1 /* $OpenBSD: cms_kari.c,v 1.13 2019/08/11 14:27:01 jsing Exp $ */
2 /*
3 * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
4 * project.
5 */
6 /* ====================================================================
7 * Copyright (c) 2013 The OpenSSL Project. All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 *
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 *
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in
18 * the documentation and/or other materials provided with the
19 * distribution.
20 *
21 * 3. All advertising materials mentioning features or use of this
22 * software must display the following acknowledgment:
23 * "This product includes software developed by the OpenSSL Project
24 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
25 *
26 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
27 * endorse or promote products derived from this software without
28 * prior written permission. For written permission, please contact
29 * licensing@OpenSSL.org.
30 *
31 * 5. Products derived from this software may not be called "OpenSSL"
32 * nor may "OpenSSL" appear in their names without prior written
33 * permission of the OpenSSL Project.
34 *
35 * 6. Redistributions of any form whatsoever must retain the following
36 * acknowledgment:
37 * "This product includes software developed by the OpenSSL Project
38 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
39 *
40 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
41 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
43 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
44 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
45 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
46 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
47 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
49 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
50 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
51 * OF THE POSSIBILITY OF SUCH DAMAGE.
52 * ====================================================================
53 */
54
55 #include <string.h>
56
57 #include "cryptlib.h"
58 #include <openssl/asn1t.h>
59 #include <openssl/pem.h>
60 #include <openssl/x509v3.h>
61 #include <openssl/err.h>
62 #include <openssl/cms.h>
63 #include <openssl/aes.h>
64 #include "cms_lcl.h"
65 #include "asn1/asn1_locl.h"
66
67 /* Key Agreement Recipient Info (KARI) routines */
68
69 int
CMS_RecipientInfo_kari_get0_alg(CMS_RecipientInfo * ri,X509_ALGOR ** palg,ASN1_OCTET_STRING ** pukm)70 CMS_RecipientInfo_kari_get0_alg(CMS_RecipientInfo *ri, X509_ALGOR **palg,
71 ASN1_OCTET_STRING **pukm)
72 {
73 if (ri->type != CMS_RECIPINFO_AGREE) {
74 CMSerror(CMS_R_NOT_KEY_AGREEMENT);
75 return 0;
76 }
77 if (palg)
78 *palg = ri->d.kari->keyEncryptionAlgorithm;
79 if (pukm)
80 *pukm = ri->d.kari->ukm;
81
82 return 1;
83 }
84
85 /* Retrieve recipient encrypted keys from a kari */
86
STACK_OF(CMS_RecipientEncryptedKey)87 STACK_OF(CMS_RecipientEncryptedKey) *
88 CMS_RecipientInfo_kari_get0_reks(CMS_RecipientInfo *ri)
89 {
90 if (ri->type != CMS_RECIPINFO_AGREE) {
91 CMSerror(CMS_R_NOT_KEY_AGREEMENT);
92 return NULL;
93 }
94 return ri->d.kari->recipientEncryptedKeys;
