1 /* Sign a module file using the given key. 2 * 3 * Copyright (C) 2014 Red Hat, Inc. All Rights Reserved. 4 * Written by David Howells (dhowells@redhat.com) 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public Licence 8 * as published by the Free Software Foundation; either version 9 * 2 of the Licence, or (at your option) any later version. 10 */ 11 #define _GNU_SOURCE 12 #include <stdio.h> 13 #include <stdlib.h> 14 #include <stdint.h> 15 #include <stdbool.h> 16 #include <string.h> 17 #include <getopt.h> 18 #include <err.h> 19 #include <arpa/inet.h> 20 #include <openssl/bio.h> 21 #include <openssl/evp.h> 22 #include <openssl/pem.h> 23 #include <openssl/cms.h> 24 #include <openssl/err.h> 25 #include <openssl/engine.h> 26 27 struct module_signature { 28 uint8_t algo; /* Public-key crypto algorithm [0] */ 29 uint8_t hash; /* Digest algorithm [0] */ 30 uint8_t id_type; /* Key identifier type [PKEY_ID_PKCS7] */ 31 uint8_t signer_len; /* Length of signer's name [0] */ 32 uint8_t key_id_len; /* Length of key identifier [0] */ 33 uint8_t __pad[3]; 34 uint32_t sig_len; /* Length of signature data */ 35 }; 36 37 #define PKEY_ID_PKCS7 2 38 39 static char magic_number[] = "~Module signature appended~\n"; 40 41 static __attribute__((noreturn)) 42 void format(void) 43 { 44 fprintf(stderr, 45 "Usage: scripts/sign-file [-dp] <hash algo> <key> <x509> <module> [<dest>]\n"); 46 exit(2); 47 } 48 49 static void display_openssl_errors(int l) 50 { 51 const char *file; 52 char buf[120]; 53 int e, line; 54 55 if (ERR_peek_error() == 0) 56 return; 57 fprintf(stderr, "At main.c:%d:\n", l); 58 59 while ((e = ERR_get_error_line(&file, &line))) { 60 ERR_error_string(e, buf); 61 fprintf(stderr, "- SSL %s: %s:%d\n", buf, file, line); 62 } 63 } 64 65 static void drain_openssl_errors(void) 66 { 67 const char *file; 68 int line; 69 70 if (ERR_peek_error() == 0) 71 return; 72 while (ERR_get_error_line(&file, &line)) {} 73 } 74 75 #define ERR(cond, fmt, ...) \ 76 do { \ 77 bool __cond = (cond); \ 78 display_openssl_errors(__LINE__); \ 79 if (__cond) { \ 80 err(1, fmt, ## __VA_ARGS__); \ 81 } \ 82 } while(0) 83 84 static const char *key_pass; 85 86 static int pem_pw_cb(char *buf, int len, int w, void *v) 87 { 88 int pwlen; 89 90 if (!key_pass) 91 return -1; 92 93 pwlen = strlen(key_pass); 94 if (pwlen >= len) 95 return -1; 96 97 strcpy(buf, key_pass); 98 99 /* If it's wrong, don't keep trying it. */ 100 key_pass = NULL; 101 102 return pwlen; 103 } 104 105 int main(int argc, char **argv) 106 { 107 struct module_signature sig_info = { .id_type = PKEY_ID_PKCS7 }; 108 char *hash_algo = NULL; 109 char *private_key_name, *x509_name, *module_name, *dest_name; 110 bool save_cms = false, replace_orig; 111 bool sign_only = false; 112 unsigned char buf[4096]; 113 unsigned long module_size, cms_size; 114 unsigned int use_keyid = 0, use_signed_attrs = CMS_NOATTR; 115 const EVP_MD *digest_algo; 116 EVP_PKEY *private_key; 117 CMS_ContentInfo *cms; 118 X509 *x509; 119 BIO *b, *bd = NULL, *bm; 120 int opt, n; 121 122 OpenSSL_add_all_algorithms(); 123 ERR_load_crypto_strings(); 124 ERR_clear_error(); 125 126 key_pass = getenv("KBUILD_SIGN_PIN"); 127 128 do { 129 opt = getopt(argc, argv, "dpk"); 130 switch (opt) { 131 case 'p': save_cms = true; break; 132 case 'd': sign_only = true; save_cms = true; break; 133 case 'k': use_keyid = CMS_USE_KEYID; break; 134 case -1: break; 135 default: format(); 136 } 137 } while (opt != -1); 138 139 argc -= optind; 140 argv += optind; 141 if (argc < 4 || argc > 5) 142 format(); 143 144 hash_algo = argv[0]; 145 private_key_name = argv[1]; 146 x509_name = argv[2]; 147 module_name = argv[3]; 148 if (argc == 5) { 149 dest_name = argv[4]; 150 replace_orig = false; 151 } else { 152 ERR(asprintf(&dest_name, "%s.