usr.sbin/uefisign/uefisign.c

   1 /*-
   2  * Copyright (c) 2014 The FreeBSD Foundation
   3  * All rights reserved.
   4  *
   5  * This software was developed by Edward Tomasz Napierala under sponsorship
   6  * from the FreeBSD Foundation.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  */
  30
  31 #include <sys/cdefs.h>
  32 __FBSDID("$FreeBSD: head/usr.sbin/uefisign/uefisign.c 279315 2015-02-26 09:15:24Z trasz $");
  33
  34 #include <sys/wait.h>
  35 #include <assert.h>
  36 #include <err.h>
  37 #include <errno.h>
  38 #include <stdio.h>
  39 #include <string.h>
  40 #include <unistd.h>
  41
  42 #include <openssl/conf.h>
  43 #include <openssl/evp.h>
  44 #include <openssl/err.h>
  45 #include <openssl/pem.h>
  46 #include <openssl/pkcs7.h>
  47
  48 #include "uefisign.h"
  49 #include "magic.h"
  50
  51 static void
  52 usage(void)
  53 {
  54
  55         fprintf(stderr, "usage: uefisign -c cert -k key -o outfile [-v] file\n"
  56                         "       uefisign -V [-c cert] [-v] file\n");
  57         exit(1);
  58 }
  59
  60 static char *
  61 checked_strdup(const char *s)
  62 {
  63         char *c;
  64
  65         c = strdup(s);
  66         if (c == NULL)
  67                 err(1, "strdup");
  68         return (c);
  69 }
  70
  71 FILE *
  72 checked_fopen(const char *path, const char *mode)
  73 {
  74         FILE *fp;
  75
  76         assert(path != NULL);
  77
  78         fp = fopen(path, mode);
  79         if (fp == NULL)
  80                 err(1, "%s", path);
  81         return (fp);
  82 }
  83
  84 void
  85 send_chunk(const void *buf, size_t len, int pipefd)
  86 {
  87         ssize_t ret;
  88
  89         ret = write(pipefd, &len, sizeof(len));
  90         if (ret != sizeof(len))
  91                 err(1, "write");
  92         ret = write(pipefd, buf, len);
  93         if (ret != (ssize_t)len)
  94                 err(1, "write");
  95 }
  96
  97 void
  98 receive_chunk(void **bufp, size_t *lenp, int pipefd)
  99 {
 100         ssize_t ret;
 101         size_t len;
 102         void *buf;
 103
 104         ret = read(pipefd, &len, sizeof(len));
 105         if (ret != sizeof(len))
 106                 err(1, "read");
 107
 108         buf = calloc(1, len);
 109         if (buf == NULL)
 110                 err(1, "calloc");
 111
 112         ret = read(pipefd, buf, len);
 113         if (ret != (ssize_t)len)
 114                 err(1, "read");
 115
 116         *bufp = buf;
 117         *lenp = len;
 118 }
 119
 120 static char *
 121 bin2hex(const char *bin, size_t bin_len)
 122 {
 123         unsigned char *hex, *tmp, ch;
 124         size_t hex_len;
 125         size_t i;
 126
 127         hex_len = bin_len * 2 + 1; /* +1 for '\0'. */
 128         hex = malloc(hex_len);
 129         if (hex == NULL)
 130                 err(1, "malloc");
 131
 132         tmp = hex;
 133         for (i = 0; i < bin_len; i++) {
 134                 ch = bin[i];
 135                 tmp += sprintf(tmp, "%02x", ch);
 136         }
 137
 138         return (hex);
 139 }
 140
 141 /*
 142  * We need to replace a standard chunk of PKCS7 signature with one mandated
 143  * by Authenticode.  Problem is, replacing it just like that and then calling
 144  * PKCS7_final() would make OpenSSL segfault somewhere in PKCS7_dataFinal().
 145  * So, instead, we call PKCS7_dataInit(), then put our Authenticode-specific
 146  * data into BIO it returned, then call PKCS7_dataFinal() - which now somehow
 147  * does not panic - and _then_ we replace it in the signature.  This technique
 148  * was used in sbsigntool by Jeremy Kerr, and might have originated in
 149  * osslsigncode.
 150  */
 151 static void
 152 magic(PKCS7 *pkcs7, const char *digest, size_t digest_len)
 153 {
 154         BIO *bio, *t_bio;
 155         ASN1_TYPE *t;
 156         ASN1_STRING *s;
 157         CONF *cnf;
 158         unsigned char *buf, *tmp;
 159         char *digest_hex, *magic_conf, *str;
 160         int len, nid, ok;
 161
 162         digest_hex = bin2hex(digest, digest_len);
 163
 164         /*
 165          * Construct the SpcIndirectDataContent chunk.
