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/* pkcs7_parse_header reads the non-certificate/non-CRL prefix of a PKCS#7
31 * SignedData blob from |cbs| and sets |*out| to point to the rest of the
32 * input. If the input is in BER format, then |*der_bytes| will be set to a
33 * pointer that needs to be freed by the caller once they have finished
34 * processing |*out| (which will be pointing into |*der_bytes|).
35 *
36 * It returns one on success or zero on error. On error, |*der_bytes| is
37 * NULL. */
38static int pkcs7_parse_header(uint8_t **der_bytes, CBS *out, CBS *cbs) {
39  size_t der_len;
40  CBS in, content_info, content_type, wrapped_signed_data, signed_data;
41  uint64_t version;
42
43  /* The input may be in BER format. */
44  *der_bytes = NULL;
45  if (!CBS_asn1_ber_to_der(cbs, der_bytes, &der_len)) {
46    return 0;
47  }
48  if (*der_bytes != NULL) {
49    CBS_init(&in, *der_bytes, der_len);
50  } else {
51    CBS_init(&in, CBS_data(cbs), CBS_len(cbs));
52  }
53
54  /* See https://tools.ietf.org/html/rfc2315#section-7 */
55  if (!CBS_get_asn1(&in, &content_info, CBS_ASN1_SEQUENCE) ||
56      !CBS_get_asn1(&content_info, &content_type, CBS_ASN1_OBJECT)) {
57    goto err;
58  }
59
60  if (OBJ_cbs2nid(&content_type) != NID_pkcs7_signed) {
61    OPENSSL_PUT_ERROR(X509, X509_R_NOT_PKCS7_SIGNED_DATA);
62    goto err;
63  }
64
65  /* See https://tools.ietf.org/html/rfc2315#section-9.1 */
66  if (!CBS_get_asn1(&content_info, &wrapped_signed_data,
67                    CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0) ||
68      !CBS_get_asn1(&wrapped_signed_data, &signed_data, CBS_ASN1_SEQUENCE) ||
69      !CBS_get_asn1_uint64(&signed_data, &version) ||
70      !CBS_get_asn1(&signed_data, NULL /* digests */, CBS_ASN1_SET) ||
71      !CBS_get_asn1(&signed_data, NULL /* content */, CBS_ASN1_SEQUENCE)) {
72    goto err;
73  }
74
75  if (version < 1) {
76    OPENSSL_PUT_ERROR(X509, X509_R_BAD_PKCS7_VERSION);
77    goto err;
78  }
79
80  CBS_init(out, CBS_data(&signed_data), CBS_len(&signed_data));
81  return 1;
82
83err:
84  if (*der_bytes) {
85    OPENSSL_free(*der_bytes);
86    *der_bytes = NULL;
87  }
88
89  return 0;
90}
91
92int PKCS7_get_certificates(STACK_OF(X509) *out_certs, CBS *cbs) {
93  CBS signed_data, certificates;
94  uint8_t *der_bytes = NULL;
95  int ret = 0;
96  const size_t initial_certs_len = sk_X509_num(out_certs);
97
98  if (!pkcs7_parse_header(&der_bytes, &signed_data, cbs)) {
99    return 0;
100  }
101
102  /* See https://tools.ietf.org/html/rfc2315#section-9.1 */
103  if (!CBS_get_asn1(&signed_data, &certificates,
104                    CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0)) {
105    OPENSSL_PUT_ERROR(X509, X509_R_NO_CERTIFICATES_INCLUDED);
106    goto err;
107  }
108
109  while (CBS_len(&certificates) > 0) {
110    CBS cert;
111    X509 *x509;
112    const uint8_t *inp;
113
114    if (!CBS_get_asn1_element(&certificates, &cert, CBS_ASN1_SEQUENCE)) {
115      goto err;
116    }
117
118    if (CBS_len(&cert) > LONG_MAX) {
119      goto err;
120    }
121    inp = CBS_data(&cert);
122    x509 = d2i_X509(NULL, &inp, (long)CBS_len(&cert));
123    if (!x509) {
124      goto err;
125    }
126
127    assert(inp == CBS_data(&cert) + CBS_len(&cert));
128
129    if (sk_X509_push(out_certs, x509) == 0) {
130      X509_free(x509);
131      goto err;
132    }
133  }
134
135  ret = 1;
136
137err:
138  if (der_bytes) {
139    OPENSSL_free(der_bytes);
140  }
141
142  if (!ret) {
143    while (sk_X509_num(out_certs) != initial_certs_len) {
144      X509 *x509 = sk_X509_pop(out_certs);
145      X509_free(x509);
146    }
147  }
148
149  return ret;
150}
151
152int PKCS7_get_CRLs(STACK_OF(X509_CRL) *out_crls, CBS *cbs) {
153  CBS signed_data, crls;
154  uint8_t *der_bytes = NULL;
155  int ret = 0;
156  const size_t initial_crls_len = sk_X509_CRL_num(out_crls);
157
158  if (!pkcs7_parse_header(&der_bytes, &signed_data, cbs)) {
159    return 0;
160  }
161
162  /* See https://tools.ietf.org/html/rfc2315#section-9.1 */
163
164  /* Even if only CRLs are included, there may be an empty certificates block.