95 }
96
97 int
CMS_RecipientInfo_kari_get0_orig_id(CMS_RecipientInfo * ri,X509_ALGOR ** pubalg,ASN1_BIT_STRING ** pubkey,ASN1_OCTET_STRING ** keyid,X509_NAME ** issuer,ASN1_INTEGER ** sno)98 CMS_RecipientInfo_kari_get0_orig_id(CMS_RecipientInfo *ri, X509_ALGOR **pubalg,
99 ASN1_BIT_STRING **pubkey, ASN1_OCTET_STRING **keyid, X509_NAME **issuer,
100 ASN1_INTEGER **sno)
101 {
102 CMS_OriginatorIdentifierOrKey *oik;
103
104 if (ri->type != CMS_RECIPINFO_AGREE) {
105 CMSerror(CMS_R_NOT_KEY_AGREEMENT);
106 return 0;
107 }
108 oik = ri->d.kari->originator;
109 if (issuer)
110 *issuer = NULL;
111 if (sno)
112 *sno = NULL;
113 if (keyid)
114 *keyid = NULL;
115 if (pubalg)
116 *pubalg = NULL;
117 if (pubkey)
118 *pubkey = NULL;
119 if (oik->type == CMS_OIK_ISSUER_SERIAL) {
120 if (issuer)
121 *issuer = oik->d.issuerAndSerialNumber->issuer;
122 if (sno)
123 *sno = oik->d.issuerAndSerialNumber->serialNumber;
124 } else if (oik->type == CMS_OIK_KEYIDENTIFIER) {
125 if (keyid)
126 *keyid = oik->d.subjectKeyIdentifier;
127 } else if (oik->type == CMS_OIK_PUBKEY) {
128 if (pubalg)
129 *pubalg = oik->d.originatorKey->algorithm;
130 if (pubkey)
131 *pubkey = oik->d.originatorKey->publicKey;
132 } else
133 return 0;
134
135 return 1;
136 }
137
138 int
CMS_RecipientInfo_kari_orig_id_cmp(CMS_RecipientInfo * ri,X509 * cert)139 CMS_RecipientInfo_kari_orig_id_cmp(CMS_RecipientInfo *ri, X509 *cert)
140 {
141 CMS_OriginatorIdentifierOrKey *oik;
142
143 if (ri->type != CMS_RECIPINFO_AGREE) {
144 CMSerror(CMS_R_NOT_KEY_AGREEMENT);
145 return -2;
146 }
147 oik = ri->d.kari->originator;
148 if (oik->type == CMS_OIK_ISSUER_SERIAL)
149 return cms_ias_cert_cmp(oik->d.issuerAndSerialNumber, cert);
150 else if (oik->type == CMS_OIK_KEYIDENTIFIER)
151 return cms_keyid_cert_cmp(oik->d.subjectKeyIdentifier, cert);
152
153 return -1;
154 }
155
156 int
CMS_RecipientEncryptedKey_get0_id(CMS_RecipientEncryptedKey * rek,ASN1_OCTET_STRING ** keyid,ASN1_GENERALIZEDTIME ** tm,CMS_OtherKeyAttribute ** other,X509_NAME ** issuer,ASN1_INTEGER ** sno)157 CMS_RecipientEncryptedKey_get0_id(CMS_RecipientEncryptedKey *rek,
158 ASN1_OCTET_STRING **keyid, ASN1_GENERALIZEDTIME **tm,
159 CMS_OtherKeyAttribute **other, X509_NAME **issuer, ASN1_INTEGER **sno)
160 {
161 CMS_KeyAgreeRecipientIdentifier *rid = rek->rid;
162
163 if (rid->type == CMS_REK_ISSUER_SERIAL) {
164 if (issuer)
165 *issuer = rid->d.issuerAndSerialNumber->issuer;
166 if (sno)
167 *sno = rid->d.issuerAndSerialNumber->serialNumber;
168 if (keyid)
169 *keyid = NULL;
170 if (tm)
171 *tm = NULL;
172 if (other)
173 *other = NULL;
174 } else if (rid->type == CMS_REK_KEYIDENTIFIER) {
175 if (keyid)
176 *keyid = rid->d.rKeyId->subjectKeyIdentifier;
177 if (tm)
178 *tm = rid->d.rKeyId->date;
179 if (other)
180 *other = rid->d.rKeyId->other;
181 if (issuer)
182 *issuer = NULL;
183 if (sno)
184 *sno = NULL;
185 } else
186 return 0;
187
188 return 1;
189 }
190
191 int
CMS_RecipientEncryptedKey_cert_cmp(CMS_RecipientEncryptedKey * rek,X509 * cert)192 CMS_RecipientEncryptedKey_cert_cmp(CMS_RecipientEncryptedKey *rek, X509 *cert)
193 {
194 CMS_KeyAgreeRecipientIdentifier *rid = rek->rid;
195
