NetBSD/sys/dev/veriexec.c

/*	$NetBSD: veriexec.c,v 1.3 2022/02/12 02:40:48 riastradh Exp $	*/

/*-
 * Copyright (c) 2005, 2006 Elad Efrat <elad@NetBSD.org>
 * Copyright (c) 2005, 2006 Brett Lymn <blymn@NetBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the authors may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: veriexec.c,v 1.3 2022/02/12 02:40:48 riastradh Exp $");

#include <sys/param.h>
#include <sys/errno.h>
#include <sys/conf.h>
#include <sys/vnode.h>
#include <sys/fcntl.h>
#include <sys/namei.h>
#include <sys/verified_exec.h>
#include <sys/kauth.h>
#include <sys/syslog.h>
#include <sys/proc.h>

#include <sys/ioctl.h>
#include <sys/device_if.h>

#include <prop/proplib.h>

void veriexecattach(device_t, device_t, void *);
static dev_type_open(veriexecopen);
static dev_type_close(veriexecclose);
static dev_type_ioctl(veriexecioctl);

const struct cdevsw veriexec_cdevsw = {
	.d_open = veriexecopen,
	.d_close = veriexecclose,
	.d_read = noread,
	.d_write = nowrite,
	.d_ioctl = veriexecioctl,
	.d_stop = nostop,
	.d_tty = notty,
	.d_poll = nopoll,
	.d_mmap = nommap,
	.d_discard = nodiscard,
	.d_kqfilter = nokqfilter,
	.d_flag = D_OTHER,
};

/* count of number of times device is open (we really only allow one open) */
static unsigned int veriexec_dev_usage = 0;

void
veriexecattach(device_t parent, device_t self, void *aux)
{
	veriexec_dev_usage = 0;
}

static int
veriexecopen(dev_t dev, int flags, int fmt, struct lwp *l)
{
	if (kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_VERIEXEC,
	    KAUTH_REQ_SYSTEM_VERIEXEC_ACCESS, NULL, NULL, NULL))
		return (EPERM);

	if (veriexec_dev_usage > 0)
		return(EBUSY);

	veriexec_dev_usage++;
	return (0);
}

static int
veriexecclose(dev_t dev, int flags, int fmt, struct lwp *l)
{
	if (veriexec_dev_usage > 0)
		veriexec_dev_usage--;
	return (0);
}

static int
veriexec_delete(prop_dictionary_t dict, struct lwp *l)
{
	struct vnode *vp;
	const char *file;
	int error;

	if (!prop_dictionary_get_string(dict, "file", &file))
		return (EINVAL);

	error = namei_simple_kernel(file, NSM_FOLLOW_NOEMULROOT, &vp);
	if (error)
		return (error);

	/* XXX this should be done differently... */
	if (vp->v_type == VREG)
		error = veriexec_file_delete(l, vp);
	else if (vp->v_type == VDIR)
		error = veriexec_table_delete(l, vp->v_mount);

	vrele(vp);

	return (error);
}

static int
veriexec_query(prop_dictionary_t dict, prop_dictionary_t rdict, struct lwp *l)
{
	struct vnode *vp;
	const char *file;
	int error;

	if (!prop_dictionary_get_string(dict, "file", &file))
		return (EINVAL);

	error = namei_simple_kernel(file, NSM_FOLLOW_NOEMULROOT, &vp);
	if (error)
		return (error);

	error = veriexec_convert(vp, rdict);

	vrele(vp);

	return (error);
}

int
veriexecioctl(dev_t dev, u_long cmd, void *data, int flags, struct lwp *l)
{
	struct plistref *plistref;
	prop_dictionary_t dict;
	int error = 0;

	switch (cmd) {
	case VERIEXEC_TABLESIZE:
	case VERIEXEC_LOAD:
	case VERIEXEC_DELETE:
	case VERIEXEC_FLUSH:
		if (!(flags & FWRITE))
			return (EPERM);

		error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_VERIEXEC,
		    KAUTH_REQ_SYSTEM_VERIEXEC_MODIFY, KAUTH_ARG(cmd), NULL,
		    NULL);
		if (error)
			return error;

		break;

	case VERIEXEC_QUERY:
	case VERIEXEC_DUMP:
		if (!(flags & FREAD))
			return (EPERM);

		break;

	default:
		/* Invalid operation. */
		return (ENODEV);
	}

	plistref = (struct plistref *)data;

	switch (cmd) {
	case VERIEXEC_TABLESIZE:
		/* Do nothing. Kept for binary compatibility. */
		break;

	case VERIEXEC_LOAD:
		error = prop_dictionary_copyin_ioctl(plistref, cmd, &dict);
		if (error)
			break;

		error = veriexec_file_add(l, dict);
		prop_object_release(dict);
		break;

	case VERIEXEC_DELETE:
		error = prop_dictionary_copyin_ioctl(plistref, cmd, &dict);
		if (error)
			break;

		error = veriexec_delete(dict, l);
		prop_object_release(dict);
		break;

	case VERIEXEC_QUERY: {
		prop_dictionary_t rdict;

		error = prop_dictionary_copyin_ioctl(plistref, cmd, &dict);
		if (error)
			return (error);

		rdict = prop_dictionary_create();
		if (rdict == NULL) {
			prop_object_release(dict);
			error = ENOMEM;
			break;
		}

		error = veriexec_query(dict, rdict, l);
		if (error == 0) {
			error = prop_dictionary_copyout_ioctl(plistref, cmd,
			    rdict);
		}

		prop_object_release(rdict);
		prop_object_release(dict);

		break;
		}

	case VERIEXEC_DUMP: {
		prop_array_t rarray;

		rarray = prop_array_create();
		if (rarray == NULL) {
			error = ENOMEM;
			break;
		}

		error = veriexec_dump(l, rarray);
		if (error == 0) {
			error = prop_array_copyout_ioctl(plistref, cmd,
			    rarray);
		}

		prop_object_release(rarray);

		break;
		}

	case VERIEXEC_FLUSH:
		error = veriexec_flush(l);
		break;

	default:
		/* Invalid operation. */
		error = ENODEV;
		break;
	}

	return (error);
}