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e0751257 DK |
1 | /* |
2 | * Copyright (C) 2013 Intel Corporation | |
3 | * | |
4 | * Author: | |
5 | * Dmitry Kasatkin <dmitry.kasatkin@intel.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License as published by | |
9 | * the Free Software Foundation, version 2 of the License. | |
10 | * | |
11 | */ | |
12 | ||
13 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
14 | ||
15 | #include <linux/err.h> | |
d9a2e5d7 | 16 | #include <linux/ratelimit.h> |
e0751257 DK |
17 | #include <linux/key-type.h> |
18 | #include <crypto/public_key.h> | |
19 | #include <keys/asymmetric-type.h> | |
41c89b64 | 20 | #include <keys/system_keyring.h> |
e0751257 DK |
21 | |
22 | #include "integrity.h" | |
23 | ||
e0751257 DK |
24 | /* |
25 | * Request an asymmetric key. | |
26 | */ | |
27 | static struct key *request_asymmetric_key(struct key *keyring, uint32_t keyid) | |
28 | { | |
29 | struct key *key; | |
30 | char name[12]; | |
31 | ||
594081ee | 32 | sprintf(name, "id:%08x", keyid); |
e0751257 DK |
33 | |
34 | pr_debug("key search: \"%s\"\n", name); | |
35 | ||
41c89b64 PM |
36 | key = get_ima_blacklist_keyring(); |
37 | if (key) { | |
38 | key_ref_t kref; | |
39 | ||
40 | kref = keyring_search(make_key_ref(key, 1), | |
41 | &key_type_asymmetric, name); | |
42 | if (!IS_ERR(kref)) { | |
43 | pr_err("Key '%s' is in ima_blacklist_keyring\n", name); | |
44 | return ERR_PTR(-EKEYREJECTED); | |
45 | } | |
46 | } | |
47 | ||
e0751257 DK |
48 | if (keyring) { |
49 | /* search in specific keyring */ | |
50 | key_ref_t kref; | |
41c89b64 | 51 | |
e0751257 DK |
52 | kref = keyring_search(make_key_ref(keyring, 1), |
53 | &key_type_asymmetric, name); | |
54 | if (IS_ERR(kref)) | |
55 | key = ERR_CAST(kref); | |
56 | else | |
57 | key = key_ref_to_ptr(kref); | |
58 | } else { | |
59 | key = request_key(&key_type_asymmetric, name, NULL); | |
60 | } | |
61 | ||
62 | if (IS_ERR(key)) { | |
d9a2e5d7 DK |
63 | pr_err_ratelimited("Request for unknown key '%s' err %ld\n", |
64 | name, PTR_ERR(key)); | |
e0751257 DK |
65 | switch (PTR_ERR(key)) { |
66 | /* Hide some search errors */ | |
67 | case -EACCES: | |
68 | case -ENOTDIR: | |
69 | case -EAGAIN: | |
70 | return ERR_PTR(-ENOKEY); | |
71 | default: | |
72 | return key; | |
73 | } | |
74 | } | |
75 | ||
76 | pr_debug("%s() = 0 [%x]\n", __func__, key_serial(key)); | |
77 | ||
78 | return key; | |
79 | } | |
80 | ||
81 | int asymmetric_verify(struct key *keyring, const char *sig, | |
82 | int siglen, const char *data, int datalen) | |
83 | { | |
84 | struct public_key_signature pks; | |
85 | struct signature_v2_hdr *hdr = (struct signature_v2_hdr *)sig; | |
86 | struct key *key; | |
87 | int ret = -ENOMEM; | |
88 | ||
89 | if (siglen <= sizeof(*hdr)) | |
90 | return -EBADMSG; | |
91 | ||
92 | siglen -= sizeof(*hdr); | |
93 | ||
94 | if (siglen != __be16_to_cpu(hdr->sig_size)) | |
95 | return -EBADMSG; | |
96 | ||
97 | if (hdr->hash_algo >= PKEY_HASH__LAST) | |
98 | return -ENOPKG; | |
99 | ||
100 | key = request_asymmetric_key(keyring, __be32_to_cpu(hdr->keyid)); | |
101 | if (IS_ERR(key)) | |
102 | return PTR_ERR(key); | |
103 | ||
104 | memset(&pks, 0, sizeof(pks)); | |
105 | ||
106 | pks.pkey_hash_algo = hdr->hash_algo; | |
107 | pks.digest = (u8 *)data; | |
108 | pks.digest_size = datalen; | |
109 | pks.nr_mpi = 1; | |
110 | pks.rsa.s = mpi_read_raw_data(hdr->sig, siglen); | |
111 | ||
112 | if (pks.rsa.s) | |
113 | ret = verify_signature(key, &pks); | |
114 | ||
115 | mpi_free(pks.rsa.s); | |
116 | key_put(key); | |
117 | pr_debug("%s() = %d\n", __func__, ret); | |
118 | return ret; | |
119 | } |