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8fe1681c MM |
1 | /* |
2 | * libkmod - module signature display | |
3 | * | |
4 | * Copyright (C) 2013 Michal Marek, SUSE | |
5 | * | |
6 | * This library is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; either | |
9 | * version 2.1 of the License, or (at your option) any later version. | |
10 | * | |
11 | * This library is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * Lesser General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU Lesser General Public | |
dea2dfee | 17 | * License along with this library; if not, see <http://www.gnu.org/licenses/>. |
8fe1681c MM |
18 | */ |
19 | ||
20 | #include <endian.h> | |
b18979b7 | 21 | #include <inttypes.h> |
c2e4286b | 22 | #include <stdio.h> |
8fe1681c MM |
23 | #include <stdlib.h> |
24 | #include <string.h> | |
8fe1681c | 25 | |
8b7189bc | 26 | #include <shared/missing.h> |
96573a02 | 27 | #include <shared/util.h> |
8b7189bc | 28 | |
83b855a6 | 29 | #include "libkmod-internal.h" |
8fe1681c MM |
30 | |
31 | /* These types and tables were copied from the 3.7 kernel sources. | |
32 | * As this is just description of the signature format, it should not be | |
33 | * considered derived work (so libkmod can use the LGPL license). | |
34 | */ | |
35 | enum pkey_algo { | |
36 | PKEY_ALGO_DSA, | |
37 | PKEY_ALGO_RSA, | |
38 | PKEY_ALGO__LAST | |
39 | }; | |
40 | ||
41 | static const char *const pkey_algo[PKEY_ALGO__LAST] = { | |
42 | [PKEY_ALGO_DSA] = "DSA", | |
43 | [PKEY_ALGO_RSA] = "RSA", | |
44 | }; | |
45 | ||
46 | enum pkey_hash_algo { | |
47 | PKEY_HASH_MD4, | |
48 | PKEY_HASH_MD5, | |
49 | PKEY_HASH_SHA1, | |
50 | PKEY_HASH_RIPE_MD_160, | |
51 | PKEY_HASH_SHA256, | |
52 | PKEY_HASH_SHA384, | |
53 | PKEY_HASH_SHA512, | |
54 | PKEY_HASH_SHA224, | |
55 | PKEY_HASH__LAST | |
56 | }; | |
57 | ||
58 | const char *const pkey_hash_algo[PKEY_HASH__LAST] = { | |
59 | [PKEY_HASH_MD4] = "md4", | |
60 | [PKEY_HASH_MD5] = "md5", | |
61 | [PKEY_HASH_SHA1] = "sha1", | |
62 | [PKEY_HASH_RIPE_MD_160] = "rmd160", | |
63 | [PKEY_HASH_SHA256] = "sha256", | |
64 | [PKEY_HASH_SHA384] = "sha384", | |
65 | [PKEY_HASH_SHA512] = "sha512", | |
66 | [PKEY_HASH_SHA224] = "sha224", | |
67 | }; | |
68 | ||
69 | enum pkey_id_type { | |
70 | PKEY_ID_PGP, /* OpenPGP generated key ID */ | |
71 | PKEY_ID_X509, /* X.509 arbitrary subjectKeyIdentifier */ | |
72 | PKEY_ID_TYPE__LAST | |
73 | }; | |
74 | ||
75 | const char *const pkey_id_type[PKEY_ID_TYPE__LAST] = { | |
76 | [PKEY_ID_PGP] = "PGP", | |
77 | [PKEY_ID_X509] = "X509", | |
78 | }; | |
79 | ||
80 | /* | |
81 | * Module signature information block. | |
82 | * | |
83 | * The constituents of the signature section are, in order: | |
84 | * | |
85 | * - Signer's name | |
86 | * - Key identifier | |
87 | * - Signature data | |
88 | * - Information block | |
89 | */ | |
90 | struct module_signature { | |
91 | uint8_t algo; /* Public-key crypto algorithm [enum pkey_algo] */ | |
92 | uint8_t hash; /* Digest algorithm [enum pkey_hash_algo] */ | |
93 | uint8_t id_type; /* Key identifier type [enum pkey_id_type] */ | |
94 | uint8_t signer_len; /* Length of signer's name */ | |
95 | uint8_t key_id_len; /* Length of key identifier */ | |
96 | uint8_t __pad[3]; | |
97 | uint32_t sig_len; /* Length of signature data (big endian) */ | |
98 | }; | |
99 | ||
100 | #define SIG_MAGIC "~Module signature appended~\n" | |
101 | ||
102 | bool kmod_module_signature_info(const struct kmod_file *file, struct kmod_signature_info *sig_info) | |
103 | { | |
104 | const char *mem; | |
105 | off_t size; | |
106 | const struct module_signature *modsig; | |
107 | size_t sig_len; | |
108 | ||
109 | ||
110 | size = kmod_file_get_size(file); | |
111 | mem = kmod_file_get_contents(file); | |
112 | if (size < (off_t)strlen(SIG_MAGIC)) | |
113 | return false; | |
114 | size -= strlen(SIG_MAGIC); | |
115 | if (memcmp(SIG_MAGIC, mem + size, strlen(SIG_MAGIC)) != 0) | |
116 | return false; | |
117 | ||
118 | if (size < (off_t)sizeof(struct module_signature)) | |
119 | return false; | |
120 | size -= sizeof(struct module_signature); | |
121 | modsig = (struct module_signature *)(mem + size); | |
122 | if (modsig->algo >= PKEY_ALGO__LAST || | |
123 | modsig->hash >= PKEY_HASH__LAST || | |
124 | modsig->id_type >= PKEY_ID_TYPE__LAST) | |
125 | return false; | |
f87dc57a | 126 | sig_len = be32toh(get_unaligned(&modsig->sig_len)); |
dcbe1846 LDM |
127 | if (sig_len == 0 || |
128 | size < (int64_t)(modsig->signer_len + modsig->key_id_len + sig_len)) | |
8fe1681c MM |
129 | return false; |
130 | ||
131 | size -= modsig->key_id_len + sig_len; | |
132 | sig_info->key_id = mem + size; | |
133 | sig_info->key_id_len = modsig->key_id_len; | |
134 | ||
135 | size -= modsig->signer_len; | |
136 | sig_info->signer = mem + size; | |
137 | sig_info->signer_len = modsig->signer_len; | |
138 | ||
139 | sig_info->algo = pkey_algo[modsig->algo]; | |
140 | sig_info->hash_algo = pkey_hash_algo[modsig->hash]; | |
141 | sig_info->id_type = pkey_id_type[modsig->id_type]; | |
142 | ||
143 | return true; | |
144 | } |