ethtool: Use kcalloc instead of kmalloc for ethtool_get_strings
[deliverable/linux.git] / crypto / asymmetric_keys / x509_public_key.c
CommitLineData
c26fd69f
DH
1/* Instantiate a public key crypto key from an X.509 Certificate
2 *
3 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
10 */
11
12#define pr_fmt(fmt) "X.509: "fmt
13#include <linux/module.h>
14#include <linux/kernel.h>
15#include <linux/slab.h>
16#include <linux/err.h>
17#include <linux/mpi.h>
18#include <linux/asn1_decoder.h>
19#include <keys/asymmetric-subtype.h>
20#include <keys/asymmetric-parser.h>
3be4beaf 21#include <keys/system_keyring.h>
c26fd69f
DH
22#include <crypto/hash.h>
23#include "asymmetric_keys.h"
24#include "public_key.h"
25#include "x509_parser.h"
26
32c4741c 27static bool use_builtin_keys;
46963b77 28static struct asymmetric_key_id *ca_keyid;
ffb70f61
DK
29
30#ifndef MODULE
f2b3dee4
MZ
31static struct {
32 struct asymmetric_key_id id;
33 unsigned char data[10];
34} cakey;
35
ffb70f61
DK
36static int __init ca_keys_setup(char *str)
37{
38 if (!str) /* default system keyring */
39 return 1;
40
46963b77 41 if (strncmp(str, "id:", 3) == 0) {
f2b3dee4
MZ
42 struct asymmetric_key_id *p = &cakey.id;
43 size_t hexlen = (strlen(str) - 3) / 2;
44 int ret;
45
46 if (hexlen == 0 || hexlen > sizeof(cakey.data)) {
47 pr_err("Missing or invalid ca_keys id\n");
48 return 1;
49 }
50
51 ret = __asymmetric_key_hex_to_key_id(str + 3, p, hexlen);
52 if (ret < 0)
53 pr_err("Unparsable ca_keys id hex string\n");
54 else
46963b77
DH
55 ca_keyid = p; /* owner key 'id:xxxxxx' */
56 } else if (strcmp(str, "builtin") == 0) {
32c4741c 57 use_builtin_keys = true;
46963b77 58 }
ffb70f61
DK
59
60 return 1;
61}
62__setup("ca_keys=", ca_keys_setup);
63#endif
64
5ce43ad2
DH
65/**
66 * x509_request_asymmetric_key - Request a key by X.509 certificate params.
67 * @keyring: The keys to search.
4573b64a
DH
68 * @id: The issuer & serialNumber to look for or NULL.
69 * @skid: The subjectKeyIdentifier to look for or NULL.
f1b731db 70 * @partial: Use partial match if true, exact if false.
5ce43ad2 71 *
4573b64a
DH
72 * Find a key in the given keyring by identifier. The preferred identifier is
73 * the issuer + serialNumber and the fallback identifier is the
74 * subjectKeyIdentifier. If both are given, the lookup is by the former, but
75 * the latter must also match.
