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bc1c373d DH |
1 | /* Sign a module file using the given key. |
2 | * | |
3 | * Copyright (C) 2014 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public Licence | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the Licence, or (at your option) any later version. | |
10 | */ | |
11 | #define _GNU_SOURCE | |
12 | #include <stdio.h> | |
13 | #include <stdlib.h> | |
14 | #include <stdint.h> | |
15 | #include <stdbool.h> | |
16 | #include <string.h> | |
17 | #include <getopt.h> | |
18 | #include <err.h> | |
19 | #include <arpa/inet.h> | |
20 | #include <openssl/bio.h> | |
21 | #include <openssl/evp.h> | |
22 | #include <openssl/pem.h> | |
23 | #include <openssl/pkcs7.h> | |
24 | #include <openssl/err.h> | |
25 | ||
26 | struct module_signature { | |
27 | uint8_t algo; /* Public-key crypto algorithm [0] */ | |
28 | uint8_t hash; /* Digest algorithm [0] */ | |
29 | uint8_t id_type; /* Key identifier type [PKEY_ID_PKCS7] */ | |
30 | uint8_t signer_len; /* Length of signer's name [0] */ | |
31 | uint8_t key_id_len; /* Length of key identifier [0] */ | |
32 | uint8_t __pad[3]; | |
33 | uint32_t sig_len; /* Length of signature data */ | |
34 | }; | |
35 | ||
36 | #define PKEY_ID_PKCS7 2 | |
37 | ||
38 | static char magic_number[] = "~Module signature appended~\n"; | |
39 | ||
40 | static __attribute__((noreturn)) | |
41 | void format(void) | |
42 | { | |
43 | fprintf(stderr, | |
44 | "Usage: scripts/sign-file [-dp] <hash algo> <key> <x509> <module> [<dest>]\n"); | |
45 | exit(2); | |
46 | } | |
47 | ||
48 | static void display_openssl_errors(int l) | |
49 | { | |
50 | const char *file; | |
51 | char buf[120]; | |
52 | int e, line; | |
53 | ||
54 | if (ERR_peek_error() == 0) | |
55 | return; | |
56 | fprintf(stderr, "At main.c:%d:\n", l); | |
57 | ||
58 | while ((e = ERR_get_error_line(&file, &line))) { | |
59 | ERR_error_string(e, buf); | |
60 | fprintf(stderr, "- SSL %s: %s:%d\n", buf, file, line); | |
61 | } | |
62 | } | |
63 | ||
64 | static void drain_openssl_errors(void) | |
65 | { | |
66 | const char *file; | |
67 | int line; | |
68 | ||
69 | if (ERR_peek_error() == 0) | |
70 | return; | |
71 | while (ERR_get_error_line(&file, &line)) {} | |
72 | } | |
73 | ||
74 | #define ERR(cond, fmt, ...) \ | |
75 | do { \ | |
76 | bool __cond = (cond); \ | |
77 | display_openssl_errors(__LINE__); \ | |
78 | if (__cond) { \ | |
79 | err(1, fmt, ## __VA_ARGS__); \ | |
80 | } \ | |
81 | } while(0) | |
82 | ||
af1eb291 DW |
83 | static const char *key_pass; |
84 | ||
85 | static int pem_pw_cb(char *buf, int len, int w, void *v) | |
86 | { | |
87 | int pwlen; | |
88 | ||
89 | if (!key_pass) | |
90 | return -1; | |
91 | ||
92 | pwlen = strlen(key_pass); | |
93 | if (pwlen >= len) | |
94 | return -1; | |
95 | ||
96 | strcpy(buf, key_pass); | |
97 | ||
98 | /* If it's wrong, don't keep trying it. */ | |
99 | key_pass = NULL; | |
100 | ||
101 | return pwlen; | |
102 | } | |
103 | ||
bc1c373d DH |
104 | int main(int argc, char **argv) |
105 | { | |
106 | struct module_signature sig_info = { .id_type = PKEY_ID_PKCS7 }; | |
107 | char *hash_algo = NULL; | |
108 | char *private_key_name, *x509_name, *module_name, *dest_name; | |
109 | bool save_pkcs7 = false, replace_orig; | |
23dfbbab | 110 | bool sign_only = false; |
bc1c373d DH |
111 | unsigned char buf[4096]; |
112 | unsigned long module_size, pkcs7_size; | |
113 | const EVP_MD *digest_algo; | |
114 | EVP_PKEY *private_key; | |
115 | PKCS7 *pkcs7; | |
116 | X509 *x509; | |
23dfbbab | 117 | BIO *b, *bd = NULL, *bm; |
bc1c373d DH |
118 | int opt, n; |
119 | ||
af1eb291 | 120 | OpenSSL_add_all_algorithms(); |
bc1c373d DH |
121 | ERR_load_crypto_strings(); |
122 | ERR_clear_error(); | |
123 | ||
af1eb291 DW |
124 | key_pass = getenv("KBUILD_SIGN_PIN"); |
125 | ||
bc1c373d DH |
126 | do { |
127 | opt = getopt(argc, argv, "dp"); | |
128 | switch (opt) { | |
129 | case 'p': save_pkcs7 = true; break; | |
23dfbbab | 130 | case 'd': sign_only = true; save_pkcs7 = true; break; |
