1 // SPDX-License-Identifier: GPL-2.0-or-later 1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* System hash blacklist. 2 /* System hash blacklist.
3 * 3 *
4 * Copyright (C) 2016 Red Hat, Inc. All Rights 4 * Copyright (C) 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) "blacklist: "fmt 8 #define pr_fmt(fmt) "blacklist: "fmt
9 #include <linux/module.h> 9 #include <linux/module.h>
10 #include <linux/slab.h> 10 #include <linux/slab.h>
11 #include <linux/key.h> 11 #include <linux/key.h>
12 #include <linux/key-type.h> 12 #include <linux/key-type.h>
13 #include <linux/sched.h> 13 #include <linux/sched.h>
14 #include <linux/ctype.h> 14 #include <linux/ctype.h>
15 #include <linux/err.h> 15 #include <linux/err.h>
16 #include <linux/seq_file.h> 16 #include <linux/seq_file.h>
17 #include <linux/uidgid.h> 17 #include <linux/uidgid.h>
18 #include <keys/asymmetric-type.h> <<
19 #include <keys/system_keyring.h> 18 #include <keys/system_keyring.h>
20 #include "blacklist.h" 19 #include "blacklist.h"
21 !! 20 #include "common.h"
22 /* <<
23 * According to crypto/asymmetric_keys/x509_ce <<
24 * the size of the currently longest supported <<
25 * which translates into 128 hex characters. <<
26 */ <<
27 #define MAX_HASH_LEN 128 <<
28 <<
29 #define BLACKLIST_KEY_PERM (KEY_POS_SEARCH | K <<
30 KEY_USR_SEARCH | K <<
31 <<
32 static const char tbs_prefix[] = "tbs"; <<
33 static const char bin_prefix[] = "bin"; <<
34 21
35 static struct key *blacklist_keyring; 22 static struct key *blacklist_keyring;
36 23
37 #ifdef CONFIG_SYSTEM_REVOCATION_LIST 24 #ifdef CONFIG_SYSTEM_REVOCATION_LIST
38 extern __initconst const u8 revocation_certifi 25 extern __initconst const u8 revocation_certificate_list[];
39 extern __initconst const unsigned long revocat 26 extern __initconst const unsigned long revocation_certificate_list_size;
40 #endif 27 #endif
41 28
42 /* 29 /*
43 * The description must be a type prefix, a co 30 * The description must be a type prefix, a colon and then an even number of
44 * hex digits. The hash is kept in the descri 31 * hex digits. The hash is kept in the description.
45 */ 32 */
46 static int blacklist_vet_description(const cha 33 static int blacklist_vet_description(const char *desc)
47 { 34 {
48 int i, prefix_len, tbs_step = 0, bin_s !! 35 int n = 0;
49 36
50 /* The following algorithm only works !! 37 if (*desc == ':')
51 BUILD_BUG_ON(sizeof(tbs_prefix) != siz !! 38 return -EINVAL;
52 prefix_len = sizeof(tbs_prefix) - 1; !! 39 for (; *desc; desc++)
53 for (i = 0; *desc; desc++, i++) { !! 40 if (*desc == ':')
54 if (*desc == ':') { !! 41 goto found_colon;
55 if (tbs_step == prefix <<
56 goto found_col <<
57 if (bin_step == prefix <<
58 goto found_col <<
59 return -EINVAL; <<
60 } <<
61 if (i >= prefix_len) <<
62 return -EINVAL; <<
63 if (*desc == tbs_prefix[i]) <<
64 tbs_step++; <<
65 if (*desc == bin_prefix[i]) <<
66 bin_step++; <<
67 } <<
68 return -EINVAL; 42 return -EINVAL;
69 43
70 found_colon: 44 found_colon:
71 desc++; 45 desc++;
72 for (i = 0; *desc && i < MAX_HASH_LEN; !! 46 for (; *desc; desc++) {
73 if (!isxdigit(*desc) || isuppe 47 if (!isxdigit(*desc) || isupper(*desc))
74 return -EINVAL; 48 return -EINVAL;
>> 49 n++;
75 } 50 }
76 if (*desc) <<
77 /* The hash is greater than MA <<
78 return -ENOPKG; <<
79 51
80 /* Checks for an even number of hexade !! 52 if (n == 0 || n & 1)
81 if (i == 0 || i & 1) <<
82 return -EINVAL; 53 return -EINVAL;
83 return 0; 54 return 0;
84 } 55 }
85 56
86 static int blacklist_key_instantiate(struct ke !! 57 /*
87 struct key_preparsed_payload * !! 58 * The hash to be blacklisted is expected to be in the description. There will
>> 59 * be no payload.
