1 /*
2 * Copyright 2006-2023 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 <limits.h>
12 #include <openssl/cms.h>
13 #include <openssl/err.h>
14 #include <openssl/decoder.h>
15 #include "internal/sizes.h"
16 #include "crypto/asn1.h"
17 #include "crypto/evp.h"
18 #include "cms_local.h"
19
pkey_type2param(int ptype,const void * pval,OSSL_LIB_CTX * libctx,const char * propq)20 static EVP_PKEY *pkey_type2param(int ptype, const void *pval,
21 OSSL_LIB_CTX *libctx, const char *propq)
22 {
23 EVP_PKEY *pkey = NULL;
24 EVP_PKEY_CTX *pctx = NULL;
25 OSSL_DECODER_CTX *ctx = NULL;
26
27 if (ptype == V_ASN1_SEQUENCE) {
28 const ASN1_STRING *pstr = pval;
29 const unsigned char *pm = pstr->data;
30 size_t pmlen = (size_t)pstr->length;
31 int selection = OSSL_KEYMGMT_SELECT_ALL_PARAMETERS;
32
33 ctx = OSSL_DECODER_CTX_new_for_pkey(&pkey, "DER", NULL, "EC",
34 selection, libctx, propq);
35 if (ctx == NULL)
36 goto err;
37
38 if (!OSSL_DECODER_from_data(ctx, &pm, &pmlen)) {
39 ERR_raise(ERR_LIB_CMS, CMS_R_DECODE_ERROR);
40 goto err;
41 }
42 OSSL_DECODER_CTX_free(ctx);
43 return pkey;
44 } else if (ptype == V_ASN1_OBJECT) {
45 const ASN1_OBJECT *poid = pval;
46 char groupname[OSSL_MAX_NAME_SIZE];
47
48 /* type == V_ASN1_OBJECT => the parameters are given by an asn1 OID */
49 pctx = EVP_PKEY_CTX_new_from_name(libctx, "EC", propq);
50 if (pctx == NULL || EVP_PKEY_paramgen_init(pctx) <= 0)
51 goto err;
52 if (OBJ_obj2txt(groupname, sizeof(groupname), poid, 0) <= 0
53 || EVP_PKEY_CTX_set_group_name(pctx, groupname) <= 0) {
54 ERR_raise(ERR_LIB_CMS, CMS_R_DECODE_ERROR);
55 goto err;
56 }
57 if (EVP_PKEY_paramgen(pctx, &pkey) <= 0)
58 goto err;
59 EVP_PKEY_CTX_free(pctx);
60 return pkey;
61 }
62
63 ERR_raise(ERR_LIB_CMS, CMS_R_DECODE_ERROR);
64 return NULL;
65
66 err:
67 EVP_PKEY_free(pkey);
68 EVP_PKEY_CTX_free(pctx);
69 OSSL_DECODER_CTX_free(ctx);
70 return NULL;
71 }
72
ecdh_cms_set_peerkey(EVP_PKEY_CTX * pctx,X509_ALGOR * alg,ASN1_BIT_STRING * pubkey)73 static int ecdh_cms_set_peerkey(EVP_PKEY_CTX *pctx,
74 X509_ALGOR *alg, ASN1_BIT_STRING *pubkey)
75 {
76 const ASN1_OBJECT *aoid;
77 int atype;
78 const void *aval;
79 int rv = 0;
80 EVP_PKEY *pkpeer = NULL;
81 const unsigned char *p;
82 int plen;
83
84 X509_ALGOR_get0(&aoid, &atype, &aval, alg);
85 if (OBJ_obj2nid(aoid) != NID_X9_62_id_ecPublicKey)
86 goto err;
87
88 /* If absent parameters get group from main key */
89 if (atype == V_ASN1_UNDEF || atype == V_ASN1_NULL) {
90 EVP_PKEY *pk;
91
92 pk = EVP_PKEY_CTX_get0_pkey(pctx);
93 if (pk == NULL)
94 goto err;
95
96 pkpeer = EVP_PKEY_new();
97 if (pkpeer == NULL)
98 goto err;
99 if (!EVP_PKEY_copy_parameters(pkpeer, pk))
100 goto err;
101 } else {
102 pkpeer = pkey_type2param(atype, aval,
103 EVP_PKEY_CTX_get0_libctx(pctx),
104 EVP_PKEY_CTX_get0_propq(pctx));
