include/crypto/gcm.h

   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  */
  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  */
  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  */
  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