165   * OpenSSL does this, for example. */
166  if (CBS_peek_asn1_tag(&signed_data,
167                        CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0) &&
168      !CBS_get_asn1(&signed_data, NULL /* certificates */,
169                    CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0)) {
170    goto err;
171  }
172
173  if (!CBS_get_asn1(&signed_data, &crls,
174                    CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 1)) {
175    OPENSSL_PUT_ERROR(X509, X509_R_NO_CRLS_INCLUDED);
176    goto err;
177  }
178
179  while (CBS_len(&crls) > 0) {
180    CBS crl_data;
181    X509_CRL *crl;
182    const uint8_t *inp;
183
184    if (!CBS_get_asn1_element(&crls, &crl_data, CBS_ASN1_SEQUENCE)) {
185      goto err;
186    }
187
188    if (CBS_len(&crl_data) > LONG_MAX) {
189      goto err;
190    }
191    inp = CBS_data(&crl_data);
192    crl = d2i_X509_CRL(NULL, &inp, (long)CBS_len(&crl_data));
193    if (!crl) {
194      goto err;
195    }
196
197    assert(inp == CBS_data(&crl_data) + CBS_len(&crl_data));
198
199    if (sk_X509_CRL_push(out_crls, crl) == 0) {
200      X509_CRL_free(crl);
201      goto err;
202    }
203  }
204
205  ret = 1;
206
207err:
208  if (der_bytes) {
209    OPENSSL_free(der_bytes);
210  }
211
212  if (!ret) {
213    while (sk_X509_CRL_num(out_crls) != initial_crls_len) {
214      X509_CRL_free(sk_X509_CRL_pop(out_crls));
215    }
216  }
217
218  return ret;
219}
220
221int PKCS7_get_PEM_certificates(STACK_OF(X509) *out_certs, BIO *pem_bio) {
222  uint8_t *data;
223  long len;
224  int ret;
225
226  /* Even though we pass PEM_STRING_PKCS7 as the expected PEM type here, PEM
227   * internally will actually allow several other values too, including
228   * "CERTIFICATE". */
229  if (!PEM_bytes_read_bio(&data, &len, NULL /* PEM type output */,
230                          PEM_STRING_PKCS7, pem_bio,
231                          NULL /* password callback */,
232                          NULL /* password callback argument */)) {
233    return 0;
234  }
235
236  CBS cbs;
237  CBS_init(&cbs, data, len);
238  ret = PKCS7_get_certificates(out_certs, &cbs);
239  OPENSSL_free(data);
240  return ret;
241}
242
243int PKCS7_get_PEM_CRLs(STACK_OF(X509_CRL) *out_crls, BIO *pem_bio) {
244  uint8_t *data;
245  long len;
246  int ret;
247
248  /* Even though we pass PEM_STRING_PKCS7 as the expected PEM type here, PEM
249   * internally will actually allow several other values too, including
250   * "CERTIFICATE". */
251  if (!PEM_bytes_read_bio(&data, &len, NULL /* PEM type output */,
252                          PEM_STRING_PKCS7, pem_bio,
253                          NULL /* password callback */,
254                          NULL /* password callback argument */)) {
255    return 0;
256  }
257
258  CBS cbs;
259  CBS_init(&cbs, data, len);
260  ret = PKCS7_get_CRLs(out_crls, &cbs);
261  OPENSSL_free(data);
262  return ret;
263}
264
265/* pkcs7_bundle writes a PKCS#7, SignedData structure to |out| and then calls
266 * |cb| with a CBB to which certificate or CRL data can be written, and the
267 * opaque context pointer, |arg|. The callback can return zero to indicate an
268 * error.
