1 // SPDX-License-Identifier: GPL-2.0-or-later 1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Instantiate a public key crypto key from an 2 /* Instantiate a public key crypto key from an X.509 Certificate
3 * 3 *
4 * Copyright (C) 2012, 2016 Red Hat, Inc. All 4 * Copyright (C) 2012, 2016 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.c 5 * Written by David Howells (dhowells@redhat.com)
6 */ 6 */
7 7
8 #define pr_fmt(fmt) "ASYM: "fmt 8 #define pr_fmt(fmt) "ASYM: "fmt
9 #include <linux/module.h> 9 #include <linux/module.h>
10 #include <linux/kernel.h> 10 #include <linux/kernel.h>
11 #include <linux/err.h> 11 #include <linux/err.h>
12 #include <crypto/public_key.h> 12 #include <crypto/public_key.h>
13 #include "asymmetric_keys.h" 13 #include "asymmetric_keys.h"
14 14
15 static bool use_builtin_keys; 15 static bool use_builtin_keys;
16 static struct asymmetric_key_id *ca_keyid; 16 static struct asymmetric_key_id *ca_keyid;
17 17
18 #ifndef MODULE 18 #ifndef MODULE
19 static struct { 19 static struct {
20 struct asymmetric_key_id id; 20 struct asymmetric_key_id id;
21 unsigned char data[10]; 21 unsigned char data[10];
22 } cakey; 22 } cakey;
23 23
24 static int __init ca_keys_setup(char *str) 24 static int __init ca_keys_setup(char *str)
25 { 25 {
26 if (!str) /* default sys 26 if (!str) /* default system keyring */
27 return 1; 27 return 1;
28 28
29 if (strncmp(str, "id:", 3) == 0) { 29 if (strncmp(str, "id:", 3) == 0) {
30 struct asymmetric_key_id *p = 30 struct asymmetric_key_id *p = &cakey.id;
31 size_t hexlen = (strlen(str) - 31 size_t hexlen = (strlen(str) - 3) / 2;
32 int ret; 32 int ret;
33 33
34 if (hexlen == 0 || hexlen > si 34 if (hexlen == 0 || hexlen > sizeof(cakey.data)) {
35 pr_err("Missing or inv 35 pr_err("Missing or invalid ca_keys id\n");
36 return 1; 36 return 1;
37 } 37 }
38 38
39 ret = __asymmetric_key_hex_to_ 39 ret = __asymmetric_key_hex_to_key_id(str + 3, p, hexlen);
40 if (ret < 0) 40 if (ret < 0)
41 pr_err("Unparsable ca_ 41 pr_err("Unparsable ca_keys id hex string\n");
42 else 42 else
43 ca_keyid = p; /* own 43 ca_keyid = p; /* owner key 'id:xxxxxx' */
44 } else if (strcmp(str, "builtin") == 0 44 } else if (strcmp(str, "builtin") == 0) {
45 use_builtin_keys = true; 45 use_builtin_keys = true;
46 } 46 }
47 47
48 return 1; 48 return 1;
49 } 49 }
50 __setup("ca_keys=", ca_keys_setup); 50 __setup("ca_keys=", ca_keys_setup);
51 #endif 51 #endif
52 52
53 /** 53 /**
54 * restrict_link_by_signature - Restrict addit 54 * restrict_link_by_signature - Restrict additions to a ring of public keys
55 * @dest_keyring: Keyring being linked to. 55 * @dest_keyring: Keyring being linked to.
56 * @type: The type of key being added. 56 * @type: The type of key being added.
57 * @payload: The payload of the new key. 57 * @payload: The payload of the new key.
58 * @trust_keyring: A ring of keys that can be 58 * @trust_keyring: A ring of keys that can be used to vouch for the new cert.
59 * 59 *
60 * Check the new certificate against the ones 60 * Check the new certificate against the ones in the trust keyring. If one of
61 * those is the signing key and validates the 61 * those is the signing key and validates the new certificate, then mark the
62 * new certificate as being trusted. 62 * new certificate as being trusted.
