1 /*
2 * Copyright 2013-2021 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 * Low level key APIs (DH etc) are deprecated for public use, but still ok for
12 * internal use.
13 */
14 #include "internal/deprecated.h"
15
16 #include "internal/cryptlib.h"
17 #include <openssl/asn1t.h>
18 #include <openssl/pem.h>
19 #include <openssl/x509v3.h>
20 #include <openssl/err.h>
21 #include <openssl/cms.h>
22 #include <openssl/aes.h>
23 #include "cms_local.h"
24 #include "crypto/asn1.h"
25
26 /* Key Agreement Recipient Info (KARI) routines */
27
CMS_RecipientInfo_kari_get0_alg(CMS_RecipientInfo * ri,X509_ALGOR ** palg,ASN1_OCTET_STRING ** pukm)28 int CMS_RecipientInfo_kari_get0_alg(CMS_RecipientInfo *ri,
29 X509_ALGOR **palg,
30 ASN1_OCTET_STRING **pukm)
31 {
32 if (ri->type != CMS_RECIPINFO_AGREE) {
33 ERR_raise(ERR_LIB_CMS, CMS_R_NOT_KEY_AGREEMENT);
34 return 0;
35 }
36 if (palg)
37 *palg = ri->d.kari->keyEncryptionAlgorithm;
38 if (pukm)
39 *pukm = ri->d.kari->ukm;
40 return 1;
41 }
42
43 /* Retrieve recipient encrypted keys from a kari */
44
STACK_OF(CMS_RecipientEncryptedKey)45 STACK_OF(CMS_RecipientEncryptedKey)
46 *CMS_RecipientInfo_kari_get0_reks(CMS_RecipientInfo *ri)
47 {
48 if (ri->type != CMS_RECIPINFO_AGREE) {
49 ERR_raise(ERR_LIB_CMS, CMS_R_NOT_KEY_AGREEMENT);
50 return NULL;
51 }
52 return ri->d.kari->recipientEncryptedKeys;
53 }
54
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)55 int CMS_RecipientInfo_kari_get0_orig_id(CMS_RecipientInfo *ri,
56 X509_ALGOR **pubalg,
57 ASN1_BIT_STRING **pubkey,
58 ASN1_OCTET_STRING **keyid,
59 X509_NAME **issuer,
60 ASN1_INTEGER **sno)
61 {
62 CMS_OriginatorIdentifierOrKey *oik;
63
64 if (ri->type != CMS_RECIPINFO_AGREE) {
65 ERR_raise(ERR_LIB_CMS, CMS_R_NOT_KEY_AGREEMENT);
66 return 0;
67 }
68 oik = ri->d.kari->originator;
69 if (issuer)
70 *issuer = NULL;
71 if (sno)
72 *sno = NULL;
73 if (keyid)
74 *keyid = NULL;
75 if (pubalg)
76 *pubalg = NULL;
77 if (pubkey)
78 *pubkey = NULL;
79 if (oik->type == CMS_OIK_ISSUER_SERIAL) {
80 if (issuer)
81 *issuer = oik->d.issuerAndSerialNumber->issuer;
82 if (sno)
83 *sno = oik->d.issuerAndSerialNumber->serialNumber;
84 } else if (oik->type == CMS_OIK_KEYIDENTIFIER) {
85 if (keyid)
86 *keyid = oik->d.subjectKeyIdentifier;
87 } else if (oik->type == CMS_OIK_PUBKEY) {
88 if (pubalg)
89 *pubalg = oik->d.originatorKey->algorithm;
90 if (pubkey)
91 *pubkey = oik->d.originatorKey->publicKey;
92 } else
93 return 0;
94 return 1;
95 }
96
CMS_RecipientInfo_kari_orig_id_cmp(CMS_RecipientInfo * ri,X509 * cert)97 int CMS_RecipientInfo_kari_orig_id_cmp(CMS_RecipientInfo *ri, X509 *cert)
98 {
99 CMS_OriginatorIdentifierOrKey *oik;
100
101 if (ri->type != CMS_RECIPINFO_AGREE) {
102 ERR_raise(ERR_LIB_CMS, CMS_R_NOT_KEY_AGREEMENT);
