scripts/sign-file.c

   1 /* Sign a module file using the given key.
   2  *
   3  * Copyright © 2014-2016 Red Hat, Inc. All Rights Reserved.
   4  * Copyright © 2015      Intel Corporation.
   5  * Copyright © 2016      Hewlett Packard Enterprise Development LP
   6  *
   7  * Authors: David Howells <dhowells@redhat.com>
   8  *          David Woodhouse <dwmw2@infradead.org>
   9  *          Juerg Haefliger <juerg.haefliger@hpe.com>
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU Lesser General Public License
  13  * as published by the Free Software Foundation; either version 2.1
  14  * of the licence, or (at your option) any later version.
  15  */
  16 #define _GNU_SOURCE
  17 #include <stdio.h>
  18 #include <stdlib.h>
  19 #include <stdint.h>
  20 #include <stdbool.h>
  21 #include <string.h>
  22 #include <getopt.h>
  23 #include <err.h>
  24 #include <arpa/inet.h>
  25 #include <openssl/opensslv.h>
  26 #include <openssl/bio.h>
  27 #include <openssl/evp.h>
  28 #include <openssl/pem.h>
  29 #include <openssl/err.h>
  30 #if OPENSSL_VERSION_MAJOR >= 3
  31 # define USE_PKCS11_PROVIDER
  32 # include <openssl/provider.h>
  33 # include <openssl/store.h>
  34 #else
  35 # if !defined(OPENSSL_NO_ENGINE) && !defined(OPENSSL_NO_DEPRECATED_3_0)
  36 #  define USE_PKCS11_ENGINE
  37 #  include <openssl/engine.h>
  38 # endif
  39 #endif
  40 #include "ssl-common.h"
  41
  42 /*
  43  * Use CMS if we have openssl-1.0.0 or newer available - otherwise we have to
  44  * assume that it's not available and its header file is missing and that we
  45  * should use PKCS#7 instead.  Switching to the older PKCS#7 format restricts
  46  * the options we have on specifying the X.509 certificate we want.
  47  *
  48  * Further, older versions of OpenSSL don't support manually adding signers to
  49  * the PKCS#7 message so have to accept that we get a certificate included in
  50  * the signature message.  Nor do such older versions of OpenSSL support
  51  * signing with anything other than SHA1 - so we're stuck with that if such is
  52  * the case.
  53  */
  54 #if defined(LIBRESSL_VERSION_NUMBER) || \
  55         OPENSSL_VERSION_NUMBER < 0x10000000L || \
  56         defined(OPENSSL_NO_CMS)
  57 #define USE_PKCS7
  58 #endif
  59 #ifndef USE_PKCS7
  60 #include <openssl/cms.h>
  61 #else
  62 #include <openssl/pkcs7.h>
  63 #endif
  64
  65 struct module_signature {
  66         uint8_t         algo;           /* Public-key crypto algorithm [0] */
  67         uint8_t         hash;           /* Digest algorithm [0] */
  68         uint8_t         id_type;        /* Key identifier type [PKEY_ID_PKCS7] */
  69         uint8_t         signer_len;     /* Length of signer's name [0] */
  70         uint8_t         key_id_len;     /* Length of key identifier [0] */
  71         uint8_t         __pad[3];
  72         uint32_t        sig_len;        /* Length of signature data */
  73 };
  74
  75 #define PKEY_ID_PKCS7 2
  76
  77 static char magic_number[] = "~Module signature appended~\n";
  78
  79 static __attribute__((noreturn))
  80 void format(void)
  81 {
  82         fprintf(stderr,
  83                 "Usage: scripts/sign-file [-dp] <hash algo> <key> <x509> <module> [<dest>]\n");
  84         fprintf(stderr,
  85                 "       scripts/sign-file -s <raw sig> <hash algo> <x509> <module> [<dest>]\n");
  86         exit(2);
  87 }
  88
  89 static const char *key_pass;
  90
  91 static int pem_pw_cb(char *buf, int len, int w, void *v)
  92 {
  93         int pwlen;
  94
  95         if (!key_pass)
  96                 return -1;
  97
  98         pwlen = strlen(key_pass);
  99         if (pwlen >= len)
 100                 return -1;