>> 60 */
>> 61 static int blacklist_preparse(struct key_preparsed_payload *prep)
88 { 62 {
89 #ifdef CONFIG_SYSTEM_BLACKLIST_AUTH_UPDATE !! 63 if (prep->datalen > 0)
90 int err; !! 64 return -EINVAL;
91 #endif !! 65 return 0;
92 <<
93 /* Sets safe default permissions for k <<
94 key->perm = BLACKLIST_KEY_PERM; <<
95 <<
96 /* <<
97 * Skips the authentication step for b <<
98 * signed but still trusted. <<
99 */ <<
100 if (key->flags & (1 << KEY_FLAG_BUILTI <<
101 goto out; <<
102 <<
103 #ifdef CONFIG_SYSTEM_BLACKLIST_AUTH_UPDATE <<
104 /* <<
105 * Verifies the description's PKCS#7 s <<
106 * trusted keyring. <<
107 */ <<
108 err = verify_pkcs7_signature(key->desc <<
109 strlen(key->descriptio <<
110 NULL, VERIFYING_UNSPEC <<
111 if (err) <<
112 return err; <<
113 #else <<
114 /* <<
115 * It should not be possible to come h <<
116 * have KEY_USR_WRITE and the only oth <<
117 * for builtin hashes. <<
118 */ <<
119 WARN_ON_ONCE(1); <<
120 return -EPERM; <<
121 #endif <<
122 <<
123 out: <<
124 return generic_key_instantiate(key, pr <<
125 } 66 }
126 67
127 static int blacklist_key_update(struct key *ke !! 68 static void blacklist_free_preparse(struct key_preparsed_payload *prep)
128 struct key_preparsed_payload * <<
129 { 69 {
130 return -EPERM; <<
131 } 70 }
132 71
133 static void blacklist_describe(const struct ke 72 static void blacklist_describe(const struct key *key, struct seq_file *m)
134 { 73 {
135 seq_puts(m, key->description); 74 seq_puts(m, key->description);
136 } 75 }
137 76
138 static struct key_type key_type_blacklist = { 77 static struct key_type key_type_blacklist = {
139 .name = "blacklist", 78 .name = "blacklist",
140 .vet_description = blacklist_ve 79 .vet_description = blacklist_vet_description,
141 .instantiate = blacklist_ke !! 80 .preparse = blacklist_preparse,
142 .update = blacklist_ke !! 81 .free_preparse = blacklist_free_preparse,
>> 82 .instantiate = generic_key_instantiate,
143 .describe = blacklist_de 83 .describe = blacklist_describe,
144 }; 84 };
145 85
146 static char *get_raw_hash(const u8 *hash, size <<
147 enum blacklist_hash_type hash_ <<
148 { <<
149 size_t type_len; <<
150 const char *type_prefix; <<
151 char *buffer, *p; <<
152 <<
153 switch (hash_type) { <<
154 case BLACKLIST_HASH_X509_TBS: <<
155 type_len = sizeof(tbs_prefix) <<
156 type_prefix = tbs_prefix; <<
157 break; <<
158 case BLACKLIST_HASH_BINARY: <<
159 type_len = sizeof(bin_prefix) <<
160 type_prefix = bin_prefix; <<
161 break; <<
162 default: <<
163 WARN_ON_ONCE(1); <<
164 return ERR_PTR(-EINVAL); <<
165 } <<
166 buffer = kmalloc(type_len + 1 + hash_l <<
167 if (!buffer) <<
168 return ERR_PTR(-ENOMEM); <<
169 p = memcpy(buffer, type_prefix, type_l <<
170 p += type_len; <<
171 *p++ = ':'; <<
172 bin2hex(p, hash, hash_len); <<
173 p += hash_len * 2; <<
174 *p = '\0'; <<
175 return buffer; <<
176 } <<
177 <<
178 /** 86 /**
179 * mark_raw_hash_blacklisted - Add a hash to t !! 87 * mark_hash_blacklisted - Add a hash to the system blacklist