~signed~", module_name) < 0, 153 "asprintf"); 154 replace_orig = true; 155 } 156 157 /* Read the private key and the X.509 cert the PKCS#7 message 158 * will point to. 159 */ 160 if (!strncmp(private_key_name, "pkcs11:", 7)) { 161 ENGINE *e; 162 163 ENGINE_load_builtin_engines(); 164 drain_openssl_errors(); 165 e = ENGINE_by_id("pkcs11"); 166 ERR(!e, "Load PKCS#11 ENGINE"); 167 if (ENGINE_init(e)) 168 drain_openssl_errors(); 169 else 170 ERR(1, "ENGINE_init"); 171 if (key_pass) 172 ERR(!ENGINE_ctrl_cmd_string(e, "PIN", key_pass, 0), "Set PKCS#11 PIN"); 173 private_key = ENGINE_load_private_key(e, private_key_name, NULL, 174 NULL); 175 ERR(!private_key, "%s", private_key_name); 176 } else { 177 b = BIO_new_file(private_key_name, "rb"); 178 ERR(!b, "%s", private_key_name); 179 private_key = PEM_read_bio_PrivateKey(b, NULL, pem_pw_cb, NULL); 180 ERR(!private_key, "%s", private_key_name); 181 BIO_free(b); 182 } 183 184 b = BIO_new_file(x509_name, "rb"); 185 ERR(!b, "%s", x509_name); 186 x509 = d2i_X509_bio(b, NULL); /* Binary encoded X.509 */ 187 if (!x509) { 188 ERR(BIO_reset(b) != 1, "%s", x509_name); 189 x509 = PEM_read_bio_X509(b, NULL, NULL, NULL); /* PEM encoded X.509 */ 190 if (x509) 191 drain_openssl_errors(); 192 } 193 BIO_free(b); 194 ERR(!x509, "%s", x509_name); 195 196 /* Open the destination file now so that we can shovel the module data 197 * across as we read it. 198 */ 199 if (!sign_only) { 200 bd = BIO_new_file(dest_name, "wb"); 201 ERR(!bd, "%s", dest_name); 202 } 203 204 /* Digest the module data. */ 205 OpenSSL_add_all_digests(); 206 display_openssl_errors(__LINE__); 207 digest_algo = EVP_get_digestbyname(hash_algo); 208 ERR(!digest_algo, "EVP_get_digestbyname"); 209 210 bm = BIO_new_file(module_name, "rb"); 211 ERR(!bm, "%s", module_name); 212 213 /* Load the CMS message from the digest buffer. */ 214 cms = CMS_sign(NULL, NULL, NULL, NULL, 215 CMS_NOCERTS | CMS_PARTIAL | CMS_BINARY | CMS_DETACHED | CMS_STREAM); 216 ERR(!cms, "CMS_sign"); 217 218 ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo, 219 CMS_NOCERTS | CMS_BINARY | CMS_NOSMIMECAP | 220 use_keyid | use_signed_attrs), 221 "CMS_sign_add_signer"); 222 ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) < 0, 223 "CMS_final"); 224 225 if (save_cms) { 226 char *cms_name; 227 228 ERR(asprintf(&cms_name, "%s.p7s", module_name) < 0, "asprintf"); 229 b = BIO_new_file(cms_name, "wb"); 230 ERR(!b, "%s", cms_name); 231 ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) < 0, "%s", cms_name); 232 BIO_free(b); 233 } 234 235 if (sign_only) 236 return 0; 237 238 /* Append the marker and the PKCS#7 message to the destination file */ 239 ERR(BIO_reset(bm) < 0, "%s", module_name); 240 while ((n = BIO_read(bm, buf, sizeof(buf))), 241 n > 0) { 242 ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name); 243 } 244 ERR(n < 0, "%s", module_name); 245 module_size = BIO_number_written(bd); 246 247 ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) < 0, "%s", dest_name); 248 cms_size = BIO_number_written(bd) - module_size; 249 sig_info.sig_len = htonl(cms_size); 250 ERR(BIO_write(bd, &sig_info, sizeof(sig_info)) < 0, "%s", dest_name); 251 ERR(BIO_write(bd, magic_number, sizeof(magic_number) - 1) < 0, "%s", dest_name); 252 253 ERR(BIO_free(bd) < 0, "%s", dest_name); 254 255 /* Finally, if we're signing in place, replace the original. */ 256 if (replace_orig) 257 ERR(rename(dest_name, module_name) < 0, "%s", dest_name); 258 259 return 0; 260 } 261