[thirdparty/rng-tools.git] / rngd.c

/*
 * rngd.c -- Random Number Generator daemon
 *
 * rngd reads data from a hardware random number generator, verifies it
 * looks like random data, and adds it to /dev/random's entropy store.
 *
 * In theory, this should allow you to read very quickly from
 * /dev/random; rngd also adds bytes to the entropy store periodically
 * when it's full, which makes predicting the entropy store's contents
 * harder.
 *
 * Copyright (C) 2001 Philipp Rumpf
 *
 * 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
 * (at your option) 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#define _GNU_SOURCE

#ifndef HAVE_CONFIG_H
#error Invalid or missing autoconf build environment
#endif

#include "rng-tools-config.h"

#include <unistd.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <argp.h>
#include <syslog.h>
#include <signal.h>

#include "rngd.h"
#include "fips.h"
#include "exits.h"
#include "rngd_entsource.h"
#include "rngd_linux.h"

/*
 * Globals
 */

/* Background/daemon mode */
bool am_daemon;				/* True if we went daemon */

bool server_running = true;		/* set to false, to stop daemon */

/* Command line arguments and processing */
const char *argp_program_version =
	"rngd " VERSION "\n"
	"Copyright 2001-2004 Jeff Garzik\n"
	"Copyright (c) 2001 by Philipp Rumpf\n"
	"This is free software; see the source for copying conditions.  There is NO "
	"warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.";

const char *argp_program_bug_address = PACKAGE_BUGREPORT;

static char doc[] =
	"Check and feed random data from hardware device to kernel entropy pool.\n";

static struct argp_option options[] = {
	{ "foreground",	'f', 0, 0, "Do not fork and become a daemon" },

	{ "background", 'b', 0, 0, "Become a daemon (default)" },

	{ "random-device", 'o', "file", 0,
	  "Kernel device used for random number output (default: /dev/random)" },

	{ "rng-device", 'r', "file", 0,
	  "Kernel device used for random number input (default: /dev/hwrng)" },

	{ "pid-file", 'p', "file", 0,
	  "File used for recording daemon PID, and multiple exclusion (default: /var/run/rngd.pid)" },

	{ "random-step", 's', "nnn", 0,
	  "Number of bytes written to random-device at a time (default: 64)" },

	{ "fill-watermark", 'W', "n", 0,
	  "Do not stop feeding entropy to random-device until at least n bits of entropy are available in the pool (default: 2048), 0 <= n <= 4096" },

	{ "quiet", 'q', 0, 0, "Suppress error messages" },

	{ "verbose" ,'v', 0, 0, "Report available entropy sources" },

	{ "no-drng", 'd', "1|0", 0,
	  "Do not use drng as a source of random number input (default: 0)" },
	
	{ "no-tpm", 'n', "1|0", 0,
	  "Do not use tpm as a source of random number input (default: 0)" },

	{ 0 },
};

static struct arguments default_arguments = {
	.random_name	= "/dev/random",
	.pid_file	= "/var/run/rngd.pid",
	.random_step	= 64,
	.daemon		= true,
	.enable_drng	= true,
	.enable_tpm	= true,
	.quiet		= false,
	.verbose	= false,
};
struct arguments *arguments = &default_arguments;

static struct rng rng_default = {
	.rng_name	= "/dev/hwrng",
	.rng_fd		= -1,
	.xread		= xread,
};

static struct rng rng_drng = {
	.rng_name	= "drng",
	.rng_fd  	= -1,
	.xread  	= xread_drng,
};

static struct rng rng_tpm = {
	.rng_name	= "/dev/tpm0",
	.rng_fd		= -1,
	.xread		= xread_tpm,
};

struct rng *rng_list;