103 return -2;
104 }
105 oik = ri->d.kari->originator;
106 if (oik->type == CMS_OIK_ISSUER_SERIAL)
107 return ossl_cms_ias_cert_cmp(oik->d.issuerAndSerialNumber, cert);
108 else if (oik->type == CMS_OIK_KEYIDENTIFIER)
109 return ossl_cms_keyid_cert_cmp(oik->d.subjectKeyIdentifier, cert);
110 return -1;
111 }
112
CMS_RecipientEncryptedKey_get0_id(CMS_RecipientEncryptedKey * rek,ASN1_OCTET_STRING ** keyid,ASN1_GENERALIZEDTIME ** tm,CMS_OtherKeyAttribute ** other,X509_NAME ** issuer,ASN1_INTEGER ** sno)113 int CMS_RecipientEncryptedKey_get0_id(CMS_RecipientEncryptedKey *rek,
114 ASN1_OCTET_STRING **keyid,
115 ASN1_GENERALIZEDTIME **tm,
116 CMS_OtherKeyAttribute **other,
117 X509_NAME **issuer, ASN1_INTEGER **sno)
118 {
119 CMS_KeyAgreeRecipientIdentifier *rid = rek->rid;
120
121 if (rid->type == CMS_REK_ISSUER_SERIAL) {
122 if (issuer)
123 *issuer = rid->d.issuerAndSerialNumber->issuer;
124 if (sno)
125 *sno = rid->d.issuerAndSerialNumber->serialNumber;
126 if (keyid)
127 *keyid = NULL;
128 if (tm)
129 *tm = NULL;
130 if (other)
131 *other = NULL;
132 } else if (rid->type == CMS_REK_KEYIDENTIFIER) {
133 if (keyid)
134 *keyid = rid->d.rKeyId->subjectKeyIdentifier;
135 if (tm)
136 *tm = rid->d.rKeyId->date;
137 if (other)
138 *other = rid->d.rKeyId->other;
139 if (issuer)
140 *issuer = NULL;
141 if (sno)
142 *sno = NULL;
143 } else
144 return 0;
145 return 1;
146 }
147
CMS_RecipientEncryptedKey_cert_cmp(CMS_RecipientEncryptedKey * rek,X509 * cert)148 int CMS_RecipientEncryptedKey_cert_cmp(CMS_RecipientEncryptedKey *rek,
149 X509 *cert)
150 {
151 CMS_KeyAgreeRecipientIdentifier *rid = rek->rid;
152
153 if (rid->type == CMS_REK_ISSUER_SERIAL)
154 return ossl_cms_ias_cert_cmp(rid->d.issuerAndSerialNumber, cert);
155 else if (rid->type == CMS_REK_KEYIDENTIFIER)
156 return ossl_cms_keyid_cert_cmp(rid->d.rKeyId->subjectKeyIdentifier,
157 cert);
158 else
159 return -1;
160 }
161
CMS_RecipientInfo_kari_set0_pkey_and_peer(CMS_RecipientInfo * ri,EVP_PKEY * pk,X509 * peer)162 int CMS_RecipientInfo_kari_set0_pkey_and_peer(CMS_RecipientInfo *ri,
163 EVP_PKEY *pk, X509 *peer)
164 {
165 EVP_PKEY_CTX *pctx;
166 CMS_KeyAgreeRecipientInfo *kari = ri->d.kari;
167
168 EVP_PKEY_CTX_free(kari->pctx);
169 kari->pctx = NULL;
170 if (pk == NULL)
171 return 1;
172
173 pctx = EVP_PKEY_CTX_new_from_pkey(ossl_cms_ctx_get0_libctx(kari->cms_ctx),
174 pk,
175 ossl_cms_ctx_get0_propq(kari->cms_ctx));
176 if (pctx == NULL || EVP_PKEY_derive_init(pctx) <= 0)
177 goto err;
178
179 if (peer != NULL) {
180 EVP_PKEY *pub_pkey = X509_get0_pubkey(peer);
181
182 if (EVP_PKEY_derive_set_peer(pctx, pub_pkey) <= 0)
183 goto err;
184 }
185
186 kari->pctx = pctx;
187 return 1;
188 err:
189 EVP_PKEY_CTX_free(pctx);
190 return 0;