105 if (pkpeer == NULL)
106 goto err;
107 }
108 /* We have parameters now set public key */
109 plen = ASN1_STRING_length(pubkey);
110 p = ASN1_STRING_get0_data(pubkey);
111 if (p == NULL || plen == 0)
112 goto err;
113
114 if (EVP_PKEY_set1_encoded_public_key(pkpeer, p, plen) <= 0)
115 goto err;
116
117 if (EVP_PKEY_derive_set_peer(pctx, pkpeer) > 0)
118 rv = 1;
119 err:
120 EVP_PKEY_free(pkpeer);
121 return rv;
122 }
123
124 /* Set KDF parameters based on KDF NID */
ecdh_cms_set_kdf_param(EVP_PKEY_CTX * pctx,int eckdf_nid)125 static int ecdh_cms_set_kdf_param(EVP_PKEY_CTX *pctx, int eckdf_nid)
126 {
127 int kdf_nid, kdfmd_nid, cofactor;
128 const EVP_MD *kdf_md;
129
130 if (eckdf_nid == NID_undef)
131 return 0;
132
133 /* Lookup KDF type, cofactor mode and digest */
134 if (!OBJ_find_sigid_algs(eckdf_nid, &kdfmd_nid, &kdf_nid))
135 return 0;
136
137 if (kdf_nid == NID_dh_std_kdf)
138 cofactor = 0;
139 else if (kdf_nid == NID_dh_cofactor_kdf)
140 cofactor = 1;
141 else
142 return 0;
143
144 if (EVP_PKEY_CTX_set_ecdh_cofactor_mode(pctx, cofactor) <= 0)
145 return 0;
146
147 if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, EVP_PKEY_ECDH_KDF_X9_63) <= 0)
148 return 0;
149
150 kdf_md = EVP_get_digestbynid(kdfmd_nid);
151 if (!kdf_md)
152 return 0;
153
154 if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
155 return 0;
156 return 1;
157 }
158
ecdh_cms_set_shared_info(EVP_PKEY_CTX * pctx,CMS_RecipientInfo * ri)159 static int ecdh_cms_set_shared_info(EVP_PKEY_CTX *pctx, CMS_RecipientInfo *ri)
160 {
161 int rv = 0;
162 X509_ALGOR *alg, *kekalg = NULL;
163 ASN1_OCTET_STRING *ukm;
164 const unsigned char *p;
165 unsigned char *der = NULL;
166 int plen, keylen;
167 EVP_CIPHER *kekcipher = NULL;
168 EVP_CIPHER_CTX *kekctx;
169 char name[OSSL_MAX_NAME_SIZE];
170
171 if (!CMS_RecipientInfo_kari_get0_alg(ri, &alg, &ukm))
172 return 0;
173
174 if (!ecdh_cms_set_kdf_param(pctx, OBJ_obj2nid(alg->algorithm))) {
175 ERR_raise(ERR_LIB_CMS, CMS_R_KDF_PARAMETER_ERROR);
176 return 0;
177 }
178
179 if (alg->parameter->type != V_ASN1_SEQUENCE)
180 return 0;
181
182 p = alg->parameter->value.sequence->data;
183 plen = alg->parameter->value.sequence->length;
184 kekalg = d2i_X509_ALGOR(NULL, &p, plen);
185 if (kekalg == NULL)
186 goto err;
187 kekctx = CMS_RecipientInfo_kari_get0_ctx(ri);
188 if (kekctx == NULL)
189 goto err;
190 OBJ_obj2txt(name, sizeof(name), kekalg->algorithm, 0);
191 kekcipher = EVP_CIPHER_fetch(pctx->libctx, name, pctx->propquery);
192 if (kekcipher == NULL || EVP_CIPHER_get_mode(kekcipher) != EVP_CIPH_WRAP_MODE)
193 goto err;
194 if (!EVP_EncryptInit_ex(kekctx, kekcipher, NULL, NULL, NULL))
195 goto err;
196 if (EVP_CIPHER_asn1_to_param(kekctx, kekalg->parameter) <= 0)
197 goto err;
198
199 keylen = EVP_CIPHER_CTX_get_key_length(kekctx);
