mirror of https://gitee.com/openkylin/linux.git
MODSIGN: Provide a utility to append a PKCS#7 signature to a module
Provide a utility that:
(1) Digests a module using the specified hash algorithm (typically sha256).
[The digest can be dumped into a file by passing the '-d' flag]
(2) Generates a PKCS#7 message that:
(a) Has detached data (ie. the module content).
(b) Is signed with the specified private key.
(c) Refers to the specified X.509 certificate.
(d) Has an empty X.509 certificate list.
[The PKCS#7 message can be dumped into a file by passing the '-p' flag]
(3) Generates a signed module by concatenating the old module, the PKCS#7
message, a descriptor and a magic string. The descriptor contains the
size of the PKCS#7 message and indicates the id_type as PKEY_ID_PKCS7.
(4) Either writes the signed module to the specified destination or renames
it over the source module.
This allows module signing to reuse the PKCS#7 handling code that was added
for PE file parsing for signed kexec.
Note that the utility is written in C and must be linked against the OpenSSL
crypto library.
Note further that I have temporarily dropped support for handling externally
created signatures until we can work out the best way to do those. Hopefully,
whoever creates the signature can give me a PKCS#7 certificate.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Vivek Goyal <vgoyal@redhat.com>
This commit is contained in:
David Howells
parent
4ebdb76f7d
commit
bc1c373dd2
|
|
@ -33,6 +33,7 @@ extern const struct public_key_algorithm *pkey_algo[PKEY_ALGO__LAST];
|
|||
enum pkey_id_type {
|
||||
PKEY_ID_PGP, /* OpenPGP generated key ID */
|
||||
PKEY_ID_X509, /* X.509 arbitrary subjectKeyIdentifier */
|
||||
PKEY_ID_PKCS7, /* Signature in PKCS#7 message */
|
||||
PKEY_ID_TYPE__LAST
|
||||
};
|
||||
|
||||
|
|
|
|||
|
|
@ -0,0 +1,205 @@
|
|||
/* 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/pkcs7.h>
|
||||
#include <openssl/err.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)
|
||||
|
||||
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_pkcs7 = false, replace_orig;
|
||||
unsigned char buf[4096];
|
||||
unsigned long module_size, pkcs7_size;
|
||||
const EVP_MD *digest_algo;
|
||||
EVP_PKEY *private_key;
|
||||
PKCS7 *pkcs7;
|
||||
X509 *x509;
|
||||
BIO *b, *bd, *bm;
|
||||
int opt, n;
|
||||
|
||||
ERR_load_crypto_strings();
|
||||
ERR_clear_error();
|
||||
|
||||
do {
|
||||
opt = getopt(argc, argv, "dp");
|
||||
switch (opt) {
|
||||
case 'p': save_pkcs7 = true; 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.
|
||||
*/
|
||||
b = BIO_new_file(private_key_name, "rb");
|
||||
ERR(!b, "%s", private_key_name);
|
||||
private_key = PEM_read_bio_PrivateKey(b, NULL, NULL, NULL);
|
||||
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) {
|
||||
BIO_reset(b);
|
||||
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.
|
||||
*/
|
||||
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 PKCS#7 message from the digest buffer. */
|
||||
pkcs7 = PKCS7_sign(NULL, NULL, NULL, NULL,
|
||||
PKCS7_NOCERTS | PKCS7_PARTIAL | PKCS7_BINARY | PKCS7_DETACHED | PKCS7_STREAM);
|
||||
ERR(!pkcs7, "PKCS7_sign");
|
||||
|
||||
ERR(!PKCS7_sign_add_signer(pkcs7, x509, private_key, digest_algo, PKCS7_NOCERTS | PKCS7_BINARY),
|
||||
"PKCS7_sign_add_signer");
|
||||
ERR(PKCS7_final(pkcs7, bm, PKCS7_NOCERTS | PKCS7_BINARY) < 0,
|
||||
"PKCS7_final");
|
||||
|
||||
if (save_pkcs7) {
|
||||
char *pkcs7_name;
|
||||
|
||||
ERR(asprintf(&pkcs7_name, "%s.pkcs7", module_name) < 0, "asprintf");
|
||||
b = BIO_new_file(pkcs7_name, "wb");
|
||||
ERR(!b, "%s", pkcs7_name);
|
||||
ERR(i2d_PKCS7_bio_stream(b, pkcs7, NULL, 0) < 0, "%s", pkcs7_name);
|
||||
BIO_free(b);
|
||||
}
|
||||
|
||||
/* 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_PKCS7_bio_stream(bd, pkcs7, NULL, 0) < 0, "%s", dest_name);
|
||||
pkcs7_size = BIO_number_written(bd) - module_size;
|
||||
sig_info.sig_len = htonl(pkcs7_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;
|
||||
}
|
||||
Loading…
Reference in New Issue