xref: /openssl/crypto/x509/v3_akid.c (revision fecb3aae)
1 /*
2  * Copyright 1999-2022 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 <stdio.h>
11 #include "internal/cryptlib.h"
12 #include <openssl/conf.h>
13 #include <openssl/asn1.h>
14 #include <openssl/asn1t.h>
15 #include <openssl/x509v3.h>
16 #include "crypto/x509.h"
17 #include "ext_dat.h"
18 
19 static STACK_OF(CONF_VALUE) *i2v_AUTHORITY_KEYID(X509V3_EXT_METHOD *method,
20                                                  AUTHORITY_KEYID *akeyid,
21                                                  STACK_OF(CONF_VALUE)
22                                                  *extlist);
23 static AUTHORITY_KEYID *v2i_AUTHORITY_KEYID(X509V3_EXT_METHOD *method,
24                                             X509V3_CTX *ctx,
25                                             STACK_OF(CONF_VALUE) *values);
26 
27 const X509V3_EXT_METHOD ossl_v3_akey_id = {
28     NID_authority_key_identifier,
29     X509V3_EXT_MULTILINE, ASN1_ITEM_ref(AUTHORITY_KEYID),
30     0, 0, 0, 0,
31     0, 0,
32     (X509V3_EXT_I2V) i2v_AUTHORITY_KEYID,
33     (X509V3_EXT_V2I)v2i_AUTHORITY_KEYID,
34     0, 0,
35     NULL
36 };
37 
STACK_OF(CONF_VALUE)38 static STACK_OF(CONF_VALUE) *i2v_AUTHORITY_KEYID(X509V3_EXT_METHOD *method,
39                                                  AUTHORITY_KEYID *akeyid,
40                                                  STACK_OF(CONF_VALUE)
41                                                  *extlist)
42 {
43     char *tmp = NULL;
44     STACK_OF(CONF_VALUE) *origextlist = extlist, *tmpextlist;
45 
46     if (akeyid->keyid) {
47         tmp = i2s_ASN1_OCTET_STRING(NULL, akeyid->keyid);
48         if (tmp == NULL) {
49             ERR_raise(ERR_LIB_X509V3, ERR_R_MALLOC_FAILURE);
50             return NULL;
51         }
52         if (!X509V3_add_value((akeyid->issuer || akeyid->serial) ? "keyid" : NULL,
53                               tmp, &extlist)) {
54             OPENSSL_free(tmp);
55             ERR_raise(ERR_LIB_X509V3, ERR_R_X509_LIB);
56             goto err;
57         }
58         OPENSSL_free(tmp);
59     }
60     if (akeyid->issuer) {
61         tmpextlist = i2v_GENERAL_NAMES(NULL, akeyid->issuer, extlist);
62         if (tmpextlist == NULL) {
63             ERR_raise(ERR_LIB_X509V3, ERR_R_X509_LIB);
64             goto err;
65         }
66         extlist = tmpextlist;
67     }
68     if (akeyid->serial) {
69         tmp = i2s_ASN1_OCTET_STRING(NULL, akeyid->serial);
70         if (tmp == NULL) {
71             ERR_raise(ERR_LIB_X509V3, ERR_R_MALLOC_FAILURE);
72             goto err;
73         }
74         if (!X509V3_add_value("serial", tmp, &extlist)) {
75             OPENSSL_free(tmp);
76             goto err;
77         }
78         OPENSSL_free(tmp);
79     }
80     return extlist;
81  err:
82     if (origextlist == NULL)
83         sk_CONF_VALUE_pop_free(extlist, X509V3_conf_free);
84     return NULL;
85 }
86 
87 /*-
88  * Three explicit tags may be given, where 'keyid' and 'issuer' may be combined:
89  * 'none': do not add any authority key identifier.
90  * 'keyid': use the issuer's subject keyid; the option 'always' means its is
91  * an error if the issuer certificate doesn't have a subject key id.
92  * 'issuer': use the issuer's cert issuer and serial number. The default is
93  * to only use this if 'keyid' is not present. With the option 'always'
94  * this is always included.