63 * 63 *
64 * Returns 0 if the new certificate was accept 64 * Returns 0 if the new certificate was accepted, -ENOKEY if we couldn't find a
65 * matching parent certificate in the trusted 65 * matching parent certificate in the trusted list, -EKEYREJECTED if the
66 * signature check fails or the key is blackli 66 * signature check fails or the key is blacklisted, -ENOPKG if the signature
67 * uses unsupported crypto, or some other erro 67 * uses unsupported crypto, or some other error if there is a matching
68 * certificate but the signature check cannot 68 * certificate but the signature check cannot be performed.
69 */ 69 */
70 int restrict_link_by_signature(struct key *des 70 int restrict_link_by_signature(struct key *dest_keyring,
71 const struct ke 71 const struct key_type *type,
72 const union key 72 const union key_payload *payload,
73 struct key *tru 73 struct key *trust_keyring)
74 { 74 {
75 const struct public_key_signature *sig 75 const struct public_key_signature *sig;
76 struct key *key; 76 struct key *key;
77 int ret; 77 int ret;
78 78
79 pr_devel("==>%s()\n", __func__); 79 pr_devel("==>%s()\n", __func__);
80 80
81 if (!trust_keyring) 81 if (!trust_keyring)
82 return -ENOKEY; 82 return -ENOKEY;
83 83
84 if (type != &key_type_asymmetric) 84 if (type != &key_type_asymmetric)
85 return -EOPNOTSUPP; 85 return -EOPNOTSUPP;
86 86
87 sig = payload->data[asym_auth]; 87 sig = payload->data[asym_auth];
88 if (!sig) 88 if (!sig)
89 return -ENOPKG; 89 return -ENOPKG;
90 if (!sig->auth_ids[0] && !sig->auth_id 90 if (!sig->auth_ids[0] && !sig->auth_ids[1] && !sig->auth_ids[2])
91 return -ENOKEY; 91 return -ENOKEY;
92 92
93 if (ca_keyid && !asymmetric_key_id_par 93 if (ca_keyid && !asymmetric_key_id_partial(sig->auth_ids[1], ca_keyid))
94 return -EPERM; 94 return -EPERM;
95 95
96 /* See if we have a key that signed th 96 /* See if we have a key that signed this one. */
97 key = find_asymmetric_key(trust_keyrin 97 key = find_asymmetric_key(trust_keyring,
98 sig->auth_id 98 sig->auth_ids[0], sig->auth_ids[1],
99 sig->auth_id 99 sig->auth_ids[2], false);
100 if (IS_ERR(key)) 100 if (IS_ERR(key))
101 return -ENOKEY; 101 return -ENOKEY;
102 102
103 if (use_builtin_keys && !test_bit(KEY_ 103 if (use_builtin_keys && !test_bit(KEY_FLAG_BUILTIN, &key->flags))
104 ret = -ENOKEY; 104 ret = -ENOKEY;
105 else if (IS_BUILTIN(CONFIG_SECONDARY_T 105 else if (IS_BUILTIN(CONFIG_SECONDARY_TRUSTED_KEYRING_SIGNED_BY_BUILTIN) &&
106 !strcmp(dest_keyring->descrip 106 !strcmp(dest_keyring->description, ".secondary_trusted_keys") &&
107 !test_bit(KEY_FLAG_BUILTIN, & 107 !test_bit(KEY_FLAG_BUILTIN, &key->flags))
108 ret = -ENOKEY; 108 ret = -ENOKEY;
109 else 109 else
110 ret = verify_signature(key, si 110 ret = verify_signature(key, sig);
111 key_put(key); 111 key_put(key);
112 return ret; 112 return ret;
113 } 113 }
114 114
115 /** 115 /**
116 * restrict_link_by_ca - Restrict additions to 116 * restrict_link_by_ca - Restrict additions to a ring of CA keys
117 * @dest_keyring: Keyring being linked to. 117 * @dest_keyring: Keyring being linked to.
118 * @type: The type of key being added. 118 * @type: The type of key being added.
119 * @payload: The payload of the new key. 119 * @payload: The payload of the new key.