196 if (rid->type == CMS_REK_ISSUER_SERIAL)
197 return cms_ias_cert_cmp(rid->d.issuerAndSerialNumber, cert);
198 else if (rid->type == CMS_REK_KEYIDENTIFIER)
199 return cms_keyid_cert_cmp(rid->d.rKeyId->subjectKeyIdentifier, cert);
200 else
201 return -1;
202 }
203
204 int
CMS_RecipientInfo_kari_set0_pkey(CMS_RecipientInfo * ri,EVP_PKEY * pk)205 CMS_RecipientInfo_kari_set0_pkey(CMS_RecipientInfo *ri, EVP_PKEY *pk)
206 {
207 EVP_PKEY_CTX *pctx;
208 CMS_KeyAgreeRecipientInfo *kari = ri->d.kari;
209
210 EVP_PKEY_CTX_free(kari->pctx);
211 kari->pctx = NULL;
212 if (!pk)
213 return 1;
214 pctx = EVP_PKEY_CTX_new(pk, NULL);
215 if (!pctx || !EVP_PKEY_derive_init(pctx))
216 goto err;
217 kari->pctx = pctx;
218 return 1;
219
220 err:
221 EVP_PKEY_CTX_free(pctx);
222 return 0;
223 }
224
225 EVP_CIPHER_CTX *
CMS_RecipientInfo_kari_get0_ctx(CMS_RecipientInfo * ri)226 CMS_RecipientInfo_kari_get0_ctx(CMS_RecipientInfo *ri)
227 {
228 if (ri->type == CMS_RECIPINFO_AGREE)
229 return ri->d.kari->ctx;
230 return NULL;
231 }
232
233 /*
234 * Derive KEK and decrypt/encrypt with it to produce either the original CEK
235 * or the encrypted CEK.
236 */
237
238 static int
cms_kek_cipher(unsigned char ** pout,size_t * poutlen,const unsigned char * in,size_t inlen,CMS_KeyAgreeRecipientInfo * kari,int enc)239 cms_kek_cipher(unsigned char **pout, size_t *poutlen, const unsigned char *in,
240 size_t inlen, CMS_KeyAgreeRecipientInfo *kari, int enc)
241 {
242 /* Key encryption key */
243 unsigned char kek[EVP_MAX_KEY_LENGTH];
244 size_t keklen;
245 int rv = 0;
246 unsigned char *out = NULL;
247 int outlen;
248
249 keklen = EVP_CIPHER_CTX_key_length(kari->ctx);
250 if (keklen > EVP_MAX_KEY_LENGTH)
251 return 0;
252 /* Derive KEK */
253 if (EVP_PKEY_derive(kari->pctx, kek, &keklen) <= 0)
254 goto err;
255 /* Set KEK in context */
256 if (!EVP_CipherInit_ex(kari->ctx, NULL, NULL, kek, NULL, enc))
257 goto err;
258 /* obtain output length of ciphered key */
259 if (!EVP_CipherUpdate(kari->ctx, NULL, &outlen, in, inlen))
260 goto err;
261 out = malloc(outlen);
262 if (out == NULL)
263 goto err;
264 if (!EVP_CipherUpdate(kari->ctx, out, &outlen, in, inlen))
265 goto err;
266 *pout = out;
267 *poutlen = (size_t)outlen;
268 rv = 1;
269
270 err:
271 explicit_bzero(kek, keklen);
272 if (!rv)
273 free(out);
274 EVP_CIPHER_CTX_reset(kari->ctx);
275 /* FIXME: WHY IS kari->pctx freed here? /RL */
276 EVP_PKEY_CTX_free(kari->pctx);
277 kari->pctx = NULL;
278
279 return rv;
280 }
281
282 int
CMS_RecipientInfo_kari_decrypt(CMS_ContentInfo * cms,CMS_RecipientInfo * ri,CMS_RecipientEncryptedKey * rek)283 CMS_RecipientInfo_kari_decrypt(CMS_ContentInfo *cms, CMS_RecipientInfo *ri,
284 CMS_RecipientEncryptedKey *rek)
285 {
286 int rv = 0;
287 unsigned char *enckey = NULL, *cek = NULL;
288 size_t enckeylen;
289 size_t ceklen;
290 CMS_EncryptedContentInfo *ec;
291
292 enckeylen = rek->encryptedKey->length;
293 enckey = rek->encryptedKey->data;
294 /* Setup all parameters to derive KEK */
295 if (!cms_env_asn1_ctrl(ri, 1))
296 goto err;
297 /* Attempt to decrypt CEK */
298 if (!cms_kek_cipher(&cek, &ceklen, enckey, enckeylen, ri->d.kari, 0))
299 goto err;
300 ec = cms->d.envelopedData->encryptedContentInfo;