3be4beaf 76 */
5ce43ad2 77struct key *x509_request_asymmetric_key(struct key *keyring,
4573b64a
DH
78 const struct asymmetric_key_id *id,
79 const struct asymmetric_key_id *skid,
f1b731db 80 bool partial)
3be4beaf 81{
4573b64a
DH
82 struct key *key;
83 key_ref_t ref;
84 const char *lookup;
85 char *req, *p;
86 int len;
87
88 if (id) {
89 lookup = id->data;
90 len = id->len;
91 } else {
92 lookup = skid->data;
93 len = skid->len;
94 }
95
46963b77 96 /* Construct an identifier "id:<keyid>". */
4573b64a
DH
97 p = req = kmalloc(2 + 1 + len * 2 + 1, GFP_KERNEL);
98 if (!req)
3be4beaf
MZ
99 return ERR_PTR(-ENOMEM);
100
f1b731db
DK
101 if (partial) {
102 *p++ = 'i';
103 *p++ = 'd';
104 } else {
105 *p++ = 'e';
106 *p++ = 'x';
107 }
46963b77 108 *p++ = ':';
4573b64a 109 p = bin2hex(p, lookup, len);
46963b77 110 *p = 0;
3be4beaf 111
4573b64a 112 pr_debug("Look up: \"%s\"\n", req);
3be4beaf 113
4573b64a
DH
114 ref = keyring_search(make_key_ref(keyring, 1),
115 &key_type_asymmetric, req);
116 if (IS_ERR(ref))
117 pr_debug("Request for key '%s' err %ld\n", req, PTR_ERR(ref));
118 kfree(req);
3be4beaf 119
4573b64a
DH
120 if (IS_ERR(ref)) {
121 switch (PTR_ERR(ref)) {
3be4beaf
MZ
122 /* Hide some search errors */
123 case -EACCES:
124 case -ENOTDIR:
125 case -EAGAIN:
126 return ERR_PTR(-ENOKEY);
127 default:
4573b64a
DH
128 return ERR_CAST(ref);
129 }
130 }
131
132 key = key_ref_to_ptr(ref);
133 if (id && skid) {
134 const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
135 if (!kids->id[1]) {
136 pr_debug("issuer+serial match, but expected SKID missing\n");
137 goto reject;
138 }
139 if (!asymmetric_key_id_same(skid, kids->id[1])) {
140 pr_debug("issuer+serial match, but SKID does not\n");
141 goto reject;
3be4beaf
MZ
142 }
143 }
4573b64a
DH
144
145 pr_devel("<==%s() = 0 [%x]\n", __func__, key_serial(key));
146 return key;
3be4beaf 147
4573b64a
DH
148reject:
149 key_put(key);
150 return ERR_PTR(-EKEYREJECTED);
3be4beaf 151}
cf5b50fd 152EXPORT_SYMBOL_GPL(x509_request_asymmetric_key);
3be4beaf 153
c26fd69f 154/*
b426beb6
DH
155 * Set up the signature parameters in an X.509 certificate. This involves
156 * digesting the signed data and extracting the signature.
c26fd69f 157 */
b426beb6 158int x509_get_sig_params(struct x509_certificate *cert)
c26fd69f 159{
c26fd69f
DH
160 struct crypto_shash *tfm;
161 struct shash_desc *desc;
162 size_t digest_size, desc_size;
b426beb6 163 void *digest;
c26fd69f
DH
164 int ret;
165
166 pr_devel("==>%s()\n", __func__);
b426beb6 167
41559420
DH
168 if (cert->unsupported_crypto)
169 return -ENOPKG;
b426beb6
DH
170 if (cert->sig.rsa.s)
171 return 0;
172
173 cert->sig.rsa.s = mpi_read_raw_data(cert->raw_sig, cert->raw_sig_size);
174 if (!cert->sig.rsa.s)
175 return -ENOMEM;
176 cert->sig.nr_mpi = 1;
177
c26fd69f
DH
178 /* Allocate the hashing algorithm we're going to need and find out how
179 * big the hash operational data will be.
180 */
3fe78ca2 181 tfm = crypto_alloc_shash(hash_algo_name[cert->sig.pkey_hash_algo], 0, 0);
41559420
DH
182 if (IS_ERR(tfm)) {
183 if (PTR_ERR(tfm) == -ENOENT) {
184 cert->unsupported_crypto = true;
185 return -ENOPKG;
186 }
187 return PTR_ERR(tfm);
188 }
c26fd69f
DH
189
190 desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
191 digest_size = crypto_shash_digestsize(tfm);
192
b426beb6
DH
193 /* We allocate the hash operational data storage on the end of the
194 * digest storage space.