 101
 102         strcpy(buf, key_pass);
 103
 104         /* If it's wrong, don't keep trying it. */
 105         key_pass = NULL;
 106
 107         return pwlen;
 108 }
 109
 110 static EVP_PKEY *read_private_key_pkcs11(const char *private_key_name)
 111 {
 112         EVP_PKEY *private_key = NULL;
 113 #ifdef USE_PKCS11_PROVIDER
 114         OSSL_STORE_CTX *store;
 115
 116         if (!OSSL_PROVIDER_try_load(NULL, "pkcs11", true))
 117                 ERR(1, "OSSL_PROVIDER_try_load(pkcs11)");
 118         if (!OSSL_PROVIDER_try_load(NULL, "default", true))
 119                 ERR(1, "OSSL_PROVIDER_try_load(default)");
 120
 121         store = OSSL_STORE_open(private_key_name, NULL, NULL, NULL, NULL);
 122         ERR(!store, "OSSL_STORE_open");
 123
 124         while (!OSSL_STORE_eof(store)) {
 125                 OSSL_STORE_INFO *info = OSSL_STORE_load(store);
 126
 127                 if (!info) {
 128                         drain_openssl_errors(__LINE__, 0);
 129                         continue;
 130                 }
 131                 if (OSSL_STORE_INFO_get_type(info) == OSSL_STORE_INFO_PKEY) {
 132                         private_key = OSSL_STORE_INFO_get1_PKEY(info);
 133                         ERR(!private_key, "OSSL_STORE_INFO_get1_PKEY");
 134                 }
 135                 OSSL_STORE_INFO_free(info);
 136                 if (private_key)
 137                         break;
 138         }
 139         OSSL_STORE_close(store);
 140 #elif defined(USE_PKCS11_ENGINE)
 141         ENGINE *e;
 142
 143         ENGINE_load_builtin_engines();
 144         drain_openssl_errors(__LINE__, 1);
 145         e = ENGINE_by_id("pkcs11");
 146         ERR(!e, "Load PKCS#11 ENGINE");
 147         if (ENGINE_init(e))
 148                 drain_openssl_errors(__LINE__, 1);
 149         else
 150                 ERR(1, "ENGINE_init");
 151         if (key_pass)
 152                 ERR(!ENGINE_ctrl_cmd_string(e, "PIN", key_pass, 0), "Set PKCS#11 PIN");
 153         private_key = ENGINE_load_private_key(e, private_key_name, NULL, NULL);
 154         ERR(!private_key, "%s", private_key_name);
 155 #else
 156         fprintf(stderr, "no pkcs11 engine/provider available\n");
 157         exit(1);
 158 #endif
 159         return private_key;
 160 }
 161
 162 static EVP_PKEY *read_private_key(const char *private_key_name)
 163 {
 164         if (!strncmp(private_key_name, "pkcs11:", 7)) {
 165                 return read_private_key_pkcs11(private_key_name);
 166         } else {
 167                 EVP_PKEY *private_key;
 168                 BIO *b;
 169
 170                 b = BIO_new_file(private_key_name, "rb");
 171                 ERR(!b, "%s", private_key_name);
 172                 private_key = PEM_read_bio_PrivateKey(b, NULL, pem_pw_cb,
 173                                                       NULL);
 174                 ERR(!private_key, "%s", private_key_name);
 175                 BIO_free(b);
 176
 177                 return private_key;
 178         }
 179 }
 180
 181 static X509 *read_x509(const char *x509_name)
 182 {
 183         unsigned char buf[2];
 184         X509 *x509;
 185         BIO *b;
 186         int n;
 187
 188         b = BIO_new_file(x509_name, "rb");
 189         ERR(!b, "%s", x509_name);
 190
 191         /* Look at the first two bytes of the file to determine the encoding */
 192         n = BIO_read(b, buf, 2);
 193         if (n != 2) {
 194                 if (BIO_should_retry(b)) {
 195                         fprintf(stderr, "%s: Read wanted retry\n", x509_name);
 196                         exit(1);
 197                 }
 198                 if (n >= 0) {