301 freezero(ec->key, ec->keylen);
302 ec->key = cek;
303 ec->keylen = ceklen;
304 cek = NULL;
305 rv = 1;
306
307 err:
308 free(cek);
309
310 return rv;
311 }
312
313 /* Create ephemeral key and initialise context based on it */
314 static int
cms_kari_create_ephemeral_key(CMS_KeyAgreeRecipientInfo * kari,EVP_PKEY * pk)315 cms_kari_create_ephemeral_key(CMS_KeyAgreeRecipientInfo *kari, EVP_PKEY *pk)
316 {
317 EVP_PKEY_CTX *pctx = NULL;
318 EVP_PKEY *ekey = NULL;
319 int rv = 0;
320
321 pctx = EVP_PKEY_CTX_new(pk, NULL);
322 if (!pctx)
323 goto err;
324 if (EVP_PKEY_keygen_init(pctx) <= 0)
325 goto err;
326 if (EVP_PKEY_keygen(pctx, &ekey) <= 0)
327 goto err;
328 EVP_PKEY_CTX_free(pctx);
329 pctx = EVP_PKEY_CTX_new(ekey, NULL);
330 if (!pctx)
331 goto err;
332 if (EVP_PKEY_derive_init(pctx) <= 0)
333 goto err;
334 kari->pctx = pctx;
335 rv = 1;
336
337 err:
338 if (!rv)
339 EVP_PKEY_CTX_free(pctx);
340 EVP_PKEY_free(ekey);
341
342 return rv;
343 }
344
345 /* Initialise a kari based on passed certificate and key */
346
347 int
cms_RecipientInfo_kari_init(CMS_RecipientInfo * ri,X509 * recip,EVP_PKEY * pk,unsigned int flags)348 cms_RecipientInfo_kari_init(CMS_RecipientInfo *ri, X509 *recip, EVP_PKEY *pk,
349 unsigned int flags)
350 {
351 CMS_KeyAgreeRecipientInfo *kari;
352 CMS_RecipientEncryptedKey *rek = NULL;
353
354 ri->d.kari = (CMS_KeyAgreeRecipientInfo *)ASN1_item_new(&CMS_KeyAgreeRecipientInfo_it);
355 if (!ri->d.kari)
356 return 0;
357 ri->type = CMS_RECIPINFO_AGREE;
358
359 kari = ri->d.kari;
360 kari->version = 3;
361
362 rek = (CMS_RecipientEncryptedKey *)ASN1_item_new(&CMS_RecipientEncryptedKey_it);
363 if (rek == NULL)
364 return 0;
365
366 if (!sk_CMS_RecipientEncryptedKey_push(kari->recipientEncryptedKeys, rek)) {
367 ASN1_item_free((ASN1_VALUE *)rek, &CMS_RecipientEncryptedKey_it);
368 return 0;
369 }
370
371 if (flags & CMS_USE_KEYID) {
372 rek->rid->type = CMS_REK_KEYIDENTIFIER;
373 rek->rid->d.rKeyId = (CMS_RecipientKeyIdentifier *)ASN1_item_new(&CMS_RecipientKeyIdentifier_it);
374 if (rek->rid->d.rKeyId == NULL)
375 return 0;
376 if (!cms_set1_keyid(&rek->rid->d.rKeyId->subjectKeyIdentifier, recip))
377 return 0;
378 } else {
379 rek->rid->type = CMS_REK_ISSUER_SERIAL;
380 if (!cms_set1_ias(&rek->rid->d.issuerAndSerialNumber, recip))
381 return 0;
382 }
383
384 /* Create ephemeral key */
385 if (!cms_kari_create_ephemeral_key(kari, pk))
386 return 0;
387
388 EVP_PKEY_up_ref(pk);
389 rek->pkey = pk;
390
391 return 1;
392 }
393
394 static int
cms_wrap_init(CMS_KeyAgreeRecipientInfo * kari,const EVP_CIPHER * cipher)395 cms_wrap_init(CMS_KeyAgreeRecipientInfo *kari, const EVP_CIPHER *cipher)
396 {
397 EVP_CIPHER_CTX *ctx = kari->ctx;
398 const EVP_CIPHER *kekcipher;
399 int keylen = EVP_CIPHER_key_length(cipher);
400
401 /* If a suitable wrap algorithm is already set nothing to do */
402 kekcipher = EVP_CIPHER_CTX_cipher(ctx);
403
404 if (kekcipher) {
405 if (EVP_CIPHER_CTX_mode(ctx) != EVP_CIPH_WRAP_MODE)
406 return 0;
407 return 1;
408 }
409 /*
410 * Pick a cipher based on content encryption cipher. If it is DES3 use
411 * DES3 wrap otherwise use AES wrap similar to key size.