/*
 * command line processing
 */
static error_t parse_opt (int key, char *arg, struct argp_state *state)
{
	switch(key) {
	case 'o':
		arguments->random_name = arg;
		break;
	case 'p':
		arguments->pid_file = arg;
		break;
	case 'r':
		rng_default.rng_name = arg;
		break;
	case 'f':
		arguments->daemon = false;
		break;
	case 'b':
		arguments->daemon = true;
		break;
	case 's':
		if (sscanf(arg, "%i", &arguments->random_step) == 0)
			argp_usage(state);
		break;
	case 'W': {
		int n;
		if ((sscanf(arg, "%i", &n) == 0) || (n < 0) || (n > 4096))
			argp_usage(state);
		else
			arguments->fill_watermark = n;
		break;
	}
	case 'q':
		arguments->quiet = true;
		break;
	case 'v':
		arguments->verbose = true;
		break;
	case 'd': {
		int n;
		if ((sscanf(arg,"%i", &n) == 0) || ((n | 1)!=1))
			argp_usage(state);
		else
			arguments->enable_drng = false;
		break;
	}
	case 'n': {
		int n;
		if ((sscanf(arg,"%i", &n) == 0) || ((n | 1)!=1))
			argp_usage(state);
		else
			arguments->enable_tpm = false;
		break;
	}

	default:
		return ARGP_ERR_UNKNOWN;
	}

	return 0;
}

static struct argp argp = { options, parse_opt, NULL, doc };


static int update_kernel_random(int random_step,
	unsigned char *buf, fips_ctx_t *fipsctx_in)
{
	unsigned char *p;
	int fips;

	fips = fips_run_rng_test(fipsctx_in, buf);
	if (fips) {
		if (!arguments->quiet)
			message(LOG_DAEMON|LOG_ERR, "failed fips test\n");
		return 1;
	}

	for (p = buf; p + random_step <= &buf[FIPS_RNG_BUFFER_SIZE];
		 p += random_step) {
		random_add_entropy(p, random_step);
		random_sleep();
	}
	return 0;
}

static void do_loop(int random_step)
{
	unsigned char buf[FIPS_RNG_BUFFER_SIZE];
	int retval = 0;
	int no_work = 0;

	while (no_work < 100) {
		struct rng *iter;
		bool work_done;

		work_done = false;
		for (iter = rng_list; iter; iter = iter->next)
		{
			int rc;

			if (!server_running)
				return;

			if (iter->disabled)
				continue;	/* failed, no work */

			retval = iter->xread(buf, sizeof buf, iter);
			if (retval)
				continue;	/* failed, no work */

			work_done = true;

			rc = update_kernel_random(random_step,
					     buf, iter->fipsctx);
			if (rc == 0)
				break;	/* succeeded, work done */

			iter->failures++;
			if (iter->failures == MAX_RNG_FAILURES) {
				if (!arguments->quiet)
					message(LOG_DAEMON|LOG_ERR,
					"too many FIPS failures, disabling entropy source\n");
				iter->disabled = true;
			}
		}

		if (!work_done)
			no_work++;
	}

	if (!arguments->quiet)
		message(LOG_DAEMON|LOG_ERR,
		"No entropy sources working, exiting rngd\n");
}

static void term_signal(int signo)
{
	server_running = false;
}

int main(int argc, char **argv)
{
	int rc_rng = 1;
	int rc_drng = 1;
	int rc_tpm = 1;
	int pid_fd = -1;

	openlog("rngd", 0, LOG_DAEMON);

	/* Get the default watermark level for this platform */
	arguments->fill_watermark = default_watermark();

	/* Parsing of commandline parameters */
	argp_parse(&argp, argc, argv, 0, 0, arguments);

	/* Init entropy sources, and open TRNG device */
	rc_rng = init_entropy_source(&rng_default);
	if (arguments->enable_drng)
		rc_drng = init_drng_entropy_source(&rng_drng);
	if (arguments->enable_tpm && rc_rng)
		rc_tpm = init_tpm_entropy_source(&rng_tpm);

	if (rc_rng && rc_drng && rc_tpm) {
		if (!arguments->quiet) {
			message(LOG_DAEMON|LOG_ERR,
				"can't open any entropy source");
			message(LOG_DAEMON|LOG_ERR,
				"Maybe RNG device modules are not loaded\n");
		}
		return 1;
	}

	if (arguments->verbose) {
		printf("Available entropy sources:\n");
		if (!rc_rng)
			printf("\tIntel/AMD hardware rng\n");
		if (!rc_drng)
			printf("\tDRNG\n");
		if (!rc_tpm)
			printf("\tTPM\n");
	}

	if (rc_rng
		&& (rc_drng || !arguments->enable_drng)
		&& (rc_tpm || !arguments->enable_tpm)) {
		if (!arguments->quiet)
			message(LOG_DAEMON|LOG_ERR,
		"No entropy source available, shutting down\n");
		return 1;
	}