c26fd69f
DH
195 */
196 ret = -ENOMEM;
b426beb6
DH
197 digest = kzalloc(digest_size + desc_size, GFP_KERNEL);
198 if (!digest)
199 goto error;
c26fd69f 200
b426beb6
DH
201 cert->sig.digest = digest;
202 cert->sig.digest_size = digest_size;
c26fd69f 203
b426beb6
DH
204 desc = digest + digest_size;
205 desc->tfm = tfm;
206 desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
c26fd69f
DH
207
208 ret = crypto_shash_init(desc);
209 if (ret < 0)
210 goto error;
b426beb6
DH
211 might_sleep();
212 ret = crypto_shash_finup(desc, cert->tbs, cert->tbs_size, digest);
213error:
214 crypto_free_shash(tfm);
215 pr_devel("<==%s() = %d\n", __func__, ret);
216 return ret;
217}
218EXPORT_SYMBOL_GPL(x509_get_sig_params);
c26fd69f 219
b426beb6
DH
220/*
221 * Check the signature on a certificate using the provided public key
222 */
223int x509_check_signature(const struct public_key *pub,
224 struct x509_certificate *cert)
225{
226 int ret;
c26fd69f 227
b426beb6 228 pr_devel("==>%s()\n", __func__);
c26fd69f 229
b426beb6
DH
230 ret = x509_get_sig_params(cert);
231 if (ret < 0)
232 return ret;
c26fd69f 233
b426beb6 234 ret = public_key_verify_signature(pub, &cert->sig);
41559420
DH
235 if (ret == -ENOPKG)
236 cert->unsupported_crypto = true;
c26fd69f 237 pr_debug("Cert Verification: %d\n", ret);
c26fd69f
DH
238 return ret;
239}
b426beb6 240EXPORT_SYMBOL_GPL(x509_check_signature);
c26fd69f 241
3be4beaf
MZ
242/*
243 * Check the new certificate against the ones in the trust keyring. If one of
244 * those is the signing key and validates the new certificate, then mark the
245 * new certificate as being trusted.
246 *
247 * Return 0 if the new certificate was successfully validated, 1 if we couldn't
248 * find a matching parent certificate in the trusted list and an error if there
249 * is a matching certificate but the signature check fails.
250 */
251static int x509_validate_trust(struct x509_certificate *cert,
252 struct key *trust_keyring)
253{
3be4beaf
MZ
254 struct key *key;
255 int ret = 1;
256
257 if (!trust_keyring)
258 return -EOPNOTSUPP;
259
b92e6570 260 if (ca_keyid && !asymmetric_key_id_partial(cert->akid_skid, ca_keyid))
ffb70f61
DK
261 return -EPERM;
262
4573b64a
DH
263 key = x509_request_asymmetric_key(trust_keyring,
264 cert->akid_id, cert->akid_skid,
f1b731db 265 false);
3be4beaf 266 if (!IS_ERR(key)) {
32c4741c
DK
267 if (!use_builtin_keys
268 || test_bit(KEY_FLAG_BUILTIN, &key->flags))
269 ret = x509_check_signature(key->payload.data, cert);
3be4beaf
MZ
270 key_put(key);
271 }
272 return ret;
273}
274
c26fd69f
DH
275/*
276 * Attempt to parse a data blob for a key as an X509 certificate.
277 */
278static int x509_key_preparse(struct key_preparsed_payload *prep)
279{
46963b77 280 struct asymmetric_key_ids *kids;
c26fd69f 281 struct x509_certificate *cert;
46963b77 282 const char *q;
c26fd69f 283 size_t srlen, sulen;
46963b77 284 char *desc = NULL, *p;
c26fd69f
DH
285 int ret;
286
287 cert = x509_cert_parse(prep->data, prep->datalen);
288 if (IS_ERR(cert))
289 return PTR_ERR(cert);
290
291 pr_devel("Cert Issuer: %s\n", cert->issuer);
292 pr_devel("Cert Subject: %s\n", cert->subject);
2ecdb23b
DH
293
294 if (cert->pub->pkey_algo >= PKEY_ALGO__LAST ||
295 cert->sig.pkey_algo >= PKEY_ALGO__LAST ||
