diff options
Diffstat (limited to 'kernel/scripts/sign-file.c')
| -rwxr-xr-x | kernel/scripts/sign-file.c | 323 |
1 files changed, 323 insertions, 0 deletions
diff --git a/kernel/scripts/sign-file.c b/kernel/scripts/sign-file.c new file mode 100755 index 000000000..250a7a645 --- /dev/null +++ b/kernel/scripts/sign-file.c @@ -0,0 +1,323 @@ +/* Sign a module file using the given key. + * + * Copyright © 2014-2015 Red Hat, Inc. All Rights Reserved. + * Copyright © 2015 Intel Corporation. + * + * Authors: David Howells <dhowells@redhat.com> + * David Woodhouse <dwmw2@infradead.org> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public License + * as published by the Free Software Foundation; either version 2.1 + * of the licence, or (at your option) any later version. + */ +#define _GNU_SOURCE +#include <stdio.h> +#include <stdlib.h> +#include <stdint.h> +#include <stdbool.h> +#include <string.h> +#include <getopt.h> +#include <err.h> +#include <arpa/inet.h> +#include <openssl/opensslv.h> +#include <openssl/bio.h> +#include <openssl/evp.h> +#include <openssl/pem.h> +#include <openssl/err.h> +#include <openssl/engine.h> + +/* + * Use CMS if we have openssl-1.0.0 or newer available - otherwise we have to + * assume that it's not available and its header file is missing and that we + * should use PKCS#7 instead. Switching to the older PKCS#7 format restricts + * the options we have on specifying the X.509 certificate we want. + * + * Further, older versions of OpenSSL don't support manually adding signers to + * the PKCS#7 message so have to accept that we get a certificate included in + * the signature message. Nor do such older versions of OpenSSL support + * signing with anything other than SHA1 - so we're stuck with that if such is + * the case. + */ +#if OPENSSL_VERSION_NUMBER < 0x10000000L +#define USE_PKCS7 +#endif +#ifndef USE_PKCS7 +#include <openssl/cms.h> +#else +#include <openssl/pkcs7.h> +#endif + +struct module_signature { + uint8_t algo; /* Public-key crypto algorithm [0] */ + uint8_t hash; /* Digest algorithm [0] */ + uint8_t id_type; /* Key identifier type [PKEY_ID_PKCS7] */ + uint8_t signer_len; /* Length of signer's name [0] */ + uint8_t key_id_len; /* Length of key identifier [0] */ + uint8_t __pad[3]; + uint32_t sig_len; /* Length of signature data */ +}; + +#define PKEY_ID_PKCS7 2 + +static char magic_number[] = "~Module signature appended~\n"; + +static __attribute__((noreturn)) +void format(void) +{ + fprintf(stderr, + "Usage: scripts/sign-file [-dp] <hash algo> <key> <x509> <module> [<dest>]\n"); + exit(2); +} + +static void display_openssl_errors(int l) +{ + const char *file; + char buf[120]; + int e, line; + + if (ERR_peek_error() == 0) + return; + fprintf(stderr, "At main.c:%d:\n", l); + + while ((e = ERR_get_error_line(&file, &line))) { + ERR_error_string(e, buf); + fprintf(stderr, "- SSL %s: %s:%d\n", buf, file, line); + } +} + +static void drain_openssl_errors(void) +{ + const char *file; + int line; + + if (ERR_peek_error() == 0) + return; + while (ERR_get_error_line(&file, &line)) {} +} + +#define ERR(cond, fmt, ...) \ + do { \ + bool __cond = (cond); \ + display_openssl_errors(__LINE__); \ + if (__cond) { \ + err(1, fmt, ## __VA_ARGS__); \ + } \ + } while(0) + +static const char *key_pass; + +static int pem_pw_cb(char *buf, int len, int w, void *v) +{ + int pwlen; + + if (!key_pass) + return -1; + + pwlen = strlen(key_pass); + if (pwlen >= len) + return -1; + + strcpy(buf, key_pass); + + /* If it's wrong, don't keep trying it. */ + key_pass = NULL; + + return pwlen; +} + +int main(int argc, char **argv) +{ + struct module_signature sig_info = { .id_type = PKEY_ID_PKCS7 }; + char *hash_algo = NULL; + char *private_key_name, *x509_name, *module_name, *dest_name; + bool save_sig = false, replace_orig; + bool sign_only = false; + unsigned char buf[4096]; + unsigned long module_size, sig_size; + unsigned int use_signed_attrs; + const EVP_MD *digest_algo; + EVP_PKEY *private_key; +#ifndef USE_PKCS7 + CMS_ContentInfo *cms; + unsigned int use_keyid = 0; +#else + PKCS7 *pkcs7; +#endif + X509 *x509; + BIO *b, *bd = NULL, *bm; + int opt, n; + OpenSSL_add_all_algorithms(); + ERR_load_crypto_strings(); + ERR_clear_error(); + + key_pass = getenv("KBUILD_SIGN_PIN"); + +#ifndef USE_PKCS7 + use_signed_attrs = CMS_NOATTR; +#else + use_signed_attrs = PKCS7_NOATTR; +#endif + + do { + opt = getopt(argc, argv, "dpk"); + switch (opt) { + case 'p': save_sig = true; break; + case 'd': sign_only = true; save_sig = true; break; +#ifndef USE_PKCS7 + case 'k': use_keyid = CMS_USE_KEYID; break; +#endif + case -1: break; + default: format(); + } + } while (opt != -1); + + argc -= optind; + argv += optind; + if (argc < 4 || argc > 5) + format(); + + hash_algo = argv[0]; + private_key_name = argv[1]; + x509_name = argv[2]; + module_name = argv[3]; + if (argc == 5) { + dest_name = argv[4]; + replace_orig = false; + } else { + ERR(asprintf(&dest_name, "%s.