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b4d0d230 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
c26fd69f DH |
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) | |
c26fd69f DH |
6 | */ |
7 | ||
8 | #define pr_fmt(fmt) "X.509: "fmt | |
e5221fa6 HX |
9 | #include <crypto/hash.h> |
10 | #include <crypto/sm2.h> | |
11 | #include <keys/asymmetric-parser.h> | |
12 | #include <keys/asymmetric-subtype.h> | |
13 | #include <keys/system_keyring.h> | |
c26fd69f DH |
14 | #include <linux/module.h> |
15 | #include <linux/kernel.h> | |
16 | #include <linux/slab.h> | |
e5221fa6 | 17 | #include <linux/string.h> |
c26fd69f | 18 | #include "asymmetric_keys.h" |
c26fd69f DH |
19 | #include "x509_parser.h" |
20 | ||
c26fd69f | 21 | /* |
b426beb6 DH |
22 | * Set up the signature parameters in an X.509 certificate. This involves |
23 | * digesting the signed data and extracting the signature. | |
c26fd69f | 24 | */ |
b426beb6 | 25 | int x509_get_sig_params(struct x509_certificate *cert) |
c26fd69f | 26 | { |
77d0910d | 27 | struct public_key_signature *sig = cert->sig; |
c26fd69f DH |
28 | struct crypto_shash *tfm; |
29 | struct shash_desc *desc; | |
77d0910d | 30 | size_t desc_size; |
c26fd69f DH |
31 | int ret; |
32 | ||
33 | pr_devel("==>%s()\n", __func__); | |
b426beb6 | 34 | |
77d0910d DH |
35 | sig->s = kmemdup(cert->raw_sig, cert->raw_sig_size, GFP_KERNEL); |
36 | if (!sig->s) | |
b426beb6 | 37 | return -ENOMEM; |
db6c43bd | 38 | |
77d0910d | 39 | sig->s_size = cert->raw_sig_size; |
b426beb6 | 40 | |
c26fd69f DH |
41 | /* Allocate the hashing algorithm we're going to need and find out how |
42 | * big the hash operational data will be. | |
43 | */ | |
77d0910d | 44 | tfm = crypto_alloc_shash(sig->hash_algo, 0, 0); |
41559420 DH |
45 | if (IS_ERR(tfm)) { |
46 | if (PTR_ERR(tfm) == -ENOENT) { | |
6c2dc5ae DH |
47 | cert->unsupported_sig = true; |
48 | return 0; | |
41559420 DH |
49 | } |
50 | return PTR_ERR(tfm); | |
51 | } | |
c26fd69f DH |
52 | |
53 | desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); | |
77d0910d | 54 | sig->digest_size = crypto_shash_digestsize(tfm); |
c26fd69f | 55 | |
c26fd69f | 56 | ret = -ENOMEM; |
77d0910d DH |
57 | sig->digest = kmalloc(sig->digest_size, GFP_KERNEL); |
58 | if (!sig->digest) | |
b426beb6 | 59 | goto error; |
c26fd69f | 60 | |
77d0910d DH |
61 | desc = kzalloc(desc_size, GFP_KERNEL); |
62 | if (!desc) | |
63 | goto error; | |
c26fd69f | 64 | |
b426beb6 | 65 | desc->tfm = tfm; |
c26fd69f | 66 | |
e5221fa6 HX |
67 | if (strcmp(cert->pub->pkey_algo, "sm2") == 0) { |
68 | ret = strcmp(sig->hash_algo, "sm3") != 0 ? -EINVAL : | |
69 | crypto_shash_init(desc) ?: | |
70 | sm2_compute_z_digest(desc, cert->pub->key, | |
71 | cert->pub->keylen, sig->digest) ?: | |
72 | crypto_shash_init(desc) ?: | |
73 | crypto_shash_update(desc, sig->digest, | |
74 | sig->digest_size) ?: | |
75 | crypto_shash_finup(desc, cert->tbs, cert->tbs_size, | |
76 | sig->digest); | |
77 | } else { | |
78 | ret = crypto_shash_digest(desc, cert->tbs, cert->tbs_size, | |
79 | sig->digest); | |
80 | } | |
81 | ||
43652956 DH |
82 | if (ret < 0) |
83 | goto error_2; | |
84 | ||
141e5239 MS |
