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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> | |
20 | ||
21 | #include "integrity.h" | |
22 | ||
e0751257 DK |
23 | /* |
24 | * Request an asymmetric key. | |
25 | */ | |
26 | static struct key *request_asymmetric_key(struct key *keyring, uint32_t keyid) | |
27 | { | |
28 | struct key *key; | |
29 | char name[12]; | |
30 | ||
594081ee | 31 | sprintf(name, "id:%08x", keyid); |
e0751257 DK |
32 | |
33 | pr_debug("key search: \"%s\"\n", name); | |
34 | ||
35 | if (keyring) { | |
36 | /* search in specific keyring */ | |
37 | key_ref_t kref; | |
38 | kref = keyring_search(make_key_ref(keyring, 1), | |
39 | &key_type_asymmetric, name); | |
40 | if (IS_ERR(kref)) | |
41 | key = ERR_CAST(kref); | |
42 | else | |
43 | key = key_ref_to_ptr(kref); | |
44 | } else { | |
45 | key = request_key(&key_type_asymmetric, name, NULL); | |
46 | } | |
47 | ||
48 | if (IS_ERR(key)) { | |
d9a2e5d7 DK |
49 | pr_err_ratelimited("Request for unknown key '%s' err %ld\n", |
50 | name, PTR_ERR(key)); | |
e0751257 DK |
51 | switch (PTR_ERR(key)) { |
52 | /* Hide some search errors */ | |
53 | case -EACCES: | |
54 | case -ENOTDIR: | |
55 | case -EAGAIN: | |
56 | return ERR_PTR(-ENOKEY); | |
57 | default: | |
58 | return key; | |
59 | } | |
60 | } | |
61 | ||
62 | pr_debug("%s() = 0 [%x]\n", __func__, key_serial(key)); | |
63 | ||
64 | return key; | |
65 | } | |
66 | ||
67 | int asymmetric_verify(struct key *keyring, const char *sig, | |
68 | int siglen, const char *data, int datalen) | |
69 | { | |
70 | struct public_key_signature pks; | |
71 | struct signature_v2_hdr *hdr = (struct signature_v2_hdr *)sig; | |
72 | struct key *key; | |
73 | int ret = -ENOMEM; | |
74 | ||
75 | if (siglen <= sizeof(*hdr)) | |
76 | return -EBADMSG; | |
77 | ||
78 | siglen -= sizeof(*hdr); | |
79 | ||
80 | if (siglen != __be16_to_cpu(hdr->sig_size)) | |
81 | return -EBADMSG; | |
82 | ||
83 | if (hdr->hash_algo >= PKEY_HASH__LAST) | |
84 | return -ENOPKG; | |
85 | ||
86 | key = request_asymmetric_key(keyring, __be32_to_cpu(hdr->keyid)); | |
87 | if (IS_ERR(key)) | |
88 | return PTR_ERR(key); | |
89 | ||
90 | memset(&pks, 0, sizeof(pks)); | |
91 | ||
92 | pks.pkey_hash_algo = hdr->hash_algo; | |
93 | pks.digest = (u8 *)data; | |
94 | pks.digest_size = datalen; | |
95 | pks.nr_mpi = 1; | |
96 | pks.rsa.s = mpi_read_raw_data(hdr->sig, siglen); | |
97 | ||
98 | if (pks.rsa.s) | |
99 | ret = verify_signature(key, &pks); | |
100 | ||
101 | mpi_free(pks.rsa.s); | |
102 | key_put(key); | |
103 | pr_debug("%s() = %d\n", __func__, ret); | |
104 | return ret; | |
105 | } |