~signed~", module_name) < 0, + "asprintf"); + replace_orig = true; + } + +#ifdef USE_PKCS7 + if (strcmp(hash_algo, "sha1") != 0) { + fprintf(stderr, "sign-file: %s only supports SHA1 signing\n", + OPENSSL_VERSION_TEXT); + exit(3); + } +#endif + + /* Read the private key and the X.509 cert the PKCS#7 message + * will point to. + */ + if (!strncmp(private_key_name, "pkcs11:", 7)) { + ENGINE *e; + + ENGINE_load_builtin_engines(); + drain_openssl_errors(); + e = ENGINE_by_id("pkcs11"); + ERR(!e, "Load PKCS#11 ENGINE"); + if (ENGINE_init(e)) + drain_openssl_errors(); + else + ERR(1, "ENGINE_init"); + if (key_pass) + ERR(!ENGINE_ctrl_cmd_string(e, "PIN", key_pass, 0), "Set PKCS#11 PIN"); + private_key = ENGINE_load_private_key(e, private_key_name, NULL, + NULL); + ERR(!private_key, "%s", private_key_name); + } else { + b = BIO_new_file(private_key_name, "rb"); + ERR(!b, "%s", private_key_name); + private_key = PEM_read_bio_PrivateKey(b, NULL, pem_pw_cb, NULL); + ERR(!private_key, "%s", private_key_name); + BIO_free(b); + } + + b = BIO_new_file(x509_name, "rb"); + ERR(!b, "%s", x509_name); + x509 = d2i_X509_bio(b, NULL); /* Binary encoded X.509 */ + if (!x509) { + ERR(BIO_reset(b) != 1, "%s", x509_name); + x509 = PEM_read_bio_X509(b, NULL, NULL, NULL); /* PEM encoded X.509 */ + if (x509) + drain_openssl_errors(); + } + BIO_free(b); + ERR(!x509, "%s", x509_name); + + /* Open the destination file now so that we can shovel the module data + * across as we read it. + */ + if (!sign_only) { + bd = BIO_new_file(dest_name, "wb"); + ERR(!bd, "%s", dest_name); + } + + /* Digest the module data. */ + OpenSSL_add_all_digests(); + display_openssl_errors(__LINE__); + digest_algo = EVP_get_digestbyname(hash_algo); + ERR(!digest_algo, "EVP_get_digestbyname"); + + bm = BIO_new_file(module_name, "rb"); + ERR(!bm, "%s", module_name); + +#ifndef USE_PKCS7 + /* Load the signature message from the digest buffer. */ + cms = CMS_sign(NULL, NULL, NULL, NULL, + CMS_NOCERTS | CMS_PARTIAL | CMS_BINARY | CMS_DETACHED | CMS_STREAM); + ERR(!cms, "CMS_sign"); + + ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo, + CMS_NOCERTS | CMS_BINARY | CMS_NOSMIMECAP | + use_keyid | use_signed_attrs), + "CMS_add1_signer"); + ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) < 0, + "CMS_final"); + +#else + pkcs7 = PKCS7_sign(x509, private_key, NULL, bm, + PKCS7_NOCERTS | PKCS7_BINARY | + PKCS7_DETACHED | use_signed_attrs); + ERR(!pkcs7, "PKCS7_sign"); +#endif + + if (save_sig) { + char *sig_file_name; + + ERR(asprintf(&sig_file_name, "%s.p7s", module_name) < 0, + "asprintf"); + b = BIO_new_file(sig_file_name, "wb"); + ERR(!b, "%s", sig_file_name); +#ifndef USE_PKCS7 + ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) < 0, + "%s", sig_file_name); +#else + ERR(i2d_PKCS7_bio(b, pkcs7) < 0, + "%s", sig_file_name); +#endif + BIO_free(b); + } + + if (sign_only) + return 0; + + /* Append the marker and the PKCS#7 message to the destination file */ + ERR(BIO_reset(bm) < 0, "%s", module_name); + while ((n = BIO_read(bm, buf, sizeof(buf))), + n > 0) { + ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name); + } + ERR(n < 0, "%s", module_name); + module_size = BIO_number_written(bd); + +#ifndef USE_PKCS7 + ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) < 0, "%s", dest_name); +#else + ERR(i2d_PKCS7_bio(bd, pkcs7) < 0, "%s", dest_name); +#endif + sig_size = BIO_number_written(bd) - module_size; + sig_info.sig_len = htonl(sig_size); + ERR(BIO_write(bd, &sig_info, sizeof(sig_info)) < 0, "%s", dest_name); + ERR(BIO_write(bd, magic_number, sizeof(magic_number) - 1) < 0, "%s", dest_name); + + ERR(BIO_free(bd) < 0, "%s", dest_name); + + /* Finally, if we're signing in place, replace the original. */ + if (replace_orig) + ERR(rename(dest_name, module_name) < 0, "%s", dest_name); + + return 0; +} |