1 /*
2 * Copyright 2006-2024 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 <assert.h>
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/asn1.h"
17 #include "crypto/evp.h"
18 #include "cms_local.h"
19
dh_cms_set_peerkey(EVP_PKEY_CTX * pctx,X509_ALGOR * alg,ASN1_BIT_STRING * pubkey)20 static int dh_cms_set_peerkey(EVP_PKEY_CTX *pctx,
21 X509_ALGOR *alg, ASN1_BIT_STRING *pubkey)
22 {
23 const ASN1_OBJECT *aoid;
24 int atype;
25 const void *aval;
26 ASN1_INTEGER *public_key = NULL;
27 int rv = 0;
28 EVP_PKEY *pkpeer = NULL, *pk = NULL;
29 BIGNUM *bnpub = NULL;
30 const unsigned char *p;
31 unsigned char *buf = NULL;
32 int plen;
33
34 X509_ALGOR_get0(&aoid, &atype, &aval, alg);
35 if (OBJ_obj2nid(aoid) != NID_dhpublicnumber)
36 goto err;
37 /* Only absent parameters allowed in RFC XXXX */
38 if (atype != V_ASN1_UNDEF && atype == V_ASN1_NULL)
39 goto err;
40
41 pk = EVP_PKEY_CTX_get0_pkey(pctx);
42 if (pk == NULL || !EVP_PKEY_is_a(pk, "DHX"))
43 goto err;
44
45 /* Get public key */
46 plen = ASN1_STRING_length(pubkey);
47 p = ASN1_STRING_get0_data(pubkey);
48 if (p == NULL || plen == 0)
49 goto err;
50
51 if ((public_key = d2i_ASN1_INTEGER(NULL, &p, plen)) == NULL)
52 goto err;
53 /*
54 * Pad to full p parameter size as that is checked by
55 * EVP_PKEY_set1_encoded_public_key()
56 */
57 plen = EVP_PKEY_get_size(pk);
58 if ((bnpub = ASN1_INTEGER_to_BN(public_key, NULL)) == NULL)
59 goto err;
60 if ((buf = OPENSSL_malloc(plen)) == NULL)
61 goto err;
62 if (BN_bn2binpad(bnpub, buf, plen) < 0)
63 goto err;
64
65 pkpeer = EVP_PKEY_new();
66 if (pkpeer == NULL
67 || !EVP_PKEY_copy_parameters(pkpeer, pk)
68 || !EVP_PKEY_set1_encoded_public_key(pkpeer, buf, plen))
69 goto err;
70
71 if (EVP_PKEY_derive_set_peer(pctx, pkpeer) > 0)
72 rv = 1;
73 err:
74 ASN1_INTEGER_free(public_key);
75 BN_free(bnpub);
76 OPENSSL_free(buf);
77 EVP_PKEY_free(pkpeer);
78 return rv;
79 }
80
dh_cms_set_shared_info(EVP_PKEY_CTX * pctx,CMS_RecipientInfo * ri)81 static int dh_cms_set_shared_info(EVP_PKEY_CTX *pctx, CMS_RecipientInfo *ri)
82 {
83 int rv = 0;
84 X509_ALGOR *alg, *kekalg = NULL;
85 ASN1_OCTET_STRING *ukm;
86 const unsigned char *p;
87 unsigned char *dukm = NULL;
88 size_t dukmlen = 0;
89 int keylen, plen;
90 EVP_CIPHER *kekcipher = NULL;
91 EVP_CIPHER_CTX *kekctx;
92 char name[OSSL_MAX_NAME_SIZE];
93
94 if (!CMS_RecipientInfo_kari_get0_alg(ri, &alg, &ukm))
95 goto err;
96
97 /*
98 * For DH we only have one OID permissible. If ever any more get defined
99 * we will need something cleverer.
