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 #include <openssl/engine.h> 31 32 /* 33 * Use CMS if we have openssl-1.0.0 or newer available - otherwise we have to 34 * assume that it's not available and its header file is missing and that we 35 * should use PKCS#7 instead. Switching to the older PKCS#7 format restricts 36 * the options we have on specifying the X.509 certificate we want. 37 * 38 * Further, older versions of OpenSSL don't support manually adding signers to 39 * the PKCS#7 message so have to accept that we get a certificate included in 40 * the signature message. Nor do such older versions of OpenSSL support 41 * signing with anything other than SHA1 - so we're stuck with that if such is 42 * the case. 43 */ 44 #if OPENSSL_VERSION_NUMBER < 0x10000000L || defined(OPENSSL_NO_CMS) 45 #define USE_PKCS7 46 #endif 47 #ifndef USE_PKCS7 48 #include <openssl/cms.h> 49 #else 50 #include <openssl/pkcs7.h> 51 #endif 52 53 struct module_signature { 54 uint8_t algo; /* Public-key crypto algorithm [0] */ 55 uint8_t hash; /* Digest algorithm [0] */ 56 uint8_t id_type; /* Key identifier type [PKEY_ID_PKCS7] */ 57 uint8_t signer_len; /* Length of signer's name [0] */ 58 uint8_t key_id_len; /* Length of key identifier [0] */ 59 uint8_t __pad[3]; 60 uint32_t sig_len; /* Length of signature data */ 61 }; 62 63 #define PKEY_ID_PKCS7 2 64 65 static char magic_number[] = "~Module signature appended~\n"; 66 67 static __attribute__((noreturn)) 68 void format(void) 69 { 70 fprintf(stderr, 71 "Usage: scripts/sign-file [-dp] <hash algo> <key> <x509> <module> [<dest>]\n"); 72 fprintf(stderr, 73 " scripts/sign-file -s <raw sig> <hash algo> <x509> <module> [<dest>]\n"); 74 exit(2); 75 } 76 77 static void display_openssl_errors(int l) 78 { 79 const char *file; 80 char buf[120]; 81 int e, line; 82 83 if (ERR_peek_error() == 0) 84 return; 85 fprintf(stderr, "At main.c:%d:\n", l); 86 87 while ((e = ERR_get_error_line(&file, &line))) { 88 ERR_error_string(e, buf); 89 fprintf(stderr, "- SSL %s: %s:%d\n", buf, file, line); 90 } 91 } 92 93 static void drain_openssl_errors(void) 94 { 95 const char *file; 96 int line; 97 98 if (ERR_peek_error() == 0) 99 return; 100 while (ERR_get_error_line(&file, &line)) {} 101 } 102 103 #define ERR(cond, fmt, ...) \ 104 do { \ 105 bool __cond = (cond); \ 106 display_openssl_errors(__LINE__); \ 107 if (__cond) { \ 108 err(1, fmt, ## __VA_ARGS__); \ 109 } \ 110 } while(0) 111 112 static const char *key_pass; 113 114 static int pem_pw_cb(char *buf, int len, int w, void *v) 115 { 116 int pwlen; 117 118 if (!key_pass) 119 return -1; 120 121 pwlen = strlen(key_pass); 122 if (pwlen >= len) 123 return -1; 124 125 strcpy(buf, key_pass); 126 127 /* If it's wrong, don't keep trying it. */ 128 key_pass = NULL; 129 130 return pwlen; 131 } 132 133 static EVP_PKEY *read_private_key(const char *private_key_name) 134 { 135 EVP_PKEY *private_key; 136 137 if (!strncmp(private_key_name, "pkcs11:", 7)) { 138 ENGINE *e; 139 140 ENGINE_load_builtin_engines(); 141 drain_openssl_errors(); 142 e = ENGINE_by_id("pkcs11"); 143 ERR(!e, "Load PKCS#11 ENGINE"); 144 if (ENGINE_init(e)) 145 drain_openssl_errors(); 146 else 147 ERR(1, "ENGINE_init"); 148 if (key_pass) 149 ERR(!ENGINE_ctrl_cmd_string(e, "PIN", key_pass, 0), 150 "Set PKCS#11 PIN"); 