	/* Init entropy sink and open random device */
	init_kernel_rng(arguments->random_name);

	if (arguments->daemon) {
		am_daemon = true;

		if (daemon(0, 0) < 0) {
			if(!arguments->quiet)
				fprintf(stderr, "can't daemonize: %s\n",
				strerror(errno));
			return 1;
		}

		/* require valid, locked PID file to proceed */
		pid_fd = write_pid_file(arguments->pid_file);
		if (pid_fd < 0)
			return 1;

		signal(SIGHUP, SIG_IGN);
		signal(SIGPIPE, SIG_IGN);
		signal(SIGINT, term_signal);
		signal(SIGTERM, term_signal);
	}

	do_loop(arguments->random_step);

	if (pid_fd >= 0)
		unlink(arguments->pid_file);

	return 0;
}
Commit	Line	Data
61af3de3 JG	1	/*
	2	* rngd.c -- Random Number Generator daemon
	3	*
	4	* rngd reads data from a hardware random number generator, verifies it
	5	* looks like random data, and adds it to /dev/random's entropy store.
d1b4c504	6	*
61af3de3 JG	7	* In theory, this should allow you to read very quickly from
	8	* /dev/random; rngd also adds bytes to the entropy store periodically
	9	* when it's full, which makes predicting the entropy store's contents
	10	* harder.
	11	*
	12	* Copyright (C) 2001 Philipp Rumpf
	13	*
	14	* This program is free software; you can redistribute it and/or modify
	15	* it under the terms of the GNU General Public License as published by
	16	* the Free Software Foundation; either version 2 of the License, or
	17	* (at your option) any later version.
d1b4c504	18	*
61af3de3 JG	19	* This program is distributed in the hope that it will be useful,
	20	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	21	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	22	* GNU General Public License for more details.
	23	*
	24	* You should have received a copy of the GNU General Public License
	25	* along with this program; if not, write to the Free Software
	26	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	27	*/
	28
	29	#define _GNU_SOURCE
	30
	31	#ifndef HAVE_CONFIG_H
	32	#error Invalid or missing autoconf build environment
	33	#endif
	34
	35	#include "rng-tools-config.h"
	36
	37	#include <unistd.h>
	38	#include <stdint.h>
	39	#include <stdio.h>
	40	#include <stdlib.h>
	41	#include <sys/types.h>
	42	#include <sys/stat.h>
	43	#include <fcntl.h>
	44	#include <errno.h>
	45	#include <string.h>
	46	#include <argp.h>
	47	#include <syslog.h>
c192b4cf	48	#include <signal.h>
61af3de3 JG	49
	50	#include "rngd.h"
	51	#include "fips.h"
	52	#include "exits.h"
	53	#include "rngd_entsource.h"
	54	#include "rngd_linux.h"
	55
	56	/*
	57	* Globals
	58	*/
	59
	60	/* Background/daemon mode */
ca6941f8	61	bool am_daemon; /* True if we went daemon */
61af3de3	62
c192b4cf JG	63	bool server_running = true; /* set to false, to stop daemon */
c192b4cf JG	64
61af3de3	65	/* Command line arguments and processing */
d1b4c504	66	const char *argp_program_version =
61af3de3 JG	67	"rngd " VERSION "\n"
	68	"Copyright 2001-2004 Jeff Garzik\n"
	69	"Copyright (c) 2001 by Philipp Rumpf\n"
