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