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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Instantiate a public key crypto key from an X.509 Certificate
3 *
4 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#define pr_fmt(fmt) "X.509: "fmt
9#include <linux/module.h>
10#include <linux/kernel.h>
11#include <linux/slab.h>
12#include <keys/asymmetric-subtype.h>
13#include <keys/asymmetric-parser.h>
14#include <keys/system_keyring.h>
15#include <crypto/hash.h>
16#include "asymmetric_keys.h"
17#include "x509_parser.h"
18
19/*
20 * Set up the signature parameters in an X.509 certificate. This involves
21 * digesting the signed data and extracting the signature.
22 */
23int x509_get_sig_params(struct x509_certificate *cert)
24{
25 struct public_key_signature *sig = cert->sig;
26 struct crypto_shash *tfm;
27 struct shash_desc *desc;
28 size_t desc_size;
29 int ret;
30
31 pr_devel("==>%s()\n", __func__);
32
33 sig->data = cert->tbs;
34 sig->data_size = cert->tbs_size;
35
36 sig->s = kmemdup(cert->raw_sig, cert->raw_sig_size, GFP_KERNEL);
37 if (!sig->s)
38 return -ENOMEM;
39
40 sig->s_size = cert->raw_sig_size;
41
42 /* Allocate the hashing algorithm we're going to need and find out how
43 * big the hash operational data will be.
44 */
45 tfm = crypto_alloc_shash(sig->hash_algo, 0, 0);
46 if (IS_ERR(tfm)) {
47 if (PTR_ERR(tfm) == -ENOENT) {
48 cert->unsupported_sig = true;
49 return 0;
50 }
51 return PTR_ERR(tfm);
52 }
53
54 desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
55 sig->digest_size = crypto_shash_digestsize(tfm);
56
57 ret = -ENOMEM;
58 sig->digest = kmalloc(sig->digest_size, GFP_KERNEL);
59 if (!sig->digest)
60 goto error;
61
62 desc = kzalloc(desc_size, GFP_KERNEL);
63 if (!desc)
64 goto error;
65
66 desc->tfm = tfm;
67
68 ret = crypto_shash_digest(desc, cert->tbs, cert->tbs_size, sig->digest);
69 if (ret < 0)
70 goto error_2;
71
72 ret = is_hash_blacklisted(sig->digest, sig->digest_size,
73 BLACKLIST_HASH_X509_TBS);
74 if (ret == -EKEYREJECTED) {
75 pr_err("Cert %*phN is blacklisted\n",
76 sig->digest_size, sig->digest);
77 cert->blacklisted = true;
78 ret = 0;
79 }
80
81error_2:
82 kfree(desc);
83error:
84 crypto_free_shash(tfm);
85 pr_devel("<==%s() = %d\n", __func__, ret);
86 return ret;
87}
88
89/*
90 * Check for self-signedness in an X.509 cert and if found, check the signature
91 * immediately if we can.
92 */
93int x509_check_for_self_signed(struct x509_certificate *cert)
94{
95 int ret = 0;
96
97 pr_devel("==>%s()\n", __func__);
98
99 if (cert->raw_subject_size != cert->raw_issuer_size ||
100 memcmp(cert->raw_subject, cert->raw_issuer,
101 cert->raw_issuer_size) != 0)
102 goto not_self_signed;
103
104 if (cert->sig->auth_ids[0] || cert->sig->auth_ids[1]) {
105 /* If the AKID is present it may have one or two parts. If
106 * both are supplied, both must match.
107 */
108 bool a = asymmetric_key_id_same(cert->skid, cert->sig->auth_ids[1]);
109 bool b = asymmetric_key_id_same(cert->id, cert->sig->auth_ids[0]);
110
111 if (!a && !b)
112 goto not_self_signed;
113
114 ret = -EKEYREJECTED;
115 if (((a && !b) || (b && !a)) &&
116 cert->sig->auth_ids[0] && cert->sig->auth_ids[1])
117 goto out;
118 }
119
120 ret = public_key_verify_signature(cert->pub, cert->sig);
121 if (ret < 0) {
122 if (ret == -ENOPKG) {
123 cert->unsupported_sig = true;
124 ret = 0;
125 }
126 goto out;
127 }
128
129 pr_devel("Cert Self-signature verified");
130 cert->self_signed = true;
131
132out:
133 pr_devel("<==%s() = %d\n", __func__, ret);
134 return ret;
135
136not_self_signed:
137 pr_devel("<==%s() = 0 [not]\n", __func__);
138 return 0;
139}
140
141/*
142 * Attempt to parse a data blob for a key as an X509 certificate.
