1/* Copyright (c) 2014, Google Inc.
2 *
3 * Permission to use, copy, modify, and/or distribute this software for any
4 * purpose with or without fee is hereby granted, provided that the above
5 * copyright notice and this permission notice appear in all copies.
6 *
7 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
8 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
10 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
11 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
12 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
13 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
14
15#include <openssl/x509.h>
16
17#include <assert.h>
18#include <limits.h>
19
20#include <openssl/bytestring.h>
21#include <openssl/err.h>
22#include <openssl/mem.h>
23#include <openssl/obj.h>
24#include <openssl/pem.h>
25#include <openssl/stack.h>
26
27#include "../bytestring/internal.h"
28
29
30/* 1.2.840.113549.1.7.1 */
31static const uint8_t kPKCS7Data[] = {0x2a, 0x86, 0x48, 0x86, 0xf7,
32                                     0x0d, 0x01, 0x07, 0x01};
33
34/* 1.2.840.113549.1.7.2 */
35static const uint8_t kPKCS7SignedData[] = {0x2a, 0x86, 0x48, 0x86, 0xf7,
36                                           0x0d, 0x01, 0x07, 0x02};
37
38/* pkcs7_parse_header reads the non-certificate/non-CRL prefix of a PKCS#7
39 * SignedData blob from |cbs| and sets |*out| to point to the rest of the
40 * input. If the input is in BER format, then |*der_bytes| will be set to a
41 * pointer that needs to be freed by the caller once they have finished
42 * processing |*out| (which will be pointing into |*der_bytes|).
43 *
44 * It returns one on success or zero on error. On error, |*der_bytes| is
45 * NULL. */
46static int pkcs7_parse_header(uint8_t **der_bytes, CBS *out, CBS *cbs) {
47  size_t der_len;
48  CBS in, content_info, content_type, wrapped_signed_data, signed_data;
49  uint64_t version;
50
51  /* The input may be in BER format. */
52  *der_bytes = NULL;
53  if (!CBS_asn1_ber_to_der(cbs, der_bytes, &der_len)) {
54    return 0;
55  }
56  if (*der_bytes != NULL) {
57    CBS_init(&in, *der_bytes, der_len);
58  } else {
59    CBS_init(&in, CBS_data(cbs), CBS_len(cbs));
60  }
61
62  /* See https://tools.ietf.org/html/rfc2315#section-7 */
63  if (!CBS_get_asn1(&in, &content_info, CBS_ASN1_SEQUENCE) ||
64      !CBS_get_asn1(&content_info, &content_type, CBS_ASN1_OBJECT)) {
65    goto err;
66  }
67
68  if (!CBS_mem_equal(&content_type, kPKCS7SignedData,
69                     sizeof(kPKCS7SignedData))) {
70    OPENSSL_PUT_ERROR(X509, X509_R_NOT_PKCS7_SIGNED_DATA);
71    goto err;
72  }
73
74  /* See https://tools.ietf.org/html/rfc2315#section-9.1 */
75  if (!CBS_get_asn1(&content_info, &wrapped_signed_data,
76                    CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0) ||
77      !CBS_get_asn1(&wrapped_signed_data, &signed_data, CBS_ASN1_SEQUENCE) ||
78      !CBS_get_asn1_uint64(&signed_data, &version) ||
79      !CBS_get_asn1(&signed_data, NULL /* digests */, CBS_ASN1_SET) ||
80      !CBS_get_asn1(&signed_data, NULL /* content */, CBS_ASN1_SEQUENCE)) {
81    goto err;
82  }
83
84  if (version < 1) {
85    OPENSSL_PUT_ERROR(X509, X509_R_BAD_PKCS7_VERSION);
86    goto err;
87  }
88
89  CBS_init(out, CBS_data(&signed_data), CBS_len(&signed_data));
90  return 1;
91
92err:
93  OPENSSL_free(*der_bytes);
94  *der_bytes = NULL;
95  return 0;
96}
97
98int PKCS7_get_certificates(STACK_OF(X509) *out_certs, CBS *cbs) {
99  CBS signed_data, certificates;
100  uint8_t *der_bytes = NULL;
101  int ret = 0;
102  const size_t initial_certs_len = sk_X509_num(out_certs);
103
104  if (!pkcs7_parse_header(&der_bytes, &signed_data, cbs)) {
105    return 0;
106  }
107
108  /* See https://tools.ietf.org/html/rfc2315#section-9.1 */
109  if (!CBS_get_asn1(&signed_data, &certificates,
110                    CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0)) {
111    OPENSSL_PUT_ERROR(X509, X509_R_NO_CERTIFICATES_INCLUDED);
112    goto err;
113  }
114
115  while (CBS_len(&certificates) > 0) {
116    CBS cert;
117    X509 *x509;
118    const uint8_t *inp;
119
120    if (!CBS_get_asn1_element(&certificates, &cert, CBS_ASN1_SEQUENCE)) {
121      goto err;
122    }
123
