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/*
* Copyright (C) 2025 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.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
FILE_SECBOOT ( PERMITTED );
/** @file
*
* EFI CA certificates
*
*/
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <ipxe/init.h>
#include <ipxe/x509.h>
#include <ipxe/rootcert.h>
#include <ipxe/efi/efi.h>
#include <ipxe/efi/efi_siglist.h>
#include <ipxe/efi/Guid/TlsAuthentication.h>
/** List of EFI CA certificates */
static struct x509_chain efi_cacerts = {
.refcnt = REF_INIT ( ref_no_free ),
.links = LIST_HEAD_INIT ( efi_cacerts.links ),
};
/**
* Retrieve EFI CA certificate
*
* @v data TlsCaCertificate variable data
* @v len Length of TlsCaCertificate
* @v offset Offset within data
* @v next Next offset, or negative error
*/
static int efi_cacert ( const void *data, size_t len, size_t offset ) {
struct asn1_cursor *cursor;
struct x509_certificate *cert;
int next;
int rc;
/* Extract ASN.1 object */
next = efisig_asn1 ( data, len, offset, &cursor );
if ( next < 0 ) {
rc = next;
DBGC ( &efi_cacerts, "EFICA could not parse at +%#zx: %s\n",
offset, strerror ( rc ) );
goto err_asn1;
}
/* Append to list of EFI CA certificates */
if ( ( rc = x509_append_raw ( &efi_cacerts, cursor->data,
cursor->len ) ) != 0 ) {
DBGC ( &efi_cacerts, "EFICA could not append at +%#zx: %s\n",
offset, strerror ( rc ) );
goto err_append;
}
cert = x509_last ( &efi_cacerts );
DBGC ( &efi_cacerts, "EFICA found certificate %s\n",
x509_name ( cert ) );
/* Mark certificate as valid (i.e. trusted) if permitted */
if ( allow_trust_override ) {
DBGC ( &efi_cacerts, "EFICA trusting certificate %s\n",
x509_name ( cert ) );
x509_set_valid ( cert, NULL, &root_certificates );
}
/* Free ASN.1 object */
free ( cursor );
return next;
err_append:
free ( cursor );
err_asn1:
return rc;
}
/**
* Retrieve all EFI CA certificates
*
* @ret rc Return status code
*/
static int efi_cacert_all ( void ) {
EFI_RUNTIME_SERVICES *rs = efi_systab->RuntimeServices;
EFI_GUID *guid = &efi_tls_ca_certificate_guid;
static CHAR16 *wname = EFI_TLS_CA_CERTIFICATE_VARIABLE;
int offset = 0;
UINT32 attrs;
UINTN size;
void *data;
EFI_STATUS efirc;
int rc;
/* Get variable length */
size = 0;
if ( ( efirc = rs->GetVariable ( wname, guid, &attrs, &size,
NULL ) ) != EFI_BUFFER_TOO_SMALL ) {
rc = -EEFI ( efirc );
DBGC ( &efi_cacerts, "EFICA could not get %ls size: %s\n",
wname, strerror ( rc ) );
goto err_len;
}
/* Allocate temporary buffer */
data = malloc ( size );
if ( ! data ) {
rc = -ENOMEM;
goto err_alloc;
}
/* Read variable */
if ( ( efirc = rs->GetVariable ( wname, guid, &attrs, &size,
data ) ) != 0 ) {
rc = -EEFI ( efirc );
DBGC ( &efi_cacerts, "EFICA could not read %ls: %s\n",
wname, strerror ( rc ) );
goto err_get;
}
/* Parse certificates */
while ( ( ( size_t ) offset ) < size ) {
offset = efi_cacert ( data, size, offset );
if ( offset < 0 ) {
rc = offset;
goto err_cacert;
}
}
/* Success */
rc = 0;
err_cacert:
err_get:
free ( data );
err_alloc:
err_len:
return rc;
}
/**
* Initialise EFI CA certificates
*
*/
static void efi_cacert_init ( void ) {
int rc;
/* Initialise all certificates */
if ( ( rc = efi_cacert_all() ) != 0 ) {
DBGC ( &efi_cacert, "EFICA could not initialise: %s\n",
strerror ( rc ) );
/* Nothing we can do at this point */
return;
}
}
/** EFI CA certificates initialisation function */
struct init_fn efi_cacert_init_fn __init_fn ( INIT_LATE ) = {
.name = "eficacert",
.initialise = efi_cacert_init,
};
/**
* Discard any EFI CA certificates
*
*/
static void efi_cacert_shutdown ( int booting __unused ) {
/* Drop our references to the certificates */
DBGC ( &efi_cacert, "EFICA discarding certificates\n" );
x509_truncate ( &efi_cacerts, NULL );
assert ( list_empty ( &efi_cacerts.links ) );
}
/** EFI CA certificates shutdown function */
struct startup_fn efi_cacert_shutdown_fn __startup_fn ( STARTUP_NORMAL ) = {
.name = "efi_cacert",
.shutdown = efi_cacert_shutdown,
};
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