scripts/extract-cert.c

   1 /* Extract X.509 certificate in DER form from PKCS#11 or PEM.
   2  *
   3  * Copyright © 2014 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 General Public Licence
  11  * as published by the Free Software Foundation; either version
  12  * 2 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 <getopt.h>
  21 #include <err.h>
  22 #include <arpa/inet.h>
  23 #include <openssl/bio.h>
  24 #include <openssl/evp.h>
  25 #include <openssl/pem.h>
  26 #include <openssl/pkcs7.h>
  27 #include <openssl/err.h>
  28 #include <openssl/engine.h>
  29
  30 #define PKEY_ID_PKCS7 2
  31
  32 static __attribute__((noreturn))
  33 void format(void)
  34 {
  35         fprintf(stderr,
  36                 "Usage: scripts/extract-cert <source> <dest>\n");
  37         exit(2);
  38 }
  39
  40 static void display_openssl_errors(int l)
  41 {
  42         const char *file;
  43         char buf[120];
  44         int e, line;
  45
  46         if (ERR_peek_error() == 0)
  47                 return;
  48         fprintf(stderr, "At main.c:%d:\n", l);
  49
  50         while ((e = ERR_get_error_line(&file, &line))) {
  51                 ERR_error_string(e, buf);
  52                 fprintf(stderr, "- SSL %s: %s:%d\n", buf, file, line);
  53         }
  54 }
  55
  56 static void drain_openssl_errors(void)
  57 {
  58         const char *file;
  59         int line;
  60
  61         if (ERR_peek_error() == 0)
  62                 return;
  63         while (ERR_get_error_line(&file, &line)) {}
  64 }
  65
  66 #define ERR(cond, fmt, ...)                             \
  67         do {                                            \
  68                 bool __cond = (cond);                   \
  69                 display_openssl_errors(__LINE__);       \
  70                 if (__cond) {                           \
  71                         err(1, fmt, ## __VA_ARGS__);    \
  72                 }                                       \
  73         } while(0)
  74
  75 static const char *key_pass;
  76 static BIO *wb;
  77 static char *cert_dst;
  78 int kbuild_verbose;
  79
  80 static void write_cert(X509 *x509)
  81 {
  82         char buf[200];
  83
  84         if (!wb) {
  85                 wb = BIO_new_file(cert_dst, "wb");
  86                 ERR(!wb, "%s", cert_dst);
  87         }
  88         X509_NAME_oneline(X509_get_subject_name(x509), buf, sizeof(buf));
  89         ERR(!i2d_X509_bio(wb, x509), "%s", cert_dst);
  90         if (kbuild_verbose)
  91                 fprintf(stderr, "Extracted cert: %s\n", buf);
  92 }
  93
  94 int main(int argc, char **argv)
  95 {
  96         char *cert_src;
  97
  98         OpenSSL_add_all_algorithms();
  99         ERR_load_crypto_strings();
 100         ERR_clear_error();
 101
 102         kbuild_verbose = atoi(getenv("KBUILD_VERBOSE")?:"0");
 103
 104         key_pass = getenv("KBUILD_SIGN_PIN");
 105
 106         if (argc != 3)
 107                 format();
 108
 109         cert_src = argv[1];
 110         cert_dst = argv[2];
 111
 112         if (!cert_src[0]) {
 113                 /* Invoked with no input; create empty file */
 114                 FILE *f = fopen(cert_dst, "wb");
 115                 ERR(!f, "%s", cert_dst);
 116                 fclose(f);
 117                 exit(0);
 118         } else if (!strncmp(cert_src, "pkcs11:", 7)) {
 119                 ENGINE *e;
 120                 struct {
 121                         const char *cert_id;
 122                         X509 *cert;
 123                 } parms;
 124
 125                 parms.cert_id = cert_src;
 126                 parms.cert = NULL;
 127
 128                 ENGINE_load_builtin_engines();
 129                 drain_openssl_errors();
 130                 e = ENGINE_by_id("pkcs11");
 131                 ERR(!e, "Load PKCS#11 ENGINE");
 132                 if (ENGINE_init(e))
 133                         drain_openssl_errors();
 134                 else
 135                         ERR(1, "ENGINE_init");
 136                 if (key_pass)
 137                         ERR(!ENGINE_ctrl_cmd_string(e, "PIN", key_pass, 0), "Set PKCS#11 PIN");
 138                 ENGINE_ctrl_cmd(e, "LOAD_CERT_CTRL", 0, &parms, NULL, 1);
 139                 ERR(!parms.cert, "Get X.509 from PKCS#11");
 140                 write_cert(parms.cert);
 141         } else {
 142                 BIO *b;
 143                 X509 *x509;
 144
 145                 b = BIO_new_file(cert_src, "rb");
 146                 ERR(!b, "%s", cert_src);
 147
 148                 while (1) {
 149                         x509 = PEM_read_bio_X509(b, NULL, NULL, NULL);
 150                         if (wb && !x509) {
 151                                 unsigned long err = ERR_peek_last_error();
 152                                 if (ERR_GET_LIB(err) == ERR_LIB_PEM &&
 153                                     ERR_GET_REASON(err) == PEM_R_NO_START_LINE) {
 154                                         ERR_clear_error();
 155                                         break;
 156                                 }
 157                         }
 158                         ERR(!x509, "%s", cert_src);
 159                         write_cert(x509);
 160                 }
 161         }
 162
 163         BIO_free(wb);
 164
 165         return 0;
 166 }