res)
	130	goto out;
	131
	132	crypt_info->ci_keyring_key = keyring_key;
	133	return 0;
	134	out:
	135	key_put(keyring_key);
	136	return res;
	137	}
	138
8f39850d EB	139	static int determine_cipher_type(struct fscrypt_info ci, struct inode inode,
	140	const char *cipher_str_ret, int keysize_ret)
	141	{
	142	if (S_ISREG(inode->i_mode)) {
	143	if (ci->ci_data_mode == FS_ENCRYPTION_MODE_AES_256_XTS) {
	144	*cipher_str_ret = "xts(aes)";
	145	*keysize_ret = FS_AES_256_XTS_KEY_SIZE;
	146	return 0;
	147	}
	148	pr_warn_once("fscrypto: unsupported contents encryption mode "
	149	"%d for inode %lu\n",
	150	ci->ci_data_mode, inode->i_ino);
	151	return -ENOKEY;
	152	}
	153
	154	if (S_ISDIR(inode->i_mode) \|\| S_ISLNK(inode->i_mode)) {
	155	if (ci->ci_filename_mode == FS_ENCRYPTION_MODE_AES_256_CTS) {
	156	*cipher_str_ret = "cts(cbc(aes))";
	157	*keysize_ret = FS_AES_256_CTS_KEY_SIZE;
	158	return 0;
	159	}
	160	pr_warn_once("fscrypto: unsupported filenames encryption mode "
	161	"%d for inode %lu\n",
	162	ci->ci_filename_mode, inode->i_ino);
	163	return -ENOKEY;
	164	}
	165
	166	pr_warn_once("fscrypto: unsupported file type %d for inode %lu\n",
	167	(inode->i_mode & S_IFMT), inode->i_ino);
	168	return -ENOKEY;
	169	}
	170
0b81d077	171	static void put_crypt_info(struct fscrypt_info *ci)
0adda907	172	{
0adda907 JK	173	if (!ci)
	174	return;
	175
d407574e LT	176	key_put(ci->ci_keyring_key);
d407574e LT	177	crypto_free_skcipher(ci->ci_ctfm);
0b81d077	178	kmem_cache_free(fscrypt_info_cachep, ci);
0adda907 JK	179	}
0adda907 JK	180
3325bea5	181	int fscrypt_get_crypt_info(struct inode *inode)
0adda907	182	{
0b81d077	183	struct fscrypt_info *crypt_info;
0b81d077	184	struct fscrypt_context ctx;
d407574e	185	struct crypto_skcipher *ctfm;
26bf3dc7	186	const char *cipher_str;
8f39850d	187	int keysize;
a6e08912	188	u8 *raw_key = NULL;
0adda907 JK	189	int res;
0adda907 JK	190
f32d7ac2	191	res = fscrypt_initialize(inode->i_sb->s_cop->flags);
cfc4d971 JK	192	if (res)
cfc4d971 JK	193	return res;
0b81d077 JK	194
	195	if (!inode->i_sb->s_cop->get_context)
	196	return -EOPNOTSUPP;
26bf3dc7	197	retry:
0b81d077	198	crypt_info = ACCESS_ONCE(inode->i_crypt_info);
26bf3dc7 JK	199	if (crypt_info) {
	200	if (!crypt_info->ci_keyring_key \|\|
	201	key_validate(crypt_info->ci_keyring_key) == 0)
0adda907	202	return 0;
0b81d077	203	fscrypt_put_encryption_info(inode, crypt_info);
26bf3dc7	204	goto retry;
0adda907 JK	205	}
0adda907 JK	206
0b81d077 JK	207	res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
	208	if (res < 0) {
	209	if (!fscrypt_dummy_context_enabled(inode))
	210	return res;
8f39850d	211	ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
0b81d077 JK	212	ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
	213	ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
	214	ctx.flags = 0;
	215	} else if (res != sizeof(ctx)) {
0adda907	216	return -EINVAL;
0b81d077	217	}
8f39850d EB	218
	219	if (ctx.format != FS_ENCRYPTION_CONTEXT_FORMAT_V1)
	220	return -EINVAL;
	221
	222	if (ctx.flags & ~FS_POLICY_FLAGS_VALID)
	223	return -EINVAL;
0adda907	224
0b81d077	225	crypt_info = kmem_cache_alloc(fscrypt_info_cachep, GFP_NOFS);
0adda907 JK	226	if (!crypt_info)
	227	return -ENOMEM;
	228
	229	crypt_info->ci_flags = ctx.flags;
	230	crypt_info->ci_data_mode = ctx.contents_encryption_mode;
	231	crypt_info->ci_filename_mode = ctx.filenames_encryption_mode;
	232	crypt_info->ci_ctfm = NULL;
26bf3dc7	233	crypt_info->ci_keyring_key = NULL;
0adda907 JK	234	memcpy(crypt_info->ci_master_key, ctx.master_key_descriptor,
0adda907 JK	235	sizeof(crypt_info->ci_master_key));
640778fb	236
8f39850d EB	237	res = determine_cipher_type(crypt_info, inode, &cipher_str, &keysize);
8f39850d EB	238	if (res)
26bf3dc7	239	goto out;
8f39850d	240
a6e08912 EB	241	/*
	242	* This cannot be a stack buffer because it is passed to the scatterlist
	243	* crypto API as part of key derivation.