180 * @hash: The hash as a hex string with a type 88 * @hash: The hash as a hex string with a type prefix (eg. "tbs:23aa429783")
181 */ 89 */
182 static int mark_raw_hash_blacklisted(const cha !! 90 int mark_hash_blacklisted(const char *hash)
183 { 91 {
184 key_ref_t key; 92 key_ref_t key;
185 93
186 key = key_create(make_key_ref(blacklis !! 94 key = key_create_or_update(make_key_ref(blacklist_keyring, true),
187 "blacklist", !! 95 "blacklist",
188 hash, !! 96 hash,
189 NULL, !! 97 NULL,
190 0, !! 98 0,
191 BLACKLIST_KEY_PERM, !! 99 ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
192 KEY_ALLOC_NOT_IN_QUOT !! 100 KEY_USR_VIEW),
193 KEY_ALLOC_BUILT_IN); !! 101 KEY_ALLOC_NOT_IN_QUOTA |
>> 102 KEY_ALLOC_BUILT_IN);
194 if (IS_ERR(key)) { 103 if (IS_ERR(key)) {
195 if (PTR_ERR(key) == -EEXIST) !! 104 pr_err("Problem blacklisting hash (%ld)\n", PTR_ERR(key));
196 pr_warn("Duplicate bla <<
197 else <<
198 pr_err("Problem blackl <<
199 return PTR_ERR(key); 105 return PTR_ERR(key);
200 } 106 }
201 return 0; 107 return 0;
202 } 108 }
203 109
204 int mark_hash_blacklisted(const u8 *hash, size <<
205 enum blacklist_hash_type hash_ <<
206 { <<
207 const char *buffer; <<
208 int err; <<
209 <<
210 buffer = get_raw_hash(hash, hash_len, <<
211 if (IS_ERR(buffer)) <<
212 return PTR_ERR(buffer); <<
213 err = mark_raw_hash_blacklisted(buffer <<
214 kfree(buffer); <<
215 return err; <<
216 } <<
217 <<
218 /** 110 /**
219 * is_hash_blacklisted - Determine if a hash i 111 * is_hash_blacklisted - Determine if a hash is blacklisted
220 * @hash: The hash to be checked as a binary b 112 * @hash: The hash to be checked as a binary blob
221 * @hash_len: The length of the binary hash 113 * @hash_len: The length of the binary hash
222 * @hash_type: Type of hash !! 114 * @type: Type of hash
223 */ 115 */
224 int is_hash_blacklisted(const u8 *hash, size_t !! 116 int is_hash_blacklisted(const u8 *hash, size_t hash_len, const char *type)
225 enum blacklist_hash_type hash_ <<
226 { 117 {
227 key_ref_t kref; 118 key_ref_t kref;
228 const char *buffer; !! 119 size_t type_len = strlen(type);
>> 120 char *buffer, *p;
229 int ret = 0; 121 int ret = 0;
230 122
231 buffer = get_raw_hash(hash, hash_len, !! 123 buffer = kmalloc(type_len + 1 + hash_len * 2 + 1, GFP_KERNEL);
232 if (IS_ERR(buffer)) !! 124 if (!buffer)
233 return PTR_ERR(buffer); !! 125 return -ENOMEM;
>> 126 p = memcpy(buffer, type, type_len);
>> 127 p += type_len;
>> 128 *p++ = ':';
>> 129 bin2hex(p, hash, hash_len);
>> 130 p += hash_len * 2;
>> 131 *p = 0;
>> 132
234 kref = keyring_search(make_key_ref(bla 133 kref = keyring_search(make_key_ref(blacklist_keyring, true),
235 &key_type_blackl 134 &key_type_blacklist, buffer, false);
236 if (!IS_ERR(kref)) { 135 if (!IS_ERR(kref)) {
237 key_ref_put(kref); 136 key_ref_put(kref);
238 ret = -EKEYREJECTED; 137 ret = -EKEYREJECTED;
239 } 138 }
240 139
241 kfree(buffer); 140 kfree(buffer);
242 return ret; 141 return ret;
243 } 142 }
