providers/implementations/exchange/dh_exch.c

   1 /*
   2  * Copyright 2019 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 /*
  11  * DH low level APIs are deprecated for public use, but still ok for
  12  * internal use.
  13  */
  14 #include "internal/deprecated.h"
  15
  16 #include <openssl/crypto.h>
  17 #include <openssl/core_numbers.h>
  18 #include <openssl/core_names.h>
  19 #include <openssl/dh.h>
  20 #include <openssl/params.h>
  21 #include "prov/implementations.h"
  22 #include "prov/provider_ctx.h"
  23 #include "crypto/dh.h"
  24
  25 static OSSL_OP_keyexch_newctx_fn dh_newctx;
  26 static OSSL_OP_keyexch_init_fn dh_init;
  27 static OSSL_OP_keyexch_set_peer_fn dh_set_peer;
  28 static OSSL_OP_keyexch_derive_fn dh_derive;
  29 static OSSL_OP_keyexch_freectx_fn dh_freectx;
  30 static OSSL_OP_keyexch_dupctx_fn dh_dupctx;
  31 static OSSL_OP_keyexch_set_ctx_params_fn dh_set_ctx_params;
  32 static OSSL_OP_keyexch_settable_ctx_params_fn dh_settable_ctx_params;
  33
  34 /*
  35  * What's passed as an actual key is defined by the KEYMGMT interface.
  36  * We happen to know that our KEYMGMT simply passes DH structures, so
  37  * we use that here too.
  38  */
  39
  40 typedef struct {
  41     OPENSSL_CTX *libctx;
  42     DH *dh;
  43     DH *dhpeer;
  44     unsigned int pad : 1;
  45 } PROV_DH_CTX;
  46
  47 static void *dh_newctx(void *provctx)
  48 {
  49     PROV_DH_CTX *pdhctx = OPENSSL_zalloc(sizeof(PROV_DH_CTX));
  50
  51     if (pdhctx == NULL)
  52         return NULL;
  53     pdhctx->libctx = PROV_LIBRARY_CONTEXT_OF(provctx);
  54     return pdhctx;
  55 }
  56
  57 static int dh_init(void *vpdhctx, void *vdh)
  58 {
  59     PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
  60
  61     if (pdhctx == NULL || vdh == NULL || !DH_up_ref(vdh))
  62         return 0;
  63     DH_free(pdhctx->dh);
  64     pdhctx->dh = vdh;
  65     return 1;
  66 }
  67
  68 static int dh_set_peer(void *vpdhctx, void *vdh)
  69 {
  70     PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
  71
  72     if (pdhctx == NULL || vdh == NULL || !DH_up_ref(vdh))
  73         return 0;
  74     DH_free(pdhctx->dhpeer);
  75     pdhctx->dhpeer = vdh;
  76     return 1;
  77 }
  78
  79 static int dh_derive(void *vpdhctx, unsigned char *secret, size_t *secretlen,
  80                      size_t outlen)
  81 {
  82     PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
  83     int ret;
  84     size_t dhsize;
  85     const BIGNUM *pub_key = NULL;
  86
  87     /* TODO(3.0): Add errors to stack */
  88     if (pdhctx->dh == NULL || pdhctx->dhpeer == NULL)
  89         return 0;
  90
  91     dhsize = (size_t)DH_size(pdhctx->dh);
  92     if (secret == NULL) {
  93         *secretlen = dhsize;
  94         return 1;
  95     }
  96     if (outlen < dhsize)
  97         return 0;
  98
  99     DH_get0_key(pdhctx->dhpeer, &pub_key, NULL);
 100     if (pdhctx->pad)
 101         ret = DH_compute_key_padded(secret, pub_key, pdhctx->dh);
 102     else
 103         ret = DH_compute_key(secret, pub_key, pdhctx->dh);
 104     if (ret <= 0)
 105         return 0;
 106
 107     *secretlen = ret;
 108     return 1;
 109 }
 110
 111 static void dh_freectx(void *vpdhctx)
 112 {
 113     PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
 114
 115     DH_free(pdhctx->dh);
 116     DH_free(pdhctx->dhpeer);
 117
 118     OPENSSL_free(pdhctx);
 119 }
 120
 121 static void *dh_dupctx(void *vpdhctx)
 122 {
 123     PROV_DH_CTX *srcctx = (PROV_DH_CTX *)vpdhctx;
 124     PROV_DH_CTX *dstctx;
 125
 126     dstctx = OPENSSL_zalloc(sizeof(*srcctx));
 127     if (dstctx == NULL)
 128         return NULL;
 129
 130     *dstctx = *srcctx;
 131     if (dstctx->dh != NULL && !DH_up_ref(dstctx->dh)) {
 132         OPENSSL_free(dstctx);
 133         return NULL;
 134     }
 135
 136     if (dstctx->dhpeer != NULL && !DH_up_ref(dstctx->dhpeer)) {
 137         DH_free(dstctx->dh);
 138         OPENSSL_free(dstctx);
 139         return NULL;
 140     }
 141
 142     return dstctx;
 143 }
 144
 145 static int dh_set_ctx_params(void *vpdhctx, const OSSL_PARAM params[])
 146 {
 147     PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
 148     const OSSL_PARAM *p;
 149     unsigned int pad;
 150
 151     if (pdhctx == NULL || params == NULL)
 152         return 0;
 153
 154     p = OSSL_PARAM_locate_const(params, OSSL_EXCHANGE_PARAM_PAD);
 155     if (p == NULL || !OSSL_PARAM_get_uint(p, &pad))
 156         return 0;
 157     pdhctx->pad = pad ? 1 : 0;
 158     return 1;
 159 }
 160
 161 static const OSSL_PARAM known_settable_ctx_params[] = {
 162     OSSL_PARAM_int(OSSL_EXCHANGE_PARAM_PAD, NULL),
 163     OSSL_PARAM_END
 164 };
 165
 166 static const OSSL_PARAM *dh_settable_ctx_params(void)
 167 {
 168     return known_settable_ctx_params;
 169 }
 170
 171 const OSSL_DISPATCH dh_keyexch_functions[] = {
 172     { OSSL_FUNC_KEYEXCH_NEWCTX, (void (*)(void))dh_newctx },
 173     { OSSL_FUNC_KEYEXCH_INIT, (void (*)(void))dh_init },
 174     { OSSL_FUNC_KEYEXCH_DERIVE, (void (*)(void))dh_derive },
 175     { OSSL_FUNC_KEYEXCH_SET_PEER, (void (*)(void))dh_set_peer },
 176     { OSSL_FUNC_KEYEXCH_FREECTX, (void (*)(void))dh_freectx },
 177     { OSSL_FUNC_KEYEXCH_DUPCTX, (void (*)(void))dh_dupctx },
 178     { OSSL_FUNC_KEYEXCH_SET_CTX_PARAMS, (void (*)(void))dh_set_ctx_params },
 179     { OSSL_FUNC_KEYEXCH_SETTABLE_CTX_PARAMS,
 180       (void (*)(void))dh_settable_ctx_params },
 181     { 0, NULL }
 182 };