151 private_key = ENGINE_load_private_key(e, private_key_name, 152 NULL, NULL); 153 ERR(!private_key, "%s", private_key_name); 154 } else { 155 BIO *b; 156 157 b = BIO_new_file(private_key_name, "rb"); 158 ERR(!b, "%s", private_key_name); 159 private_key = PEM_read_bio_PrivateKey(b, NULL, pem_pw_cb, 160 NULL); 161 ERR(!private_key, "%s", private_key_name); 162 BIO_free(b); 163 } 164 165 return private_key; 166 } 167 168 static X509 *read_x509(const char *x509_name) 169 { 170 unsigned char buf[2]; 171 X509 *x509; 172 BIO *b; 173 int n; 174 175 b = BIO_new_file(x509_name, "rb"); 176 ERR(!b, "%s", x509_name); 177 178 /* Look at the first two bytes of the file to determine the encoding */ 179 n = BIO_read(b, buf, 2); 180 if (n != 2) { 181 if (BIO_should_retry(b)) { 182 fprintf(stderr, "%s: Read wanted retry\n", x509_name); 183 exit(1); 184 } 185 if (n >= 0) { 186 fprintf(stderr, "%s: Short read\n", x509_name); 187 exit(1); 188 } 189 ERR(1, "%s", x509_name); 190 } 191 192 ERR(BIO_reset(b) != 0, "%s", x509_name); 193 194 if (buf[0] == 0x30 && buf[1] >= 0x81 && buf[1] <= 0x84) 195 /* Assume raw DER encoded X.509 */ 196 x509 = d2i_X509_bio(b, NULL); 197 else 198 /* Assume PEM encoded X.509 */ 199 x509 = PEM_read_bio_X509(b, NULL, NULL, NULL); 200 201 BIO_free(b); 202 ERR(!x509, "%s", x509_name); 203 204 return x509; 205 } 206 207 int main(int argc, char **argv) 208 { 209 struct module_signature sig_info = { .id_type = PKEY_ID_PKCS7 }; 210 char *hash_algo = NULL; 211 char *private_key_name = NULL, *raw_sig_name = NULL; 212 char *x509_name, *module_name, *dest_name; 213 bool save_sig = false, replace_orig; 214 bool sign_only = false; 215 bool raw_sig = false; 216 unsigned char buf[4096]; 217 unsigned long module_size, sig_size; 218 unsigned int use_signed_attrs; 219 const EVP_MD *digest_algo; 220 EVP_PKEY *private_key; 221 #ifndef USE_PKCS7 222 CMS_ContentInfo *cms = NULL; 223 unsigned int use_keyid = 0; 224 #else 225 PKCS7 *pkcs7 = NULL; 226 #endif 227 X509 *x509; 228 BIO *bd, *bm; 229 int opt, n; 230 OpenSSL_add_all_algorithms(); 231 ERR_load_crypto_strings(); 232 ERR_clear_error(); 233 234 key_pass = getenv("KBUILD_SIGN_PIN"); 235 236 #ifndef USE_PKCS7 237 use_signed_attrs = CMS_NOATTR; 238 #else 239 use_signed_attrs = PKCS7_NOATTR; 240 #endif 241 242 do { 243 opt = getopt(argc, argv, "sdpk"); 244 switch (opt) { 245 case 's': raw_sig = true; break; 246 case 'p': save_sig = true; break; 247 case 'd': sign_only = true; save_sig = true; break; 248 #ifndef USE_PKCS7 249 case 'k': use_keyid = CMS_USE_KEYID; break; 250 #endif 251 case -1: break; 252 default: format(); 253 } 254 } while (opt != -1); 255 256 argc -= optind; 257 argv += optind; 258 if (argc < 4 || argc > 5) 259 format(); 260 261 if (raw_sig) { 262 raw_sig_name = argv[0]; 263 hash_algo = argv[1]; 264 } else { 265 hash_algo = argv[0]; 266 private_key_name = argv[1]; 267 } 268 x509_name = argv[2]; 269 module_name = argv[3]; 270 if (argc == 5) { 271 dest_name = argv[4]; 272 replace_orig = false; 273 } else { 274 ERR(asprintf(&dest_name, "%s.