143 */
144static int x509_key_preparse(struct key_preparsed_payload *prep)
145{
146 struct asymmetric_key_ids *kids;
147 struct x509_certificate *cert;
148 const char *q;
149 size_t srlen, sulen;
150 char *desc = NULL, *p;
151 int ret;
152
153 cert = x509_cert_parse(prep->data, prep->datalen);
154 if (IS_ERR(cert))
155 return PTR_ERR(cert);
156
157 pr_devel("Cert Issuer: %s\n", cert->issuer);
158 pr_devel("Cert Subject: %s\n", cert->subject);
159 pr_devel("Cert Key Algo: %s\n", cert->pub->pkey_algo);
160 pr_devel("Cert Valid period: %lld-%lld\n", cert->valid_from, cert->valid_to);
161
162 cert->pub->id_type = "X509";
163
164 if (cert->unsupported_sig) {
165 public_key_signature_free(cert->sig);
166 cert->sig = NULL;
167 } else {
168 pr_devel("Cert Signature: %s + %s\n",
169 cert->sig->pkey_algo, cert->sig->hash_algo);
170 }
171
172 /* Don't permit addition of blacklisted keys */
173 ret = -EKEYREJECTED;
174 if (cert->blacklisted)
175 goto error_free_cert;
176
177 /* Propose a description */
178 sulen = strlen(cert->subject);
179 if (cert->raw_skid) {
180 srlen = cert->raw_skid_size;
181 q = cert->raw_skid;
182 } else {
183 srlen = cert->raw_serial_size;
184 q = cert->raw_serial;
185 }
186
187 ret = -ENOMEM;
188 desc = kmalloc(sulen + 2 + srlen * 2 + 1, GFP_KERNEL);
189 if (!desc)
190 goto error_free_cert;
191 p = memcpy(desc, cert->subject, sulen);
192 p += sulen;
193 *p++ = ':';
194 *p++ = ' ';
195 p = bin2hex(p, q, srlen);
196 *p = 0;
197
198 kids = kmalloc(sizeof(struct asymmetric_key_ids), GFP_KERNEL);
199 if (!kids)
200 goto error_free_desc;
201 kids->id[0] = cert->id;
202 kids->id[1] = cert->skid;
203 kids->id[2] = asymmetric_key_generate_id(cert->raw_subject,
204 cert->raw_subject_size,
205 "", 0);
206 if (IS_ERR(kids->id[2])) {
207 ret = PTR_ERR(kids->id[2]);
208 goto error_free_kids;
209 }
210
211 /* We're pinning the module by being linked against it */
212 __module_get(public_key_subtype.owner);
213 prep->payload.data[asym_subtype] = &public_key_subtype;
214 prep->payload.data[asym_key_ids] = kids;
215 prep->payload.data[asym_crypto] = cert->pub;
216 prep->payload.data[asym_auth] = cert->sig;
217 prep->description = desc;
218 prep->quotalen = 100;
219
220 /* We've finished with the certificate */
221 cert->pub = NULL;
222 cert->id = NULL;
223 cert->skid = NULL;
224 cert->sig = NULL;
225 desc = NULL;
226 kids = NULL;
227 ret = 0;
228
229error_free_kids:
230 kfree(kids);
231error_free_desc:
232 kfree(desc);
233error_free_cert:
234 x509_free_certificate(cert);
235 return ret;
236}
237
238static struct asymmetric_key_parser x509_key_parser = {
239 .owner = THIS_MODULE,
240 .name = "x509",
241 .parse = x509_key_preparse,
242};
243
244/*
245 * Module stuff
246 */
247extern int __init certs_selftest(void);
248static int __init x509_key_init(void)
249{
250 int ret;
251
252 ret = register_asymmetric_key_parser(&x509_key_parser);
253 if (ret < 0)
254 return ret;
255 return fips_signature_selftest();
256}
257
258static void __exit x509_key_exit(void)
259{
260 unregister_asymmetric_key_parser(&x509_key_parser);
261}
262
263module_init(x509_key_init);
264module_exit(x509_key_exit);
265
266MODULE_DESCRIPTION("X.509 certificate parser");
267MODULE_AUTHOR("Red Hat, Inc.");
268MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Instantiate a public key crypto key from an X.509 Certificate
3 *
4 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#define pr_fmt(fmt) "X.509: "fmt
9#include <linux/module.h>
10#include <linux/kernel.h>
11#include <linux/slab.h>
12#include <keys/asymmetric-subtype.h>
13#include <keys/asymmetric-parser.h>
14#include <keys/system_keyring.h>
15#include <crypto/hash.h>
16#include "asymmetric_keys.h"
17#include "x509_parser.h"
18
19/*
20 * Set up the signature parameters in an X.509 certificate. This involves
21 * digesting the signed data and extracting the signature.
