aboutsummaryrefslogtreecommitdiff
path: root/scripts/sign-file.c
blob: c3899ca4811cc2e0add94f8f31e31b93be432fff (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
/* Sign a module file using the given key.
 *
 * Copyright © 2014-2015 Red Hat, Inc. All Rights Reserved.
 * Copyright © 2015      Intel Corporation.
 *
 * Authors: David Howells <dhowells@redhat.com>
 *          David Woodhouse <dwmw2@infradead.org>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1
 * of the licence, or (at your option) any later version.
 */
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <getopt.h>
#include <err.h>
#include <arpa/inet.h>
#include <openssl/bio.h>
#include <openssl/evp.h>
#include <openssl/pem.h>
#include <openssl/cms.h>
#include <openssl/err.h>
#include <openssl/engine.h>

struct module_signature {
	uint8_t		algo;		/* Public-key crypto algorithm [0] */
	uint8_t		hash;		/* Digest algorithm [0] */
	uint8_t		id_type;	/* Key identifier type [PKEY_ID_PKCS7] */
	uint8_t		signer_len;	/* Length of signer's name [0] */
	uint8_t		key_id_len;	/* Length of key identifier [0] */
	uint8_t		__pad[3];
	uint32_t	sig_len;	/* Length of signature data */
};

#define PKEY_ID_PKCS7 2

static char magic_number[] = "~Module signature appended~\n";

static __attribute__((noreturn))
void format(void)
{
	fprintf(stderr,
		"Usage: scripts/sign-file [-dp] <hash algo> <key> <x509> <module> [<dest>]\n");
	exit(2);
}

static void display_openssl_errors(int l)
{
	const char *file;
	char buf[120];
	int e, line;

	if (ERR_peek_error() == 0)
		return;
	fprintf(stderr, "At main.c:%d:\n", l);

	while ((e = ERR_get_error_line(&file, &line))) {
		ERR_error_string(e, buf);
		fprintf(stderr, "- SSL %s: %s:%d\n", buf, file, line);
	}
}

static void drain_openssl_errors(void)
{
	const char *file;
	int line;

	if (ERR_peek_error() == 0)
		return;
	while (ERR_get_error_line(&file, &line)) {}
}

#define ERR(cond, fmt, ...)				\
	do {						\
		bool __cond = (cond);			\
		display_openssl_errors(__LINE__);	\
		if (__cond) {				\
			err(1, fmt, ## __VA_ARGS__);	\
		}					\
	} while(0)

static const char *key_pass;

static int pem_pw_cb(char *buf, int len, int w, void *v)
{
	int pwlen;

	if (!key_pass)
		return -1;

	pwlen = strlen(key_pass);
	if (pwlen >= len)
		return -1;

	strcpy(buf, key_pass);

	/* If it's wrong, don't keep trying it. */
	key_pass = NULL;

	return pwlen;
}

int main(int argc, char **argv)
{
	struct module_signature sig_info = { .id_type = PKEY_ID_PKCS7 };
	char *hash_algo = NULL;
	char *private_key_name, *x509_name, *module_name, *dest_name;
	bool save_cms = false, replace_orig;
	bool sign_only = false;
	unsigned char buf[4096];
	unsigned long module_size, cms_size;
	unsigned int use_keyid = 0, use_signed_attrs = CMS_NOATTR;
	const EVP_MD *digest_algo;
	EVP_PKEY *private_key;
	CMS_ContentInfo *cms;
	X509 *x509;
	BIO *b, *bd = NULL, *bm;
	int opt, n;

	OpenSSL_add_all_algorithms();
	ERR_load_crypto_strings();
	ERR_clear_error();

	key_pass = getenv("KBUILD_SIGN_PIN");

	do {
		opt = getopt(argc, argv, "dpk");
		switch (opt) {
		case 'p': save_cms = true; break;
		case 'd': sign_only = true; save_cms = true; break;
		case 'k': use_keyid = CMS_USE_KEYID; break;
		case -1: break;
		default: format();
		}
	} while (opt != -1);

	argc -= optind;
	argv += optind;
	if (argc < 4 || argc > 5)
		format();

	hash_algo = argv[0];
	private_key_name = argv[1];
	x509_name = argv[2];
	module_name = argv[3];
	if (argc == 5) {
		dest_name = argv[4];
		replace_orig = false;
	} else {
		ERR(asprintf(&dest_name, "%s.~signed~", module_name) < 0,
		    "asprintf");
		replace_orig = true;
	}