~signed~", module_name) < 0, 275 "asprintf"); 276 replace_orig = true; 277 } 278 279 #ifdef USE_PKCS7 280 if (strcmp(hash_algo, "sha1") != 0) { 281 fprintf(stderr, "sign-file: %s only supports SHA1 signing\n", 282 OPENSSL_VERSION_TEXT); 283 exit(3); 284 } 285 #endif 286 287 /* Open the module file */ 288 bm = BIO_new_file(module_name, "rb"); 289 ERR(!bm, "%s", module_name); 290 291 if (!raw_sig) { 292 /* Read the private key and the X.509 cert the PKCS#7 message 293 * will point to. 294 */ 295 private_key = read_private_key(private_key_name); 296 x509 = read_x509(x509_name); 297 298 /* Digest the module data. */ 299 OpenSSL_add_all_digests(); 300 display_openssl_errors(__LINE__); 301 digest_algo = EVP_get_digestbyname(hash_algo); 302 ERR(!digest_algo, "EVP_get_digestbyname"); 303 304 #ifndef USE_PKCS7 305 /* Load the signature message from the digest buffer. */ 306 cms = CMS_sign(NULL, NULL, NULL, NULL, 307 CMS_NOCERTS | CMS_PARTIAL | CMS_BINARY | 308 CMS_DETACHED | CMS_STREAM); 309 ERR(!cms, "CMS_sign"); 310 311 ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo, 312 CMS_NOCERTS | CMS_BINARY | 313 CMS_NOSMIMECAP | use_keyid | 314 use_signed_attrs), 315 "CMS_add1_signer"); 316 ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) < 0, 317 "CMS_final"); 318 319 #else 320 pkcs7 = PKCS7_sign(x509, private_key, NULL, bm, 321 PKCS7_NOCERTS | PKCS7_BINARY | 322 PKCS7_DETACHED | use_signed_attrs); 323 ERR(!pkcs7, "PKCS7_sign"); 324 #endif 325 326 if (save_sig) { 327 char *sig_file_name; 328 BIO *b; 329 330 ERR(asprintf(&sig_file_name, "%s.p7s", module_name) < 0, 331 "asprintf"); 332 b = BIO_new_file(sig_file_name, "wb"); 333 ERR(!b, "%s", sig_file_name); 334 #ifndef USE_PKCS7 335 ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) < 0, 336 "%s", sig_file_name); 337 #else 338 ERR(i2d_PKCS7_bio(b, pkcs7) < 0, 339 "%s", sig_file_name); 340 #endif 341 BIO_free(b); 342 } 343 344 if (sign_only) { 345 BIO_free(bm); 346 return 0; 347 } 348 } 349 350 /* Open the destination file now so that we can shovel the module data 351 * across as we read it. 352 */ 353 bd = BIO_new_file(dest_name, "wb"); 354 ERR(!bd, "%s", dest_name); 355 356 /* Append the marker and the PKCS#7 message to the destination file */ 357 ERR(BIO_reset(bm) < 0, "%s", module_name); 358 while ((n = BIO_read(bm, buf, sizeof(buf))), 359 n > 0) { 360 ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name); 361 } 362 BIO_free(bm); 363 ERR(n < 0, "%s", module_name); 364 module_size = BIO_number_written(bd); 365 366 if (!raw_sig) { 367 #ifndef USE_PKCS7 368 ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) < 0, "%s", dest_name); 369 #else 370 ERR(i2d_PKCS7_bio(bd, pkcs7) < 0, "%s", dest_name); 371 #endif 372 } else { 373 BIO *b; 374 375 /* Read the raw signature file and write the data to the 376 * destination file 377 */ 378 b = BIO_new_file(raw_sig_name, "rb"); 379 ERR(!b, "%s", raw_sig_name); 380 while ((n = BIO_read(b, buf, sizeof(buf))), n > 0) 381 ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name); 382 BIO_free(b); 383 } 384 385 sig_size = BIO_number_written(bd) - module_size; 386 sig_info.sig_len = htonl(sig_size); 387 ERR(BIO_write(bd, &sig_info, sizeof(sig_info)) < 0, "%s", dest_name); 388 ERR(BIO_write(bd, magic_number, sizeof(magic_number) - 1) < 0, "%s", dest_name); 389 390 ERR(BIO_free(bd) < 0, "%s", dest_name); 391 392 /* Finally, if we're signing in place, replace the original. */ 393 if (replace_orig) 394 ERR(rename(dest_name, module_name) < 0, "%s", dest_name); 395 396 return 0; 397 } 398