/*

 * Copyright (C) 2013 Nikos Mavrogiannopoulos

 *

 * This file is part of GnuTLS test suite.

 *

 * ocserv 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

 * (at your option) any later version.

 *

 * ocserv 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, see <https://www.gnu.org/licenses/>.

 */

#include <config.h>

#include <stdio.h>

#include "utils.h"

#ifdef HAVE_LIBSECCOMP

#include <seccomp.h>

#include <errno.h>

#include <string.h>

#if defined(__linux__)

#  include <sys/syscall.h>

#endif

int disable_system_calls(void)

{

	int ret;

	scmp_filter_ctx ctx;

	/*ctx = seccomp_init(SCMP_ACT_ERRNO(EPERM));*/

	ctx = seccomp_init(SCMP_ACT_TRAP);

	if (ctx == NULL) {

		fprintf(stderr, "could not initialize seccomp");

		return -1;

	}

#define ADD_SYSCALL(name, ...) \

	ret = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(name), __VA_ARGS__); \

	/* libseccomp returns EDOM for pseudo-syscalls due to a bug */ \

	if (ret < 0 && ret != -EDOM) { \

		fprintf(stderr, "could not add " #name " to seccomp filter: %s", strerror(-ret)); \

		ret = -1; \

		goto fail; \

	}

	ADD_SYSCALL(nanosleep, 0);

	ADD_SYSCALL(time, 0);

	ADD_SYSCALL(getpid, 0);

	ADD_SYSCALL(gettimeofday, 0);

#if defined(HAVE_CLOCK_GETTIME)

	ADD_SYSCALL(clock_gettime, 0);

#endif

	ADD_SYSCALL(getrusage, 0);

	/* recv/send for the default pull/push functions. It is unknown

	 * which syscall is used by libc and varies from system to system

	 * so we enable all */

	ADD_SYSCALL(recvmsg, 0);

	ADD_SYSCALL(sendmsg, 0);

	ADD_SYSCALL(send, 0);

	ADD_SYSCALL(recv, 0);

	ADD_SYSCALL(sendto, 0);

	ADD_SYSCALL(recvfrom, 0);

	/* to read from /dev/urandom */

	ADD_SYSCALL(read, 0);

#ifdef SYS_getrandom

	ADD_SYSCALL(getrandom, 0);

#endif

	/* we use it in select */

	ADD_SYSCALL(sigprocmask, 0);

	ADD_SYSCALL(rt_sigprocmask, 0);

	/* used in to detect reading timeouts */

	ADD_SYSCALL(poll, 0);

	/* for memory allocation */

	ADD_SYSCALL(brk, 0);

	/* the following are for generic operations, not specific to

	 * gnutls. */

	ADD_SYSCALL(close, 0);

	ADD_SYSCALL(exit, 0);

	ADD_SYSCALL(exit_group, 0);

	/* allow returning from signal handlers */

	ADD_SYSCALL(sigreturn, 0);

	ADD_SYSCALL(rt_sigreturn, 0);

	ret = seccomp_load(ctx);

	if (ret < 0) {

		fprintf(stderr, "could not load seccomp filter");

		ret = -1;

		goto fail;

	}

	ret = 0;

fail:

	seccomp_release(ctx);

	return ret;

}

#else

int disable_system_calls(void)

{

	return 0;

}

#endif