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#include <openssl/engine.h>
25
26/*
27 * OpenSSL 3.0 deprecates the OpenSSL's ENGINE API.
28 *
29 * Remove this if/when that API is no longer used
30 */
31#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
32
33#define PKEY_ID_PKCS7 2
34
35static __attribute__((noreturn))
36void format(void)
37{
38	fprintf(stderr,
39		"Usage: extract-cert <source> <dest>\n");
40	exit(2);
41}
42
43static void display_openssl_errors(int l)
44{
45	const char *file;
46	char buf[120];
47	int e, line;
48
49	if (ERR_peek_error() == 0)
50		return;
51	fprintf(stderr, "At main.c:%d:\n", l);
52
53	while ((e = ERR_get_error_line(&file, &line))) {
54		ERR_error_string(e, buf);
55		fprintf(stderr, "- SSL %s: %s:%d\n", buf, file, line);
56	}
57}
58
59static void drain_openssl_errors(void)
60{
61	const char *file;
62	int line;
63
64	if (ERR_peek_error() == 0)
65		return;
66	while (ERR_get_error_line(&file, &line)) {}
67}
68
69#define ERR(cond, fmt, ...)				\
70	do {						\
71		bool __cond = (cond);			\
72		display_openssl_errors(__LINE__);	\
73		if (__cond) {				\
74			err(1, fmt, ## __VA_ARGS__);	\
75		}					\
76	} while(0)
77
78static const char *key_pass;
79static BIO *wb;
80static char *cert_dst;
81static bool verbose;
82
83static void write_cert(X509 *x509)
84{
85	char buf[200];
86
87	if (!wb) {
88		wb = BIO_new_file(cert_dst, "wb");
89		ERR(!wb, "%s", cert_dst);
90	}
91	X509_NAME_oneline(X509_get_subject_name(x509), buf, sizeof(buf));
92	ERR(!i2d_X509_bio(wb, x509), "%s", cert_dst);
93	if (verbose)
94		fprintf(stderr, "Extracted cert: %s\n", buf);
95}
96
97int main(int argc, char **argv)
98{
99	char *cert_src;
100	char *verbose_env;
101
102	OpenSSL_add_all_algorithms();
103	ERR_load_crypto_strings();
104	ERR_clear_error();
105
106	verbose_env = getenv("KBUILD_VERBOSE");
107	if (verbose_env && strchr(verbose_env, '1'))
108		verbose = true;
109
110        key_pass = getenv("KBUILD_SIGN_PIN");
111
112	if (argc != 3)
113		format();
114
115	cert_src = argv[1];
116	cert_dst = argv[2];
117
118	if (!cert_src[0]) {
119		/* Invoked with no input; create empty file */
120		FILE *f = fopen(cert_dst, "wb");
121		ERR(!f, "%s", cert_dst);
122		fclose(f);
123		exit(0);
124	} else if (!strncmp(cert_src, "pkcs11:", 7)) {
125		ENGINE *e;
126		struct {
127			const char *cert_id;
128			X509 *cert;
129		} parms;
130
131		parms.cert_id = cert_src;
132		parms.cert = NULL;
133
134		ENGINE_load_builtin_engines();
135		drain_openssl_errors();
136		e = ENGINE_by_id("pkcs11");
137		ERR(!e, "Load PKCS#11 ENGINE");
138		if (ENGINE_init(e))
139			drain_openssl_errors();
140		else
141			ERR(1, "ENGINE_init");
142		if (key_pass)
143			ERR(!ENGINE_ctrl_cmd_string(e, "PIN", key_pass, 0), "Set PKCS#11 PIN");
144		ENGINE_ctrl_cmd(e, "LOAD_CERT_CTRL", 0, &parms, NULL, 1);
145		ERR(!parms.cert, "Get X.509 from PKCS#11");
146		write_cert(parms.cert);
147	} else {
148		BIO *b;
149		X509 *x509;
150
151		b = BIO_new_file(cert_src, "rb");
152		ERR(!b, "%s", cert_src);
153
154		while (1) {
155			x509 = PEM_read_bio_X509(b, NULL, NULL, NULL);
156			if (wb && !x509) {
157				unsigned long err = ERR_peek_last_error();
158				if (ERR_GET_LIB(err) == ERR_LIB_PEM &&
159				    ERR_GET_REASON(err) == PEM_R_NO_START_LINE) {
160					ERR_clear_error();
161					break;
162				}
163			}
164			ERR(!x509, "%s", cert_src);
165			write_cert(x509);
166		}
167	}
168
169	BIO_free(wb);
170
171	return 0;
172}
173