22 */
23int x509_get_sig_params(struct x509_certificate *cert)
24{
25 struct public_key_signature *sig = cert->sig;
26 struct crypto_shash *tfm;
27 struct shash_desc *desc;
28 size_t desc_size;
29 int ret;
30
31 pr_devel("==>%s()\n", __func__);
32
33 sig->data = cert->tbs;
34 sig->data_size = cert->tbs_size;
35
36 if (!cert->pub->pkey_algo)
37 cert->unsupported_key = true;
38
39 if (!sig->pkey_algo)
40 cert->unsupported_sig = true;
41
42 /* We check the hash if we can - even if we can't then verify it */
43 if (!sig->hash_algo) {
44 cert->unsupported_sig = true;
45 return 0;
46 }
47
48 sig->s = kmemdup(cert->raw_sig, cert->raw_sig_size, GFP_KERNEL);
49 if (!sig->s)
50 return -ENOMEM;
51
52 sig->s_size = cert->raw_sig_size;
53
54 /* Allocate the hashing algorithm we're going to need and find out how
55 * big the hash operational data will be.
56 */
57 tfm = crypto_alloc_shash(sig->hash_algo, 0, 0);
58 if (IS_ERR(tfm)) {
59 if (PTR_ERR(tfm) == -ENOENT) {
60 cert->unsupported_sig = true;
61 return 0;
62 }
63 return PTR_ERR(tfm);
64 }
65
66 desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
67 sig->digest_size = crypto_shash_digestsize(tfm);
68
69 ret = -ENOMEM;
70 sig->digest = kmalloc(sig->digest_size, GFP_KERNEL);
71 if (!sig->digest)
72 goto error;
73
74 desc = kzalloc(desc_size, GFP_KERNEL);
75 if (!desc)
76 goto error;
77
78 desc->tfm = tfm;
79
80 ret = crypto_shash_digest(desc, cert->tbs, cert->tbs_size, sig->digest);
81 if (ret < 0)
82 goto error_2;
83
84 ret = is_hash_blacklisted(sig->digest, sig->digest_size, "tbs");
85 if (ret == -EKEYREJECTED) {
86 pr_err("Cert %*phN is blacklisted\n",
87 sig->digest_size, sig->digest);
88 cert->blacklisted = true;
89 ret = 0;
90 }
91
92error_2:
93 kfree(desc);
94error:
95 crypto_free_shash(tfm);
96 pr_devel("<==%s() = %d\n", __func__, ret);
97 return ret;
98}
99
100/*
101 * Check for self-signedness in an X.509 cert and if found, check the signature
102 * immediately if we can.
103 */
104int x509_check_for_self_signed(struct x509_certificate *cert)
105{
106 int ret = 0;
107
108 pr_devel("==>%s()\n", __func__);
109
110 if (cert->raw_subject_size != cert->raw_issuer_size ||
111 memcmp(cert->raw_subject, cert->raw_issuer,
112 cert->raw_issuer_size) != 0)
113 goto not_self_signed;
114
115 if (cert->sig->auth_ids[0] || cert->sig->auth_ids[1]) {
116 /* If the AKID is present it may have one or two parts. If
117 * both are supplied, both must match.
118 */
119 bool a = asymmetric_key_id_same(cert->skid, cert->sig->auth_ids[1]);
120 bool b = asymmetric_key_id_same(cert->id, cert->sig->auth_ids[0]);
121
122 if (!a && !b)
123 goto not_self_signed;
124
125 ret = -EKEYREJECTED;
126 if (((a && !b) || (b && !a)) &&
127 cert->sig->auth_ids[0] && cert->sig->auth_ids[1])
128 goto out;
129 }
130
131 ret = -EKEYREJECTED;
132 if (strcmp(cert->pub->pkey_algo, cert->sig->pkey_algo) != 0 &&
133 (strncmp(cert->pub->pkey_algo, "ecdsa-", 6) != 0 ||
134 strcmp(cert->sig->pkey_algo, "ecdsa") != 0))
135 goto out;
136
137 ret = public_key_verify_signature(cert->pub, cert->sig);
138 if (ret < 0) {
139 if (ret == -ENOPKG) {
140 cert->unsupported_sig = true;
141 ret = 0;
142 }
143 goto out;
144 }
145
146 pr_devel("Cert Self-signature verified");
147 cert->self_signed = true;
148
149out:
150 pr_devel("<==%s() = %d\n", __func__, ret);
151 return ret;
152
153not_self_signed:
154 pr_devel("<==%s() = 0 [not]\n", __func__);
155 return 0;
156}
157
158/*
159 * Attempt to parse a data blob for a key as an X509 certificate.
