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/bio.h> 24 #include <openssl/evp.h> 25 #include <openssl/pem.h> 26 #include <openssl/cms.h> 27 #include <openssl/err.h> 28 #include <openssl/engine.h> 29 30 struct module_signature { 31 uint8_t algo; /* Public-key crypto algorithm [0] */ 32 uint8_t hash; /* Digest algorithm [0] */ 33 uint8_t id_type; /* Key identifier type [PKEY_ID_PKCS7] */ 34 uint8_t signer_len; /* Length of signer's name [0] */ 35 uint8_t key_id_len; /* Length of key identifier [0] */ 36 uint8_t __pad[3]; 37 uint32_t sig_len; /* Length of signature data */ 38 }; 39 40 #define PKEY_ID_PKCS7 2 41 42 static char magic_number[] = "~Module signature appended~\n"; 43 44 static __attribute__((noreturn)) 45 void format(void) 46 { 47 fprintf(stderr, 48 "Usage: scripts/sign-file [-dp] <hash algo> <key> <x509> <module> [<dest>]\n"); 49 exit(2); 50 } 51 52 static void display_openssl_errors(int l) 53 { 54 const char *file; 55 char buf[120]; 56 int e, line; 57 58 if (ERR_peek_error() == 0) 59 return; 60 fprintf(stderr, "At main.c:%d:\n", l); 61 62 while ((e = ERR_get_error_line(&file, &line))) { 63 ERR_error_string(e, buf); 64 fprintf(stderr, "- SSL %s: %s:%d\n", buf, file, line); 65 } 66 } 67 68 static void drain_openssl_errors(void) 69 { 70 const char *file; 71 int line; 72 73 if (ERR_peek_error() == 0) 74 return; 75 while (ERR_get_error_line(&file, &line)) {} 76 } 77 78 #define ERR(cond, fmt, ...) \ 79 do { \ 80 bool __cond = (cond); \ 81 display_openssl_errors(__LINE__); \ 82 if (__cond) { \ 83 err(1, fmt, ## __VA_ARGS__); \ 84 } \ 85 } while(0) 86 87 static const char *key_pass; 88 89 static int pem_pw_cb(char *buf, int len, int w, void *v) 90 { 91 int pwlen; 92 93 if (!key_pass) 94 return -1; 95 96 pwlen = strlen(key_pass); 97 if (pwlen >= len) 98 return -1; 99 100 strcpy(buf, key_pass); 101 102 /* If it's wrong, don't keep trying it. */ 103 key_pass = NULL; 104 105 return pwlen; 106 } 107 108 int main(int argc, char **argv) 109 { 110 struct module_signature sig_info = { .id_type = PKEY_ID_PKCS7 }; 111 char *hash_algo = NULL; 112 char *private_key_name, *x509_name, *module_name, *dest_name; 113 bool save_cms = false, replace_orig; 114 bool sign_only = false; 115 unsigned char buf[4096]; 116 unsigned long module_size, cms_size; 117 unsigned int use_keyid = 0, use_signed_attrs = CMS_NOATTR; 118 const EVP_MD *digest_algo; 119 EVP_PKEY *private_key; 120 CMS_ContentInfo *cms; 121 X509 *x509; 122 BIO *b, *bd = NULL, *bm; 123 int opt, n; 124 125 OpenSSL_add_all_algorithms(); 126 ERR_load_crypto_strings(); 127 ERR_clear_error(); 128 129 key_pass = getenv("KBUILD_SIGN_PIN"); 130 131 do { 132 opt = getopt(argc, argv, "dpk"); 133 switch (opt) { 134 case 'p': save_cms = true; break; 135 case 'd': sign_only = true; save_cms = true; break; 136 case 'k': use_keyid = CMS_USE_KEYID; break; 137 case -1: break; 138 default: format(); 139 } 140 } while (opt != -1); 141 142 argc -= optind; 143 argv += optind; 144 if (argc < 4 || argc > 5) 145 format(); 146 147 hash_algo = argv[0]; 148 private_key_name = argv[1]; 149 x509_name = argv[2]; 150 module_name = argv[3]; 151 if (argc == 5) { 152 dest_name = argv[4]; 153 replace_orig = false; 154 } else { 155 ERR(asprintf(&dest_name, "%s.