191 }
192
CMS_RecipientInfo_kari_set0_pkey(CMS_RecipientInfo * ri,EVP_PKEY * pk)193 int CMS_RecipientInfo_kari_set0_pkey(CMS_RecipientInfo *ri, EVP_PKEY *pk)
194 {
195 return CMS_RecipientInfo_kari_set0_pkey_and_peer(ri, pk, NULL);
196 }
197
CMS_RecipientInfo_kari_get0_ctx(CMS_RecipientInfo * ri)198 EVP_CIPHER_CTX *CMS_RecipientInfo_kari_get0_ctx(CMS_RecipientInfo *ri)
199 {
200 if (ri->type == CMS_RECIPINFO_AGREE)
201 return ri->d.kari->ctx;
202 return NULL;
203 }
204
205 /*
206 * Derive KEK and decrypt/encrypt with it to produce either the original CEK
207 * or the encrypted CEK.
208 */
209
cms_kek_cipher(unsigned char ** pout,size_t * poutlen,const unsigned char * in,size_t inlen,CMS_KeyAgreeRecipientInfo * kari,int enc)210 static int cms_kek_cipher(unsigned char **pout, size_t *poutlen,
211 const unsigned char *in, size_t inlen,
212 CMS_KeyAgreeRecipientInfo *kari, int enc)
213 {
214 /* Key encryption key */
215 unsigned char kek[EVP_MAX_KEY_LENGTH];
216 size_t keklen;
217 int rv = 0;
218 unsigned char *out = NULL;
219 int outlen;
220
221 keklen = EVP_CIPHER_CTX_get_key_length(kari->ctx);
222 if (keklen > EVP_MAX_KEY_LENGTH)
223 return 0;
224 /* Derive KEK */
225 if (EVP_PKEY_derive(kari->pctx, kek, &keklen) <= 0)
226 goto err;
227 /* Set KEK in context */
228 if (!EVP_CipherInit_ex(kari->ctx, NULL, NULL, kek, NULL, enc))
229 goto err;
230 /* obtain output length of ciphered key */
231 if (!EVP_CipherUpdate(kari->ctx, NULL, &outlen, in, inlen))
232 goto err;
233 out = OPENSSL_malloc(outlen);
234 if (out == NULL)
235 goto err;
236 if (!EVP_CipherUpdate(kari->ctx, out, &outlen, in, inlen))
237 goto err;
238 *pout = out;
239 *poutlen = (size_t)outlen;
240 rv = 1;
241
242 err:
243 OPENSSL_cleanse(kek, keklen);
244 if (!rv)
245 OPENSSL_free(out);
246 EVP_CIPHER_CTX_reset(kari->ctx);
247 /* FIXME: WHY IS kari->pctx freed here? /RL */
248 EVP_PKEY_CTX_free(kari->pctx);
249 kari->pctx = NULL;
250 return rv;
251 }
252
CMS_RecipientInfo_kari_decrypt(CMS_ContentInfo * cms,CMS_RecipientInfo * ri,CMS_RecipientEncryptedKey * rek)253 int CMS_RecipientInfo_kari_decrypt(CMS_ContentInfo *cms,
254 CMS_RecipientInfo *ri,
255 CMS_RecipientEncryptedKey *rek)
256 {
257 int rv = 0;
258 unsigned char *enckey = NULL, *cek = NULL;
259 size_t enckeylen;
260 size_t ceklen;
261 CMS_EncryptedContentInfo *ec;
262
263 enckeylen = rek->encryptedKey->length;
264 enckey = rek->encryptedKey->data;
265 /* Setup all parameters to derive KEK */
266 if (!ossl_cms_env_asn1_ctrl(ri, 1))
267 goto err;
268 /* Attempt to decrypt CEK */
269 if (!cms_kek_cipher(&cek, &ceklen, enckey, enckeylen, ri->d.kari, 0))
270 goto err;
271 ec = ossl_cms_get0_env_enc_content(cms);
272 OPENSSL_clear_free(ec->key, ec->keylen);
273 ec->key = cek;
