2 * linux/fs/f2fs/crypto_key.c
4 * Copied from linux/fs/f2fs/crypto_key.c
6 * Copyright (C) 2015, Google, Inc.
8 * This contains encryption key functions for f2fs
10 * Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
12 #include <keys/encrypted-type.h>
13 #include <keys/user-type.h>
14 #include <linux/random.h>
15 #include <linux/scatterlist.h>
16 #include <uapi/linux/keyctl.h>
17 #include <crypto/hash.h>
18 #include <linux/f2fs_fs.h>
23 static void derive_crypt_complete(struct crypto_async_request
*req
, int rc
)
25 struct f2fs_completion_result
*ecr
= req
->data
;
27 if (rc
== -EINPROGRESS
)
31 complete(&ecr
->completion
);
35 * f2fs_derive_key_aes() - Derive a key using AES-128-ECB
36 * @deriving_key: Encryption key used for derivatio.
37 * @source_key: Source key to which to apply derivation.
38 * @derived_key: Derived key.
40 * Return: Zero on success; non-zero otherwise.
42 static int f2fs_derive_key_aes(char deriving_key
[F2FS_AES_128_ECB_KEY_SIZE
],
43 char source_key
[F2FS_AES_256_XTS_KEY_SIZE
],
44 char derived_key
[F2FS_AES_256_XTS_KEY_SIZE
])
47 struct ablkcipher_request
*req
= NULL
;
48 DECLARE_F2FS_COMPLETION_RESULT(ecr
);
49 struct scatterlist src_sg
, dst_sg
;
50 struct crypto_ablkcipher
*tfm
= crypto_alloc_ablkcipher("ecb(aes)", 0,
58 crypto_ablkcipher_set_flags(tfm
, CRYPTO_TFM_REQ_WEAK_KEY
);
59 req
= ablkcipher_request_alloc(tfm
, GFP_NOFS
);
64 ablkcipher_request_set_callback(req
,
65 CRYPTO_TFM_REQ_MAY_BACKLOG
| CRYPTO_TFM_REQ_MAY_SLEEP
,
66 derive_crypt_complete
, &ecr
);
67 res
= crypto_ablkcipher_setkey(tfm
, deriving_key
,
68 F2FS_AES_128_ECB_KEY_SIZE
);
72 sg_init_one(&src_sg
, source_key
, F2FS_AES_256_XTS_KEY_SIZE
);
73 sg_init_one(&dst_sg
, derived_key
, F2FS_AES_256_XTS_KEY_SIZE
);
74 ablkcipher_request_set_crypt(req
, &src_sg
, &dst_sg
,
75 F2FS_AES_256_XTS_KEY_SIZE
, NULL
);
76 res
= crypto_ablkcipher_encrypt(req
);
77 if (res
== -EINPROGRESS
|| res
== -EBUSY
) {
78 BUG_ON(req
->base
.data
!= &ecr
);
79 wait_for_completion(&ecr
.completion
);
84 ablkcipher_request_free(req
);
86 crypto_free_ablkcipher(tfm
);
90 void f2fs_free_encryption_info(struct inode
*inode
)
92 struct f2fs_inode_info
*fi
= F2FS_I(inode
);
93 struct f2fs_crypt_info
*ci
= fi
->i_crypt_info
;
98 if (ci
->ci_keyring_key
)
99 key_put(ci
->ci_keyring_key
);
100 crypto_free_ablkcipher(ci
->ci_ctfm
);
101 memzero_explicit(&ci
->ci_raw
, sizeof(ci
->ci_raw
));
103 fi
->i_crypt_info
= NULL
;
106 int _f2fs_get_encryption_info(struct inode
*inode
)
108 struct f2fs_inode_info
*fi
= F2FS_I(inode
);
109 struct f2fs_crypt_info
*crypt_info
;
110 char full_key_descriptor
