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/*
* Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
FILE_LICENCE ( GPL2_OR_LATER );
#include <stdlib.h>
#include <ipxe/crypto.h>
#include <ipxe/sha256.h>
#include <ipxe/x509.h>
#include <ipxe/settings.h>
#include <ipxe/dhcp.h>
#include <ipxe/init.h>
#include <ipxe/rootcert.h>
/** @file
*
* Root certificate store
*
*/
/** Length of a root certificate fingerprint */
#define FINGERPRINT_LEN SHA256_DIGEST_SIZE
/* Allow trusted certificates to be overridden if not explicitly specified */
#ifdef TRUSTED
#define ALLOW_TRUST_OVERRIDE 0
#else
#define ALLOW_TRUST_OVERRIDE 1
#endif
/* Use iPXE root CA if no trusted certificates are explicitly specified */
#ifndef TRUSTED
#define TRUSTED \
/* iPXE root CA */ \
0x9f, 0xaf, 0x71, 0x7b, 0x7f, 0x8c, 0xa2, 0xf9, 0x3c, 0x25, \
0x6c, 0x79, 0xf8, 0xac, 0x55, 0x91, 0x89, 0x5d, 0x66, 0xd1, \
0xff, 0x3b, 0xee, 0x63, 0x97, 0xa7, 0x0d, 0x29, 0xc6, 0x5e, \
0xed, 0x1a,
#endif
/** Root certificate fingerprints */
static const uint8_t fingerprints[] = { TRUSTED };
/** Root certificate fingerprint setting */
static struct setting trust_setting __setting ( SETTING_CRYPTO ) = {
.name = "trust",
.description = "Trusted root certificate fingerprints",
.tag = DHCP_EB_TRUST,
.type = &setting_type_hex,
};
/** Root certificates */
struct x509_root root_certificates = {
.digest = &sha256_algorithm,
.count = ( sizeof ( fingerprints ) / FINGERPRINT_LEN ),
.fingerprints = fingerprints,
};
/**
* Initialise root certificate
*
* The list of trusted root certificates can be specified at build
* time using the TRUST= build parameter. If no certificates are
* specified, then the default iPXE root CA certificate is trusted.
*
* If no certificates were explicitly specified, then we allow the
* list of trusted root certificate fingerprints to be overridden
* using the "trust" setting, but only at the point of iPXE
* initialisation. This prevents untrusted sources of settings
* (e.g. DHCP) from subverting the chain of trust, while allowing
* trustworthy sources (e.g. VMware GuestInfo or non-volatile stored
* options) to specify the trusted root certificate without requiring
* a rebuild.
*/
static void rootcert_init ( void ) {
void *external = NULL;
int len;
int rc;
/* Allow trusted root certificates to be overridden only if
* not explicitly specified at build time.
*/
if ( ALLOW_TRUST_OVERRIDE ) {
/* Fetch copy of "trust" setting, if it exists. This
* memory will never be freed.
*/
len = fetch_setting_copy ( NULL, &trust_setting, &external );
if ( len < 0 ) {
rc = len;
DBGC ( &root_certificates, "ROOTCERT cannot fetch "
"trusted root certificate fingerprints: %s\n",
strerror ( rc ) );
/* No way to prevent startup; fail safe by
* trusting no certificates.
*/
root_certificates.count = 0;
return;
}
/* Use certificates from "trust" setting, if present */
if ( external ) {
root_certificates.fingerprints = external;
root_certificates.count = ( len / FINGERPRINT_LEN );
}
}
DBGC ( &root_certificates, "ROOTCERT using %d %s certificate(s):\n",
root_certificates.count, ( external ? "external" : "built-in" ));
DBGC_HDA ( &root_certificates, 0, root_certificates.fingerprints,
( root_certificates.count * FINGERPRINT_LEN ) );
}
/** Root certificate initialiser */
struct init_fn rootcert_init_fn __init_fn ( INIT_LATE ) = {
.initialise = rootcert_init,
};
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