274 ec->keylen = ceklen;
275 cek = NULL;
276 rv = 1;
277 err:
278 OPENSSL_free(cek);
279 return rv;
280 }
281
282 /* Create ephemeral key and initialise context based on it */
cms_kari_create_ephemeral_key(CMS_KeyAgreeRecipientInfo * kari,EVP_PKEY * pk)283 static int cms_kari_create_ephemeral_key(CMS_KeyAgreeRecipientInfo *kari,
284 EVP_PKEY *pk)
285 {
286 EVP_PKEY_CTX *pctx = NULL;
287 EVP_PKEY *ekey = NULL;
288 int rv = 0;
289 const CMS_CTX *ctx = kari->cms_ctx;
290 OSSL_LIB_CTX *libctx = ossl_cms_ctx_get0_libctx(ctx);
291 const char *propq = ossl_cms_ctx_get0_propq(ctx);
292
293 pctx = EVP_PKEY_CTX_new_from_pkey(libctx, pk, propq);
294 if (pctx == NULL)
295 goto err;
296 if (EVP_PKEY_keygen_init(pctx) <= 0)
297 goto err;
298 if (EVP_PKEY_keygen(pctx, &ekey) <= 0)
299 goto err;
300 EVP_PKEY_CTX_free(pctx);
301 pctx = EVP_PKEY_CTX_new_from_pkey(libctx, ekey, propq);
302 if (pctx == NULL)
303 goto err;
304 if (EVP_PKEY_derive_init(pctx) <= 0)
305 goto err;
306 kari->pctx = pctx;
307 rv = 1;
308 err:
309 if (!rv)
310 EVP_PKEY_CTX_free(pctx);
311 EVP_PKEY_free(ekey);
312 return rv;
313 }
314
315 /* Set originator private key and initialise context based on it */
cms_kari_set_originator_private_key(CMS_KeyAgreeRecipientInfo * kari,EVP_PKEY * originatorPrivKey)316 static int cms_kari_set_originator_private_key(CMS_KeyAgreeRecipientInfo *kari,
317 EVP_PKEY *originatorPrivKey )
318 {
319 EVP_PKEY_CTX *pctx = NULL;
320 int rv = 0;
321 const CMS_CTX *ctx = kari->cms_ctx;
322
323 pctx = EVP_PKEY_CTX_new_from_pkey(ossl_cms_ctx_get0_libctx(ctx),
324 originatorPrivKey,
325 ossl_cms_ctx_get0_propq(ctx));
326 if (pctx == NULL)
327 goto err;
328 if (EVP_PKEY_derive_init(pctx) <= 0)
329 goto err;
330
331 kari->pctx = pctx;
332 rv = 1;
333 err:
334 if (rv == 0)
335 EVP_PKEY_CTX_free(pctx);
336 return rv;
337 }
338
339 /* Initialise a kari based on passed certificate and key */
340
ossl_cms_RecipientInfo_kari_init(CMS_RecipientInfo * ri,X509 * recip,EVP_PKEY * recipPubKey,X509 * originator,EVP_PKEY * originatorPrivKey,unsigned int flags,const CMS_CTX * ctx)341 int ossl_cms_RecipientInfo_kari_init(CMS_RecipientInfo *ri, X509 *recip,
342 EVP_PKEY *recipPubKey, X509 *originator,
343 EVP_PKEY *originatorPrivKey,
344 unsigned int flags, const CMS_CTX *ctx)
345 {
346 CMS_KeyAgreeRecipientInfo *kari;
347 CMS_RecipientEncryptedKey *rek = NULL;
348
349 ri->d.kari = M_ASN1_new_of(CMS_KeyAgreeRecipientInfo);
350 if (ri->d.kari == NULL)
351 return 0;
352 ri->type = CMS_RECIPINFO_AGREE;
353
354 kari = ri->d.kari;
355 kari->version = 3;
356 kari->cms_ctx = ctx;
357
358 rek = M_ASN1_new_of(CMS_RecipientEncryptedKey);
359 if (rek == NULL)
360 return 0;
361
362 if (!sk_CMS_RecipientEncryptedKey_push(kari->recipientEncryptedKeys, rek)) {