 199                         fprintf(stderr, "%s: Short read\n", x509_name);
 200                         exit(1);
 201                 }
 202                 ERR(1, "%s", x509_name);
 203         }
 204
 205         ERR(BIO_reset(b) != 0, "%s", x509_name);
 206
 207         if (buf[0] == 0x30 && buf[1] >= 0x81 && buf[1] <= 0x84)
 208                 /* Assume raw DER encoded X.509 */
 209                 x509 = d2i_X509_bio(b, NULL);
 210         else
 211                 /* Assume PEM encoded X.509 */
 212                 x509 = PEM_read_bio_X509(b, NULL, NULL, NULL);
 213
 214         BIO_free(b);
 215         ERR(!x509, "%s", x509_name);
 216
 217         return x509;
 218 }
 219
 220 int main(int argc, char **argv)
 221 {
 222         struct module_signature sig_info = { .id_type = PKEY_ID_PKCS7 };
 223         char *hash_algo = NULL;
 224         char *private_key_name = NULL, *raw_sig_name = NULL;
 225         char *x509_name, *module_name, *dest_name;
 226         bool save_sig = false, replace_orig;
 227         bool sign_only = false;
 228         bool raw_sig = false;
 229         unsigned char buf[4096];
 230         unsigned long module_size, sig_size;
 231         unsigned int use_signed_attrs;
 232         const EVP_MD *digest_algo;
 233         EVP_PKEY *private_key;
 234 #ifndef USE_PKCS7
 235         CMS_ContentInfo *cms = NULL;
 236         unsigned int use_keyid = 0;
 237 #else
 238         PKCS7 *pkcs7 = NULL;
 239 #endif
 240         X509 *x509;
 241         BIO *bd, *bm;
 242         int opt, n;
 243         OpenSSL_add_all_algorithms();
 244         ERR_load_crypto_strings();
 245         ERR_clear_error();
 246
 247         key_pass = getenv("KBUILD_SIGN_PIN");
 248
 249 #ifndef USE_PKCS7
 250         use_signed_attrs = CMS_NOATTR;
 251 #else
 252         use_signed_attrs = PKCS7_NOATTR;
 253 #endif
 254
 255         do {
 256                 opt = getopt(argc, argv, "sdpk");
 257                 switch (opt) {
 258                 case 's': raw_sig = true; break;
 259                 case 'p': save_sig = true; break;
 260                 case 'd': sign_only = true; save_sig = true; break;
 261 #ifndef USE_PKCS7
 262                 case 'k': use_keyid = CMS_USE_KEYID; break;
 263 #endif
 264                 case -1: break;
 265                 default: format();
 266                 }
 267         } while (opt != -1);
 268
 269         argc -= optind;
 270         argv += optind;
 271         if (argc < 4 || argc > 5)
 272                 format();
 273
 274         if (raw_sig) {
 275                 raw_sig_name = argv[0];
 276                 hash_algo = argv[1];
 277         } else {
 278                 hash_algo = argv[0];
 279                 private_key_name = argv[1];
 280         }
 281         x509_name = argv[2];
 282         module_name = argv[3];
 283         if (argc == 5 && strcmp(argv[3], argv[4]) != 0) {
 284                 dest_name = argv[4];
 285                 replace_orig = false;
 286         } else {
 287                 ERR(asprintf(&dest_name, "%s.~signed~", module_name) < 0,
 288                     "asprintf");
 289                 replace_orig = true;
 290         }
 291
 292 #ifdef USE_PKCS7
 293         if (strcmp(hash_algo, "sha1") != 0) {
 294                 fprintf(stderr, "sign-file: %s only supports SHA1 signing\n",
 295                         OPENSSL_VERSION_TEXT);
 296                 exit(3);
 297         }
 298 #endif
 299
 300         /* Open the module file */
 301         bm = BIO_new_file(module_name, "rb");
 302         ERR(!bm, "%s", module_name);
 303
 304         if (!raw_sig) {
 305                 /* Read the private key and the X.509 cert the PKCS#7 message
 306                  * will point to.