269 *
270 * pkcs7_bundle returns one on success or zero on error. */
271static int pkcs7_bundle(CBB *out, int (*cb)(CBB *out, const void *arg),
272                        const void *arg) {
273  CBB outer_seq, wrapped_seq, seq, version_bytes, digest_algos_set,
274      content_info;
275
276  /* See https://tools.ietf.org/html/rfc2315#section-7 */
277  if (!CBB_add_asn1(out, &outer_seq, CBS_ASN1_SEQUENCE) ||
278      !OBJ_nid2cbb(&outer_seq, NID_pkcs7_signed) ||
279      !CBB_add_asn1(&outer_seq, &wrapped_seq,
280                    CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0) ||
281      /* See https://tools.ietf.org/html/rfc2315#section-9.1 */
282      !CBB_add_asn1(&wrapped_seq, &seq, CBS_ASN1_SEQUENCE) ||
283      !CBB_add_asn1(&seq, &version_bytes, CBS_ASN1_INTEGER) ||
284      !CBB_add_u8(&version_bytes, 1) ||
285      !CBB_add_asn1(&seq, &digest_algos_set, CBS_ASN1_SET) ||
286      !CBB_add_asn1(&seq, &content_info, CBS_ASN1_SEQUENCE) ||
287      !OBJ_nid2cbb(&content_info, NID_pkcs7_data) ||
288      !cb(&seq, arg)) {
289    return 0;
290  }
291
292  return CBB_flush(out);
293}
294
295static int pkcs7_bundle_certificates_cb(CBB *out, const void *arg) {
296  const STACK_OF(X509) *certs = arg;
297  size_t i;
298  CBB certificates;
299
300  /* See https://tools.ietf.org/html/rfc2315#section-9.1 */
301  if (!CBB_add_asn1(out, &certificates,
302                    CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0)) {
303    return 0;
304  }
305
306  for (i = 0; i < sk_X509_num(certs); i++) {
307    X509 *x509 = sk_X509_value(certs, i);
308    uint8_t *buf;
309    int len = i2d_X509(x509, NULL);
310
311    if (len < 0 ||
312        !CBB_add_space(&certificates, &buf, len) ||
313        i2d_X509(x509, &buf) < 0) {
314      return 0;
315    }
316  }
317
318  return CBB_flush(out);
319}
320
321int PKCS7_bundle_certificates(CBB *out, const STACK_OF(X509) *certs) {
322  return pkcs7_bundle(out, pkcs7_bundle_certificates_cb, certs);
323}
324
325static int pkcs7_bundle_crls_cb(CBB *out, const void *arg) {
326  const STACK_OF(X509_CRL) *crls = arg;
327  size_t i;
328  CBB crl_data;
329
330  /* See https://tools.ietf.org/html/rfc2315#section-9.1 */
331  if (!CBB_add_asn1(out, &crl_data,
332                    CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 1)) {
333    return 0;
334  }
335
336  for (i = 0; i < sk_X509_CRL_num(crls); i++) {
337    X509_CRL *crl = sk_X509_CRL_value(crls, i);
338    uint8_t *buf;
339    int len = i2d_X509_CRL(crl, NULL);
340
341    if (len < 0 ||
342        !CBB_add_space(&crl_data, &buf, len) ||
343        i2d_X509_CRL(crl, &buf) < 0) {
344      return 0;
345    }
346  }
347
348  return CBB_flush(out);
349}
350
351int PKCS7_bundle_CRLs(CBB *out, const STACK_OF(X509_CRL) *crls) {
352  return pkcs7_bundle(out, pkcs7_bundle_crls_cb, crls);
353}
354