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 int kbuild_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 (kbuild_verbose)
 94		fprintf(stderr, "Extracted cert: %s\n", buf);
 95}
 96
 97int main(int argc, char **argv)
 98{
 99	char *cert_src;
100
101	OpenSSL_add_all_algorithms();
102	ERR_load_crypto_strings();
103	ERR_clear_error();
104
105	kbuild_verbose = atoi(getenv("KBUILD_VERBOSE")?:"0");
106
107        key_pass = getenv("KBUILD_SIGN_PIN");
108
109	if (argc != 3)
110		format();
111
112	cert_src = argv[1];
113	cert_dst = argv[2];
114
115	if (!cert_src[0]) {
116		/* Invoked with no input; create empty file */
117		FILE *f = fopen(cert_dst, "wb");
118		ERR(!f, "%s", cert_dst);
119		fclose(f);
120		exit(0);
121	} else if (!strncmp(cert_src, "pkcs11:", 7)) {
122		ENGINE *e;
123		struct {
124			const char *cert_id;
125			X509 *cert;
126		} parms;
127
128		parms.cert_id = cert_src;
129		parms.cert = NULL;
130
131		ENGINE_load_builtin_engines();
132		drain_openssl_errors();
133		e = ENGINE_by_id("pkcs11");
134		ERR(!e, "Load PKCS#11 ENGINE");
135		if (ENGINE_init(e))
136			drain_openssl_errors();
137		else
138			ERR(1, "ENGINE_init");
139		if (key_pass)
140			ERR(!ENGINE_ctrl_cmd_string(e, "PIN", key_pass, 0), "Set PKCS#11 PIN");
141		ENGINE_ctrl_cmd(e, "LOAD_CERT_CTRL", 0, &parms, NULL, 1);
142		ERR(!parms.cert, "Get X.509 from PKCS#11");
143		write_cert(parms.cert);
144	} else {
145		BIO *b;
146		X509 *x509;
147
148		b = BIO_new_file(cert_src, "rb");
149		ERR(!b, "%s", cert_src);
150
151		while (1) {
152			x509 = PEM_read_bio_X509(b, NULL, NULL, NULL);
153			if (wb && !x509) {
154				unsigned long err = ERR_peek_last_error();
155				if (ERR_GET_LIB(err) == ERR_LIB_PEM &&
156				    ERR_GET_REASON(err) == PEM_R_NO_START_LINE) {
157					ERR_clear_error();
158					break;
159				}
160			}
161			ERR(!x509, "%s", cert_src);
162			write_cert(x509);
163		}
164	}
165
166	BIO_free(wb);
167
168	return 0;
169}