1 /* Sign a module file using the given key. 2 * 3 * Copyright © 2014-2015 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 X509 *x509; 171 BIO *b; 172 173 b = BIO_new_file(x509_name, "rb"); 174 ERR(!b, "%s", x509_name); 175 x509 = d2i_X509_bio(b, NULL); /* Binary encoded X.509 */ 176 if (!x509) { 177 ERR(BIO_reset(b) != 1, "%s", x509_name); 178 x509 = PEM_read_bio_X509(b, NULL, NULL, 179 NULL); /* PEM encoded X.509 */ 180 if (x509) 181 drain_openssl_errors(); 182 } 183 BIO_free(b); 184 ERR(!x509, "%s", x509_name); 185 186 return x509; 187 } 188 189 int main(int argc, char **argv) 190 { 191 struct module_signature sig_info = { .id_type = PKEY_ID_PKCS7 }; 192 char *hash_algo = NULL; 193 char *private_key_name = NULL, *raw_sig_name = NULL; 194 char *x509_name, *module_name, *dest_name; 195 bool save_sig = false, replace_orig; 196 bool sign_only = false; 197 bool raw_sig = false; 198 unsigned char buf[4096]; 199 unsigned long module_size, sig_size; 200 unsigned int use_signed_attrs; 201 const EVP_MD *digest_algo; 202 EVP_PKEY *private_key; 203 #ifndef USE_PKCS7 204 CMS_ContentInfo *cms = NULL; 205 unsigned int use_keyid = 0; 206 #else 207 PKCS7 *pkcs7 = NULL; 208 #endif 209 X509 *x509; 210 BIO *bd, *bm; 211 int opt, n; 212 OpenSSL_add_all_algorithms(); 213 ERR_load_crypto_strings(); 214 ERR_clear_error(); 215 216 key_pass = getenv("KBUILD_SIGN_PIN"); 217 218 #ifndef USE_PKCS7 219 use_signed_attrs = CMS_NOATTR; 220 #else 221 use_signed_attrs = PKCS7_NOATTR; 222 #endif 223 224 do { 225 opt = getopt(argc, argv, "sdpk"); 226 switch (opt) { 227 case 's': raw_sig = true; break; 228 case 'p': save_sig = true; break; 229 case 'd': sign_only = true; save_sig = true; break; 230 #ifndef USE_PKCS7 231 case 'k': use_keyid = CMS_USE_KEYID; break; 232 #endif 233 case -1: break; 234 default: format(); 235 } 236 } while (opt != -1); 237 238 argc -= optind; 239 argv += optind; 240 if (argc < 4 || argc > 5) 241 format(); 242 243 if (raw_sig) { 244 raw_sig_name = argv[0]; 245 hash_algo = argv[1]; 246 } else { 247 hash_algo = argv[0]; 248 private_key_name = argv[1]; 249 } 250 x509_name = argv[2]; 251 module_name = argv[3]; 252 if (argc == 5) { 253 dest_name = argv[4]; 254 replace_orig = false; 255 } else { 256 ERR(asprintf(&dest_name, "%s.~signed~", module_name) < 0, 257 "asprintf"); 258 replace_orig = true; 259 } 260 261 #ifdef USE_PKCS7 262 if (strcmp(hash_algo, "sha1") != 0) { 263 fprintf(stderr, "sign-file: %s only supports SHA1 signing\n", 264 OPENSSL_VERSION_TEXT); 265 exit(3); 266 } 267 #endif 268 269 /* Open the module file */ 270 bm = BIO_new_file(module_name, "rb"); 271 ERR(!bm, "%s", module_name); 272 273 if (!raw_sig) { 274 /* Read the private key and the X.509 cert the PKCS#7 message 275 * will point to. 276 */ 277 private_key = read_private_key(private_key_name); 278 x509 = read_x509(x509_name); 279 280 /* Digest the module data. */ 281 OpenSSL_add_all_digests(); 282 display_openssl_errors(__LINE__); 283 digest_algo = EVP_get_digestbyname(hash_algo); 284 ERR(!digest_algo, "EVP_get_digestbyname"); 285 286 #ifndef USE_PKCS7 287 /* Load the signature message from the digest buffer. */ 288 cms = CMS_sign(NULL, NULL, NULL, NULL, 289 CMS_NOCERTS | CMS_PARTIAL | CMS_BINARY | 290 CMS_DETACHED | CMS_STREAM); 291 ERR(!cms, "CMS_sign"); 292 293 ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo, 294 CMS_NOCERTS | CMS_BINARY | 295 CMS_NOSMIMECAP | use_keyid | 296 use_signed_attrs), 297 "CMS_add1_signer"); 298 ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) < 0, 299 "CMS_final"); 300 301 #else 302 pkcs7 = PKCS7_sign(x509, private_key, NULL, bm, 303 PKCS7_NOCERTS | PKCS7_BINARY | 304 PKCS7_DETACHED | use_signed_attrs); 305 ERR(!pkcs7, "PKCS7_sign"); 306 #endif 307 308 if (save_sig) { 309 char *sig_file_name; 310 BIO *b; 311 312 ERR(asprintf(&sig_file_name, "%s.p7s", module_name) < 0, 313 "asprintf"); 314 b = BIO_new_file(sig_file_name, "wb"); 315 ERR(!b, "%s", sig_file_name); 316 #ifndef USE_PKCS7 317 ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) < 0, 318 "%s", sig_file_name); 319 #else 320 ERR(i2d_PKCS7_bio(b, pkcs7) < 0, 321 "%s", sig_file_name); 322 #endif 323 BIO_free(b); 324 } 325 326 if (sign_only) { 327 BIO_free(bm); 328 return 0; 329 } 330 } 331 332 /* Open the destination file now so that we can shovel the module data 333 * across as we read it. 334 */ 335 bd = BIO_new_file(dest_name, "wb"); 336 ERR(!bd, "%s", dest_name); 337 338 /* Append the marker and the PKCS#7 message to the destination file */ 339 ERR(BIO_reset(bm) < 0, "%s", module_name); 340 while ((n = BIO_read(bm, buf, sizeof(buf))), 341 n > 0) { 342 ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name); 343 } 344 BIO_free(bm); 345 ERR(n < 0, "%s", module_name); 346 module_size = BIO_number_written(bd); 347 348 if (!raw_sig) { 349 #ifndef USE_PKCS7 350 ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) < 0, "%s", dest_name); 351 #else 352 ERR(i2d_PKCS7_bio(bd, pkcs7) < 0, "%s", dest_name); 353 #endif 354 } else { 355 BIO *b; 356 357 /* Read the raw signature file and write the data to the 358 * destination file 359 */ 360 b = BIO_new_file(raw_sig_name, "rb"); 361 ERR(!b, "%s", raw_sig_name); 362 while ((n = BIO_read(b, buf, sizeof(buf))), n > 0) 363 ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name); 364 BIO_free(b); 365 } 366 367 sig_size = BIO_number_written(bd) - module_size; 368 sig_info.sig_len = htonl(sig_size); 369 ERR(BIO_write(bd, &sig_info, sizeof(sig_info)) < 0, "%s", dest_name); 370 ERR(BIO_write(bd, magic_number, sizeof(magic_number) - 1) < 0, "%s", dest_name); 371 372 ERR(BIO_free(bd) < 0, "%s", dest_name); 373 374 /* Finally, if we're signing in place, replace the original. */ 375 if (replace_orig) 376 ERR(rename(dest_name, module_name) < 0, "%s", dest_name); 377 378 return 0; 379 } 380