124    if (CBS_len(&cert) > LONG_MAX) {
125      goto err;
126    }
127    inp = CBS_data(&cert);
128    x509 = d2i_X509(NULL, &inp, (long)CBS_len(&cert));
129    if (!x509) {
130      goto err;
131    }
132
133    assert(inp == CBS_data(&cert) + CBS_len(&cert));
134
135    if (sk_X509_push(out_certs, x509) == 0) {
136      X509_free(x509);
137      goto err;
138    }
139  }
140
141  ret = 1;
142
143err:
144  OPENSSL_free(der_bytes);
145
146  if (!ret) {
147    while (sk_X509_num(out_certs) != initial_certs_len) {
148      X509 *x509 = sk_X509_pop(out_certs);
149      X509_free(x509);
150    }
151  }
152
153  return ret;
154}
155
156int PKCS7_get_CRLs(STACK_OF(X509_CRL) *out_crls, CBS *cbs) {
157  CBS signed_data, crls;
158  uint8_t *der_bytes = NULL;
159  int ret = 0;
160  const size_t initial_crls_len = sk_X509_CRL_num(out_crls);
161
162  if (!pkcs7_parse_header(&der_bytes, &signed_data, cbs)) {
163    return 0;
164  }
165
166  /* See https://tools.ietf.org/html/rfc2315#section-9.1 */
167
168  /* Even if only CRLs are included, there may be an empty certificates block.
169   * OpenSSL does this, for example. */
170  if (CBS_peek_asn1_tag(&signed_data,
171                        CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0) &&
172      !CBS_get_asn1(&signed_data, NULL /* certificates */,
173                    CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0)) {
174    goto err;
175  }
176
177  if (!CBS_get_asn1(&signed_data, &crls,
178                    CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 1)) {
179    OPENSSL_PUT_ERROR(X509, X509_R_NO_CRLS_INCLUDED);
180    goto err;
181  }
182
183  while (CBS_len(&crls) > 0) {
184    CBS crl_data;
185    X509_CRL *crl;
186    const uint8_t *inp;
187
188    if (!CBS_get_asn1_element(&crls, &crl_data, CBS_ASN1_SEQUENCE)) {
189      goto err;
190    }
191
192    if (CBS_len(&crl_data) > LONG_MAX) {
193      goto err;
194    }
195    inp = CBS_data(&crl_data);
196    crl = d2i_X509_CRL(NULL, &inp, (long)CBS_len(&crl_data));
197    if (!crl) {
198      goto err;
199    }
200
201    assert(inp == CBS_data(&crl_data) + CBS_len(&crl_data));
202
203    if (sk_X509_CRL_push(out_crls, crl) == 0) {
204      X509_CRL_free(crl);
205      goto err;
206    }
207  }
208
209  ret = 1;
210
211err:
212  OPENSSL_free(der_bytes);
213
214  if (!ret) {
215    while (sk_X509_CRL_num(out_crls) != initial_crls_len) {
216      X509_CRL_free(sk_X509_CRL_pop(out_crls));
217    }
218  }
219
220  return ret;
221}
222
223int PKCS7_get_PEM_certificates(STACK_OF(X509) *out_certs, BIO *pem_bio) {
224  uint8_t *data;
225  long len;
226  int ret;
227
228  /* Even though we pass PEM_STRING_PKCS7 as the expected PEM type here, PEM
229   * internally will actually allow several other values too, including
230   * "CERTIFICATE". */
231  if (!PEM_bytes_read_bio(&data, &len, NULL /* PEM type output */,
232                          PEM_STRING_PKCS7, pem_bio,
233                          NULL /* password callback */,
234                          NULL /* password callback argument */)) {
235    return 0;
236  }
237
238  CBS cbs;
239  CBS_init(&cbs, data, len);
240  ret = PKCS7_get_certificates(out_certs, &cbs);
241  OPENSSL_free(data);
242  return ret;
243}
244
245int PKCS7_get_PEM_CRLs(STACK_OF(X509_CRL) *out_crls, BIO *pem_bio) {
246  uint8_t *data;
247  long len;
248  int ret;
249
250  /* Even though we pass PEM_STRING_PKCS7 as the expected PEM type here, PEM
251   * internally will actually allow several other values too, including
252   * "CERTIFICATE". */
253  if (!PEM_bytes_read_bio(&data, &len, NULL /* PEM type output */,
254                          PEM_STRING_PKCS7, pem_bio,
255                          NULL /* password callback */,
256                          NULL /* password callback argument */)) {
257    return 0;
258  }
259
260  CBS cbs;
261  CBS_init(&cbs, data, len);
262  ret = PKCS7_get_CRLs(out_crls, &cbs);
263  OPENSSL_free(data);
264  return ret;
265}
266
267/* pkcs7_bundle writes a PKCS#7, SignedData structure to |out| and then calls
268 * |cb| with a CBB to which certificate or CRL data can be written, and the
269 * opaque context pointer, |arg|. The callback can return zero to indicate an
270 * error.