	70	"This is free software; see the source for copying conditions. There is NO "
	71	"warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.";
	72
	73	const char *argp_program_bug_address = PACKAGE_BUGREPORT;
	74
	75	static char doc[] =
	76	"Check and feed random data from hardware device to kernel entropy pool.\n";
	77
	78	static struct argp_option options[] = {
	79	{ "foreground", 'f', 0, 0, "Do not fork and become a daemon" },
	80
	81	{ "background", 'b', 0, 0, "Become a daemon (default)" },
	82
	83	{ "random-device", 'o', "file", 0,
	84	"Kernel device used for random number output (default: /dev/random)" },
	85
	86	{ "rng-device", 'r', "file", 0,
47c3d388	87	"Kernel device used for random number input (default: /dev/hwrng)" },
61af3de3	88
c192b4cf JG	89	{ "pid-file", 'p', "file", 0,
	90	"File used for recording daemon PID, and multiple exclusion (default: /var/run/rngd.pid)" },
	91
61af3de3 JG	92	{ "random-step", 's', "nnn", 0,
	93	"Number of bytes written to random-device at a time (default: 64)" },
	94
	95	{ "fill-watermark", 'W', "n", 0,
	96	"Do not stop feeding entropy to random-device until at least n bits of entropy are available in the pool (default: 2048), 0 <= n <= 4096" },
	97
e42da63c BH	98	{ "quiet", 'q', 0, 0, "Suppress error messages" },
	99
	100	{ "verbose" ,'v', 0, 0, "Report available entropy sources" },
	101
2a014536 BH	102	{ "no-drng", 'd', "1\|0", 0,
	103	"Do not use drng as a source of random number input (default: 0)" },
	104
d1b4c504	105	{ "no-tpm", 'n', "1\|0", 0,
2a014536	106	"Do not use tpm as a source of random number input (default: 0)" },
61af3de3 JG	107
	108	{ 0 },
	109	};
	110
	111	static struct arguments default_arguments = {
61af3de3	112	.random_name = "/dev/random",
c192b4cf	113	.pid_file = "/var/run/rngd.pid",
61af3de3	114	.random_step = 64,
ca6941f8	115	.daemon = true,
2a014536	116	.enable_drng = true,
ca6941f8 JG	117	.enable_tpm = true,
	118	.quiet = false,
	119	.verbose = false,
61af3de3 JG	120	};
	121	struct arguments *arguments = &default_arguments;
	122
d1b4c504	123	static struct rng rng_default = {
47c3d388	124	.rng_name = "/dev/hwrng",
d1b4c504 JG	125	.rng_fd = -1,
d1b4c504 JG	126	.xread = xread,
d1b4c504 JG	127	};
d1b4c504 JG	128
2a014536 BH	129	static struct rng rng_drng = {
	130	.rng_name = "drng",
	131	.rng_fd = -1,
	132	.xread = xread_drng,
	133	};
	134
d1b4c504 JG	135	static struct rng rng_tpm = {
	136	.rng_name = "/dev/tpm0",
	137	.rng_fd = -1,
	138	.xread = xread_tpm,
d1b4c504 JG	139	};
	140
	141	struct rng *rng_list;
61af3de3 JG	142
	143	/*
	144	* command line processing
	145	*/
	146	static error_t parse_opt (int key, char arg, struct argp_state state)
	147	{
61af3de3 JG	148	switch(key) {
	149	case 'o':
	150	arguments->random_name = arg;
	151	break;
c192b4cf JG	152	case 'p':
	153	arguments->pid_file = arg;
	154	break;
61af3de3	155	case 'r':
d1b4c504	156	rng_default.rng_name = arg;
61af3de3	157	break;
61af3de3	158	case 'f':
ca6941f8	159	arguments->daemon = false;
61af3de3 JG	160	break;
61af3de3 JG	161	case 'b':
