1/*
2 * Copyright 2008-2016 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 <openssl/asn1t.h>
11#include <openssl/pem.h>
12#include <openssl/x509v3.h>
13#include <openssl/err.h>
14#include <openssl/cms.h>
15#include "cms_local.h"
16#include "internal/nelem.h"
17
18/*-
19 * Attribute flags.
20 * CMS attribute restrictions are discussed in
21 * - RFC 5652 Section 11.
22 * ESS attribute restrictions are discussed in
23 * - RFC 2634 Section 1.3.4 AND
24 * - RFC 5035 Section 5.4
25 */
26/* This is a signed attribute */
27#define CMS_ATTR_F_SIGNED 0x01
28/* This is an unsigned attribute */
29#define CMS_ATTR_F_UNSIGNED 0x02
30/* Must be present if there are any other attributes of the same type */
31#define CMS_ATTR_F_REQUIRED_COND 0x10
32/* There can only be one instance of this attribute */
33#define CMS_ATTR_F_ONLY_ONE 0x20
34/* The Attribute's value must have exactly one entry */
35#define CMS_ATTR_F_ONE_ATTR_VALUE 0x40
36
37/* Attributes rules for different attributes */
38static const struct {
39 int nid; /* The attribute id */
40 int flags;
41} cms_attribute_properties[] = {
42 /* See RFC Section 11 */
43 { NID_pkcs9_contentType, CMS_ATTR_F_SIGNED
44 | CMS_ATTR_F_ONLY_ONE
45 | CMS_ATTR_F_ONE_ATTR_VALUE
46 | CMS_ATTR_F_REQUIRED_COND },
47 { NID_pkcs9_messageDigest, CMS_ATTR_F_SIGNED
48 | CMS_ATTR_F_ONLY_ONE
49 | CMS_ATTR_F_ONE_ATTR_VALUE
50 | CMS_ATTR_F_REQUIRED_COND },
51 { NID_pkcs9_signingTime, CMS_ATTR_F_SIGNED
52 | CMS_ATTR_F_ONLY_ONE
53 | CMS_ATTR_F_ONE_ATTR_VALUE },
54 { NID_pkcs9_countersignature, CMS_ATTR_F_UNSIGNED },
55 /* ESS */
56 { NID_id_smime_aa_signingCertificate, CMS_ATTR_F_SIGNED
57 | CMS_ATTR_F_ONLY_ONE
58 | CMS_ATTR_F_ONE_ATTR_VALUE },
59 { NID_id_smime_aa_signingCertificateV2, CMS_ATTR_F_SIGNED
60 | CMS_ATTR_F_ONLY_ONE
61 | CMS_ATTR_F_ONE_ATTR_VALUE },
62 { NID_id_smime_aa_receiptRequest, CMS_ATTR_F_SIGNED
63 | CMS_ATTR_F_ONLY_ONE
64 | CMS_ATTR_F_ONE_ATTR_VALUE }
65};
66
67/* CMS SignedData Attribute utilities */
68
69int CMS_signed_get_attr_count(const CMS_SignerInfo *si)
70{
71 return X509at_get_attr_count(si->signedAttrs);
72}
73
74int CMS_signed_get_attr_by_NID(const CMS_SignerInfo *si, int nid, int lastpos)
75{
76 return X509at_get_attr_by_NID(si->signedAttrs, nid, lastpos);
77}
78
79int CMS_signed_get_attr_by_OBJ(const CMS_SignerInfo *si, const ASN1_OBJECT *obj,
80 int lastpos)
81{
82 return X509at_get_attr_by_OBJ(si->signedAttrs, obj, lastpos);
83}
84
85X509_ATTRIBUTE *CMS_signed_get_attr(const CMS_SignerInfo *si, int loc)
86{
87 return X509at_get_attr(si->signedAttrs, loc);
88}
89
90X509_ATTRIBUTE *CMS_signed_delete_attr(CMS_SignerInfo *si, int loc)
91{
92 return X509at_delete_attr(si->signedAttrs, loc);
93}
94
95int CMS_signed_add1_attr(CMS_SignerInfo *si, X509_ATTRIBUTE *attr)
96{
97 if (X509at_add1_attr(&si->signedAttrs, attr))
98 return 1;
99 return 0;
100}
101
102int CMS_signed_add1_attr_by_OBJ(CMS_SignerInfo *si,
103 const ASN1_OBJECT *obj, int type,
104 const void *bytes, int len)
105{
106 if (X509at_add1_attr_by_OBJ(&si->signedAttrs, obj, type, bytes, len))
107 return 1;
108 return 0;
109}
110
111int CMS_signed_add1_attr_by_NID(CMS_SignerInfo *si,
112 int nid, int type, const void *bytes, int len)
113{
114 if (X509at_add1_attr_by_NID(&si->signedAttrs, nid, type, bytes, len))
115 return 1;
116 return 0;
117}
118
119int CMS_signed_add1_attr_by_txt(CMS_SignerInfo *si,
120 const char *attrname, int type,
121 const void *bytes, int len)
122{
123 if (X509at_add1_attr_by_txt(&si->signedAttrs, attrname, type, bytes, len))
124 return 1;
125 return 0;
126}
127
128void *CMS_signed_get0_data_by_OBJ(CMS_SignerInfo *si, const ASN1_OBJECT *oid,
129 int lastpos, int type)
130{
131 return X509at_get0_data_by_OBJ(si->signedAttrs, oid, lastpos, type);
132}
133
134int CMS_unsigned_get_attr_count(const CMS_SignerInfo *si)
135{
136 return X509at_get_attr_count(si->unsignedAttrs);
137}
138
139int CMS_unsigned_get_attr_by_NID(const CMS_SignerInfo *si, int nid,
140 int lastpos)
141{
142 return X509at_get_attr_by_NID(si->unsignedAttrs, nid, lastpos);
143}
144
145int CMS_unsigned_get_attr_by_OBJ(const CMS_SignerInfo *si,
146 const ASN1_OBJECT *obj, int lastpos)
147{
148 return X509at_get_attr_by_OBJ(si->unsignedAttrs, obj, lastpos);