	/* Read the private key and the X.509 cert the PKCS#7 message
	 * will point to.
	 */
	if (!strncmp(private_key_name, "pkcs11:", 7)) {
		ENGINE *e;

		ENGINE_load_builtin_engines();
		drain_openssl_errors();
		e = ENGINE_by_id("pkcs11");
		ERR(!e, "Load PKCS#11 ENGINE");
		if (ENGINE_init(e))
			drain_openssl_errors();
		else
			ERR(1, "ENGINE_init");
		if (key_pass)
			ERR(!ENGINE_ctrl_cmd_string(e, "PIN", key_pass, 0), "Set PKCS#11 PIN");
		private_key = ENGINE_load_private_key(e, private_key_name, NULL,
						      NULL);
		ERR(!private_key, "%s", private_key_name);
	} else {
		b = BIO_new_file(private_key_name, "rb");
		ERR(!b, "%s", private_key_name);
		private_key = PEM_read_bio_PrivateKey(b, NULL, pem_pw_cb, NULL);
		ERR(!private_key, "%s", private_key_name);
		BIO_free(b);
	}

	b = BIO_new_file(x509_name, "rb");
	ERR(!b, "%s", x509_name);
	x509 = d2i_X509_bio(b, NULL); /* Binary encoded X.509 */
	if (!x509) {
		ERR(BIO_reset(b) != 1, "%s", x509_name);
		x509 = PEM_read_bio_X509(b, NULL, NULL, NULL); /* PEM encoded X.509 */
		if (x509)
			drain_openssl_errors();
	}
	BIO_free(b);
	ERR(!x509, "%s", x509_name);

	/* Open the destination file now so that we can shovel the module data
	 * across as we read it.
	 */
	if (!sign_only) {
		bd = BIO_new_file(dest_name, "wb");
		ERR(!bd, "%s", dest_name);
	}

	/* Digest the module data. */
	OpenSSL_add_all_digests();
	display_openssl_errors(__LINE__);
	digest_algo = EVP_get_digestbyname(hash_algo);
	ERR(!digest_algo, "EVP_get_digestbyname");

	bm = BIO_new_file(module_name, "rb");
	ERR(!bm, "%s", module_name);

	/* Load the CMS message from the digest buffer. */
	cms = CMS_sign(NULL, NULL, NULL, NULL,
		       CMS_NOCERTS | CMS_PARTIAL | CMS_BINARY | CMS_DETACHED | CMS_STREAM);
	ERR(!cms, "CMS_sign");

	ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo,
			     CMS_NOCERTS | CMS_BINARY | CMS_NOSMIMECAP |
			     use_keyid | use_signed_attrs),
	    "CMS_sign_add_signer");
	ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) < 0,
	    "CMS_final");

	if (save_cms) {
		char *cms_name;

		ERR(asprintf(&cms_name, "%s.p7s", module_name) < 0, "asprintf");
		b = BIO_new_file(cms_name, "wb");
		ERR(!b, "%s", cms_name);
		ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) < 0, "%s", cms_name);
		BIO_free(b);
	}

	if (sign_only)
		return 0;

	/* Append the marker and the PKCS#7 message to the destination file */
	ERR(BIO_reset(bm) < 0, "%s", module_name);
	while ((n = BIO_read(bm, buf, sizeof(buf))),
	       n > 0) {
		ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name);
	}
	ERR(n < 0, "%s", module_name);
	module_size = BIO_number_written(bd);

	ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) < 0, "%s", dest_name);
	cms_size = BIO_number_written(bd) - module_size;
	sig_info.sig_len = htonl(cms_size);
	ERR(BIO_write(bd, &sig_info, sizeof(sig_info)) < 0, "%s", dest_name);
	ERR(BIO_write(bd, magic_number, sizeof(magic_number) - 1) < 0, "%s", dest_name);

	ERR(BIO_free(bd) < 0, "%s", dest_name);

	/* Finally, if we're signing in place, replace the original. */
	if (replace_orig)
		ERR(rename(dest_name, module_name) < 0, "%s", dest_name);

	return 0;
}