ca6941f8	162	arguments->daemon = true;
61af3de3 JG	163	break;
	164	case 's':
	165	if (sscanf(arg, "%i", &arguments->random_step) == 0)
	166	argp_usage(state);
	167	break;
	168	case 'W': {
	169	int n;
	170	if ((sscanf(arg, "%i", &n) == 0) \|\| (n < 0) \|\| (n > 4096))
	171	argp_usage(state);
	172	else
	173	arguments->fill_watermark = n;
	174	break;
	175	}
e42da63c	176	case 'q':
ca6941f8	177	arguments->quiet = true;
e42da63c BH	178	break;
e42da63c BH	179	case 'v':
ca6941f8	180	arguments->verbose = true;
e42da63c	181	break;
2a014536 BH	182	case 'd': {
	183	int n;
	184	if ((sscanf(arg,"%i", &n) == 0) \|\| ((n \| 1)!=1))
	185	argp_usage(state);
	186	else
	187	arguments->enable_drng = false;
	188	break;
	189	}
d1b4c504 JG	190	case 'n': {
	191	int n;
	192	if ((sscanf(arg,"%i", &n) == 0) \|\| ((n \| 1)!=1))
	193	argp_usage(state);
	194	else
ca6941f8	195	arguments->enable_tpm = false;
d1b4c504 JG	196	break;
d1b4c504 JG	197	}
61af3de3 JG	198
	199	default:
	200	return ARGP_ERR_UNKNOWN;
	201	}
	202
	203	return 0;
	204	}
	205
	206	static struct argp argp = { options, parse_opt, NULL, doc };
	207
	208
a9b9bb1d	209	static int update_kernel_random(int random_step,
5db96329	210	unsigned char buf, fips_ctx_t fipsctx_in)
61af3de3	211	{
61af3de3 JG	212	unsigned char *p;
	213	int fips;
	214
5db96329	215	fips = fips_run_rng_test(fipsctx_in, buf);
d1b4c504	216	if (fips) {
e42da63c BH	217	if (!arguments->quiet)
e42da63c BH	218	message(LOG_DAEMON\|LOG_ERR, "failed fips test\n");
d1b4c504 JG	219	return 1;
d1b4c504 JG	220	}
61af3de3	221
d1b4c504 JG	222	for (p = buf; p + random_step <= &buf[FIPS_RNG_BUFFER_SIZE];
	223	p += random_step) {
	224	random_add_entropy(p, random_step);
a9b9bb1d	225	random_sleep();
d1b4c504 JG	226	}
	227	return 0;
	228	}
61af3de3	229
a9b9bb1d	230	static void do_loop(int random_step)
d1b4c504 JG	231	{
d1b4c504 JG	232	unsigned char buf[FIPS_RNG_BUFFER_SIZE];
e42da63c	233	int retval = 0;
62838c65	234	int no_work = 0;
61af3de3	235
62838c65	236	while (no_work < 100) {
d1b4c504	237	struct rng *iter;
62838c65 JG	238	bool work_done;
	239
	240	work_done = false;
d1b4c504 JG	241	for (iter = rng_list; iter; iter = iter->next)
d1b4c504 JG	242	{
62838c65 JG	243	int rc;
62838c65 JG	244
c192b4cf JG	245	if (!server_running)
	246	return;
	247
62838c65 JG	248	if (iter->disabled)
	249	continue; /* failed, no work */
	250
d1b4c504	251	retval = iter->xread(buf, sizeof buf, iter);
62838c65 JG	252	if (retval)
	253	continue; /* failed, no work */
	254
	255	work_done = true;
	256
	257	rc = update_kernel_random(random_step,
a9b9bb1d	258	buf, iter->fipsctx);
62838c65	259	if (rc == 0)
2a014536	260	break; /* succeeded, work done */
62838c65 JG	261
	262	iter->failures++;
	263	if (iter->failures == MAX_RNG_FAILURES) {
e42da63c BH	264	if (!arguments->quiet)
e42da63c BH	265	message(LOG_DAEMON\|LOG_ERR,
62838c65 JG	266	"too many FIPS failures, disabling entropy source\n");
	267	iter->disabled = true;
	268	}
61af3de3	269	}
62838c65 JG	270
	271	if (!work_done)