296 cert->sig.pkey_hash_algo >= PKEY_HASH__LAST ||
297 !pkey_algo[cert->pub->pkey_algo] ||
298 !pkey_algo[cert->sig.pkey_algo] ||
3fe78ca2 299 !hash_algo_name[cert->sig.pkey_hash_algo]) {
2ecdb23b
DH
300 ret = -ENOPKG;
301 goto error_free_cert;
302 }
303
67f7d60b 304 pr_devel("Cert Key Algo: %s\n", pkey_algo_name[cert->pub->pkey_algo]);
fd19a3d1 305 pr_devel("Cert Valid period: %lld-%lld\n", cert->valid_from, cert->valid_to);
c7c8bb23
DK
306 pr_devel("Cert Signature: %s + %s\n",
307 pkey_algo_name[cert->sig.pkey_algo],
3fe78ca2 308 hash_algo_name[cert->sig.pkey_hash_algo]);
c26fd69f 309
67f7d60b 310 cert->pub->algo = pkey_algo[cert->pub->pkey_algo];
c26fd69f
DH
311 cert->pub->id_type = PKEY_ID_X509;
312
17334cab 313 /* Check the signature on the key if it appears to be self-signed */
4573b64a
DH
314 if ((!cert->akid_skid && !cert->akid_id) ||
315 asymmetric_key_id_same(cert->skid, cert->akid_skid) ||
316 asymmetric_key_id_same(cert->id, cert->akid_id)) {
3be4beaf 317 ret = x509_check_signature(cert->pub, cert); /* self-signed */
c26fd69f
DH
318 if (ret < 0)
319 goto error_free_cert;
3be4beaf
MZ
320 } else if (!prep->trusted) {
321 ret = x509_validate_trust(cert, get_system_trusted_keyring());
322 if (!ret)
323 prep->trusted = 1;
c26fd69f
DH
324 }
325
326 /* Propose a description */
327 sulen = strlen(cert->subject);
dd2f6c44
DH
328 if (cert->raw_skid) {
329 srlen = cert->raw_skid_size;
330 q = cert->raw_skid;
331 } else {
332 srlen = cert->raw_serial_size;
333 q = cert->raw_serial;
334 }
46963b77 335
c26fd69f 336 ret = -ENOMEM;
46963b77 337 desc = kmalloc(sulen + 2 + srlen * 2 + 1, GFP_KERNEL);
c26fd69f
DH
338 if (!desc)
339 goto error_free_cert;
46963b77
DH
340 p = memcpy(desc, cert->subject, sulen);
341 p += sulen;
342 *p++ = ':';
343 *p++ = ' ';
344 p = bin2hex(p, q, srlen);
345 *p = 0;
346
347 kids = kmalloc(sizeof(struct asymmetric_key_ids), GFP_KERNEL);
348 if (!kids)
349 goto error_free_desc;
350 kids->id[0] = cert->id;
351 kids->id[1] = cert->skid;
c26fd69f
DH
352
353 /* We're pinning the module by being linked against it */
354 __module_get(public_key_subtype.owner);
355 prep->type_data[0] = &public_key_subtype;
46963b77 356 prep->type_data[1] = kids;
fc7c70e0 357 prep->payload[0] = cert->pub;
c26fd69f
DH
358 prep->description = desc;
359 prep->quotalen = 100;
360
361 /* We've finished with the certificate */
362 cert->pub = NULL;
46963b77
DH
363 cert->id = NULL;
364 cert->skid = NULL;
c26fd69f
DH
365 desc = NULL;
366 ret = 0;
367
46963b77
DH
368error_free_desc:
369 kfree(desc);
c26fd69f
DH
370error_free_cert:
371 x509_free_certificate(cert);
372 return ret;
373}
374
375static struct asymmetric_key_parser x509_key_parser = {
376 .owner = THIS_MODULE,
377 .name = "x509",
378 .parse = x509_key_preparse,
379};
380
381/*
382 * Module stuff
383 */
384static int __init x509_key_init(void)
385{
386 return register_asymmetric_key_parser(&x509_key_parser);
387}
388
389static void __exit x509_key_exit(void)
390{
391 unregister_asymmetric_key_parser(&x509_key_parser);
392}
393
394module_init(x509_key_init);
395module_exit(x509_key_exit);
e19aaa7d
KK
396
397MODULE_DESCRIPTION("X.509 certificate parser");
398MODULE_LICENSE("GPL");
This page took 0.115769 seconds and 5 git commands to generate.