xref: /openbmc/linux/include/crypto/gcm.h (revision 520af5da)
1 #ifndef _CRYPTO_GCM_H
2 #define _CRYPTO_GCM_H
3 
4 #include <linux/errno.h>
5 
6 #include <crypto/aes.h>
7 #include <crypto/gf128mul.h>
8 
9 #define GCM_AES_IV_SIZE 12
10 #define GCM_RFC4106_IV_SIZE 8
11 #define GCM_RFC4543_IV_SIZE 8
12 
13 /*
14  * validate authentication tag for GCM
15  */
crypto_gcm_check_authsize(unsigned int authsize)16 static inline int crypto_gcm_check_authsize(unsigned int authsize)
17 {
18 	switch (authsize) {
19 	case 4:
20 	case 8:
21 	case 12:
22 	case 13:
23 	case 14:
24 	case 15:
25 	case 16:
26 		break;
27 	default:
28 		return -EINVAL;
29 	}
30 
31 	return 0;
32 }
33 
34 /*
35  * validate authentication tag for RFC4106
36  */
crypto_rfc4106_check_authsize(unsigned int authsize)37 static inline int crypto_rfc4106_check_authsize(unsigned int authsize)
38 {
39 	switch (authsize) {
40 	case 8:
41 	case 12:
42 	case 16:
43 		break;
44 	default:
45 		return -EINVAL;
46 	}
47 
48 	return 0;
49 }
50 
51 /*
52  * validate assoclen for RFC4106/RFC4543
53  */
crypto_ipsec_check_assoclen(unsigned int assoclen)54 static inline int crypto_ipsec_check_assoclen(unsigned int assoclen)
55 {
56 	switch (assoclen) {
57 	case 16:
58 	case 20:
59 		break;
60 	default:
61 		return -EINVAL;
62 	}
63 
64 	return 0;
65 }
66 
67 struct aesgcm_ctx {
68 	be128			ghash_key;
69 	struct crypto_aes_ctx	aes_ctx;
70 	unsigned int		authsize;
71 };
72 
73 int aesgcm_expandkey(struct aesgcm_ctx *ctx, const u8 *key,
74 		     unsigned int keysize, unsigned int authsize);
75 
76 void aesgcm_encrypt(const struct aesgcm_ctx *ctx, u8 *dst, const u8 *src,
77 		    int crypt_len, const u8 *assoc, int assoc_len,
78 		    const u8 iv[GCM_AES_IV_SIZE], u8 *authtag);
79 
80 bool __must_check aesgcm_decrypt(const struct aesgcm_ctx *ctx, u8 *dst,
81 				 const u8 *src, int crypt_len, const u8 *assoc,
82 				 int assoc_len, const u8 iv[GCM_AES_IV_SIZE],
83 				 const u8 *authtag);
84 
85 #endif
86