	272	no_work++;
61af3de3	273	}
62838c65	274
e42da63c BH	275	if (!arguments->quiet)
e42da63c BH	276	message(LOG_DAEMON\|LOG_ERR,
62838c65	277	"No entropy sources working, exiting rngd\n");
61af3de3 JG	278	}
61af3de3 JG	279
c192b4cf JG	280	static void term_signal(int signo)
	281	{
	282	server_running = false;
	283	}
	284
61af3de3 JG	285	int main(int argc, char **argv)
61af3de3 JG	286	{
2a014536 BH	287	int rc_rng = 1;
	288	int rc_drng = 1;
	289	int rc_tpm = 1;
c192b4cf	290	int pid_fd = -1;
e42da63c BH	291
e42da63c BH	292	openlog("rngd", 0, LOG_DAEMON);
d1b4c504	293
870f0d5d PA	294	/* Get the default watermark level for this platform */
	295	arguments->fill_watermark = default_watermark();
	296
d1b4c504	297	/* Parsing of commandline parameters */
61af3de3 JG	298	argp_parse(&argp, argc, argv, 0, 0, arguments);
61af3de3 JG	299
d1b4c504 JG	300	/* Init entropy sources, and open TRNG device */
d1b4c504 JG	301	rc_rng = init_entropy_source(&rng_default);
2a014536 BH	302	if (arguments->enable_drng)
2a014536 BH	303	rc_drng = init_drng_entropy_source(&rng_drng);
9b1a3bbb	304	if (arguments->enable_tpm && rc_rng)
d1b4c504 JG	305	rc_tpm = init_tpm_entropy_source(&rng_tpm);
d1b4c504 JG	306
2a014536	307	if (rc_rng && rc_drng && rc_tpm) {
e42da63c BH	308	if (!arguments->quiet) {
e42da63c BH	309	message(LOG_DAEMON\|LOG_ERR,
9b1a3bbb	310	"can't open any entropy source");
e42da63c BH	311	message(LOG_DAEMON\|LOG_ERR,
	312	"Maybe RNG device modules are not loaded\n");
	313	}
	314	return 1;
	315	}
c192b4cf	316
e42da63c BH	317	if (arguments->verbose) {
	318	printf("Available entropy sources:\n");
	319	if (!rc_rng)
	320	printf("\tIntel/AMD hardware rng\n");
2a014536 BH	321	if (!rc_drng)
2a014536 BH	322	printf("\tDRNG\n");
e42da63c BH	323	if (!rc_tpm)
	324	printf("\tTPM\n");
	325	}
	326
c192b4cf	327	if (rc_rng
2a014536	328	&& (rc_drng \|\| !arguments->enable_drng)
e42da63c BH	329	&& (rc_tpm \|\| !arguments->enable_tpm)) {
	330	if (!arguments->quiet)
	331	message(LOG_DAEMON\|LOG_ERR,
	332	"No entropy source available, shutting down\n");
d1b4c504 JG	333	return 1;
d1b4c504 JG	334	}
61af3de3 JG	335
	336	/* Init entropy sink and open random device */
	337	init_kernel_rng(arguments->random_name);
	338
	339	if (arguments->daemon) {
ca6941f8	340	am_daemon = true;
61af3de3 JG	341
61af3de3 JG	342	if (daemon(0, 0) < 0) {
e42da63c BH	343	if(!arguments->quiet)
e42da63c BH	344	fprintf(stderr, "can't daemonize: %s\n",
61af3de3 JG	345	strerror(errno));
	346	return 1;
	347	}
c192b4cf JG	348
	349	/* require valid, locked PID file to proceed */
	350	pid_fd = write_pid_file(arguments->pid_file);
	351	if (pid_fd < 0)
	352	return 1;
	353
	354	signal(SIGHUP, SIG_IGN);
	355	signal(SIGPIPE, SIG_IGN);
	356	signal(SIGINT, term_signal);
	357	signal(SIGTERM, term_signal);
61af3de3 JG	358	}
61af3de3 JG	359
a9b9bb1d	360	do_loop(arguments->random_step);
61af3de3	361
c192b4cf JG	362	if (pid_fd >= 0)
	363	unlink(arguments->pid_file);
	364
61af3de3 JG	365	return 0;
61af3de3 JG	366	}