crypto/poly1305/poly1305_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 "crypto/asn1.h"
  14 #include "crypto/poly1305.h"
  15 #include "crypto/evp.h"
  16
  17 /*
  18  * POLY1305 "ASN1" method. This is just here to indicate the maximum
  19  * POLY1305 output length and to free up a POLY1305 key.
  20  */
  21
  22 static int poly1305_size(const EVP_PKEY *pkey)
  23 {
  24     return POLY1305_DIGEST_SIZE;
  25 }
  26
  27 static void poly1305_key_free(EVP_PKEY *pkey)
  28 {
  29     ASN1_OCTET_STRING *os = EVP_PKEY_get0(pkey);
  30     if (os != NULL) {
  31         if (os->data != NULL)
  32             OPENSSL_cleanse(os->data, os->length);
  33         ASN1_OCTET_STRING_free(os);
  34     }
  35 }
  36
  37 static int poly1305_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
  38 {
  39     /* nothing, (including ASN1_PKEY_CTRL_DEFAULT_MD_NID), is supported */
  40     return -2;
  41 }
  42
  43 static int poly1305_pkey_public_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
  44 {
  45     return ASN1_OCTET_STRING_cmp(EVP_PKEY_get0(a), EVP_PKEY_get0(b));
  46 }
  47
  48 static int poly1305_set_priv_key(EVP_PKEY *pkey, const unsigned char *priv,
  49                                  size_t len)
  50 {
  51     ASN1_OCTET_STRING *os;
  52
  53     if (pkey->pkey.ptr != NULL || len != POLY1305_KEY_SIZE)
  54         return 0;
  55
  56     os = ASN1_OCTET_STRING_new();
  57     if (os == NULL)
  58         return 0;
  59
  60     if (!ASN1_OCTET_STRING_set(os, priv, len)) {
  61         ASN1_OCTET_STRING_free(os);
  62         return 0;
  63     }
  64
  65     pkey->pkey.ptr = os;
  66     return 1;
  67 }
  68
  69 static int poly1305_get_priv_key(const EVP_PKEY *pkey, unsigned char *priv,
  70                                  size_t *len)
  71 {
  72     ASN1_OCTET_STRING *os = (ASN1_OCTET_STRING *)pkey->pkey.ptr;
  73
  74     if (priv == NULL) {
  75         *len = POLY1305_KEY_SIZE;
  76         return 1;
  77     }
  78
  79     if (os == NULL || *len < POLY1305_KEY_SIZE)
  80         return 0;
  81
  82     memcpy(priv, ASN1_STRING_get0_data(os), ASN1_STRING_length(os));
  83     *len = POLY1305_KEY_SIZE;
  84
  85     return 1;
  86 }
  87
  88 const EVP_PKEY_ASN1_METHOD poly1305_asn1_meth = {
  89     EVP_PKEY_POLY1305,
  90     EVP_PKEY_POLY1305,
  91     0,
  92
  93     "POLY1305",
  94     "OpenSSL POLY1305 method",
  95
  96     0, 0, poly1305_pkey_public_cmp, 0,
  97
  98     0, 0, 0,
  99
 100     poly1305_size,
 101     0, 0,
 102     0, 0, 0, 0, 0, 0, 0,
 103
 104     poly1305_key_free,
 105     poly1305_pkey_ctrl,
 106     NULL,
 107     NULL,
 108
 109     NULL,
 110     NULL,
 111     NULL,
 112
 113     NULL,
 114     NULL,
 115     NULL,
 116
 117     poly1305_set_priv_key,
 118     NULL,
 119     poly1305_get_priv_key,
 120     NULL,
 121 };