	244	*/
	245	res = -ENOMEM;
	246	raw_key = kmalloc(FS_MAX_KEY_SIZE, GFP_NOFS);
	247	if (!raw_key)
	248	goto out;
	249
0b81d077	250	if (fscrypt_dummy_context_enabled(inode)) {
fe4f6c80 TT	251	memset(raw_key, 0x42, keysize/2);
fe4f6c80 TT	252	memset(raw_key+keysize/2, 0x24, keysize - (keysize/2));
0b81d077 JK	253	goto got_key;
0b81d077 JK	254	}
0b81d077	255
b5a7aef1 JK	256	res = validate_user_key(crypt_info, &ctx, raw_key,
	257	FS_KEY_DESC_PREFIX, FS_KEY_DESC_PREFIX_SIZE);
	258	if (res && inode->i_sb->s_cop->key_prefix) {
	259	u8 *prefix = NULL;
	260	int prefix_size, res2;
	261
	262	prefix_size = inode->i_sb->s_cop->key_prefix(inode, &prefix);
	263	res2 = validate_user_key(crypt_info, &ctx, raw_key,
	264	prefix, prefix_size);
	265	if (res2) {
	266	if (res2 == -ENOKEY)
	267	res = -ENOKEY;
	268	goto out;
	269	}
	270	} else if (res) {
66aa3e12 JK	271	goto out;
66aa3e12 JK	272	}
0b81d077	273	got_key:
d407574e	274	ctfm = crypto_alloc_skcipher(cipher_str, 0, 0);
26bf3dc7 JK	275	if (!ctfm \|\| IS_ERR(ctfm)) {
	276	res = ctfm ? PTR_ERR(ctfm) : -ENOMEM;
	277	printk(KERN_DEBUG
	278	"%s: error %d (inode %u) allocating crypto tfm\n",
	279	__func__, res, (unsigned) inode->i_ino);
	280	goto out;
0adda907	281	}
26bf3dc7	282	crypt_info->ci_ctfm = ctfm;
d407574e LT	283	crypto_skcipher_clear_flags(ctfm, ~0);
d407574e LT	284	crypto_skcipher_set_flags(ctfm, CRYPTO_TFM_REQ_WEAK_KEY);
8f39850d	285	res = crypto_skcipher_setkey(ctfm, raw_key, keysize);
26bf3dc7 JK	286	if (res)
	287	goto out;
	288
a6e08912 EB	289	kzfree(raw_key);
a6e08912 EB	290	raw_key = NULL;
0b81d077 JK	291	if (cmpxchg(&inode->i_crypt_info, NULL, crypt_info) != NULL) {
0b81d077 JK	292	put_crypt_info(crypt_info);
26bf3dc7 JK	293	goto retry;
	294	}
	295	return 0;
	296
	297	out:
0b81d077	298	if (res == -ENOKEY)
26bf3dc7	299	res = 0;
0b81d077	300	put_crypt_info(crypt_info);
a6e08912	301	kzfree(raw_key);
0adda907 JK	302	return res;
	303	}
	304
0b81d077	305	void fscrypt_put_encryption_info(struct inode inode, struct fscrypt_info ci)
0adda907	306	{
0b81d077 JK	307	struct fscrypt_info *prev;
	308
	309	if (ci == NULL)
	310	ci = ACCESS_ONCE(inode->i_crypt_info);
	311	if (ci == NULL)
	312	return;
0adda907	313
0b81d077 JK	314	prev = cmpxchg(&inode->i_crypt_info, ci, NULL);
	315	if (prev != ci)
	316	return;
	317
	318	put_crypt_info(ci);
	319	}
	320	EXPORT_SYMBOL(fscrypt_put_encryption_info);
	321
	322	int fscrypt_get_encryption_info(struct inode *inode)
	323	{
	324	struct fscrypt_info *ci = inode->i_crypt_info;
	325
	326	if (!ci \|\|
	327	(ci->ci_keyring_key &&
	328	(ci->ci_keyring_key->flags & ((1 << KEY_FLAG_INVALIDATED) \|
	329	(1 << KEY_FLAG_REVOKED) \|
	330	(1 << KEY_FLAG_DEAD)))))
3325bea5	331	return fscrypt_get_crypt_info(inode);
0b81d077	332	return 0;
0adda907	333	}
0b81d077	334	EXPORT_SYMBOL(fscrypt_get_encryption_info);