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b4d0d230 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
734114f8 DH |
2 | /* System hash blacklist. |
3 | * | |
4 | * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved. | |
5 | * Written by David Howells (dhowells@redhat.com) | |
734114f8 DH |
6 | */ |
7 | ||
8 | #define pr_fmt(fmt) "blacklist: "fmt | |
9 | #include <linux/module.h> | |
10 | #include <linux/slab.h> | |
11 | #include <linux/key.h> | |
12 | #include <linux/key-type.h> | |
13 | #include <linux/sched.h> | |
14 | #include <linux/ctype.h> | |
15 | #include <linux/err.h> | |
16 | #include <linux/seq_file.h> | |
a6cb0ab7 | 17 | #include <linux/uidgid.h> |
734114f8 DH |
18 | #include <keys/system_keyring.h> |
19 | #include "blacklist.h" | |
d1f04410 | 20 | #include "common.h" |
734114f8 DH |
21 | |
22 | static struct key *blacklist_keyring; | |
23 | ||
d1f04410 ES |
24 | #ifdef CONFIG_SYSTEM_REVOCATION_LIST |
25 | extern __initconst const u8 revocation_certificate_list[]; | |
26 | extern __initconst const unsigned long revocation_certificate_list_size; | |
27 | #endif | |
28 | ||
734114f8 DH |
29 | /* |
30 | * The description must be a type prefix, a colon and then an even number of | |
31 | * hex digits. The hash is kept in the description. | |
32 | */ | |
33 | static int blacklist_vet_description(const char *desc) | |
34 | { | |
35 | int n = 0; | |
36 | ||
37 | if (*desc == ':') | |
38 | return -EINVAL; | |
39 | for (; *desc; desc++) | |
40 | if (*desc == ':') | |
41 | goto found_colon; | |
42 | return -EINVAL; | |
43 | ||
44 | found_colon: | |
45 | desc++; | |
46 | for (; *desc; desc++) { | |
84ffbefd | 47 | if (!isxdigit(*desc) || isupper(*desc)) |
734114f8 DH |
48 | return -EINVAL; |
49 | n++; | |
50 | } | |
51 | ||
52 | if (n == 0 || n & 1) | |
53 | return -EINVAL; | |
54 | return 0; | |
55 | } | |
56 | ||
57 | /* | |
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) | |
62 | { | |
63 | if (prep->datalen > 0) | |
64 | return -EINVAL; | |
65 | return 0; | |
66 | } | |
67 | ||
68 | static void blacklist_free_preparse(struct key_preparsed_payload *prep) | |
69 | { | |
70 | } | |
71 | ||
72 | static void blacklist_describe(const struct key *key, struct seq_file *m) | |
73 | { | |
74 | seq_puts(m, key->description); | |
75 | } | |
76 | ||
77 | static struct key_type key_type_blacklist = { | |
78 | .name = "blacklist", | |
79 | .vet_description = blacklist_vet_description, | |
80 | .preparse = blacklist_preparse, | |
81 | .free_preparse = blacklist_free_preparse, | |
82 | .instantiate = generic_key_instantiate, | |
83 | .describe = blacklist_describe, | |
84 | }; | |
85 | ||
86 | /** | |
87 | * mark_hash_blacklisted - Add a hash to the system blacklist | |
0b2d443b | 88 | * @hash: The hash as a hex string with a type prefix (eg. "tbs:23aa429783") |
734114f8 DH |
89 | */ |
90 | int mark_hash_blacklisted(const char *hash) | |
91 | { | |
92 | key_ref_t key; | |
93 | ||
94 | key = key_create_or_update(make_key_ref(blacklist_keyring, true), | |
95 | "blacklist", | |
96 | hash, | |
97 | NULL, | |
98 | 0, | |
028db3e2 LT |
99 | ((KEY_POS_ALL & ~KEY_POS_SETATTR) | |
100 | KEY_USR_VIEW), | |
734114f8 DH |
101 | KEY_ALLOC_NOT_IN_QUOTA | |
102 | KEY_ALLOC_BUILT_IN); | |
103 | if (IS_ERR(key)) { | |
104 | pr_err("Problem blacklisting hash (%ld)\n", PTR_ERR(key)); | |
105 | return PTR_ERR(key); | |
106 | } | |
107 | return 0; | |
108 | } | |
109 | ||
110 | /** | |
111 | * is_hash_blacklisted - Determine if a hash is blacklisted | |
112 | * @hash: The hash to be checked as a binary blob | |
113 | * @hash_len: The length of the binary hash | |
114 | * @type: Type of hash | |
115 | */ | |
116 | int is_hash_blacklisted(const u8 *hash, size_t hash_len, const char *type) | |
117 | { | |
118 | key_ref_t kref; | |
119 | size_t type_len = strlen(type); | |
120 | char *buffer, *p; | |
121 | int ret = 0; | |
122 | ||
