Kyle Swenson | 8d8f654 | 2021-03-15 11:02:55 -0600 | [diff] [blame] | 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 | } |