bc1c373d DH |
131 | case -1: break; |
132 | default: format(); | |
133 | } | |
134 | } while (opt != -1); | |
135 | ||
136 | argc -= optind; | |
137 | argv += optind; | |
138 | if (argc < 4 || argc > 5) | |
139 | format(); | |
140 | ||
141 | hash_algo = argv[0]; | |
142 | private_key_name = argv[1]; | |
143 | x509_name = argv[2]; | |
144 | module_name = argv[3]; | |
145 | if (argc == 5) { | |
146 | dest_name = argv[4]; | |
147 | replace_orig = false; | |
148 | } else { | |
149 | ERR(asprintf(&dest_name, "%s.~signed~", module_name) < 0, | |
150 | "asprintf"); | |
151 | replace_orig = true; | |
152 | } | |
153 | ||
154 | /* Read the private key and the X.509 cert the PKCS#7 message | |
155 | * will point to. | |
156 | */ | |
157 | b = BIO_new_file(private_key_name, "rb"); | |
158 | ERR(!b, "%s", private_key_name); | |
af1eb291 DW |
159 | private_key = PEM_read_bio_PrivateKey(b, NULL, pem_pw_cb, NULL); |
160 | ERR(!private_key, "%s", private_key_name); | |
bc1c373d DH |
161 | BIO_free(b); |
162 | ||
163 | b = BIO_new_file(x509_name, "rb"); | |
164 | ERR(!b, "%s", x509_name); | |
165 | x509 = d2i_X509_bio(b, NULL); /* Binary encoded X.509 */ | |
166 | if (!x509) { | |
167 | BIO_reset(b); | |
168 | x509 = PEM_read_bio_X509(b, NULL, NULL, NULL); /* PEM encoded X.509 */ | |
169 | if (x509) | |
170 | drain_openssl_errors(); | |
171 | } | |
172 | BIO_free(b); | |
173 | ERR(!x509, "%s", x509_name); | |
174 | ||
175 | /* Open the destination file now so that we can shovel the module data | |
176 | * across as we read it. | |
177 | */ | |
23dfbbab LR |
178 | if (!sign_only) { |
179 | bd = BIO_new_file(dest_name, "wb"); | |
180 | ERR(!bd, "%s", dest_name); | |
181 | } | |
bc1c373d DH |
182 | |
183 | /* Digest the module data. */ | |
184 | OpenSSL_add_all_digests(); | |
185 | display_openssl_errors(__LINE__); | |
186 | digest_algo = EVP_get_digestbyname(hash_algo); | |
187 | ERR(!digest_algo, "EVP_get_digestbyname"); | |
188 | ||
189 | bm = BIO_new_file(module_name, "rb"); | |
190 | ERR(!bm, "%s", module_name); | |
191 | ||
192 | /* Load the PKCS#7 message from the digest buffer. */ | |
193 | pkcs7 = PKCS7_sign(NULL, NULL, NULL, NULL, | |
194 | PKCS7_NOCERTS | PKCS7_PARTIAL | PKCS7_BINARY | PKCS7_DETACHED | PKCS7_STREAM); | |
195 | ERR(!pkcs7, "PKCS7_sign"); | |
196 | ||
197 | ERR(!PKCS7_sign_add_signer(pkcs7, x509, private_key, digest_algo, PKCS7_NOCERTS | PKCS7_BINARY), | |
198 | "PKCS7_sign_add_signer"); | |
199 | ERR(PKCS7_final(pkcs7, bm, PKCS7_NOCERTS | PKCS7_BINARY) < 0, | |
200 | "PKCS7_final"); | |
201 | ||
202 | if (save_pkcs7) { | |
203 | char *pkcs7_name; | |
204 | ||
205 | ERR(asprintf(&pkcs7_name, "%s.pkcs7", module_name) < 0, "asprintf"); | |
206 | b = BIO_new_file(pkcs7_name, "wb"); | |
207 | ERR(!b, "%s", pkcs7_name); | |
208 | ERR(i2d_PKCS7_bio_stream(b, pkcs7, NULL, 0) < 0, "%s", pkcs7_name); | |
209 | BIO_free(b); | |
210 | } | |
211 | ||
23dfbbab LR |
212 | if (sign_only) |
213 | return 0; | |
214 | ||
bc1c373d DH |
215 | /* Append the marker and the PKCS#7 message to the destination file */ |
216 | ERR(BIO_reset(bm) < 0, "%s", module_name); | |
217 | while ((n = BIO_read(bm, buf, sizeof(buf))), | |
218 | n > 0) { | |
219 | ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name); | |
220 | } | |
221 | ERR(n < 0, "%s", module_name); | |
222 | module_size = BIO_number_written(bd); | |
223 | ||
224 | ERR(i2d_PKCS7_bio_stream(bd, pkcs7, NULL, 0) < 0, "%s", dest_name); | |
225 | pkcs7_size = BIO_number_written(bd) - module_size; | |
226 | sig_info.sig_len = htonl(pkcs7_size); | |
227 | ERR(BIO_write(bd, &sig_info, sizeof(sig_info)) < 0, "%s", dest_name); | |
228 | ERR(BIO_write(bd, magic_number, sizeof(magic_number) - 1) < 0, "%s", dest_name); | |
229 | ||
230 | ERR(BIO_free(bd) < 0, "%s", dest_name); | |
231 | ||
232 | /* Finally, if we're signing in place, replace the original. */ | |
233 | if (replace_orig) | |
234 | ERR(rename(dest_name, module_name) < 0, "%s", dest_name); | |
235 | ||
236 | return 0; | |
237 | } |