[F2FS_KEY_DESC_PREFIX_SIZE
+
111 (F2FS_KEY_DESCRIPTOR_SIZE
* 2) + 1];
112 struct key
*keyring_key
= NULL
;
113 struct f2fs_encryption_key
*master_key
;
114 struct f2fs_encryption_context ctx
;
115 struct user_key_payload
*ukp
;
118 if (!f2fs_read_workqueue
) {
119 res
= f2fs_init_crypto();
124 if (fi
->i_crypt_info
) {
125 if (!fi
->i_crypt_info
->ci_keyring_key
||
126 key_validate(fi
->i_crypt_info
->ci_keyring_key
) == 0)
128 f2fs_free_encryption_info(inode
);
131 res
= f2fs_getxattr(inode
, F2FS_XATTR_INDEX_ENCRYPTION
,
132 F2FS_XATTR_NAME_ENCRYPTION_CONTEXT
,
133 &ctx
, sizeof(ctx
), NULL
);
136 else if (res
!= sizeof(ctx
))
140 crypt_info
= kmalloc(sizeof(struct f2fs_crypt_info
), GFP_NOFS
);
144 crypt_info
->ci_flags
= ctx
.flags
;
145 crypt_info
->ci_data_mode
= ctx
.contents_encryption_mode
;
146 crypt_info
->ci_filename_mode
= ctx
.filenames_encryption_mode
;
147 crypt_info
->ci_ctfm
= NULL
;
148 memcpy(crypt_info
->ci_master_key
, ctx
.master_key_descriptor
,
149 sizeof(crypt_info
->ci_master_key
));
150 if (S_ISREG(inode
->i_mode
))
151 crypt_info
->ci_mode
= ctx
.contents_encryption_mode
;
152 else if (S_ISDIR(inode
->i_mode
) || S_ISLNK(inode
->i_mode
))
153 crypt_info
->ci_mode
= ctx
.filenames_encryption_mode
;
155 printk(KERN_ERR
"f2fs crypto: Unsupported inode type.\n");
158 crypt_info
->ci_size
= f2fs_encryption_key_size(crypt_info
->ci_mode
);
159 BUG_ON(!crypt_info
->ci_size
);
161 memcpy(full_key_descriptor
, F2FS_KEY_DESC_PREFIX
,
162 F2FS_KEY_DESC_PREFIX_SIZE
);
163 sprintf(full_key_descriptor
+ F2FS_KEY_DESC_PREFIX_SIZE
,
164 "%*phN", F2FS_KEY_DESCRIPTOR_SIZE
,
165 ctx
.master_key_descriptor
);
166 full_key_descriptor
[F2FS_KEY_DESC_PREFIX_SIZE
+
167 (2 * F2FS_KEY_DESCRIPTOR_SIZE
)] = '\0';
168 keyring_key
= request_key(&key_type_logon
, full_key_descriptor
, NULL
);
169 if (IS_ERR(keyring_key
)) {
170 res
= PTR_ERR(keyring_key
);
174 BUG_ON(keyring_key
->type
!= &key_type_logon
);
175 ukp
= ((struct user_key_payload
*)keyring_key
->payload
.data
);
176 if (ukp
->datalen
!= sizeof(struct f2fs_encryption_key
)) {
180 master_key
= (struct f2fs_encryption_key
*)ukp
->data
;
181 BUILD_BUG_ON(F2FS_AES_128_ECB_KEY_SIZE
!=
182 F2FS_KEY_DERIVATION_NONCE_SIZE
);
183 BUG_ON(master_key
->size
!= F2FS_AES_256_XTS_KEY_SIZE
);
184 res
= f2fs_derive_key_aes(ctx
.nonce
, master_key
->raw
,
192 fi
->i_crypt_info
= crypt_info
;
193 crypt_info
->ci_keyring_key
= keyring_key
;
197 key_put(keyring_key
);
201 int f2fs_has_encryption_key(struct inode
*inode
)
203 struct f2fs_inode_info
*fi
= F2FS_I(inode
);
205 return (fi
->i_crypt_info
!= NULL
);