95  */
v2i_AUTHORITY_KEYID(X509V3_EXT_METHOD * method,X509V3_CTX * ctx,STACK_OF (CONF_VALUE)* values)96 static AUTHORITY_KEYID *v2i_AUTHORITY_KEYID(X509V3_EXT_METHOD *method,
97                                             X509V3_CTX *ctx,
98                                             STACK_OF(CONF_VALUE) *values)
99 {
100     char keyid = 0, issuer = 0;
101     int i, n = sk_CONF_VALUE_num(values);
102     CONF_VALUE *cnf;
103     ASN1_OCTET_STRING *ikeyid = NULL;
104     X509_NAME *isname = NULL;
105     GENERAL_NAMES *gens = NULL;
106     GENERAL_NAME *gen = NULL;
107     ASN1_INTEGER *serial = NULL;
108     X509_EXTENSION *ext;
109     X509 *issuer_cert;
110     int same_issuer, ss;
111     AUTHORITY_KEYID *akeyid = AUTHORITY_KEYID_new();
112 
113     if (akeyid == NULL)
114         goto err;
115 
116     if (n == 1 && strcmp(sk_CONF_VALUE_value(values, 0)->name, "none") == 0) {
117         return akeyid;
118     }
119 
120     for (i = 0; i < n; i++) {
121         cnf = sk_CONF_VALUE_value(values, i);
122         if (cnf->value != NULL && strcmp(cnf->value, "always") != 0) {
123             ERR_raise_data(ERR_LIB_X509V3, X509V3_R_UNKNOWN_OPTION,
124                            "name=%s option=%s", cnf->name, cnf->value);
125             goto err;
126         }
127         if (strcmp(cnf->name, "keyid") == 0 && keyid == 0) {
128             keyid = 1;
129             if (cnf->value != NULL)
130                 keyid = 2;
131         } else if (strcmp(cnf->name, "issuer") == 0 && issuer == 0) {
132             issuer = 1;
133             if (cnf->value != NULL)
134                 issuer = 2;
135         } else if (strcmp(cnf->name, "none") == 0
136                    || strcmp(cnf->name, "keyid") == 0
137                    || strcmp(cnf->name, "issuer") == 0) {
138             ERR_raise_data(ERR_LIB_X509V3, X509V3_R_BAD_VALUE,
139                            "name=%s", cnf->name);
140             goto err;
141         } else {
142             ERR_raise_data(ERR_LIB_X509V3, X509V3_R_UNKNOWN_VALUE,
143                            "name=%s", cnf->name);
144             goto err;
145         }
146     }
147 
148     if (ctx != NULL && (ctx->flags & X509V3_CTX_TEST) != 0)
149         return akeyid;
150 
151     if (ctx == NULL) {
152         ERR_raise(ERR_LIB_X509V3, ERR_R_PASSED_NULL_PARAMETER);
153         goto err;
154     }
155     if ((issuer_cert = ctx->issuer_cert) == NULL) {
156         ERR_raise(ERR_LIB_X509V3, X509V3_R_NO_ISSUER_CERTIFICATE);
157         goto err;
158     }
159     same_issuer = ctx->subject_cert == ctx->issuer_cert;
160     ERR_set_mark();
161     if (ctx->issuer_pkey != NULL)
162         ss = X509_check_private_key(ctx->subject_cert, ctx->issuer_pkey);
163     else
164         ss = same_issuer;
165     ERR_pop_to_mark();
166 
167     /* unless forced with "always", AKID is suppressed for self-signed certs */
168     if (keyid == 2 || (keyid == 1 && !ss)) {
169         /*
170          * prefer any pre-existing subject key identifier of the issuer cert
171          * except issuer cert is same as subject cert and is not self-signed
172          */
173         i = X509_get_ext_by_NID(issuer_cert, NID_subject_key_identifier, -1);
174         if (i >= 0 && (ext = X509_get_ext(issuer_cert, i)) != NULL
175             && !(same_issuer && !ss)) {
176             ikeyid = X509V3_EXT_d2i(ext);
177             if (ASN1_STRING_length(ikeyid) == 0) /* indicating "none" */ {
178                 ASN1_OCTET_STRING_free(ikeyid);
179                 ikeyid = NULL;
180             }
181         }
182         if (ikeyid == NULL && same_issuer && ctx->issuer_pkey != NULL) {
183             /* generate fallback AKID, emulating s2i_skey_id(..., "hash") */
184             X509_PUBKEY *pubkey = NULL;
185 
186             if (X509_PUBKEY_set(&pubkey, ctx->issuer_pkey))
187                 ikeyid = ossl_x509_pubkey_hash(pubkey);
188             X509_PUBKEY_free(pubkey);
189         }
190         if (keyid == 2 && ikeyid == NULL) {
191             ERR_raise(ERR_LIB_X509V3, X509V3_R_UNABLE_TO_GET_ISSUER_KEYID);
192             goto err;
193         }
194     }
195 
196     if (issuer == 2 || (issuer == 1 && !ss && ikeyid == NULL)) {
197         isname = X509_NAME_dup(X509_get_issuer_name(issuer_cert));
198         serial = ASN1_INTEGER_dup(X509_get0_serialNumber(issuer_cert));
199         if (isname == NULL || serial == NULL) {
200             ERR_raise(ERR_LIB_X509V3, X509V3_R_UNABLE_TO_GET_ISSUER_DETAILS);
201             goto err;
202         }
203     }
204 
205     if (isname != NULL) {
206         if ((gens = sk_GENERAL_NAME_new_null()) == NULL
207             || (gen = GENERAL_NAME_new()) == NULL
208             || !sk_GENERAL_NAME_push(gens, gen)) {
209             ERR_raise(ERR_LIB_X509V3, ERR_R_MALLOC_FAILURE);
210             goto err;
211         }
212         gen->type = GEN_DIRNAME;
213         gen->d.dirn = isname;
214     }
215 
216     akeyid->issuer = gens;
217     gen = NULL;
218     gens = NULL;
219     akeyid->serial = serial;
220     akeyid->keyid = ikeyid;
221 
222     return akeyid;
223 
224  err:
225     sk_GENERAL_NAME_free(gens);
226     GENERAL_NAME_free(gen);
227     X509_NAME_free(isname);
228     ASN1_INTEGER_free(serial);
229     ASN1_OCTET_STRING_free(ikeyid);
230     AUTHORITY_KEYID_free(akeyid);
231     return NULL;
232 }
233