244 EXPORT_SYMBOL_GPL(is_hash_blacklisted); 143 EXPORT_SYMBOL_GPL(is_hash_blacklisted);
245 144
246 int is_binary_blacklisted(const u8 *hash, size 145 int is_binary_blacklisted(const u8 *hash, size_t hash_len)
247 { 146 {
248 if (is_hash_blacklisted(hash, hash_len !! 147 if (is_hash_blacklisted(hash, hash_len, "bin") == -EKEYREJECTED)
249 -EKEYREJECTED) <<
250 return -EPERM; 148 return -EPERM;
251 149
252 return 0; 150 return 0;
253 } 151 }
254 EXPORT_SYMBOL_GPL(is_binary_blacklisted); 152 EXPORT_SYMBOL_GPL(is_binary_blacklisted);
255 153
256 #ifdef CONFIG_SYSTEM_REVOCATION_LIST 154 #ifdef CONFIG_SYSTEM_REVOCATION_LIST
257 /** 155 /**
258 * add_key_to_revocation_list - Add a revocati 156 * add_key_to_revocation_list - Add a revocation certificate to the blacklist
259 * @data: The data blob containing the certifi 157 * @data: The data blob containing the certificate
260 * @size: The size of data blob 158 * @size: The size of data blob
261 */ 159 */
262 int add_key_to_revocation_list(const char *dat 160 int add_key_to_revocation_list(const char *data, size_t size)
263 { 161 {
264 key_ref_t key; 162 key_ref_t key;
265 163
266 key = key_create_or_update(make_key_re 164 key = key_create_or_update(make_key_ref(blacklist_keyring, true),
267 "asymmetric 165 "asymmetric",
268 NULL, 166 NULL,
269 data, 167 data,
270 size, 168 size,
271 KEY_POS_VIE !! 169 ((KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW),
272 | KEY_USR_V !! 170 KEY_ALLOC_NOT_IN_QUOTA | KEY_ALLOC_BUILT_IN);
273 KEY_ALLOC_N <<
274 | KEY_ALLOC <<
275 171
276 if (IS_ERR(key)) { 172 if (IS_ERR(key)) {
277 pr_err("Problem with revocatio 173 pr_err("Problem with revocation key (%ld)\n", PTR_ERR(key));
278 return PTR_ERR(key); 174 return PTR_ERR(key);
279 } 175 }
280 176
281 return 0; 177 return 0;
282 } 178 }
283 179
284 /** 180 /**
285 * is_key_on_revocation_list - Determine if th 181 * is_key_on_revocation_list - Determine if the key for a PKCS#7 message is revoked
286 * @pkcs7: The PKCS#7 message to check 182 * @pkcs7: The PKCS#7 message to check
287 */ 183 */
288 int is_key_on_revocation_list(struct pkcs7_mes 184 int is_key_on_revocation_list(struct pkcs7_message *pkcs7)
289 { 185 {
290 int ret; 186 int ret;
291 187
292 ret = pkcs7_validate_trust(pkcs7, blac 188 ret = pkcs7_validate_trust(pkcs7, blacklist_keyring);
293 189
294 if (ret == 0) 190 if (ret == 0)
295 return -EKEYREJECTED; 191 return -EKEYREJECTED;
296 192
297 return -ENOKEY; 193 return -ENOKEY;
298 } 194 }
299 #endif 195 #endif
300 196
301 static int restrict_link_for_blacklist(struct <<
302 const struct key_type *type, c <<
303 struct key *restrict_key) <<
304 { <<
305 if (type == &key_type_blacklist) <<
306 return 0; <<
307 return -EOPNOTSUPP; <<
308 } <<
309 <<
310 /* 197 /*
311 * Initialise the blacklist 198 * Initialise the blacklist
312 * <<
313 * The blacklist_init() function is registered <<
314 * device_initcall(). As a result if the blac <<
315 * any reason the kernel continues to execute. <<
316 * could be acceptable for some non-critical k <<