120 * @trust_keyring: Unused. 120 * @trust_keyring: Unused.
121 * 121 *
122 * Check if the new certificate is a CA. If it 122 * Check if the new certificate is a CA. If it is a CA, then mark the new
123 * certificate as being ok to link. 123 * certificate as being ok to link.
124 * 124 *
125 * Returns 0 if the new certificate was accept 125 * Returns 0 if the new certificate was accepted, -ENOKEY if the
126 * certificate is not a CA. -ENOPKG if the sig 126 * certificate is not a CA. -ENOPKG if the signature uses unsupported
127 * crypto, or some other error if there is a m 127 * crypto, or some other error if there is a matching certificate but
128 * the signature check cannot be performed. 128 * the signature check cannot be performed.
129 */ 129 */
130 int restrict_link_by_ca(struct key *dest_keyri 130 int restrict_link_by_ca(struct key *dest_keyring,
131 const struct key_type 131 const struct key_type *type,
132 const union key_payloa 132 const union key_payload *payload,
133 struct key *trust_keyr 133 struct key *trust_keyring)
134 { 134 {
135 const struct public_key *pkey; 135 const struct public_key *pkey;
136 136
137 if (type != &key_type_asymmetric) 137 if (type != &key_type_asymmetric)
138 return -EOPNOTSUPP; 138 return -EOPNOTSUPP;
139 139
140 pkey = payload->data[asym_crypto]; 140 pkey = payload->data[asym_crypto];
141 if (!pkey) 141 if (!pkey)
142 return -ENOPKG; 142 return -ENOPKG;
143 if (!test_bit(KEY_EFLAG_CA, &pkey->key 143 if (!test_bit(KEY_EFLAG_CA, &pkey->key_eflags))
144 return -ENOKEY; 144 return -ENOKEY;
145 if (!test_bit(KEY_EFLAG_KEYCERTSIGN, & 145 if (!test_bit(KEY_EFLAG_KEYCERTSIGN, &pkey->key_eflags))
146 return -ENOKEY; 146 return -ENOKEY;
147 if (!IS_ENABLED(CONFIG_INTEGRITY_CA_MA 147 if (!IS_ENABLED(CONFIG_INTEGRITY_CA_MACHINE_KEYRING_MAX))
148 return 0; 148 return 0;
149 if (test_bit(KEY_EFLAG_DIGITALSIG, &pk 149 if (test_bit(KEY_EFLAG_DIGITALSIG, &pkey->key_eflags))
150 return -ENOKEY; 150 return -ENOKEY;
151 151
152 return 0; 152 return 0;
153 } 153 }
154 154
155 /** 155 /**
156 * restrict_link_by_digsig - Restrict addition 156 * restrict_link_by_digsig - Restrict additions to a ring of digsig keys
157 * @dest_keyring: Keyring being linked to. 157 * @dest_keyring: Keyring being linked to.
158 * @type: The type of key being added. 158 * @type: The type of key being added.
159 * @payload: The payload of the new key. 159 * @payload: The payload of the new key.
160 * @trust_keyring: A ring of keys that can be 160 * @trust_keyring: A ring of keys that can be used to vouch for the new cert.
161 * 161 *
162 * Check if the new certificate has digitalSig 162 * Check if the new certificate has digitalSignature usage set. If it is,
163 * then mark the new certificate as being ok t 163 * then mark the new certificate as being ok to link. Afterwards verify
164 * the new certificate against the ones in the 164 * the new certificate against the ones in the trust_keyring.
165 * 165 *
166 * Returns 0 if the new certificate was accept 166 * Returns 0 if the new certificate was accepted, -ENOKEY if the
167 * certificate is not a digsig. -ENOPKG if the 167 * certificate is not a digsig. -ENOPKG if the signature uses unsupported
168 * crypto, or some other error if there is a m 168 * crypto, or some other error if there is a matching certificate but
169 * the signature check cannot be performed. 169 * the signature check cannot be performed.