412 */
413 #ifndef OPENSSL_NO_DES
414 #if 0
415 /*
416 * XXX - we do not currently support DES3 wrap and probably should just
417 * drop this code.
418 */
419 if (EVP_CIPHER_type(cipher) == NID_des_ede3_cbc)
420 kekcipher = EVP_des_ede3_wrap();
421 else
422 #endif
423 #endif
424 if (keylen <= 16)
425 kekcipher = EVP_aes_128_wrap();
426 else if (keylen <= 24)
427 kekcipher = EVP_aes_192_wrap();
428 else
429 kekcipher = EVP_aes_256_wrap();
430
431 return EVP_EncryptInit_ex(ctx, kekcipher, NULL, NULL, NULL);
432 }
433
434 /* Encrypt content key in key agreement recipient info */
435
436 int
cms_RecipientInfo_kari_encrypt(CMS_ContentInfo * cms,CMS_RecipientInfo * ri)437 cms_RecipientInfo_kari_encrypt(CMS_ContentInfo *cms, CMS_RecipientInfo *ri)
438 {
439 CMS_KeyAgreeRecipientInfo *kari;
440 CMS_EncryptedContentInfo *ec;
441 CMS_RecipientEncryptedKey *rek;
442 STACK_OF(CMS_RecipientEncryptedKey) *reks;
443 int i;
444
445 if (ri->type != CMS_RECIPINFO_AGREE) {
446 CMSerror(CMS_R_NOT_KEY_AGREEMENT);
447 return 0;
448 }
449 kari = ri->d.kari;
450 reks = kari->recipientEncryptedKeys;
451 ec = cms->d.envelopedData->encryptedContentInfo;
452 /* Initialise wrap algorithm parameters */
453 if (!cms_wrap_init(kari, ec->cipher))
454 return 0;
455 /*
456 * If no originator key set up initialise for ephemeral key the public key
457 * ASN1 structure will set the actual public key value.
458 */
459 if (kari->originator->type == -1) {
460 CMS_OriginatorIdentifierOrKey *oik = kari->originator;
461 oik->type = CMS_OIK_PUBKEY;
462 oik->d.originatorKey = (CMS_OriginatorPublicKey *)ASN1_item_new(&CMS_OriginatorPublicKey_it);
463 if (!oik->d.originatorKey)
464 return 0;
465 }
466 /* Initialise KDF algorithm */
467 if (!cms_env_asn1_ctrl(ri, 0))
468 return 0;
469 /* For each rek, derive KEK, encrypt CEK */
470 for (i = 0; i < sk_CMS_RecipientEncryptedKey_num(reks); i++) {
471 unsigned char *enckey;
472 size_t enckeylen;
473 rek = sk_CMS_RecipientEncryptedKey_value(reks, i);
474 if (EVP_PKEY_derive_set_peer(kari->pctx, rek->pkey) <= 0)
475 return 0;
476 if (!cms_kek_cipher(&enckey, &enckeylen, ec->key, ec->keylen,
477 kari, 1))
478 return 0;
479 ASN1_STRING_set0(rek->encryptedKey, enckey, enckeylen);
480 }
481
482 return 1;
483 }
484