85 | ret = is_hash_blacklisted(sig->digest, sig->digest_size, |
86 | BLACKLIST_HASH_X509_TBS); | |
43652956 DH |
87 | if (ret == -EKEYREJECTED) { |
88 | pr_err("Cert %*phN is blacklisted\n", | |
89 | sig->digest_size, sig->digest); | |
90 | cert->blacklisted = true; | |
91 | ret = 0; | |
92 | } | |
77d0910d DH |
93 | |
94 | error_2: | |
95 | kfree(desc); | |
b426beb6 DH |
96 | error: |
97 | crypto_free_shash(tfm); | |
98 | pr_devel("<==%s() = %d\n", __func__, ret); | |
99 | return ret; | |
100 | } | |
c26fd69f | 101 | |
b426beb6 | 102 | /* |
6c2dc5ae DH |
103 | * Check for self-signedness in an X.509 cert and if found, check the signature |
104 | * immediately if we can. | |
b426beb6 | 105 | */ |
6c2dc5ae | 106 | int x509_check_for_self_signed(struct x509_certificate *cert) |
b426beb6 | 107 | { |
6c2dc5ae | 108 | int ret = 0; |
c26fd69f | 109 | |
b426beb6 | 110 | pr_devel("==>%s()\n", __func__); |
c26fd69f | 111 | |
ad3043fd DH |
112 | if (cert->raw_subject_size != cert->raw_issuer_size || |
113 | memcmp(cert->raw_subject, cert->raw_issuer, | |
114 | cert->raw_issuer_size) != 0) | |
115 | goto not_self_signed; | |
116 | ||
6c2dc5ae DH |
117 | if (cert->sig->auth_ids[0] || cert->sig->auth_ids[1]) { |
118 | /* If the AKID is present it may have one or two parts. If | |
119 | * both are supplied, both must match. | |
120 | */ | |
121 | bool a = asymmetric_key_id_same(cert->skid, cert->sig->auth_ids[1]); | |
122 | bool b = asymmetric_key_id_same(cert->id, cert->sig->auth_ids[0]); | |
123 | ||
124 | if (!a && !b) | |
125 | goto not_self_signed; | |
126 | ||
127 | ret = -EKEYREJECTED; | |
128 | if (((a && !b) || (b && !a)) && | |
129 | cert->sig->auth_ids[0] && cert->sig->auth_ids[1]) | |
130 | goto out; | |
131 | } | |
132 | ||
ef5b52a6 TS |
133 | if (cert->unsupported_sig) { |
134 | ret = 0; | |
135 | goto out; | |
136 | } | |
137 | ||
6c2dc5ae DH |
138 | ret = public_key_verify_signature(cert->pub, cert->sig); |
139 | if (ret < 0) { | |
140 | if (ret == -ENOPKG) { | |
141 | cert->unsupported_sig = true; | |
142 | ret = 0; | |
143 | } | |
144 | goto out; | |
145 | } | |
146 | ||
147 | pr_devel("Cert Self-signature verified"); | |
148 | cert->self_signed = true; | |
c26fd69f | 149 | |
6c2dc5ae DH |
150 | out: |
151 | pr_devel("<==%s() = %d\n", __func__, ret); | |
c26fd69f | 152 | return ret; |
6c2dc5ae DH |
153 | |
154 | not_self_signed: | |
155 | pr_devel("<==%s() = 0 [not]\n", __func__); | |
156 | return 0; | |
c26fd69f DH |
157 | } |
158 | ||
159 | /* | |
160 | * Attempt to parse a data blob for a key as an X509 certificate. | |
161 | */ | |
162 | static int x509_key_preparse(struct key_preparsed_payload *prep) | |
163 | { | |
5c6ca9d9 LW |
164 | struct x509_certificate *cert __free(x509_free_certificate); |
165 | struct asymmetric_key_ids *kids __free(kfree) = NULL; | |
166 | char *p, *desc __free(kfree) = NULL; | |
46963b77 | 167 | const char *q; |
c26fd69f | 168 | size_t srlen, sulen; |
c26fd69f DH |
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); | |
4e8ae72a | 176 | pr_devel("Cert Key Algo: %s\n", cert->pub->pkey_algo); |
fd19a3d1 | 177 | pr_devel("Cert Valid period: %lld-%lld\n", cert->valid_from, cert->valid_to); |
c26fd69f | 178 | |