317 * keyring fails to load it defeats the certif <<
318 * signed modules. If a critical piece of sec <<
319 * expect to be present fails to initialize, p <<
320 * thing to do. <<
321 */ 199 */
322 static int __init blacklist_init(void) 200 static int __init blacklist_init(void)
323 { 201 {
324 const char *const *bl; 202 const char *const *bl;
325 struct key_restriction *restriction; <<
326 203
327 if (register_key_type(&key_type_blackl 204 if (register_key_type(&key_type_blacklist) < 0)
328 panic("Can't allocate system b 205 panic("Can't allocate system blacklist key type\n");
329 206
330 restriction = kzalloc(sizeof(*restrict <<
331 if (!restriction) <<
332 panic("Can't allocate blacklis <<
333 restriction->check = restrict_link_for <<
334 <<
335 blacklist_keyring = 207 blacklist_keyring =
336 keyring_alloc(".blacklist", 208 keyring_alloc(".blacklist",
337 GLOBAL_ROOT_UID, 209 GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(),
338 KEY_POS_VIEW | K !! 210 (KEY_POS_ALL & ~KEY_POS_SETATTR) |
339 KEY_POS_WRITE | !! 211 KEY_USR_VIEW | KEY_USR_READ |
340 KEY_USR_VIEW | K !! 212 KEY_USR_SEARCH,
341 #ifdef CONFIG_SYSTEM_BLACKLIST_AUTH_UPDATE !! 213 KEY_ALLOC_NOT_IN_QUOTA |
342 | KEY_USR_WRITE <<
343 #endif <<
344 , KEY_ALLOC_NOT_ <<
345 KEY_ALLOC_SET_KE 214 KEY_ALLOC_SET_KEEP,
346 restriction, NUL !! 215 NULL, NULL);
347 if (IS_ERR(blacklist_keyring)) 216 if (IS_ERR(blacklist_keyring))
348 panic("Can't allocate system b 217 panic("Can't allocate system blacklist keyring\n");
349 218
350 for (bl = blacklist_hashes; *bl; bl++) 219 for (bl = blacklist_hashes; *bl; bl++)
351 if (mark_raw_hash_blacklisted( !! 220 if (mark_hash_blacklisted(*bl) < 0)
352 pr_err("- blacklisting 221 pr_err("- blacklisting failed\n");
353 return 0; 222 return 0;
354 } 223 }
355 224
356 /* 225 /*
357 * Must be initialised before we try and load 226 * Must be initialised before we try and load the keys into the keyring.
358 */ 227 */
359 device_initcall(blacklist_init); 228 device_initcall(blacklist_init);
360 229
361 #ifdef CONFIG_SYSTEM_REVOCATION_LIST 230 #ifdef CONFIG_SYSTEM_REVOCATION_LIST
362 /* 231 /*
363 * Load the compiled-in list of revocation X.5 232 * Load the compiled-in list of revocation X.509 certificates.
364 */ 233 */
365 static __init int load_revocation_certificate_ 234 static __init int load_revocation_certificate_list(void)
366 { 235 {
367 if (revocation_certificate_list_size) 236 if (revocation_certificate_list_size)
368 pr_notice("Loading compiled-in 237 pr_notice("Loading compiled-in revocation X.509 certificates\n");
369 238
370 return x509_load_certificate_list(revo !! 239 return load_certificate_list(revocation_certificate_list, revocation_certificate_list_size,
371 revo !! 240 blacklist_keyring);
372 blac <<
373 } 241 }
374 late_initcall(load_revocation_certificate_list 242 late_initcall(load_revocation_certificate_list);
375 #endif 243 #endif
376 244
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