200 if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
201 goto err;
202
203 plen = CMS_SharedInfo_encode(&der, kekalg, ukm, keylen);
204
205 if (plen <= 0)
206 goto err;
207
208 if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, der, plen) <= 0)
209 goto err;
210 der = NULL;
211
212 rv = 1;
213 err:
214 EVP_CIPHER_free(kekcipher);
215 X509_ALGOR_free(kekalg);
216 OPENSSL_free(der);
217 return rv;
218 }
219
ecdh_cms_decrypt(CMS_RecipientInfo * ri)220 static int ecdh_cms_decrypt(CMS_RecipientInfo *ri)
221 {
222 EVP_PKEY_CTX *pctx;
223
224 pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
225 if (pctx == NULL)
226 return 0;
227 /* See if we need to set peer key */
228 if (!EVP_PKEY_CTX_get0_peerkey(pctx)) {
229 X509_ALGOR *alg;
230 ASN1_BIT_STRING *pubkey;
231
232 if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &alg, &pubkey,
233 NULL, NULL, NULL))
234 return 0;
235 if (alg == NULL || pubkey == NULL)
236 return 0;
237 if (!ecdh_cms_set_peerkey(pctx, alg, pubkey)) {
238 ERR_raise(ERR_LIB_CMS, CMS_R_PEER_KEY_ERROR);
239 return 0;
240 }
241 }
242 /* Set ECDH derivation parameters and initialise unwrap context */
243 if (!ecdh_cms_set_shared_info(pctx, ri)) {
244 ERR_raise(ERR_LIB_CMS, CMS_R_SHARED_INFO_ERROR);
245 return 0;
246 }
247 return 1;
248 }
249
ecdh_cms_encrypt(CMS_RecipientInfo * ri)250 static int ecdh_cms_encrypt(CMS_RecipientInfo *ri)
251 {
252 EVP_PKEY_CTX *pctx;
253 EVP_PKEY *pkey;
254 EVP_CIPHER_CTX *ctx;
255 int keylen;
256 X509_ALGOR *talg, *wrap_alg = NULL;
257 const ASN1_OBJECT *aoid;
258 ASN1_BIT_STRING *pubkey;
259 ASN1_STRING *wrap_str;
260 ASN1_OCTET_STRING *ukm;
261 unsigned char *penc = NULL;
262 int penclen;
263 int rv = 0;
264 int ecdh_nid, kdf_type, kdf_nid, wrap_nid;
265 const EVP_MD *kdf_md;
266
267 pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
268 if (pctx == NULL)
269 return 0;
270 /* Get ephemeral key */
271 pkey = EVP_PKEY_CTX_get0_pkey(pctx);
272 if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &talg, &pubkey,
273 NULL, NULL, NULL))
274 goto err;
275 X509_ALGOR_get0(&aoid, NULL, NULL, talg);
276 /* Is everything uninitialised? */
277 if (aoid == OBJ_nid2obj(NID_undef)) {
278 /* Set the key */
279 size_t enckeylen;
280
281 enckeylen = EVP_PKEY_get1_encoded_public_key(pkey, &penc);
282 if (enckeylen > INT_MAX || enckeylen == 0)
283 goto err;
284 ASN1_STRING_set0(pubkey, penc, (int)enckeylen);
285 ossl_asn1_string_set_bits_left(pubkey, 0);
286
287 penc = NULL;
288 (void)X509_ALGOR_set0(talg, OBJ_nid2obj(NID_X9_62_id_ecPublicKey),
289 V_ASN1_UNDEF, NULL); /* cannot fail */
290 }
291
292 /* See if custom parameters set */
293 kdf_type = EVP_PKEY_CTX_get_ecdh_kdf_type(pctx);
294 if (kdf_type <= 0)
295 goto err;
296 if (EVP_PKEY_CTX_get_ecdh_kdf_md(pctx, &kdf_md) <= 0)