170 */ 170 */
171 int restrict_link_by_digsig(struct key *dest_k 171 int restrict_link_by_digsig(struct key *dest_keyring,
172 const struct key_t 172 const struct key_type *type,
173 const union key_pa 173 const union key_payload *payload,
174 struct key *trust_ 174 struct key *trust_keyring)
175 { 175 {
176 const struct public_key *pkey; 176 const struct public_key *pkey;
177 177
178 if (type != &key_type_asymmetric) 178 if (type != &key_type_asymmetric)
179 return -EOPNOTSUPP; 179 return -EOPNOTSUPP;
180 180
181 pkey = payload->data[asym_crypto]; 181 pkey = payload->data[asym_crypto];
182 182
183 if (!pkey) 183 if (!pkey)
184 return -ENOPKG; 184 return -ENOPKG;
185 185
186 if (!test_bit(KEY_EFLAG_DIGITALSIG, &p 186 if (!test_bit(KEY_EFLAG_DIGITALSIG, &pkey->key_eflags))
187 return -ENOKEY; 187 return -ENOKEY;
188 188
189 if (test_bit(KEY_EFLAG_CA, &pkey->key_ 189 if (test_bit(KEY_EFLAG_CA, &pkey->key_eflags))
190 return -ENOKEY; 190 return -ENOKEY;
191 191
192 if (test_bit(KEY_EFLAG_KEYCERTSIGN, &p 192 if (test_bit(KEY_EFLAG_KEYCERTSIGN, &pkey->key_eflags))
193 return -ENOKEY; 193 return -ENOKEY;
194 194
195 return restrict_link_by_signature(dest 195 return restrict_link_by_signature(dest_keyring, type, payload,
196 trus 196 trust_keyring);
197 } 197 }
198 198
199 static bool match_either_id(const struct asymm 199 static bool match_either_id(const struct asymmetric_key_id **pair,
200 const struct asymm 200 const struct asymmetric_key_id *single)
201 { 201 {
202 return (asymmetric_key_id_same(pair[0] 202 return (asymmetric_key_id_same(pair[0], single) ||
203 asymmetric_key_id_same(pair[1] 203 asymmetric_key_id_same(pair[1], single));
204 } 204 }
205 205
206 static int key_or_keyring_common(struct key *d 206 static int key_or_keyring_common(struct key *dest_keyring,
207 const struct 207 const struct key_type *type,
208 const union k 208 const union key_payload *payload,
209 struct key *t 209 struct key *trusted, bool check_dest)
210 { 210 {
211 const struct public_key_signature *sig 211 const struct public_key_signature *sig;
212 struct key *key = NULL; 212 struct key *key = NULL;
213 int ret; 213 int ret;
214 214
215 pr_devel("==>%s()\n", __func__); 215 pr_devel("==>%s()\n", __func__);
216 216
217 if (!dest_keyring) 217 if (!dest_keyring)
218 return -ENOKEY; 218 return -ENOKEY;
219 else if (dest_keyring->type != &key_ty 219 else if (dest_keyring->type != &key_type_keyring)
220 return -EOPNOTSUPP; 220 return -EOPNOTSUPP;
221 221
222 if (!trusted && !check_dest) 222 if (!trusted && !check_dest)
223 return -ENOKEY; 223 return -ENOKEY;
224 224
225 if (type != &key_type_asymmetric) 225 if (type != &key_type_asymmetric)
226 return -EOPNOTSUPP; 226 return -EOPNOTSUPP;
227 227
228 sig = payload->data[asym_auth]; 228 sig = payload->data[asym_auth];
229 if (!sig) 229 if (!sig)
230 return -ENOPKG; 230 return -ENOPKG;
231 if (!sig->auth_ids[0] && !sig->auth_id 231 if (!sig->auth_ids[0] && !sig->auth_ids[1] && !sig->auth_ids[2])
232 return -ENOKEY; 232 return -ENOKEY;
233 233
234 if (trusted) { 234 if (trusted) {
235 if (trusted->type == &key_type 235 if (trusted->type == &key_type_keyring) {
236 /* See if we have a ke 236 /* See if we have a key that signed this one. */
237 key = find_asymmetric_ 237 key = find_asymmetric_key(trusted, sig->auth_ids[0],
238 238 sig->auth_ids[1],
239 239 sig->auth_ids[2], false);
240 if (IS_ERR(key)) 240 if (IS_ERR(key))
241 key = NULL; 241 key = NULL;
242 } else if (trusted->type == &k 242 } else if (trusted->type == &key_type_asymmetric) {
243 const struct asymmetri 243 const struct asymmetric_key_id **signer_ids;
244 244
245 signer_ids = (const st 245 signer_ids = (const struct asymmetric_key_id **)
246 asymmetric_key 246 asymmetric_key_ids(trusted)->id;
247 247
248 /* 248 /*
249 * The auth_ids come f 249 * The auth_ids come from the candidate key (the
250 * one that is being c 250 * one that is being considered for addition to
251 * dest_keyring) and i 251 * dest_keyring) and identify the key that was
252 * used to sign. 252 * used to sign.
