/* Sign a module file using the given key.
*
* Copyright (C) 2014 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 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/bio.h>
#include <openssl/evp.h>
#include <openssl/pem.h>
#include <openssl/cms.h>
#include <openssl/err.h>
#include <openssl/engine.h>
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_cms = false, replace_orig;
bool sign_only = false;
unsigned char buf[4096];
unsigned long module_size, cms_size;
unsigned int use_keyid = 0, use_signed_attrs = CMS_NOATTR;
const EVP_MD *digest_algo;
EVP_PKEY *private_key;
CMS_ContentInfo *cms;
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");
do {
opt = getopt(argc, argv, "dpk");
switch (opt) {
case 'p': save_cms = true; break;
case 'd': sign_only = true; save_cms = true; break;
case 'k': use_keyid = CMS_USE_KEYID; break;
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;
}
/* 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);
/* Load the CMS 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_sign_add_signer");
ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) < 0,
"CMS_final");
if (save_cms) {
char *cms_name;
ERR(asprintf(&cms_name, "%s.p7s", module_name) < 0, "asprintf");
b = BIO_new_file(cms_name, "wb");
ERR(!b, "%s", cms_name);
ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) < 0, "%s", cms_name);
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);
ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) < 0, "%s", dest_name);
cms_size = BIO_number_written(bd) - module_size;
sig_info.sig_len = htonl(cms_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;
}