297 goto err;
298 ecdh_nid = EVP_PKEY_CTX_get_ecdh_cofactor_mode(pctx);
299 if (ecdh_nid < 0)
300 goto err;
301 else if (ecdh_nid == 0)
302 ecdh_nid = NID_dh_std_kdf;
303 else if (ecdh_nid == 1)
304 ecdh_nid = NID_dh_cofactor_kdf;
305
306 if (kdf_type == EVP_PKEY_ECDH_KDF_NONE) {
307 kdf_type = EVP_PKEY_ECDH_KDF_X9_63;
308 if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, kdf_type) <= 0)
309 goto err;
310 } else
311 /* Unknown KDF */
312 goto err;
313 if (kdf_md == NULL) {
314 /* Fixme later for better MD */
315 kdf_md = EVP_sha1();
316 if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
317 goto err;
318 }
319
320 if (!CMS_RecipientInfo_kari_get0_alg(ri, &talg, &ukm))
321 goto err;
322
323 /* Lookup NID for KDF+cofactor+digest */
324
325 if (!OBJ_find_sigid_by_algs(&kdf_nid, EVP_MD_get_type(kdf_md), ecdh_nid))
326 goto err;
327 /* Get wrap NID */
328 ctx = CMS_RecipientInfo_kari_get0_ctx(ri);
329 wrap_nid = EVP_CIPHER_CTX_get_type(ctx);
330 keylen = EVP_CIPHER_CTX_get_key_length(ctx);
331
332 /* Package wrap algorithm in an AlgorithmIdentifier */
333
334 wrap_alg = X509_ALGOR_new();
335 if (wrap_alg == NULL)
336 goto err;
337 wrap_alg->algorithm = OBJ_nid2obj(wrap_nid);
338 wrap_alg->parameter = ASN1_TYPE_new();
339 if (wrap_alg->parameter == NULL)
340 goto err;
341 if (EVP_CIPHER_param_to_asn1(ctx, wrap_alg->parameter) <= 0)
342 goto err;
343 if (ASN1_TYPE_get(wrap_alg->parameter) == NID_undef) {
344 ASN1_TYPE_free(wrap_alg->parameter);
345 wrap_alg->parameter = NULL;
346 }
347
348 if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
349 goto err;
350
351 penclen = CMS_SharedInfo_encode(&penc, wrap_alg, ukm, keylen);
352
353 if (penclen <= 0)
354 goto err;
355
356 if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, penc, penclen) <= 0)
357 goto err;
358 penc = NULL;
359
360 /*
361 * Now need to wrap encoding of wrap AlgorithmIdentifier into parameter
362 * of another AlgorithmIdentifier.
363 */
364 penclen = i2d_X509_ALGOR(wrap_alg, &penc);
365 if (penclen <= 0)
366 goto err;
367 wrap_str = ASN1_STRING_new();
368 if (wrap_str == NULL)
369 goto err;
370 ASN1_STRING_set0(wrap_str, penc, penclen);
371 penc = NULL;
372 rv = X509_ALGOR_set0(talg, OBJ_nid2obj(kdf_nid), V_ASN1_SEQUENCE, wrap_str);
373 if (!rv)
374 ASN1_STRING_free(wrap_str);
375
376 err:
377 OPENSSL_free(penc);
378 X509_ALGOR_free(wrap_alg);
379 return rv;
380 }
381
ossl_cms_ecdh_envelope(CMS_RecipientInfo * ri,int decrypt)382 int ossl_cms_ecdh_envelope(CMS_RecipientInfo *ri, int decrypt)
383 {
384 assert(decrypt == 0 || decrypt == 1);
385
386 if (decrypt == 1)
387 return ecdh_cms_decrypt(ri);
388
389 if (decrypt == 0)
390 return ecdh_cms_encrypt(ri);
391
392 ERR_raise(ERR_LIB_CMS, CMS_R_NOT_SUPPORTED_FOR_THIS_KEY_TYPE);
393 return 0;
394 }
395