253 * 253 *
254 * The signer_ids are 254 * The signer_ids are identifiers for the
255 * signing key specifi 255 * signing key specified for dest_keyring.
256 * 256 *
257 * The first auth_id i 257 * The first auth_id is the preferred id, 2nd and
258 * 3rd are the fallbac 258 * 3rd are the fallbacks. If exactly one of
259 * auth_ids[0] and aut 259 * auth_ids[0] and auth_ids[1] is present, it may
260 * match either signer 260 * match either signer_ids[0] or signed_ids[1].
261 * If both are present 261 * If both are present the first one may match
262 * either signed_id bu 262 * either signed_id but the second one must match
263 * the second signer_i 263 * the second signer_id. If neither of them is
264 * available, auth_ids 264 * available, auth_ids[2] is matched against
265 * signer_ids[2] as a 265 * signer_ids[2] as a fallback.
266 */ 266 */
267 if (!sig->auth_ids[0] 267 if (!sig->auth_ids[0] && !sig->auth_ids[1]) {
268 if (asymmetric 268 if (asymmetric_key_id_same(signer_ids[2],
269 269 sig->auth_ids[2]))
270 key = 270 key = __key_get(trusted);
271 271
272 } else if (!sig->auth_ 272 } else if (!sig->auth_ids[0] || !sig->auth_ids[1]) {
273 const struct a 273 const struct asymmetric_key_id *auth_id;
274 274
275 auth_id = sig- 275 auth_id = sig->auth_ids[0] ?: sig->auth_ids[1];
276 if (match_eith 276 if (match_either_id(signer_ids, auth_id))
277 key = 277 key = __key_get(trusted);
278 278
279 } else if (asymmetric_ 279 } else if (asymmetric_key_id_same(signer_ids[1],
280 280 sig->auth_ids[1]) &&
281 match_eithe 281 match_either_id(signer_ids,
282 282 sig->auth_ids[0])) {
283 key = __key_ge 283 key = __key_get(trusted);
284 } 284 }
285 } else { 285 } else {
286 return -EOPNOTSUPP; 286 return -EOPNOTSUPP;
287 } 287 }
288 } 288 }
289 289
290 if (check_dest && !key) { 290 if (check_dest && !key) {
291 /* See if the destination has 291 /* See if the destination has a key that signed this one. */
292 key = find_asymmetric_key(dest 292 key = find_asymmetric_key(dest_keyring, sig->auth_ids[0],
293 sig- 293 sig->auth_ids[1], sig->auth_ids[2],
294 fals 294 false);
295 if (IS_ERR(key)) 295 if (IS_ERR(key))
296 key = NULL; 296 key = NULL;
297 } 297 }
298 298
299 if (!key) 299 if (!key)
300 return -ENOKEY; 300 return -ENOKEY;
301 301
302 ret = key_validate(key); 302 ret = key_validate(key);
303 if (ret == 0) 303 if (ret == 0)
304 ret = verify_signature(key, si 304 ret = verify_signature(key, sig);
305 305
306 key_put(key); 306 key_put(key);
307 return ret; 307 return ret;
308 } 308 }
309 309
310 /** 310 /**
311 * restrict_link_by_key_or_keyring - Restrict 311 * restrict_link_by_key_or_keyring - Restrict additions to a ring of public
312 * keys using the restrict_key information sto 312 * keys using the restrict_key information stored in the ring.