149}
150
151X509_ATTRIBUTE *CMS_unsigned_get_attr(const CMS_SignerInfo *si, int loc)
152{
153 return X509at_get_attr(si->unsignedAttrs, loc);
154}
155
156X509_ATTRIBUTE *CMS_unsigned_delete_attr(CMS_SignerInfo *si, int loc)
157{
158 return X509at_delete_attr(si->unsignedAttrs, loc);
159}
160
161int CMS_unsigned_add1_attr(CMS_SignerInfo *si, X509_ATTRIBUTE *attr)
162{
163 if (X509at_add1_attr(&si->unsignedAttrs, attr))
164 return 1;
165 return 0;
166}
167
168int CMS_unsigned_add1_attr_by_OBJ(CMS_SignerInfo *si,
169 const ASN1_OBJECT *obj, int type,
170 const void *bytes, int len)
171{
172 if (X509at_add1_attr_by_OBJ(&si->unsignedAttrs, obj, type, bytes, len))
173 return 1;
174 return 0;
175}
176
177int CMS_unsigned_add1_attr_by_NID(CMS_SignerInfo *si,
178 int nid, int type,
179 const void *bytes, int len)
180{
181 if (X509at_add1_attr_by_NID(&si->unsignedAttrs, nid, type, bytes, len))
182 return 1;
183 return 0;
184}
185
186int CMS_unsigned_add1_attr_by_txt(CMS_SignerInfo *si,
187 const char *attrname, int type,
188 const void *bytes, int len)
189{
190 if (X509at_add1_attr_by_txt(&si->unsignedAttrs, attrname,
191 type, bytes, len))
192 return 1;
193 return 0;
194}
195
196void *CMS_unsigned_get0_data_by_OBJ(CMS_SignerInfo *si, ASN1_OBJECT *oid,
197 int lastpos, int type)
198{
199 return X509at_get0_data_by_OBJ(si->unsignedAttrs, oid, lastpos, type);
200}
201
202/*
203 * Retrieve an attribute by nid from a stack of attributes starting at index
204 * *lastpos + 1.
205 * Returns the attribute or NULL if there is no attribute.
206 * If an attribute was found *lastpos returns the index of the found attribute.
207 */
208static X509_ATTRIBUTE *cms_attrib_get(int nid,
209 const STACK_OF(X509_ATTRIBUTE) *attrs,
210 int *lastpos)
211{
212 X509_ATTRIBUTE *at;
213 int loc;
214
215 loc = X509at_get_attr_by_NID(attrs, nid, *lastpos);
216 if (loc < 0)
217 return NULL;
218
219 at = X509at_get_attr(attrs, loc);
220 *lastpos = loc;
221 return at;
222}
223
224static int cms_check_attribute(int nid, int flags, int type,
225 const STACK_OF(X509_ATTRIBUTE) *attrs,
226 int have_attrs)
227{
228 int lastpos = -1;
229 X509_ATTRIBUTE *at = cms_attrib_get(nid, attrs, &lastpos);
230
231 if (at != NULL) {
232 int count = X509_ATTRIBUTE_count(at);
233
234 /* Is this attribute allowed? */
235 if (((flags & type) == 0)
236 /* check if multiple attributes of the same type are allowed */
237 || (((flags & CMS_ATTR_F_ONLY_ONE) != 0)
238 && cms_attrib_get(nid, attrs, &lastpos) != NULL)
239 /* Check if attribute should have exactly one value in its set */
240 || (((flags & CMS_ATTR_F_ONE_ATTR_VALUE) != 0)
241 && count != 1)
242 /* There should be at least one value */
243 || count == 0)
244 return 0;
245 } else {
246 /* fail if a required attribute is missing */
247 if (have_attrs
248 && ((flags & CMS_ATTR_F_REQUIRED_COND) != 0)
249 && (flags & type) != 0)
250 return 0;
251 }
252 return 1;
253}
254
255/*
256 * Check that the signerinfo attributes obey the attribute rules which includes
257 * the following checks
258 * - If any signed attributes exist then there must be a Content Type
259 * and Message Digest attribute in the signed attributes.
260 * - The countersignature attribute is an optional unsigned attribute only.
261 * - Content Type, Message Digest, and Signing time attributes are signed
262 * attributes. Only one instance of each is allowed, with each of these
263 * attributes containing a single attribute value in its set.
264 */
265int CMS_si_check_attributes(const CMS_SignerInfo *si)
266{
267 int i;
268 int have_signed_attrs = (CMS_signed_get_attr_count(si) > 0);
269 int have_unsigned_attrs = (CMS_unsigned_get_attr_count(si) > 0);
270
271 for (i = 0; i < (int)OSSL_NELEM(cms_attribute_properties); ++i) {
272 int nid = cms_attribute_properties[i].nid;
273 int flags = cms_attribute_properties[i].flags;
274
275 if (!cms_check_attribute(nid, flags, CMS_ATTR_F_SIGNED,
276 si->signedAttrs, have_signed_attrs)
277 || !cms_check_attribute(nid, flags, CMS_ATTR_F_UNSIGNED,
278 si->unsignedAttrs, have_unsigned_attrs)) {
279 CMSerr(CMS_F_CMS_SI_CHECK_ATTRIBUTES, CMS_R_ATTRIBUTE_ERROR);
280 return 0;
281 }
282 }
283 return 1;
284}
285