 166          */
 167         nid = OBJ_create("1.3.6.1.4.1.311.2.1.4", NULL, NULL);
 168
 169         asprintf(&magic_conf, magic_fmt, digest_hex);
 170         if (magic_conf == NULL)
 171                 err(1, "asprintf");
 172
 173         bio = BIO_new_mem_buf((void *)magic_conf, -1);
 174         if (bio == NULL) {
 175                 ERR_print_errors_fp(stderr);
 176                 errx(1, "BIO_new_mem_buf(3) failed");
 177         }
 178
 179         cnf = NCONF_new(NULL);
 180         if (cnf == NULL) {
 181                 ERR_print_errors_fp(stderr);
 182                 errx(1, "NCONF_new(3) failed");
 183         }
 184
 185         ok = NCONF_load_bio(cnf, bio, NULL);
 186         if (ok == 0) {
 187                 ERR_print_errors_fp(stderr);
 188                 errx(1, "NCONF_load_bio(3) failed");
 189         }
 190
 191         str = NCONF_get_string(cnf, "default", "asn1");
 192         if (str == NULL) {
 193                 ERR_print_errors_fp(stderr);
 194                 errx(1, "NCONF_get_string(3) failed");
 195         }
 196
 197         t = ASN1_generate_nconf(str, cnf);
 198         if (t == NULL) {
 199                 ERR_print_errors_fp(stderr);
 200                 errx(1, "ASN1_generate_nconf(3) failed");
 201         }
 202
 203         /*
 204          * We now have our proprietary piece of ASN.1.  Let's do
 205          * the actual signing.
 206          */
 207         len = i2d_ASN1_TYPE(t, NULL);
 208         tmp = buf = calloc(1, len);
 209         if (tmp == NULL)
 210                 err(1, "calloc");
 211         i2d_ASN1_TYPE(t, &tmp);
 212
 213         /*
 214          * We now have contents of 't' stuffed into memory buffer 'buf'.
 215          */
 216         tmp = NULL;
 217         t = NULL;
 218
 219         t_bio = PKCS7_dataInit(pkcs7, NULL);
 220         if (t_bio == NULL) {
 221                 ERR_print_errors_fp(stderr);
 222                 errx(1, "PKCS7_dataInit(3) failed");
 223         }
 224
 225         BIO_write(t_bio, buf + 2, len - 2);
 226
 227         ok = PKCS7_dataFinal(pkcs7, t_bio);
 228         if (ok == 0) {
 229                 ERR_print_errors_fp(stderr);
 230                 errx(1, "PKCS7_dataFinal(3) failed");
 231         }
 232
 233         t = ASN1_TYPE_new();
 234         s = ASN1_STRING_new();
 235         ASN1_STRING_set(s, buf, len);
 236         ASN1_TYPE_set(t, V_ASN1_SEQUENCE, s);
 237
 238         PKCS7_set0_type_other(pkcs7->d.sign->contents, nid, t);
 239 }
 240
 241 static void
 242 sign(X509 *cert, EVP_PKEY *key, int pipefd)
 243 {
 244         PKCS7 *pkcs7;
 245         BIO *bio, *out;
 246         const EVP_MD *md;
 247         PKCS7_SIGNER_INFO *info;
 248         void *digest, *signature;
 249         size_t digest_len, signature_len;
 250         int ok;
 251
 252         assert(cert != NULL);
 253         assert(key != NULL);
 254
 255         receive_chunk(&digest, &digest_len, pipefd);
 256
 257         bio = BIO_new_mem_buf(digest, digest_len);
 258         if (bio == NULL) {
 259                 ERR_print_errors_fp(stderr);
 260                 errx(1, "BIO_new_mem_buf(3) failed");
 261         }
 262
 263         pkcs7 = PKCS7_sign(NULL, NULL, NULL, bio, PKCS7_BINARY | PKCS7_PARTIAL);
 264         if (pkcs7 == NULL) {
 265                 ERR_print_errors_fp(stderr);
 266                 errx(1, "PKCS7_sign(3) failed");
 267         }
 268
 269         md = EVP_get_digestbyname(DIGEST);
 270         if (md == NULL) {
 271                 ERR_print_errors_fp(stderr);
 272                 errx(1, "EVP_get_digestbyname(\"%s\") failed", DIGEST);
 273         }
 274
 275         info = PKCS7_sign_add_signer(pkcs7, cert, key, md, 0);
 276         if (info == NULL) {
 277                 ERR_print_errors_fp(stderr);
 278                 errx(1, "PKCS7_sign_add_signer(3) failed");
 279         }
 280
 281         /*
 282          * XXX: All the signed binaries seem to have this, but where is it
 283          *      described in the spec?