363 M_ASN1_free_of(rek, CMS_RecipientEncryptedKey);
364 return 0;
365 }
366
367 if (flags & CMS_USE_KEYID) {
368 rek->rid->type = CMS_REK_KEYIDENTIFIER;
369 rek->rid->d.rKeyId = M_ASN1_new_of(CMS_RecipientKeyIdentifier);
370 if (rek->rid->d.rKeyId == NULL)
371 return 0;
372 if (!ossl_cms_set1_keyid(&rek->rid->d.rKeyId->subjectKeyIdentifier, recip))
373 return 0;
374 } else {
375 rek->rid->type = CMS_REK_ISSUER_SERIAL;
376 if (!ossl_cms_set1_ias(&rek->rid->d.issuerAndSerialNumber, recip))
377 return 0;
378 }
379
380 if (originatorPrivKey == NULL && originator == NULL) {
381 /* Create ephemeral key */
382 if (!cms_kari_create_ephemeral_key(kari, recipPubKey))
383 return 0;
384 } else {
385 /* Use originator key */
386 CMS_OriginatorIdentifierOrKey *oik = ri->d.kari->originator;
387
388 if (originatorPrivKey == NULL || originator == NULL)
389 return 0;
390
391 if (flags & CMS_USE_ORIGINATOR_KEYID) {
392 oik->type = CMS_OIK_KEYIDENTIFIER;
393 oik->d.subjectKeyIdentifier = ASN1_OCTET_STRING_new();
394 if (oik->d.subjectKeyIdentifier == NULL)
395 return 0;
396 if (!ossl_cms_set1_keyid(&oik->d.subjectKeyIdentifier, originator))
397 return 0;
398 } else {
399 oik->type = CMS_REK_ISSUER_SERIAL;
400 if (!ossl_cms_set1_ias(&oik->d.issuerAndSerialNumber, originator))
401 return 0;
402 }
403
404 if (!cms_kari_set_originator_private_key(kari, originatorPrivKey))
405 return 0;
406 }
407
408 EVP_PKEY_up_ref(recipPubKey);
409 rek->pkey = recipPubKey;
410 return 1;
411 }
412
cms_wrap_init(CMS_KeyAgreeRecipientInfo * kari,const EVP_CIPHER * cipher)413 static int cms_wrap_init(CMS_KeyAgreeRecipientInfo *kari,
414 const EVP_CIPHER *cipher)
415 {
416 const CMS_CTX *cms_ctx = kari->cms_ctx;
417 EVP_CIPHER_CTX *ctx = kari->ctx;
418 const EVP_CIPHER *kekcipher;
419 EVP_CIPHER *fetched_kekcipher;
420 const char *kekcipher_name;
421 int keylen;
422 int ret;
423
424 /* If a suitable wrap algorithm is already set nothing to do */
425 kekcipher = EVP_CIPHER_CTX_get0_cipher(ctx);
426 if (kekcipher != NULL) {
427 if (EVP_CIPHER_CTX_get_mode(ctx) != EVP_CIPH_WRAP_MODE)
428 return 0;
429 return 1;
430 }
431 if (cipher == NULL)
432 return 0;
433 keylen = EVP_CIPHER_get_key_length(cipher);
434 if ((EVP_CIPHER_get_flags(cipher) & EVP_CIPH_FLAG_GET_WRAP_CIPHER) != 0) {
435 ret = EVP_CIPHER_meth_get_ctrl(cipher)(NULL, EVP_CTRL_GET_WRAP_CIPHER,
436 0, &kekcipher);
437 if (ret <= 0)
438 return 0;
439
440 if (kekcipher != NULL) {
441 if (EVP_CIPHER_get_mode(kekcipher) != EVP_CIPH_WRAP_MODE)
442 return 0;
443 kekcipher_name = EVP_CIPHER_get0_name(kekcipher);
444 goto enc;
445 }
446 }
447
448 /*
449 * Pick a cipher based on content encryption cipher. If it is DES3 use
450 * DES3 wrap otherwise use AES wrap similar to key size.
