2 * Copyright 2006-2022 The OpenSSL Project Authors. All Rights Reserved.
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
11 #include <openssl/cms.h>
12 #include <openssl/dh.h>
13 #include <openssl/err.h>
14 #include <openssl/core_names.h>
15 #include "internal/sizes.h"
16 #include "crypto/evp.h"
17 #include "cms_local.h"
19 static int dh_cms_set_peerkey(EVP_PKEY_CTX *pctx,
20 X509_ALGOR *alg, ASN1_BIT_STRING *pubkey)
22 const ASN1_OBJECT *aoid;
25 ASN1_INTEGER *public_key = NULL;
27 EVP_PKEY *pkpeer = NULL, *pk = NULL;
29 const unsigned char *p;
30 unsigned char *buf = NULL;
33 X509_ALGOR_get0(&aoid, &atype, &aval, alg);
34 if (OBJ_obj2nid(aoid) != NID_dhpublicnumber)
36 /* Only absent parameters allowed in RFC XXXX */
37 if (atype != V_ASN1_UNDEF && atype == V_ASN1_NULL)
40 pk = EVP_PKEY_CTX_get0_pkey(pctx);
41 if (pk == NULL || !EVP_PKEY_is_a(pk, "DHX"))
45 plen = ASN1_STRING_length(pubkey);
46 p = ASN1_STRING_get0_data(pubkey);
47 if (p == NULL || plen == 0)
50 if ((public_key = d2i_ASN1_INTEGER(NULL, &p, plen)) == NULL)
53 * Pad to full p parameter size as that is checked by
54 * EVP_PKEY_set1_encoded_public_key()
56 plen = EVP_PKEY_get_size(pk);
57 if ((bnpub = ASN1_INTEGER_to_BN(public_key, NULL)) == NULL)
59 if ((buf = OPENSSL_malloc(plen)) == NULL)
61 if (BN_bn2binpad(bnpub, buf, plen) < 0)
64 pkpeer = EVP_PKEY_new();
66 || !EVP_PKEY_copy_parameters(pkpeer, pk)
67 || !EVP_PKEY_set1_encoded_public_key(pkpeer, buf, plen))
70 if (EVP_PKEY_derive_set_peer(pctx, pkpeer) > 0)
73 ASN1_INTEGER_free(public_key);
76 EVP_PKEY_free(pkpeer);
80 static int dh_cms_set_shared_info(EVP_PKEY_CTX *pctx, CMS_RecipientInfo *ri)
83 X509_ALGOR *alg, *kekalg = NULL;
84 ASN1_OCTET_STRING *ukm;
85 const unsigned char *p;
86 unsigned char *dukm = NULL;
89 EVP_CIPHER *kekcipher = NULL;
90 EVP_CIPHER_CTX *kekctx;
91 char name[OSSL_MAX_NAME_SIZE];
93 if (!CMS_RecipientInfo_kari_get0_alg(ri, &alg, &ukm))
97 * For DH we only have one OID permissible. If ever any more get defined
98 * we will need something cleverer.
100 if (OBJ_obj2nid(alg->algorithm) != NID_id_smime_alg_ESDH) {
101 ERR_raise(ERR_LIB_CMS, CMS_R_KDF_PARAMETER_ERROR);
105 if (EVP_PKEY_CTX_set_dh_kdf_type(pctx, EVP_PKEY_DH_KDF_X9_42) <= 0
106 || EVP_PKEY_CTX_set_dh_kdf_md(pctx, EVP_sha1()) <= 0)
109 if (alg->parameter->type != V_ASN1_SEQUENCE)
112 p = alg->parameter->value.sequence->data;
113 plen = alg->parameter->value.sequence->length;
114 kekalg = d2i_X509_ALGOR(NULL, &p, plen);
117 kekctx = CMS_RecipientInfo_kari_get0_ctx(ri);
121 if (OBJ_obj2txt(name, sizeof(name), kekalg->algorithm, 0) <= 0)
124 kekcipher = EVP_CIPHER_fetch(pctx->libctx, name, pctx->propquery);
125 if (kekcipher == NULL
126 || EVP_CIPHER_get_mode(kekcipher) != EVP_CIPH_WRAP_MODE)
128 if (!EVP_EncryptInit_ex(kekctx, kekcipher, NULL, NULL, NULL))
130 if (EVP_CIPHER_asn1_to_param(kekctx, kekalg->parameter) <= 0)
133 keylen = EVP_CIPHER_CTX_get_key_length(kekctx);
134 if (EVP_PKEY_CTX_set_dh_kdf_outlen(pctx, keylen) <= 0)
136 /* Use OBJ_nid2obj to ensure we use built in OID that isn't freed */
137 if (EVP_PKEY_CTX_set0_dh_kdf_oid(pctx,
138 OBJ_nid2obj(EVP_CIPHER_get_type(kekcipher)))
143 dukmlen = ASN1_STRING_length(ukm);
144 dukm = OPENSSL_memdup(ASN1_STRING_get0_data(ukm), dukmlen);
149 if (EVP_PKEY_CTX_set0_dh_kdf_ukm(pctx, dukm, dukmlen) <= 0)
155 X509_ALGOR_free(kekalg);
156 EVP_CIPHER_free(kekcipher);
161 static int dh_cms_decrypt(CMS_RecipientInfo *ri)
163 EVP_PKEY_CTX *pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
167 /* See if we need to set peer key */
168 if (!EVP_PKEY_CTX_get0_peerkey(pctx)) {
170 ASN1_BIT_STRING *pubkey;
172 if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &alg, &pubkey,
