crypto/hmac/hm_ameth.c

   1 /*
   2  * Copyright 2007-2018 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include <stdio.h>
  11 #include "internal/cryptlib.h"
  12 #include <openssl/evp.h>
  13 #include "internal/asn1_int.h"
  14 #include "internal/evp_int.h"
  15
  16 /*
  17  * HMAC "ASN1" method. This is just here to indicate the maximum HMAC output
  18  * length and to free up an HMAC key.
  19  */
  20
  21 static int hmac_size(const EVP_PKEY *pkey)
  22 {
  23     return EVP_MAX_MD_SIZE;
  24 }
  25
  26 static void hmac_key_free(EVP_PKEY *pkey)
  27 {
  28     ASN1_OCTET_STRING *os = EVP_PKEY_get0(pkey);
  29     if (os) {
  30         if (os->data)
  31             OPENSSL_cleanse(os->data, os->length);
  32         ASN1_OCTET_STRING_free(os);
  33     }
  34 }
  35
  36 static int hmac_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
  37 {
  38     switch (op) {
  39     case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
  40         *(int *)arg2 = NID_sha256;
  41         return 1;
  42
  43     default:
  44         return -2;
  45     }
  46 }
  47
  48 static int hmac_pkey_public_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
  49 {
  50     return ASN1_OCTET_STRING_cmp(EVP_PKEY_get0(a), EVP_PKEY_get0(b));
  51 }
  52
  53 static int hmac_set_priv_key(EVP_PKEY *pkey, const unsigned char *priv,
  54                              size_t len)
  55 {
  56     ASN1_OCTET_STRING *os;
  57
  58     if (pkey->pkey.ptr != NULL)
  59         return 0;
  60
  61     os = ASN1_OCTET_STRING_new();
  62     if (os == NULL)
  63         return 0;
  64
  65
  66     if (!ASN1_OCTET_STRING_set(os, priv, len)) {
  67         ASN1_OCTET_STRING_free(os);
  68         return 0;
  69     }
  70
  71     pkey->pkey.ptr = os;
  72     return 1;
  73 }
  74
  75 static int hmac_get_priv_key(const EVP_PKEY *pkey, unsigned char *priv,
  76                              size_t *len)
  77 {
  78     ASN1_OCTET_STRING *os = (ASN1_OCTET_STRING *)pkey->pkey.ptr;
  79
  80     if (priv == NULL) {
  81         *len = ASN1_STRING_length(os);
  82         return 1;
  83     }
  84
  85     if (os == NULL || *len < (size_t)ASN1_STRING_length(os))
  86         return 0;
  87
  88     *len = ASN1_STRING_length(os);
  89     memcpy(priv, ASN1_STRING_get0_data(os), *len);
  90
  91     return 1;
  92 }
  93
  94 const EVP_PKEY_ASN1_METHOD hmac_asn1_meth = {
  95     EVP_PKEY_HMAC,
  96     EVP_PKEY_HMAC,
  97     0,
  98
  99     "HMAC",
 100     "OpenSSL HMAC method",
 101
 102     0, 0, hmac_pkey_public_cmp, 0,
 103
 104     0, 0, 0,
 105
 106     hmac_size,
 107     0, 0,
 108     0, 0, 0, 0, 0, 0, 0,
 109
 110     hmac_key_free,
 111     hmac_pkey_ctrl,
 112     NULL,
 113     NULL,
 114
 115     NULL,
 116     NULL,
 117     NULL,
 118
 119     NULL,
 120     NULL,
 121     NULL,
 122
 123     hmac_set_priv_key,
 124     NULL,
 125     hmac_get_priv_key,
 126     NULL,
 127 };