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 "poly1305_local.h"
  16 #include "crypto/evp.h"
  17
  18 /*
  19  * POLY1305 "ASN1" method. This is just here to indicate the maximum
  20  * POLY1305 output length and to free up a POLY1305 key.
  21  */
  22
  23 static int poly1305_size(const EVP_PKEY *pkey)
  24 {
  25     return POLY1305_DIGEST_SIZE;
  26 }
  27
  28 static void poly1305_key_free(EVP_PKEY *pkey)
  29 {
  30     ASN1_OCTET_STRING *os = EVP_PKEY_get0(pkey);
  31     if (os != NULL) {
  32         if (os->data != NULL)
  33             OPENSSL_cleanse(os->data, os->length);
  34         ASN1_OCTET_STRING_free(os);
  35     }
  36 }
  37
  38 static int poly1305_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
  39 {
  40     /* nothing, (including ASN1_PKEY_CTRL_DEFAULT_MD_NID), is supported */
  41     return -2;
  42 }
  43
  44 static int poly1305_pkey_public_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
  45 {
  46     return ASN1_OCTET_STRING_cmp(EVP_PKEY_get0(a), EVP_PKEY_get0(b));
  47 }
  48
  49 static int poly1305_set_priv_key(EVP_PKEY *pkey, const unsigned char *priv,
  50                                  size_t len)
  51 {
  52     ASN1_OCTET_STRING *os;
  53
  54     if (pkey->pkey.ptr != NULL || len != POLY1305_KEY_SIZE)
  55         return 0;
  56
  57     os = ASN1_OCTET_STRING_new();
  58     if (os == NULL)
  59         return 0;
  60
  61     if (!ASN1_OCTET_STRING_set(os, priv, len)) {
  62         ASN1_OCTET_STRING_free(os);
  63         return 0;
  64     }
  65
  66     pkey->pkey.ptr = os;
  67     return 1;
  68 }
  69
  70 static int poly1305_get_priv_key(const EVP_PKEY *pkey, unsigned char *priv,
  71                                  size_t *len)
  72 {
  73     ASN1_OCTET_STRING *os = (ASN1_OCTET_STRING *)pkey->pkey.ptr;
  74
  75     if (priv == NULL) {
  76         *len = POLY1305_KEY_SIZE;
  77         return 1;
  78     }
  79
  80     if (os == NULL || *len < POLY1305_KEY_SIZE)
  81         return 0;
  82
  83     memcpy(priv, ASN1_STRING_get0_data(os), ASN1_STRING_length(os));
  84     *len = POLY1305_KEY_SIZE;
  85
  86     return 1;
  87 }
  88
  89 const EVP_PKEY_ASN1_METHOD poly1305_asn1_meth = {
  90     EVP_PKEY_POLY1305,
  91     EVP_PKEY_POLY1305,
  92     0,
  93
  94     "POLY1305",
  95     "OpenSSL POLY1305 method",
  96
  97     0, 0, poly1305_pkey_public_cmp, 0,
  98
  99     0, 0, 0,
 100
 101     poly1305_size,
 102     0, 0,
 103     0, 0, 0, 0, 0, 0, 0,
 104
 105     poly1305_key_free,
 106     poly1305_pkey_ctrl,
 107     NULL,
 108     NULL,
 109
 110     NULL,
 111     NULL,
 112     NULL,
 113
 114     NULL,
 115     NULL,
 116     NULL,
 117
 118     poly1305_set_priv_key,
 119     NULL,
 120     poly1305_get_priv_key,
 121     NULL,
 122 };