175 if (alg == NULL || pubkey == NULL)
177 if (!dh_cms_set_peerkey(pctx, alg, pubkey)) {
178 ERR_raise(ERR_LIB_CMS, CMS_R_PEER_KEY_ERROR);
182 /* Set DH derivation parameters and initialise unwrap context */
183 if (!dh_cms_set_shared_info(pctx, ri)) {
184 ERR_raise(ERR_LIB_CMS, CMS_R_SHARED_INFO_ERROR);
190 static int dh_cms_encrypt(CMS_RecipientInfo *ri)
196 X509_ALGOR *talg, *wrap_alg = NULL;
197 const ASN1_OBJECT *aoid;
198 ASN1_BIT_STRING *pubkey;
199 ASN1_STRING *wrap_str;
200 ASN1_OCTET_STRING *ukm;
201 unsigned char *penc = NULL, *dukm = NULL;
205 int kdf_type, wrap_nid;
206 const EVP_MD *kdf_md;
208 pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
211 /* Get ephemeral key */
212 pkey = EVP_PKEY_CTX_get0_pkey(pctx);
213 if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &talg, &pubkey,
217 /* Is everything uninitialised? */
218 X509_ALGOR_get0(&aoid, NULL, NULL, talg);
219 if (aoid == OBJ_nid2obj(NID_undef)) {
220 BIGNUM *bn_pub_key = NULL;
223 if (!EVP_PKEY_get_bn_param(pkey, OSSL_PKEY_PARAM_PUB_KEY, &bn_pub_key))
226 pubk = BN_to_ASN1_INTEGER(bn_pub_key, NULL);
232 penclen = i2d_ASN1_INTEGER(pubk, &penc);
233 ASN1_INTEGER_free(pubk);
236 ASN1_STRING_set0(pubkey, penc, penclen);
237 pubkey->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);
238 pubkey->flags |= ASN1_STRING_FLAG_BITS_LEFT;
241 (void)X509_ALGOR_set0(talg, OBJ_nid2obj(NID_dhpublicnumber),
242 V_ASN1_UNDEF, NULL); /* cannot fail */
245 /* See if custom parameters set */
246 kdf_type = EVP_PKEY_CTX_get_dh_kdf_type(pctx);
247 if (kdf_type <= 0 || !EVP_PKEY_CTX_get_dh_kdf_md(pctx, &kdf_md))
250 if (kdf_type == EVP_PKEY_DH_KDF_NONE) {
251 kdf_type = EVP_PKEY_DH_KDF_X9_42;
252 if (EVP_PKEY_CTX_set_dh_kdf_type(pctx, kdf_type) <= 0)
254 } else if (kdf_type != EVP_PKEY_DH_KDF_X9_42)
257 if (kdf_md == NULL) {
258 /* Only SHA1 supported */
260 if (EVP_PKEY_CTX_set_dh_kdf_md(pctx, kdf_md) <= 0)
262 } else if (EVP_MD_get_type(kdf_md) != NID_sha1)
263 /* Unsupported digest */
266 if (!CMS_RecipientInfo_kari_get0_alg(ri, &talg, &ukm))
270 ctx = CMS_RecipientInfo_kari_get0_ctx(ri);
271 wrap_nid = EVP_CIPHER_CTX_get_type(ctx);
272 if (EVP_PKEY_CTX_set0_dh_kdf_oid(pctx, OBJ_nid2obj(wrap_nid)) <= 0)
274 keylen = EVP_CIPHER_CTX_get_key_length(ctx);
276 /* Package wrap algorithm in an AlgorithmIdentifier */
278 wrap_alg = X509_ALGOR_new();
279 if (wrap_alg == NULL)
281 wrap_alg->algorithm = OBJ_nid2obj(wrap_nid);
282 wrap_alg->parameter = ASN1_TYPE_new();
283 if (wrap_alg->parameter == NULL)
285 if (EVP_CIPHER_param_to_asn1(ctx, wrap_alg->parameter) <= 0)
287 if (ASN1_TYPE_get(wrap_alg->parameter) == NID_undef) {
288 ASN1_TYPE_free(wrap_alg->parameter);
289 wrap_alg->parameter = NULL;
292 if (EVP_PKEY_CTX_set_dh_kdf_outlen(pctx, keylen) <= 0)
296 dukmlen = ASN1_STRING_length(ukm);
297 dukm = OPENSSL_memdup(ASN1_STRING_get0_data(ukm), dukmlen);
302 if (EVP_PKEY_CTX_set0_dh_kdf_ukm(pctx, dukm, dukmlen) <= 0)
307 * Now need to wrap encoding of wrap AlgorithmIdentifier into parameter
308 * of another AlgorithmIdentifier.
311 penclen = i2d_X509_ALGOR(wrap_alg, &penc);
312 if (penc == NULL || penclen == 0)
314 wrap_str = ASN1_STRING_new();
315 if (wrap_str == NULL)
317 ASN1_STRING_set0(wrap_str, penc, penclen);
319 rv = X509_ALGOR_set0(talg, OBJ_nid2obj(NID_id_smime_alg_ESDH),
320 V_ASN1_SEQUENCE, wrap_str);
322 ASN1_STRING_free(wrap_str);
326 X509_ALGOR_free(wrap_alg);
331 int ossl_cms_dh_envelope(CMS_RecipientInfo *ri, int decrypt)
333 assert(decrypt == 0 || decrypt == 1);
336 return dh_cms_decrypt(ri);
339 return dh_cms_encrypt(ri);
341 ERR_raise(ERR_LIB_CMS, CMS_R_NOT_SUPPORTED_FOR_THIS_KEY_TYPE);