 307                  */
 308                 private_key = read_private_key(private_key_name);
 309                 x509 = read_x509(x509_name);
 310
 311                 /* Digest the module data. */
 312                 OpenSSL_add_all_digests();
 313                 drain_openssl_errors(__LINE__, 0);
 314                 digest_algo = EVP_get_digestbyname(hash_algo);
 315                 ERR(!digest_algo, "EVP_get_digestbyname");
 316
 317 #ifndef USE_PKCS7
 318                 /* Load the signature message from the digest buffer. */
 319                 cms = CMS_sign(NULL, NULL, NULL, NULL,
 320                                CMS_NOCERTS | CMS_PARTIAL | CMS_BINARY |
 321                                CMS_DETACHED | CMS_STREAM);
 322                 ERR(!cms, "CMS_sign");
 323
 324                 ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo,
 325                                      CMS_NOCERTS | CMS_BINARY |
 326                                      CMS_NOSMIMECAP | use_keyid |
 327                                      use_signed_attrs),
 328                     "CMS_add1_signer");
 329                 ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) != 1,
 330                     "CMS_final");
 331
 332 #else
 333                 pkcs7 = PKCS7_sign(x509, private_key, NULL, bm,
 334                                    PKCS7_NOCERTS | PKCS7_BINARY |
 335                                    PKCS7_DETACHED | use_signed_attrs);
 336                 ERR(!pkcs7, "PKCS7_sign");
 337 #endif
 338
 339                 if (save_sig) {
 340                         char *sig_file_name;
 341                         BIO *b;
 342
 343                         ERR(asprintf(&sig_file_name, "%s.p7s", module_name) < 0,
 344                             "asprintf");
 345                         b = BIO_new_file(sig_file_name, "wb");
 346                         ERR(!b, "%s", sig_file_name);
 347 #ifndef USE_PKCS7
 348                         ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) != 1,
 349                             "%s", sig_file_name);
 350 #else
 351                         ERR(i2d_PKCS7_bio(b, pkcs7) != 1,
 352                             "%s", sig_file_name);
 353 #endif
 354                         BIO_free(b);
 355                 }
 356
 357                 if (sign_only) {
 358                         BIO_free(bm);
 359                         return 0;
 360                 }
 361         }
 362
 363         /* Open the destination file now so that we can shovel the module data
 364          * across as we read it.
 365          */
 366         bd = BIO_new_file(dest_name, "wb");
 367         ERR(!bd, "%s", dest_name);
 368
 369         /* Append the marker and the PKCS#7 message to the destination file */
 370         ERR(BIO_reset(bm) < 0, "%s", module_name);
 371         while ((n = BIO_read(bm, buf, sizeof(buf))),
 372                n > 0) {
 373                 ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name);
 374         }
 375         BIO_free(bm);
 376         ERR(n < 0, "%s", module_name);
 377         module_size = BIO_number_written(bd);
 378
 379         if (!raw_sig) {
 380 #ifndef USE_PKCS7
 381                 ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) != 1, "%s", dest_name);
 382 #else
 383                 ERR(i2d_PKCS7_bio(bd, pkcs7) != 1, "%s", dest_name);
 384 #endif
 385         } else {
 386                 BIO *b;
 387
 388                 /* Read the raw signature file and write the data to the
 389                  * destination file
 390                  */
 391                 b = BIO_new_file(raw_sig_name, "rb");
 392                 ERR(!b, "%s", raw_sig_name);
 393                 while ((n = BIO_read(b, buf, sizeof(buf))), n > 0)
 394                         ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name);
 395                 BIO_free(b);
 396         }
 397
 398         sig_size = BIO_number_written(bd) - module_size;
 399         sig_info.sig_len = htonl(sig_size);
 400         ERR(BIO_write(bd, &sig_info, sizeof(sig_info)) < 0, "%s", dest_name);
 401         ERR(BIO_write(bd, magic_number, sizeof(magic_number) - 1) < 0, "%s", dest_name);
 402
 403         ERR(BIO_free(bd) != 1, "%s", dest_name);
 404
 405         /* Finally, if we're signing in place, replace the original. */
 406         if (replace_orig)
 407                 ERR(rename(dest_name, module_name) < 0, "%s", dest_name);
 408
 409         return 0;
 410 }