 284          */
 285         PKCS7_add_signed_attribute(info, NID_pkcs9_contentType,
 286             V_ASN1_OBJECT, OBJ_txt2obj("1.3.6.1.4.1.311.2.1.4", 1));
 287
 288         magic(pkcs7, digest, digest_len);
 289
 290 #if 0
 291         out = BIO_new(BIO_s_file());
 292         BIO_set_fp(out, stdout, BIO_NOCLOSE);
 293         PKCS7_print_ctx(out, pkcs7, 0, NULL);
 294
 295         i2d_PKCS7_bio(out, pkcs7);
 296 #endif
 297
 298         out = BIO_new(BIO_s_mem());
 299         if (out == NULL) {
 300                 ERR_print_errors_fp(stderr);
 301                 errx(1, "BIO_new(3) failed");
 302         }
 303
 304         ok = i2d_PKCS7_bio(out, pkcs7);
 305         if (ok == 0) {
 306                 ERR_print_errors_fp(stderr);
 307                 errx(1, "i2d_PKCS7_bio(3) failed");
 308         }
 309
 310         signature_len = BIO_get_mem_data(out, &signature);
 311         if (signature_len <= 0) {
 312                 ERR_print_errors_fp(stderr);
 313                 errx(1, "BIO_get_mem_data(3) failed");
 314         }
 315
 316         (void)BIO_set_close(out, BIO_NOCLOSE);
 317         BIO_free(out);
 318
 319         send_chunk(signature, signature_len, pipefd);
 320 }
 321
 322 static int
 323 wait_for_child(pid_t pid)
 324 {
 325         int status;
 326
 327         pid = waitpid(pid, &status, 0);
 328         if (pid == -1)
 329                 err(1, "waitpid");
 330
 331         return (WEXITSTATUS(status));
 332 }
 333
 334 int
 335 main(int argc, char **argv)
 336 {
 337         int ch, error;
 338         bool Vflag = false, vflag = false;
 339         const char *certpath = NULL, *keypath = NULL, *outpath = NULL, *inpath = NULL;
 340         FILE *certfp = NULL, *keyfp = NULL;
 341         X509 *cert = NULL;
 342         EVP_PKEY *key = NULL;
 343         pid_t pid;
 344         int pipefds[2];
 345
 346         while ((ch = getopt(argc, argv, "Vc:k:o:v")) != -1) {
 347                 switch (ch) {
 348                 case 'V':
 349                         Vflag = true;
 350                         break;
 351                 case 'c':
 352                         certpath = checked_strdup(optarg);
 353                         break;
 354                 case 'k':
 355                         keypath = checked_strdup(optarg);
 356                         break;
 357                 case 'o':
 358                         outpath = checked_strdup(optarg);
 359                         break;
 360                 case 'v':
 361                         vflag = true;
 362                         break;
 363                 default:
 364                         usage();
 365                 }
 366         }
 367
 368         argc -= optind;
 369         argv += optind;
 370         if (argc != 1)
 371                 usage();
 372
 373         if (Vflag) {
 374                 if (certpath != NULL)
 375                         errx(1, "-V and -c are mutually exclusive");
 376                 if (keypath != NULL)
 377                         errx(1, "-V and -k are mutually exclusive");
 378                 if (outpath != NULL)
 379                         errx(1, "-V and -o are mutually exclusive");
 380         } else {
 381                 if (certpath == NULL)
 382                         errx(1, "-c option is mandatory");
 383                 if (keypath == NULL)
 384                         errx(1, "-k option is mandatory");
 385                 if (outpath == NULL)
 386                         errx(1, "-o option is mandatory");
 387         }
 388
 389         inpath = argv[0];
 390
 391         OPENSSL_config(NULL);
 392         ERR_load_crypto_strings();
 393         OpenSSL_add_all_algorithms();
 394
 395         error = pipe(pipefds);
 396         if (error != 0)
 397                 err(1, "pipe");
 398
 399         pid = fork();
 400         if (pid < 0)
 401                 err(1, "fork");
 402
 403         if (pid == 0)
 404                 return (child(inpath, outpath, pipefds[1], Vflag, vflag));
 405
 406         if (!Vflag) {
 407                 certfp = checked_fopen(certpath, "r");
 408                 cert = PEM_read_X509(certfp, NULL, NULL, NULL);
 409                 if (cert == NULL) {
 410                         ERR_print_errors_fp(stderr);
 411                         errx(1, "failed to load certificate from %s", certpath);
 412                 }
 413
 414                 keyfp = checked_fopen(keypath, "r");
 415                 key = PEM_read_PrivateKey(keyfp, NULL, NULL, NULL);
 416                 if (key == NULL) {
 417                         ERR_print_errors_fp(stderr);
 418                         errx(1, "failed to load private key from %s", keypath);
 419                 }
 420
 421                 sign(cert, key, pipefds[0]);
 422         }
 423
 424         return (wait_for_child(pid));
 425 }