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 * 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 Lesser General Public License 11 * as published by the Free Software Foundation; either version 2.1 12 * 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/opensslv.h> 24 #include <openssl/bio.h> 25 #include <openssl/evp.h> 26 #include <openssl/pem.h> 27 #include <openssl/err.h> 28 #include <openssl/engine.h> 29 30 /* 31 * Use CMS if we have openssl-1.0.0 or newer available - otherwise we have to 32 * assume that it's not available and its header file is missing and that we 33 * should use PKCS#7 instead. Switching to the older PKCS#7 format restricts 34 * the options we have on specifying the X.509 certificate we want. 35 * 36 * Further, older versions of OpenSSL don't support manually adding signers to 37 * the PKCS#7 message so have to accept that we get a certificate included in 38 * the signature message. Nor do such older versions of OpenSSL support 39 * signing with anything other than SHA1 - so we're stuck with that if such is 40 * the case. 41 */ 42 #if OPENSSL_VERSION_NUMBER < 0x10000000L 43 #define USE_PKCS7 44 #endif 45 #ifndef USE_PKCS7 46 #include <openssl/cms.h> 47 #else 48 #include <openssl/pkcs7.h> 49 #endif 50 51 struct module_signature { 52 uint8_t algo; /* Public-key crypto algorithm [0] */ 53 uint8_t hash; /* Digest algorithm [0] */ 54 uint8_t id_type; /* Key identifier type [PKEY_ID_PKCS7] */ 55 uint8_t signer_len; /* Length of signer's name [0] */ 56 uint8_t key_id_len; /* Length of key identifier [0] */ 57 uint8_t __pad[3]; 58 uint32_t sig_len; /* Length of signature data */ 59 }; 60 61 #define PKEY_ID_PKCS7 2 62 63 static char magic_number[] = "~Module signature appended~\n"; 64 65 static __attribute__((noreturn)) 66 void format(void) 67 { 68 fprintf(stderr, 69 "Usage: scripts/sign-file [-dp] <hash algo> <key> <x509> <module> [<dest>]\n"); 70 exit(2); 71 } 72 73 static void display_openssl_errors(int l) 74 { 75 const char *file; 76 char buf[120]; 77 int e, line; 78 79 if (ERR_peek_error() == 0) 80 return; 81 fprintf(stderr, "At main.c:%d:\n", l); 82 83 while ((e = ERR_get_error_line(&file, &line))) { 84 ERR_error_string(e, buf); 85 fprintf(stderr, "- SSL %s: %s:%d\n", buf, file, line); 86 } 87 } 88 89 static void drain_openssl_errors(void) 90 { 91 const char *file; 92 int line; 93 94 if (ERR_peek_error() == 0) 95 return; 96 while (ERR_get_error_line(&file, &line)) {} 97 } 98 99 #define ERR(cond, fmt, ...) \ 100 do { \ 101 bool __cond = (cond); \ 102 display_openssl_errors(__LINE__); \ 103 if (__cond) { \ 104 err(1, fmt, ## __VA_ARGS__); \ 105 } \ 106 } while(0) 107 108 static const char *key_pass; 109 110 static int pem_pw_cb(char *buf, int len, int w, void *v) 111 { 112 int pwlen; 113 114 if (!key_pass) 115 return -1; 116 117 pwlen = strlen(key_pass); 118 if (pwlen >= len) 119 return -1; 120 121 strcpy(buf, key_pass); 122 123 /* If it's wrong, don't keep trying it. */ 124 key_pass = NULL; 125 126 return pwlen; 127 } 128 129 int main(int argc, char **argv) 130 { 131 struct module_signature sig_info = { .id_type = PKEY_ID_PKCS7 }; 132 char *hash_algo = NULL; 133 char *private_key_name, *x509_name, *module_name, *dest_name; 134 bool save_sig = false, replace_orig; 135 bool sign_only = false; 136 unsigned char buf[4096]; 137 unsigned long module_size, sig_size; 138 unsigned int use_signed_attrs; 139 const EVP_MD *digest_algo; 140 EVP_PKEY *private_key; 141 #ifndef USE_PKCS7 142 CMS_ContentInfo *cms; 143 unsigned int use_keyid = 0; 144 #else 145 PKCS7 *pkcs7; 146 #endif 147 X509 *x509; 148 BIO *b, *bd = NULL, *bm; 149 int opt, n; 150 OpenSSL_add_all_algorithms(); 151 ERR_load_crypto_strings(); 152 ERR_clear_error(); 153 154 key_pass = getenv("KBUILD_SIGN_PIN"); 155 156 #ifndef USE_PKCS7 157 use_signed_attrs = CMS_NOATTR; 158 #else 159 use_signed_attrs = PKCS7_NOATTR; 160 #endif 161 162 do { 163 opt = getopt(argc, argv, "dpk"); 164 switch (opt) { 165 case 'p': save_sig = true; break; 166 case 'd': sign_only = true; save_sig = true; break; 167 #ifndef USE_PKCS7 168 case 'k': use_keyid = CMS_USE_KEYID; break; 169 #endif 170 case -1: break; 171 default: format(); 172 } 173 } while (opt != -1); 174 175 argc -= optind; 176 argv += optind; 177 if (argc < 4 || argc > 5) 178 format(); 179 180 hash_algo = argv[0]; 181 private_key_name = argv[1]; 182 x509_name = argv[2]; 183 module_name = argv[3]; 184 if (argc == 5) { 185 dest_name = argv[4]; 186 replace_orig = false; 187 } else { 188 ERR(asprintf(&dest_name, "%s.