271 *
272 * pkcs7_bundle returns one on success or zero on error. */
273static int pkcs7_bundle(CBB *out, int (*cb)(CBB *out, const void *arg),
274                        const void *arg) {
275  CBB outer_seq, oid, wrapped_seq, seq, version_bytes, digest_algos_set,
276      content_info;
277
278  /* See https://tools.ietf.org/html/rfc2315#section-7 */
279  if (!CBB_add_asn1(out, &outer_seq, CBS_ASN1_SEQUENCE) ||
280      !CBB_add_asn1(&outer_seq, &oid, CBS_ASN1_OBJECT) ||
281      !CBB_add_bytes(&oid, kPKCS7SignedData, sizeof(kPKCS7SignedData)) ||
282      !CBB_add_asn1(&outer_seq, &wrapped_seq,
283                    CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0) ||
284      /* See https://tools.ietf.org/html/rfc2315#section-9.1 */
285      !CBB_add_asn1(&wrapped_seq, &seq, CBS_ASN1_SEQUENCE) ||
286      !CBB_add_asn1(&seq, &version_bytes, CBS_ASN1_INTEGER) ||
287      !CBB_add_u8(&version_bytes, 1) ||
288      !CBB_add_asn1(&seq, &digest_algos_set, CBS_ASN1_SET) ||
289      !CBB_add_asn1(&seq, &content_info, CBS_ASN1_SEQUENCE) ||
290      !CBB_add_asn1(&content_info, &oid, CBS_ASN1_OBJECT) ||
291      !CBB_add_bytes(&oid, kPKCS7Data, sizeof(kPKCS7Data)) ||
292      !cb(&seq, arg)) {
293    return 0;
294  }
295
296  return CBB_flush(out);
297}
298
299static int pkcs7_bundle_certificates_cb(CBB *out, const void *arg) {
300  const STACK_OF(X509) *certs = arg;
301  size_t i;
302  CBB certificates;
303
304  /* See https://tools.ietf.org/html/rfc2315#section-9.1 */
305  if (!CBB_add_asn1(out, &certificates,
306                    CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0)) {
307    return 0;
308  }
309
310  for (i = 0; i < sk_X509_num(certs); i++) {
311    X509 *x509 = sk_X509_value(certs, i);
312    uint8_t *buf;
313    int len = i2d_X509(x509, NULL);
314
315    if (len < 0 ||
316        !CBB_add_space(&certificates, &buf, len) ||
317        i2d_X509(x509, &buf) < 0) {
318      return 0;
319    }
320  }
321
322  return CBB_flush(out);
323}
324
325int PKCS7_bundle_certificates(CBB *out, const STACK_OF(X509) *certs) {
326  return pkcs7_bundle(out, pkcs7_bundle_certificates_cb, certs);
327}
328
329static int pkcs7_bundle_crls_cb(CBB *out, const void *arg) {
330  const STACK_OF(X509_CRL) *crls = arg;
331  size_t i;
332  CBB crl_data;
333
334  /* See https://tools.ietf.org/html/rfc2315#section-9.1 */
335  if (!CBB_add_asn1(out, &crl_data,
336                    CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 1)) {
337    return 0;
338  }
339
340  for (i = 0; i < sk_X509_CRL_num(crls); i++) {
341    X509_CRL *crl = sk_X509_CRL_value(crls, i);
342    uint8_t *buf;
343    int len = i2d_X509_CRL(crl, NULL);
344
345    if (len < 0 ||
346        !CBB_add_space(&crl_data, &buf, len) ||
347        i2d_X509_CRL(crl, &buf) < 0) {
348      return 0;
349    }
350  }
351
352  return CBB_flush(out);
353}
354
355int PKCS7_bundle_CRLs(CBB *out, const STACK_OF(X509_CRL) *crls) {
356  return pkcs7_bundle(out, pkcs7_bundle_crls_cb, crls);
357}
358