313 * @dest_keyring: Keyring being linked to. 313 * @dest_keyring: Keyring being linked to.
314 * @type: The type of key being added. 314 * @type: The type of key being added.
315 * @payload: The payload of the new key. 315 * @payload: The payload of the new key.
316 * @trusted: A key or ring of keys that can be 316 * @trusted: A key or ring of keys that can be used to vouch for the new cert.
317 * 317 *
318 * Check the new certificate only against the 318 * Check the new certificate only against the key or keys passed in the data
319 * parameter. If one of those is the signing k 319 * parameter. If one of those is the signing key and validates the new
320 * certificate, then mark the new certificate 320 * certificate, then mark the new certificate as being ok to link.
321 * 321 *
322 * Returns 0 if the new certificate was accept 322 * Returns 0 if the new certificate was accepted, -ENOKEY if we
323 * couldn't find a matching parent certificate 323 * couldn't find a matching parent certificate in the trusted list,
324 * -EKEYREJECTED if the signature check fails, 324 * -EKEYREJECTED if the signature check fails, -ENOPKG if the signature uses
325 * unsupported crypto, or some other error if 325 * unsupported crypto, or some other error if there is a matching certificate
326 * but the signature check cannot be performed 326 * but the signature check cannot be performed.
327 */ 327 */
328 int restrict_link_by_key_or_keyring(struct key 328 int restrict_link_by_key_or_keyring(struct key *dest_keyring,
329 const stru 329 const struct key_type *type,
330 const unio 330 const union key_payload *payload,
331 struct key 331 struct key *trusted)
332 { 332 {
333 return key_or_keyring_common(dest_keyr 333 return key_or_keyring_common(dest_keyring, type, payload, trusted,
334 false); 334 false);
335 } 335 }
336 336
337 /** 337 /**
338 * restrict_link_by_key_or_keyring_chain - Res 338 * restrict_link_by_key_or_keyring_chain - Restrict additions to a ring of
339 * public keys using the restrict_key informat 339 * public keys using the restrict_key information stored in the ring.
340 * @dest_keyring: Keyring being linked to. 340 * @dest_keyring: Keyring being linked to.
341 * @type: The type of key being added. 341 * @type: The type of key being added.
342 * @payload: The payload of the new key. 342 * @payload: The payload of the new key.
343 * @trusted: A key or ring of keys that can be 343 * @trusted: A key or ring of keys that can be used to vouch for the new cert.
344 * 344 *
345 * Check the new certificate against the key o 345 * Check the new certificate against the key or keys passed in the data
346 * parameter and against the keys already link 346 * parameter and against the keys already linked to the destination keyring. If
347 * one of those is the signing key and validat 347 * one of those is the signing key and validates the new certificate, then mark
348 * the new certificate as being ok to link. 348 * the new certificate as being ok to link.
349 * 349 *
350 * Returns 0 if the new certificate was accept 350 * Returns 0 if the new certificate was accepted, -ENOKEY if we
351 * couldn't find a matching parent certificate 351 * couldn't find a matching parent certificate in the trusted list,
352 * -EKEYREJECTED if the signature check fails, 352 * -EKEYREJECTED if the signature check fails, -ENOPKG if the signature uses
353 * unsupported crypto, or some other error if 353 * unsupported crypto, or some other error if there is a matching certificate
354 * but the signature check cannot be performed 354 * but the signature check cannot be performed.
355 */ 355 */
356 int restrict_link_by_key_or_keyring_chain(stru 356 int restrict_link_by_key_or_keyring_chain(struct key *dest_keyring,
357 cons 357 const struct key_type *type,
358 cons 358 const union key_payload *payload,
359 stru 359 struct key *trusted)
360 { 360 {
361 return key_or_keyring_common(dest_keyr 361 return key_or_keyring_common(dest_keyring, type, payload, trusted,
362 true); 362 true);
363 } 363 }
364 364
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