451 */
452 #ifndef OPENSSL_NO_DES
453 if (EVP_CIPHER_get_type(cipher) == NID_des_ede3_cbc)
454 kekcipher_name = SN_id_smime_alg_CMS3DESwrap;
455 else
456 #endif
457 if (keylen <= 16)
458 kekcipher_name = SN_id_aes128_wrap;
459 else if (keylen <= 24)
460 kekcipher_name = SN_id_aes192_wrap;
461 else
462 kekcipher_name = SN_id_aes256_wrap;
463 enc:
464 fetched_kekcipher = EVP_CIPHER_fetch(ossl_cms_ctx_get0_libctx(cms_ctx),
465 kekcipher_name,
466 ossl_cms_ctx_get0_propq(cms_ctx));
467 if (fetched_kekcipher == NULL)
468 return 0;
469 ret = EVP_EncryptInit_ex(ctx, fetched_kekcipher, NULL, NULL, NULL);
470 EVP_CIPHER_free(fetched_kekcipher);
471 return ret;
472 }
473
474 /* Encrypt content key in key agreement recipient info */
475
ossl_cms_RecipientInfo_kari_encrypt(const CMS_ContentInfo * cms,CMS_RecipientInfo * ri)476 int ossl_cms_RecipientInfo_kari_encrypt(const CMS_ContentInfo *cms,
477 CMS_RecipientInfo *ri)
478 {
479 CMS_KeyAgreeRecipientInfo *kari;
480 CMS_EncryptedContentInfo *ec;
481 CMS_RecipientEncryptedKey *rek;
482 STACK_OF(CMS_RecipientEncryptedKey) *reks;
483 int i;
484
485 if (ri->type != CMS_RECIPINFO_AGREE) {
486 ERR_raise(ERR_LIB_CMS, CMS_R_NOT_KEY_AGREEMENT);
487 return 0;
488 }
489 kari = ri->d.kari;
490 reks = kari->recipientEncryptedKeys;
491 ec = ossl_cms_get0_env_enc_content(cms);
492 /* Initialise wrap algorithm parameters */
493 if (!cms_wrap_init(kari, ec->cipher))
494 return 0;
495 /*
496 * If no originator key set up initialise for ephemeral key the public key
497 * ASN1 structure will set the actual public key value.
498 */
499 if (kari->originator->type == -1) {
500 CMS_OriginatorIdentifierOrKey *oik = kari->originator;
501 oik->type = CMS_OIK_PUBKEY;
502 oik->d.originatorKey = M_ASN1_new_of(CMS_OriginatorPublicKey);
503 if (!oik->d.originatorKey)
504 return 0;
505 }
506 /* Initialise KDF algorithm */
507 if (!ossl_cms_env_asn1_ctrl(ri, 0))
508 return 0;
509 /* For each rek, derive KEK, encrypt CEK */
510 for (i = 0; i < sk_CMS_RecipientEncryptedKey_num(reks); i++) {
511 unsigned char *enckey;
512 size_t enckeylen;
513 rek = sk_CMS_RecipientEncryptedKey_value(reks, i);
514 if (EVP_PKEY_derive_set_peer(kari->pctx, rek->pkey) <= 0)
515 return 0;
516 if (!cms_kek_cipher(&enckey, &enckeylen, ec->key, ec->keylen,
517 kari, 1))
518 return 0;
519 ASN1_STRING_set0(rek->encryptedKey, enckey, enckeylen);
520 }
521
522 return 1;
523 }
524