160 */
161static int x509_key_preparse(struct key_preparsed_payload *prep)
162{
163 struct asymmetric_key_ids *kids;
164 struct x509_certificate *cert;
165 const char *q;
166 size_t srlen, sulen;
167 char *desc = NULL, *p;
168 int ret;
169
170 cert = x509_cert_parse(prep->data, prep->datalen);
171 if (IS_ERR(cert))
172 return PTR_ERR(cert);
173
174 pr_devel("Cert Issuer: %s\n", cert->issuer);
175 pr_devel("Cert Subject: %s\n", cert->subject);
176
177 if (cert->unsupported_key) {
178 ret = -ENOPKG;
179 goto error_free_cert;
180 }
181
182 pr_devel("Cert Key Algo: %s\n", cert->pub->pkey_algo);
183 pr_devel("Cert Valid period: %lld-%lld\n", cert->valid_from, cert->valid_to);
184
185 cert->pub->id_type = "X509";
186
187 if (cert->unsupported_sig) {
188 public_key_signature_free(cert->sig);
189 cert->sig = NULL;
190 } else {
191 pr_devel("Cert Signature: %s + %s\n",
192 cert->sig->pkey_algo, cert->sig->hash_algo);
193 }
194
195 /* Don't permit addition of blacklisted keys */
196 ret = -EKEYREJECTED;
197 if (cert->blacklisted)
198 goto error_free_cert;
199
200 /* Propose a description */
201 sulen = strlen(cert->subject);
202 if (cert->raw_skid) {
203 srlen = cert->raw_skid_size;
204 q = cert->raw_skid;
205 } else {
206 srlen = cert->raw_serial_size;
207 q = cert->raw_serial;
208 }
209
210 ret = -ENOMEM;
211 desc = kmalloc(sulen + 2 + srlen * 2 + 1, GFP_KERNEL);
212 if (!desc)
213 goto error_free_cert;
214 p = memcpy(desc, cert->subject, sulen);
215 p += sulen;
216 *p++ = ':';
217 *p++ = ' ';
218 p = bin2hex(p, q, srlen);
219 *p = 0;
220
221 kids = kmalloc(sizeof(struct asymmetric_key_ids), GFP_KERNEL);
222 if (!kids)
223 goto error_free_desc;
224 kids->id[0] = cert->id;
225 kids->id[1] = cert->skid;
226
227 /* We're pinning the module by being linked against it */
228 __module_get(public_key_subtype.owner);
229 prep->payload.data[asym_subtype] = &public_key_subtype;
230 prep->payload.data[asym_key_ids] = kids;
231 prep->payload.data[asym_crypto] = cert->pub;
232 prep->payload.data[asym_auth] = cert->sig;
233 prep->description = desc;
234 prep->quotalen = 100;
235
236 /* We've finished with the certificate */
237 cert->pub = NULL;
238 cert->id = NULL;
239 cert->skid = NULL;
240 cert->sig = NULL;
241 desc = NULL;
242 ret = 0;
243
244error_free_desc:
245 kfree(desc);
246error_free_cert:
247 x509_free_certificate(cert);
248 return ret;
249}
250
251static struct asymmetric_key_parser x509_key_parser = {
252 .owner = THIS_MODULE,
253 .name = "x509",
254 .parse = x509_key_preparse,
255};
256
257/*
258 * Module stuff
259 */
260static int __init x509_key_init(void)
261{
262 return register_asymmetric_key_parser(&x509_key_parser);
263}
264
265static void __exit x509_key_exit(void)
266{
267 unregister_asymmetric_key_parser(&x509_key_parser);
268}
269
270module_init(x509_key_init);
271module_exit(x509_key_exit);
272
273MODULE_DESCRIPTION("X.509 certificate parser");
274MODULE_AUTHOR("Red Hat, Inc.");
275MODULE_LICENSE("GPL");