4e8ae72a | 179 | cert->pub->id_type = "X509"; |
c26fd69f | 180 | |
a511e1af | 181 | if (cert->unsupported_sig) { |
6c2dc5ae DH |
182 | public_key_signature_free(cert->sig); |
183 | cert->sig = NULL; | |
184 | } else { | |
185 | pr_devel("Cert Signature: %s + %s\n", | |
186 | cert->sig->pkey_algo, cert->sig->hash_algo); | |
c26fd69f DH |
187 | } |
188 | ||
43652956 | 189 | /* Don't permit addition of blacklisted keys */ |
43652956 | 190 | if (cert->blacklisted) |
5c6ca9d9 | 191 | return -EKEYREJECTED; |
43652956 | 192 | |
c26fd69f DH |
193 | /* Propose a description */ |
194 | sulen = strlen(cert->subject); | |
dd2f6c44 DH |
195 | if (cert->raw_skid) { |
196 | srlen = cert->raw_skid_size; | |
197 | q = cert->raw_skid; | |
198 | } else { | |
199 | srlen = cert->raw_serial_size; | |
200 | q = cert->raw_serial; | |
201 | } | |
46963b77 | 202 | |
46963b77 | 203 | desc = kmalloc(sulen + 2 + srlen * 2 + 1, GFP_KERNEL); |
c26fd69f | 204 | if (!desc) |
5c6ca9d9 | 205 | return -ENOMEM; |
46963b77 DH |
206 | p = memcpy(desc, cert->subject, sulen); |
207 | p += sulen; | |
208 | *p++ = ':'; | |
209 | *p++ = ' '; | |
210 | p = bin2hex(p, q, srlen); | |
211 | *p = 0; | |
212 | ||
213 | kids = kmalloc(sizeof(struct asymmetric_key_ids), GFP_KERNEL); | |
214 | if (!kids) | |
5c6ca9d9 | 215 | return -ENOMEM; |
46963b77 DH |
216 | kids->id[0] = cert->id; |
217 | kids->id[1] = cert->skid; | |
7d30198e AZ |
218 | kids->id[2] = asymmetric_key_generate_id(cert->raw_subject, |
219 | cert->raw_subject_size, | |
220 | "", 0); | |
5c6ca9d9 LW |
221 | if (IS_ERR(kids->id[2])) |
222 | return PTR_ERR(kids->id[2]); | |
c26fd69f DH |
223 | |
224 | /* We're pinning the module by being linked against it */ | |
225 | __module_get(public_key_subtype.owner); | |
146aa8b1 DH |
226 | prep->payload.data[asym_subtype] = &public_key_subtype; |
227 | prep->payload.data[asym_key_ids] = kids; | |
228 | prep->payload.data[asym_crypto] = cert->pub; | |
77d0910d | 229 | prep->payload.data[asym_auth] = cert->sig; |
c26fd69f DH |
230 | prep->description = desc; |
231 | prep->quotalen = 100; | |
232 | ||
233 | /* We've finished with the certificate */ | |
234 | cert->pub = NULL; | |
46963b77 DH |
235 | cert->id = NULL; |
236 | cert->skid = NULL; | |
77d0910d | 237 | cert->sig = NULL; |
c26fd69f | 238 | desc = NULL; |
7d30198e | 239 | kids = NULL; |
5c6ca9d9 | 240 | return 0; |
c26fd69f DH |
241 | } |
242 | ||
243 | static struct asymmetric_key_parser x509_key_parser = { | |
244 | .owner = THIS_MODULE, | |
245 | .name = "x509", | |
246 | .parse = x509_key_preparse, | |
247 | }; | |
248 | ||
249 | /* | |
250 | * Module stuff | |
251 | */ | |
252 | static int __init x509_key_init(void) | |
253 | { | |
04a93202 | 254 | return register_asymmetric_key_parser(&x509_key_parser); |
c26fd69f DH |
255 | } |
256 | ||
257 | static void __exit x509_key_exit(void) | |
258 | { | |
259 | unregister_asymmetric_key_parser(&x509_key_parser); | |
260 | } | |
261 | ||
262 | module_init(x509_key_init); | |
263 | module_exit(x509_key_exit); | |
e19aaa7d KK |
264 | |
265 | MODULE_DESCRIPTION("X.509 certificate parser"); | |
1e684d38 | 266 | MODULE_AUTHOR("Red Hat, Inc."); |
e19aaa7d | 267 | MODULE_LICENSE("GPL"); |