~signed~", module_name) < 0, 156 "asprintf"); 157 replace_orig = true; 158 } 159 160 /* Read the private key and the X.509 cert the PKCS#7 message 161 * will point to. 162 */ 163 if (!strncmp(private_key_name, "pkcs11:", 7)) { 164 ENGINE *e; 165 166 ENGINE_load_builtin_engines(); 167 drain_openssl_errors(); 168 e = ENGINE_by_id("pkcs11"); 169 ERR(!e, "Load PKCS#11 ENGINE"); 170 if (ENGINE_init(e)) 171 drain_openssl_errors(); 172 else 173 ERR(1, "ENGINE_init"); 174 if (key_pass) 175 ERR(!ENGINE_ctrl_cmd_string(e, "PIN", key_pass, 0), "Set PKCS#11 PIN"); 176 private_key = ENGINE_load_private_key(e, private_key_name, NULL, 177 NULL); 178 ERR(!private_key, "%s", private_key_name); 179 } else { 180 b = BIO_new_file(private_key_name, "rb"); 181 ERR(!b, "%s", private_key_name); 182 private_key = PEM_read_bio_PrivateKey(b, NULL, pem_pw_cb, NULL); 183 ERR(!private_key, "%s", private_key_name); 184 BIO_free(b); 185 } 186 187 b = BIO_new_file(x509_name, "rb"); 188 ERR(!b, "%s", x509_name); 189 x509 = d2i_X509_bio(b, NULL); /* Binary encoded X.509 */ 190 if (!x509) { 191 ERR(BIO_reset(b) != 1, "%s", x509_name); 192 x509 = PEM_read_bio_X509(b, NULL, NULL, NULL); /* PEM encoded X.509 */ 193 if (x509) 194 drain_openssl_errors(); 195 } 196 BIO_free(b); 197 ERR(!x509, "%s", x509_name); 198 199 /* Open the destination file now so that we can shovel the module data 200 * across as we read it. 201 */ 202 if (!sign_only) { 203 bd = BIO_new_file(dest_name, "wb"); 204 ERR(!bd, "%s", dest_name); 205 } 206 207 /* Digest the module data. */ 208 OpenSSL_add_all_digests(); 209 display_openssl_errors(__LINE__); 210 digest_algo = EVP_get_digestbyname(hash_algo); 211 ERR(!digest_algo, "EVP_get_digestbyname"); 212 213 bm = BIO_new_file(module_name, "rb"); 214 ERR(!bm, "%s", module_name); 215 216 /* Load the CMS message from the digest buffer. */ 217 cms = CMS_sign(NULL, NULL, NULL, NULL, 218 CMS_NOCERTS | CMS_PARTIAL | CMS_BINARY | CMS_DETACHED | CMS_STREAM); 219 ERR(!cms, "CMS_sign"); 220 221 ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo, 222 CMS_NOCERTS | CMS_BINARY | CMS_NOSMIMECAP | 223 use_keyid | use_signed_attrs), 224 "CMS_sign_add_signer"); 225 ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) < 0, 226 "CMS_final"); 227 228 if (save_cms) { 229 char *cms_name; 230 231 ERR(asprintf(&cms_name, "%s.p7s", module_name) < 0, "asprintf"); 232 b = BIO_new_file(cms_name, "wb"); 233 ERR(!b, "%s", cms_name); 234 ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) < 0, "%s", cms_name); 235 BIO_free(b); 236 } 237 238 if (sign_only) 239 return 0; 240 241 /* Append the marker and the PKCS#7 message to the destination file */ 242 ERR(BIO_reset(bm) < 0, "%s", module_name); 243 while ((n = BIO_read(bm, buf, sizeof(buf))), 244 n > 0) { 245 ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name); 246 } 247 ERR(n < 0, "%s", module_name); 248 module_size = BIO_number_written(bd); 249 250 ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) < 0, "%s", dest_name); 251 cms_size = BIO_number_written(bd) - module_size; 252 sig_info.sig_len = htonl(cms_size); 253 ERR(BIO_write(bd, &sig_info, sizeof(sig_info)) < 0, "%s", dest_name); 254 ERR(BIO_write(bd, magic_number, sizeof(magic_number) - 1) < 0, "%s", dest_name); 255 256 ERR(BIO_free(bd) < 0, "%s", dest_name); 257 258 /* Finally, if we're signing in place, replace the original. */ 259 if (replace_orig) 260 ERR(rename(dest_name, module_name) < 0, "%s", dest_name); 261 262 return 0; 263 } 264