~signed~", module_name) < 0, 189 "asprintf"); 190 replace_orig = true; 191 } 192 193 #ifdef USE_PKCS7 194 if (strcmp(hash_algo, "sha1") != 0) { 195 fprintf(stderr, "sign-file: %s only supports SHA1 signing\n", 196 OPENSSL_VERSION_TEXT); 197 exit(3); 198 } 199 #endif 200 201 /* Read the private key and the X.509 cert the PKCS#7 message 202 * will point to. 203 */ 204 if (!strncmp(private_key_name, "pkcs11:", 7)) { 205 ENGINE *e; 206 207 ENGINE_load_builtin_engines(); 208 drain_openssl_errors(); 209 e = ENGINE_by_id("pkcs11"); 210 ERR(!e, "Load PKCS#11 ENGINE"); 211 if (ENGINE_init(e)) 212 drain_openssl_errors(); 213 else 214 ERR(1, "ENGINE_init"); 215 if (key_pass) 216 ERR(!ENGINE_ctrl_cmd_string(e, "PIN", key_pass, 0), "Set PKCS#11 PIN"); 217 private_key = ENGINE_load_private_key(e, private_key_name, NULL, 218 NULL); 219 ERR(!private_key, "%s", private_key_name); 220 } else { 221 b = BIO_new_file(private_key_name, "rb"); 222 ERR(!b, "%s", private_key_name); 223 private_key = PEM_read_bio_PrivateKey(b, NULL, pem_pw_cb, NULL); 224 ERR(!private_key, "%s", private_key_name); 225 BIO_free(b); 226 } 227 228 b = BIO_new_file(x509_name, "rb"); 229 ERR(!b, "%s", x509_name); 230 x509 = d2i_X509_bio(b, NULL); /* Binary encoded X.509 */ 231 if (!x509) { 232 ERR(BIO_reset(b) != 1, "%s", x509_name); 233 x509 = PEM_read_bio_X509(b, NULL, NULL, NULL); /* PEM encoded X.509 */ 234 if (x509) 235 drain_openssl_errors(); 236 } 237 BIO_free(b); 238 ERR(!x509, "%s", x509_name); 239 240 /* Open the destination file now so that we can shovel the module data 241 * across as we read it. 242 */ 243 if (!sign_only) { 244 bd = BIO_new_file(dest_name, "wb"); 245 ERR(!bd, "%s", dest_name); 246 } 247 248 /* Digest the module data. */ 249 OpenSSL_add_all_digests(); 250 display_openssl_errors(__LINE__); 251 digest_algo = EVP_get_digestbyname(hash_algo); 252 ERR(!digest_algo, "EVP_get_digestbyname"); 253 254 bm = BIO_new_file(module_name, "rb"); 255 ERR(!bm, "%s", module_name); 256 257 #ifndef USE_PKCS7 258 /* Load the signature message from the digest buffer. */ 259 cms = CMS_sign(NULL, NULL, NULL, NULL, 260 CMS_NOCERTS | CMS_PARTIAL | CMS_BINARY | CMS_DETACHED | CMS_STREAM); 261 ERR(!cms, "CMS_sign"); 262 263 ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo, 264 CMS_NOCERTS | CMS_BINARY | CMS_NOSMIMECAP | 265 use_keyid | use_signed_attrs), 266 "CMS_add1_signer"); 267 ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) < 0, 268 "CMS_final"); 269 270 #else 271 pkcs7 = PKCS7_sign(x509, private_key, NULL, bm, 272 PKCS7_NOCERTS | PKCS7_BINARY | 273 PKCS7_DETACHED | use_signed_attrs); 274 ERR(!pkcs7, "PKCS7_sign"); 275 #endif 276 277 if (save_sig) { 278 char *sig_file_name; 279 280 ERR(asprintf(&sig_file_name, "%s.p7s", module_name) < 0, 281 "asprintf"); 282 b = BIO_new_file(sig_file_name, "wb"); 283 ERR(!b, "%s", sig_file_name); 284 #ifndef USE_PKCS7 285 ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) < 0, 286 "%s", sig_file_name); 287 #else 288 ERR(i2d_PKCS7_bio(b, pkcs7) < 0, 289 "%s", sig_file_name); 290 #endif 291 BIO_free(b); 292 } 293 294 if (sign_only) 295 return 0; 296 297 /* Append the marker and the PKCS#7 message to the destination file */ 298 ERR(BIO_reset(bm) < 0, "%s", module_name); 299 while ((n = BIO_read(bm, buf, sizeof(buf))), 300 n > 0) { 301 ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name); 302 } 303 ERR(n < 0, "%s", module_name); 304 module_size = BIO_number_written(bd); 305 306 #ifndef USE_PKCS7 307 ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) < 0, "%s", dest_name); 308 #else 309 ERR(i2d_PKCS7_bio(bd, pkcs7) < 0, "%s", dest_name); 310 #endif 311 sig_size = BIO_number_written(bd) - module_size; 312 sig_info.sig_len = htonl(sig_size); 313 ERR(BIO_write(bd, &sig_info, sizeof(sig_info)) < 0, "%s", dest_name); 314 ERR(BIO_write(bd, magic_number, sizeof(magic_number) - 1) < 0, "%s", dest_name); 315 316 ERR(BIO_free(bd) < 0, "%s", dest_name); 317 318 /* Finally, if we're signing in place, replace the original. */ 319 if (replace_orig) 320 ERR(rename(dest_name, module_name) < 0, "%s", dest_name); 321 322 return 0; 323 } 324