1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Common values for AES algorithms
4 */
5
6 #ifndef _CRYPTO_AES_H
7 #define _CRYPTO_AES_H
8
9 #include <linux/types.h>
10 #include <linux/crypto.h>
11
12 #define AES_MIN_KEY_SIZE 16
13 #define AES_MAX_KEY_SIZE 32
14 #define AES_KEYSIZE_128 16
15 #define AES_KEYSIZE_192 24
16 #define AES_KEYSIZE_256 32
17 #define AES_BLOCK_SIZE 16
18 #define AES_MAX_KEYLENGTH (15 * 16)
19 #define AES_MAX_KEYLENGTH_U32 (AES_MAX_KEYLENGTH / sizeof(u32))
20
21 /*
22 * Please ensure that the first two fields are 16-byte aligned
23 * relative to the start of the structure, i.e., don't move them!
24 */
25 struct crypto_aes_ctx {
26 u32 key_enc[AES_MAX_KEYLENGTH_U32];
27 u32 key_dec[AES_MAX_KEYLENGTH_U32];
28 u32 key_length;
29 };
30
31 extern const u32 crypto_ft_tab[4][256] ____cacheline_aligned;
32 extern const u32 crypto_it_tab[4][256] ____cacheline_aligned;
33
34 /*
35 * validate key length for AES algorithms
36 */
aes_check_keylen(unsigned int keylen)37 static inline int aes_check_keylen(unsigned int keylen)
38 {
39 switch (keylen) {
40 case AES_KEYSIZE_128:
41 case AES_KEYSIZE_192:
42 case AES_KEYSIZE_256:
43 break;
44 default:
45 return -EINVAL;
46 }
47
48 return 0;
49 }
50
51 int crypto_aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
52 unsigned int key_len);
53
54 /**
55 * aes_expandkey - Expands the AES key as described in FIPS-197
56 * @ctx: The location where the computed key will be stored.
57 * @in_key: The supplied key.
58 * @key_len: The length of the supplied key.
59 *
60 * Returns 0 on success. The function fails only if an invalid key size (or
61 * pointer) is supplied.
62 * The expanded key size is 240 bytes (max of 14 rounds with a unique 16 bytes
63 * key schedule plus a 16 bytes key which is used before the first round).
64 * The decryption key is prepared for the "Equivalent Inverse Cipher" as
65 * described in FIPS-197. The first slot (16 bytes) of each key (enc or dec) is
66 * for the initial combination, the second slot for the first round and so on.
67 */
68 int aes_expandkey(struct crypto_aes_ctx *ctx, const u8 *in_key,
69 unsigned int key_len);
70
71 /**
72 * aes_encrypt - Encrypt a single AES block
73 * @ctx: Context struct containing the key schedule
74 * @out: Buffer to store the ciphertext
75 * @in: Buffer containing the plaintext
76 */
77 void aes_encrypt(const struct crypto_aes_ctx *ctx, u8 *out, const u8 *in);
78
79 /**
80 * aes_decrypt - Decrypt a single AES block
81 * @ctx: Context struct containing the key schedule
82 * @out: Buffer to store the plaintext
83 * @in: Buffer containing the ciphertext
84 */
85 void aes_decrypt(const struct crypto_aes_ctx *ctx, u8 *out, const u8 *in);
86
87 extern const u8 crypto_aes_sbox[];
88 extern const u8 crypto_aes_inv_sbox[];
89
90 #endif
91