100 */
101 if (OBJ_obj2nid(alg->algorithm) != NID_id_smime_alg_ESDH) {
102 ERR_raise(ERR_LIB_CMS, CMS_R_KDF_PARAMETER_ERROR);
103 goto err;
104 }
105
106 if (EVP_PKEY_CTX_set_dh_kdf_type(pctx, EVP_PKEY_DH_KDF_X9_42) <= 0
107 || EVP_PKEY_CTX_set_dh_kdf_md(pctx, EVP_sha1()) <= 0)
108 goto err;
109
110 if (alg->parameter->type != V_ASN1_SEQUENCE)
111 goto err;
112
113 p = alg->parameter->value.sequence->data;
114 plen = alg->parameter->value.sequence->length;
115 kekalg = d2i_X509_ALGOR(NULL, &p, plen);
116 if (kekalg == NULL)
117 goto err;
118 kekctx = CMS_RecipientInfo_kari_get0_ctx(ri);
119 if (kekctx == NULL)
120 goto err;
121
122 if (OBJ_obj2txt(name, sizeof(name), kekalg->algorithm, 0) <= 0)
123 goto err;
124
125 kekcipher = EVP_CIPHER_fetch(pctx->libctx, name, pctx->propquery);
126 if (kekcipher == NULL
127 || EVP_CIPHER_get_mode(kekcipher) != EVP_CIPH_WRAP_MODE)
128 goto err;
129 if (!EVP_EncryptInit_ex(kekctx, kekcipher, NULL, NULL, NULL))
130 goto err;
131 if (EVP_CIPHER_asn1_to_param(kekctx, kekalg->parameter) <= 0)
132 goto err;
133
134 keylen = EVP_CIPHER_CTX_get_key_length(kekctx);
135 if (EVP_PKEY_CTX_set_dh_kdf_outlen(pctx, keylen) <= 0)
136 goto err;
137 /* Use OBJ_nid2obj to ensure we use built in OID that isn't freed */
138 if (EVP_PKEY_CTX_set0_dh_kdf_oid(pctx,
139 OBJ_nid2obj(EVP_CIPHER_get_type(kekcipher)))
140 <= 0)
141 goto err;
142
143 if (ukm != NULL) {
144 dukmlen = ASN1_STRING_length(ukm);
145 dukm = OPENSSL_memdup(ASN1_STRING_get0_data(ukm), dukmlen);
146 if (dukm == NULL)
147 goto err;
148 }
149
150 if (EVP_PKEY_CTX_set0_dh_kdf_ukm(pctx, dukm, dukmlen) <= 0)
151 goto err;
152 dukm = NULL;
153
154 rv = 1;
155 err:
156 X509_ALGOR_free(kekalg);
157 EVP_CIPHER_free(kekcipher);
158 OPENSSL_free(dukm);
159 return rv;
160 }
161
dh_cms_decrypt(CMS_RecipientInfo * ri)162 static int dh_cms_decrypt(CMS_RecipientInfo *ri)
163 {
164 EVP_PKEY_CTX *pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
165
166 if (pctx == NULL)
167 return 0;
168 /* See if we need to set peer key */
169 if (!EVP_PKEY_CTX_get0_peerkey(pctx)) {
170 X509_ALGOR *alg;
171 ASN1_BIT_STRING *pubkey;
172
173 if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &alg, &pubkey,
174 NULL, NULL, NULL))
175 return 0;
176 if (alg == NULL || pubkey == NULL)
177 return 0;
178 if (!dh_cms_set_peerkey(pctx, alg, pubkey)) {
179 ERR_raise(ERR_LIB_CMS, CMS_R_PEER_KEY_ERROR);
180 return 0;
181 }
182 }
183 /* Set DH derivation parameters and initialise unwrap context */
184 if (!dh_cms_set_shared_info(pctx, ri)) {
185 ERR_raise(ERR_LIB_CMS, CMS_R_SHARED_INFO_ERROR);
186 return 0;
187 }
188 return 1;
189 }
190
dh_cms_encrypt(CMS_RecipientInfo * ri)191 static int dh_cms_encrypt(CMS_RecipientInfo *ri)
192 {
193 EVP_PKEY_CTX *pctx;
194 EVP_PKEY *pkey;
195 EVP_CIPHER_CTX *ctx;
196 int keylen;
197 X509_ALGOR *talg, *wrap_alg = NULL;
198 const ASN1_OBJECT *aoid;
199 ASN1_BIT_STRING *pubkey;
200 ASN1_STRING *wrap_str;
201 ASN1_OCTET_STRING *ukm;
202 unsigned char *penc = NULL, *dukm = NULL;
203 int penclen;
204 size_t dukmlen = 0;
205 int rv = 0;
206 int kdf_type, wrap_nid;
207 const EVP_MD *kdf_md;
208
209 pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
210 if (pctx == NULL)
211 return 0;
212 /* Get ephemeral key */
213 pkey = EVP_PKEY_CTX_get0_pkey(pctx);
214 if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &talg, &pubkey,
