imgtrust.c

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/*
 * Copyright (C) 2012 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 );

#include <stdlib.h>
#include <errno.h>
#include <time.h>
#include <syslog.h>
#include <ipxe/uaccess.h>
#include <ipxe/image.h>
#include <ipxe/cms.h>
#include <ipxe/validator.h>
#include <ipxe/monojob.h>
#include <usr/imgtrust.h>

/** @file
 *
 * Image trust management
 *
 */

/**
 * Verify image using downloaded signature
 *
 * @v image             Image to verify
 * @v signature         Image containing signature
 * @v name              Required common name, or NULL to allow any name
 * @ret rc              Return status code
 */
int imgverify ( struct image *image, struct image *signature,
                const char *name ) {
        struct cms_message *cms;
        struct cms_participant *part;
        time_t now;
        int rc;

        /* Parse signature */
        if ( ( rc = cms_message ( signature, &cms ) ) != 0 )
                goto err_parse;

        /* Complete all certificate chains */
        list_for_each_entry ( part, &cms->participants, list ) {
                if ( ( rc = create_validator ( &monojob, part->chain,
                                               NULL ) ) != 0 )
                        goto err_create_validator;
                if ( ( rc = monojob_wait ( NULL, 0 ) ) != 0 )
                        goto err_validator_wait;
        }

        /* Use signature to verify image */
        now = time ( NULL );
        if ( ( rc = cms_verify ( cms, image, name, now, NULL, NULL ) ) != 0 )
                goto err_verify;

        /* Drop reference to message */
        cms_put ( cms );
        cms = NULL;

        /* Record signature verification */
        syslog ( LOG_NOTICE, "Image \"%s\" signature OK\n", image->name );

        return 0;

 err_verify:
 err_validator_wait:
 err_create_validator:
        cms_put ( cms );
 err_parse:
        syslog ( LOG_ERR, "Image \"%s\" signature bad: %s\n",
                 image->name, strerror ( rc ) );
        return rc;
}