xref: /linux/certs/extract-cert.c (revision c060f8168bdf22aa986970955af99702d142dfbe)
1 /* Extract X.509 certificate in DER form from PKCS#11 or PEM.
2  *
3  * Copyright © 2014-2015 Red Hat, Inc. All Rights Reserved.
4  * Copyright © 2015      Intel Corporation.
5  *
6  * Authors: David Howells <dhowells@redhat.com>
7  *          David Woodhouse <dwmw2@infradead.org>
8  *
9  * This program is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU Lesser General Public License
11  * as published by the Free Software Foundation; either version 2.1
12  * of the licence, or (at your option) any later version.
13  */
14 #define _GNU_SOURCE
15 #include <stdio.h>
16 #include <stdlib.h>
17 #include <stdint.h>
18 #include <stdbool.h>
19 #include <string.h>
20 #include <err.h>
21 #include <openssl/bio.h>
22 #include <openssl/pem.h>
23 #include <openssl/err.h>
24 #if OPENSSL_VERSION_MAJOR >= 3
25 # define USE_PKCS11_PROVIDER
26 # include <openssl/provider.h>
27 # include <openssl/store.h>
28 #else
29 # if !defined(OPENSSL_NO_ENGINE) && !defined(OPENSSL_NO_DEPRECATED_3_0)
30 #  define USE_PKCS11_ENGINE
31 #  include <openssl/engine.h>
32 # endif
33 #endif
34 #include "ssl-common.h"
35 
36 #define PKEY_ID_PKCS7 2
37 
38 static __attribute__((noreturn))
39 void format(void)
40 {
41 	fprintf(stderr,
42 		"Usage: extract-cert <source> <dest>\n");
43 	exit(2);
44 }
45 
46 static const char *key_pass;
47 static BIO *wb;
48 static char *cert_dst;
49 static bool verbose;
50 
51 static void write_cert(X509 *x509)
52 {
53 	char buf[200];
54 
55 	if (!wb) {
56 		wb = BIO_new_file(cert_dst, "wb");
57 		ERR(!wb, "%s", cert_dst);
58 	}
59 	X509_NAME_oneline(X509_get_subject_name(x509), buf, sizeof(buf));
60 	ERR(!i2d_X509_bio(wb, x509), "%s", cert_dst);
61 	if (verbose)
62 		fprintf(stderr, "Extracted cert: %s\n", buf);
63 }
64 
65 static X509 *load_cert_pkcs11(const char *cert_src)
66 {
67 	X509 *cert = NULL;
68 #ifdef USE_PKCS11_PROVIDER
69 	OSSL_STORE_CTX *store;
70 
71 	if (!OSSL_PROVIDER_try_load(NULL, "pkcs11", true))
72 		ERR(1, "OSSL_PROVIDER_try_load(pkcs11)");
73 	if (!OSSL_PROVIDER_try_load(NULL, "default", true))
74 		ERR(1, "OSSL_PROVIDER_try_load(default)");
75 
76 	store = OSSL_STORE_open(cert_src, NULL, NULL, NULL, NULL);
77 	ERR(!store, "OSSL_STORE_open");
78 
79 	while (!OSSL_STORE_eof(store)) {
80 		OSSL_STORE_INFO *info = OSSL_STORE_load(store);
81 
82 		if (!info) {
83 			drain_openssl_errors(__LINE__, 0);
84 			continue;
85 		}
86 		if (OSSL_STORE_INFO_get_type(info) == OSSL_STORE_INFO_CERT) {
87 			cert = OSSL_STORE_INFO_get1_CERT(info);
88 			ERR(!cert, "OSSL_STORE_INFO_get1_CERT");
89 		}
90 		OSSL_STORE_INFO_free(info);
91 		if (cert)
92 			break;
93 	}
94 	OSSL_STORE_close(store);
95 #elif defined(USE_PKCS11_ENGINE)
96 		ENGINE *e;
97 		struct {
98 			const char *cert_id;
99 			X509 *cert;
100 		} parms;
101 
102 		parms.cert_id = cert_src;
103 		parms.cert = NULL;
104 
105 		ENGINE_load_builtin_engines();
106 		drain_openssl_errors(__LINE__, 1);
107 		e = ENGINE_by_id("pkcs11");
108 		ERR(!e, "Load PKCS#11 ENGINE");
109 		if (ENGINE_init(e))
110 			drain_openssl_errors(__LINE__, 1);
111 		else
112 			ERR(1, "ENGINE_init");
113 		if (key_pass)
114 			ERR(!ENGINE_ctrl_cmd_string(e, "PIN", key_pass, 0), "Set PKCS#11 PIN");
115 		ENGINE_ctrl_cmd(e, "LOAD_CERT_CTRL", 0, &parms, NULL, 1);
116 		ERR(!parms.cert, "Get X.509 from PKCS#11");
117 		cert = parms.cert;
118 #else
119 		fprintf(stderr, "no pkcs11 engine/provider available\n");
120 		exit(1);
121 #endif
122 	return cert;
123 }
124 
125 int main(int argc, char **argv)
126 {
127 	char *cert_src;
128 	char *verbose_env;
129 
130 	OpenSSL_add_all_algorithms();
131 	ERR_load_crypto_strings();
132 	ERR_clear_error();
133 
134 	verbose_env = getenv("KBUILD_VERBOSE");
135 	if (verbose_env && strchr(verbose_env, '1'))
136 		verbose = true;
137 
138         key_pass = getenv("KBUILD_SIGN_PIN");
139 
140 	if (argc != 3)
141 		format();
142 
143 	cert_src = argv[1];
144 	cert_dst = argv[2];
145 
146 	if (!cert_src[0]) {
147 		/* Invoked with no input; create empty file */
148 		FILE *f = fopen(cert_dst, "wb");
149 		ERR(!f, "%s", cert_dst);
150 		fclose(f);
151 		exit(0);
152 	} else if (!strncmp(cert_src, "pkcs11:", 7)) {
153 		X509 *cert = load_cert_pkcs11(cert_src);
154 
155 		ERR(!cert, "load_cert_pkcs11 failed");
156 		write_cert(cert);
157 	} else {
158 		BIO *b;
159 		X509 *x509;
160 
161 		b = BIO_new_file(cert_src, "rb");
162 		ERR(!b, "%s", cert_src);
163 
164 		while (1) {
165 			x509 = PEM_read_bio_X509(b, NULL, NULL, NULL);
166 			if (wb && !x509) {
167 				unsigned long err = ERR_peek_last_error();
168 				if (ERR_GET_LIB(err) == ERR_LIB_PEM &&
169 				    ERR_GET_REASON(err) == PEM_R_NO_START_LINE) {
170 					ERR_clear_error();
171 					break;
172 				}
173 			}
174 			ERR(!x509, "%s", cert_src);
175 			write_cert(x509);
176 		}
177 	}
178 
179 	BIO_free(wb);
180 
181 	return 0;
182 }
183