215 NULL, NULL, NULL))
216 goto err;
217
218 /* Is everything uninitialised? */
219 X509_ALGOR_get0(&aoid, NULL, NULL, talg);
220 if (aoid == OBJ_nid2obj(NID_undef)) {
221 BIGNUM *bn_pub_key = NULL;
222 ASN1_INTEGER *pubk;
223
224 if (!EVP_PKEY_get_bn_param(pkey, OSSL_PKEY_PARAM_PUB_KEY, &bn_pub_key))
225 goto err;
226
227 pubk = BN_to_ASN1_INTEGER(bn_pub_key, NULL);
228 BN_free(bn_pub_key);
229 if (pubk == NULL)
230 goto err;
231
232 /* Set the key */
233 penclen = i2d_ASN1_INTEGER(pubk, &penc);
234 ASN1_INTEGER_free(pubk);
235 if (penclen <= 0)
236 goto err;
237 ASN1_STRING_set0(pubkey, penc, penclen);
238 ossl_asn1_string_set_bits_left(pubkey, 0);
239
240 penc = NULL;
241 (void)X509_ALGOR_set0(talg, OBJ_nid2obj(NID_dhpublicnumber),
242 V_ASN1_UNDEF, NULL); /* cannot fail */
243 }
244
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) <= 0)
248 goto err;
249
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)
253 goto err;
254 } else if (kdf_type != EVP_PKEY_DH_KDF_X9_42)
255 /* Unknown KDF */
256 goto err;
257 if (kdf_md == NULL) {
258 /* Only SHA1 supported */
259 kdf_md = EVP_sha1();
260 if (EVP_PKEY_CTX_set_dh_kdf_md(pctx, kdf_md) <= 0)
261 goto err;
262 } else if (EVP_MD_get_type(kdf_md) != NID_sha1)
263 /* Unsupported digest */
264 goto err;
265
266 if (!CMS_RecipientInfo_kari_get0_alg(ri, &talg, &ukm))
267 goto err;
268
269 /* Get wrap NID */
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)
273 goto err;
274 keylen = EVP_CIPHER_CTX_get_key_length(ctx);
275
276 /* Package wrap algorithm in an AlgorithmIdentifier */
277
278 wrap_alg = X509_ALGOR_new();
279 if (wrap_alg == NULL)
280 goto err;
281 wrap_alg->algorithm = OBJ_nid2obj(wrap_nid);
282 wrap_alg->parameter = ASN1_TYPE_new();
283 if (wrap_alg->parameter == NULL)
284 goto err;
285 if (EVP_CIPHER_param_to_asn1(ctx, wrap_alg->parameter) <= 0)
286 goto err;
287 if (ASN1_TYPE_get(wrap_alg->parameter) == NID_undef) {
288 ASN1_TYPE_free(wrap_alg->parameter);
289 wrap_alg->parameter = NULL;
290 }
291
292 if (EVP_PKEY_CTX_set_dh_kdf_outlen(pctx, keylen) <= 0)
293 goto err;
294
295 if (ukm != NULL) {
296 dukmlen = ASN1_STRING_length(ukm);
297 dukm = OPENSSL_memdup(ASN1_STRING_get0_data(ukm), dukmlen);
298 if (dukm == NULL)
299 goto err;
300 }
301
302 if (EVP_PKEY_CTX_set0_dh_kdf_ukm(pctx, dukm, dukmlen) <= 0)
303 goto err;
304 dukm = NULL;
305
306 /*
307 * Now need to wrap encoding of wrap AlgorithmIdentifier into parameter
308 * of another AlgorithmIdentifier.
309 */
310 penc = NULL;
311 penclen = i2d_X509_ALGOR(wrap_alg, &penc);
312 if (penclen <= 0)
313 goto err;
314 wrap_str = ASN1_STRING_new();
315 if (wrap_str == NULL)
316 goto err;
317 ASN1_STRING_set0(wrap_str, penc, penclen);
318 penc = NULL;
319 rv = X509_ALGOR_set0(talg, OBJ_nid2obj(NID_id_smime_alg_ESDH),
320 V_ASN1_SEQUENCE, wrap_str);
321 if (!rv)
322 ASN1_STRING_free(wrap_str);
323
324 err:
325 OPENSSL_free(penc);
326 X509_ALGOR_free(wrap_alg);
327 OPENSSL_free(dukm);
328 return rv;
329 }
330
ossl_cms_dh_envelope(CMS_RecipientInfo * ri,int decrypt)331 int ossl_cms_dh_envelope(CMS_RecipientInfo *ri, int decrypt)
332 {
333 assert(decrypt == 0 || decrypt == 1);
334
335 if (decrypt == 1)
336 return dh_cms_decrypt(ri);
337
338 if (decrypt == 0)
339 return dh_cms_encrypt(ri);
340
341 ERR_raise(ERR_LIB_CMS, CMS_R_NOT_SUPPORTED_FOR_THIS_KEY_TYPE);
342 return 0;
343 }
344