123 | buffer = kmalloc(type_len + 1 + hash_len * 2 + 1, GFP_KERNEL); | |
124 | if (!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 | ||
133 | kref = keyring_search(make_key_ref(blacklist_keyring, true), | |
dcf49dbc | 134 | &key_type_blacklist, buffer, false); |
734114f8 DH |
135 | if (!IS_ERR(kref)) { |
136 | key_ref_put(kref); | |
137 | ret = -EKEYREJECTED; | |
138 | } | |
139 | ||
140 | kfree(buffer); | |
141 | return ret; | |
142 | } | |
143 | EXPORT_SYMBOL_GPL(is_hash_blacklisted); | |
144 | ||
2434f7d2 NJ |
145 | int is_binary_blacklisted(const u8 *hash, size_t hash_len) |
146 | { | |
147 | if (is_hash_blacklisted(hash, hash_len, "bin") == -EKEYREJECTED) | |
148 | return -EPERM; | |
149 | ||
150 | return 0; | |
151 | } | |
152 | EXPORT_SYMBOL_GPL(is_binary_blacklisted); | |
153 | ||
56c58126 ES |
154 | #ifdef CONFIG_SYSTEM_REVOCATION_LIST |
155 | /** | |
156 | * add_key_to_revocation_list - Add a revocation certificate to the blacklist | |
157 | * @data: The data blob containing the certificate | |
158 | * @size: The size of data blob | |
159 | */ | |
160 | int add_key_to_revocation_list(const char *data, size_t size) | |
161 | { | |
162 | key_ref_t key; | |
163 | ||
164 | key = key_create_or_update(make_key_ref(blacklist_keyring, true), | |
165 | "asymmetric", | |
166 | NULL, | |
167 | data, | |
168 | size, | |
169 | ((KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW), | |
170 | KEY_ALLOC_NOT_IN_QUOTA | KEY_ALLOC_BUILT_IN); | |
171 | ||
172 | if (IS_ERR(key)) { | |
173 | pr_err("Problem with revocation key (%ld)\n", PTR_ERR(key)); | |
174 | return PTR_ERR(key); | |
175 | } | |
176 | ||
177 | return 0; | |
178 | } | |
179 | ||
180 | /** | |
181 | * is_key_on_revocation_list - Determine if the key for a PKCS#7 message is revoked | |
182 | * @pkcs7: The PKCS#7 message to check | |
183 | */ | |
184 | int is_key_on_revocation_list(struct pkcs7_message *pkcs7) | |
185 | { | |
186 | int ret; | |
187 | ||
188 | ret = pkcs7_validate_trust(pkcs7, blacklist_keyring); | |
189 | ||
190 | if (ret == 0) | |
191 | return -EKEYREJECTED; | |
192 | ||
193 | return -ENOKEY; | |
194 | } | |
195 | #endif | |
196 | ||
734114f8 | 197 | /* |
6e7c2b4d | 198 | * Initialise the blacklist |
734114f8 DH |
199 | */ |
200 | static int __init blacklist_init(void) | |
201 | { | |
202 | const char *const *bl; | |
203 | ||
204 | if (register_key_type(&key_type_blacklist) < 0) | |
205 | panic("Can't allocate system blacklist key type\n"); | |
206 | ||
207 | blacklist_keyring = | |
208 | keyring_alloc(".blacklist", | |
a6cb0ab7 | 209 | GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(), |
028db3e2 LT |
210 | (KEY_POS_ALL & ~KEY_POS_SETATTR) | |
211 | KEY_USR_VIEW | KEY_USR_READ | | |
212 | KEY_USR_SEARCH, | |
734114f8 | 213 | KEY_ALLOC_NOT_IN_QUOTA | |
4993e1f9 | 214 | KEY_ALLOC_SET_KEEP, |
734114f8 DH |
215 | NULL, NULL); |
216 | if (IS_ERR(blacklist_keyring)) | |
217 | panic("Can't allocate system blacklist keyring\n"); | |
218 | ||
219 | for (bl = blacklist_hashes; *bl; bl++) | |
220 | if (mark_hash_blacklisted(*bl) < 0) | |
221 | pr_err("- blacklisting failed\n"); | |
222 | return 0; | |
223 | } | |
224 | ||
225 | /* | |
226 | * Must be initialised before we try and load the keys into the keyring. | |
227 | */ | |
228 | device_initcall(blacklist_init); | |
d1f04410 ES |
229 | |
230 | #ifdef CONFIG_SYSTEM_REVOCATION_LIST | |
231 | /* | |
232 | * Load the compiled-in list of revocation X.509 certificates. | |
233 | */ | |
234 | static __init int load_revocation_certificate_list(void) | |
235 | { | |
236 | if (revocation_certificate_list_size) | |
237 | pr_notice("Loading compiled-in revocation X.509 certificates\n"); | |
238 | ||
239 | return load_certificate_list(revocation_certificate_list, revocation_certificate_list_size, | |
240 | blacklist_keyring); | |
241 | } | |
242 | late_initcall(load_revocation_certificate_list); | |
243 | #endif |