src/key_call.c

/*
 * Copyright (c) 2009, Sun Microsystems, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * - 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.
 * - Neither the name of Sun Microsystems, Inc. nor the names of its
 *   contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT HOLDER OR CONTRIBUTORS 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.
 */
/*
 * Copyright (c) 1986-1991 by Sun Microsystems Inc.
 */

#include <sys/cdefs.h>

/*
 * key_call.c, Interface to keyserver
 *
 * setsecretkey(key) - set your secret key
 * encryptsessionkey(agent, deskey) - encrypt a session key to talk to agent
 * decryptsessionkey(agent, deskey) - decrypt ditto
 * gendeskey(deskey) - generate a secure des key
 */

#include <pthread.h>
#include <reentrant.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <rpc/rpc.h>
#include <rpc/auth.h>
#include <rpc/auth_unix.h>
#include <rpc/key_prot.h>
#include <string.h>
#include <netconfig.h>
#include <sys/utsname.h>
#include <stdlib.h>
#include <signal.h>
#include <sys/wait.h>
#include <sys/fcntl.h>

#define	KEY_TIMEOUT	5	/* per-try timeout in seconds */
#define	KEY_NRETRY	12	/* number of retries */

#ifdef DEBUG
#define	debug(msg) \
	((void) fprintf(stderr, "%s\n", msg))

#else
#define	debug(msg)
#endif				/* DEBUG */

/*
 * Hack to allow the keyserver to use AUTH_DES (for authenticated
 * NIS+ calls, for example).  The only functions that get called
 * are key_encryptsession_pk, key_decryptsession_pk, and key_gendes.
 *
 * The approach is to have the keyserver fill in pointers to local
 * implementations of these functions, and to call those in key_call().
 */

cryptkeyres *(*__key_encryptsession_pk_LOCAL) () = 0;
cryptkeyres *(*__key_decryptsession_pk_LOCAL) () = 0;
des_block *(*__key_gendes_LOCAL) () = 0;

static int key_call(u_long, xdrproc_t, void *, xdrproc_t, void *);

int
key_setsecret(const char *secretkey)
{
	keystatus status;

	if (!key_call
	    ((u_long) KEY_SET, (xdrproc_t) xdr_keybuf, (void *)secretkey,
	     (xdrproc_t) xdr_keystatus, &status)) {
		return (-1);
	}
	if (status != KEY_SUCCESS) {
		debug("set status is nonzero");
		return (-1);
	}
	return (0);
}

/* key_secretkey_is_set() returns 1 if the keyserver has a secret key
 * stored for the caller's effective uid; it returns 0 otherwise
 *
 * N.B.:  The KEY_NET_GET key call is undocumented.  Applications shouldn't
 * be using it, because it allows them to get the user's secret key.
 */

int
key_secretkey_is_set(void)
{
	struct key_netstres kres;

	memset((void *)&kres, 0, sizeof(kres));
	if (key_call
	    ((u_long) KEY_NET_GET, (xdrproc_t) xdr_void, NULL,
	     (xdrproc_t) xdr_key_netstres, &kres)
	    && (kres.status == KEY_SUCCESS)
	    && (kres.key_netstres_u.knet.st_priv_key[0] != 0)) {
		/* avoid leaving secret key in memory */
		memset(kres.key_netstres_u.knet.st_priv_key, 0, HEXKEYBYTES);
		return (1);
	}
	return (0);
}

int
key_encryptsession_pk(char *remotename, netobj *remotekey,
		      des_block *deskey)
{
	cryptkeyarg2 arg;
	cryptkeyres res;

	arg.remotename = remotename;
	arg.remotekey = *remotekey;
	arg.deskey = *deskey;
	if (!key_call
	    ((u_long) KEY_ENCRYPT_PK, (xdrproc_t) xdr_cryptkeyarg2, &arg,
	     (xdrproc_t) xdr_cryptkeyres, &res)) {
		return (-1);
	}
	if (res.status != KEY_SUCCESS) {
		debug("encrypt status is nonzero");
		return (-1);
	}
	*deskey = res.cryptkeyres_u.deskey;
	return (0);
}

int
key_decryptsession_pk(char *remotename, netobj *remotekey,
		      des_block *deskey)
{
	cryptkeyarg2 arg;
	cryptkeyres res;

	arg.remotename = remotename;
	arg.remotekey = *remotekey;
	arg.deskey = *deskey;
	if (!key_call
	    ((u_long) KEY_DECRYPT_PK, (xdrproc_t) xdr_cryptkeyarg2, &arg,
	     (xdrproc_t) xdr_cryptkeyres, &res)) {
		return (-1);
	}
	if (res.status != KEY_SUCCESS) {
		debug("decrypt status is nonzero");
		return (-1);
	}
	*deskey = res.cryptkeyres_u.deskey;
	return (0);
}

int
key_encryptsession(const char *remotename, des_block *deskey)
{
	cryptkeyarg arg;
	cryptkeyres res;

	arg.remotename = (char *)remotename;
	arg.deskey = *deskey;
	if (!key_call
	    ((u_long) KEY_ENCRYPT, (xdrproc_t) xdr_cryptkeyarg, &arg,
	     (xdrproc_t) xdr_cryptkeyres, &res)) {
		return (-1);
	}
	if (res.status != KEY_SUCCESS) {
		debug("encrypt status is nonzero");
		return (-1);
	}
	*deskey = res.cryptkeyres_u.deskey;
	return (0);
}

int
key_decryptsession(const char *remotename, des_block *deskey)
{
	cryptkeyarg arg;
	cryptkeyres res;

	arg.remotename = (char *)remotename;
	arg.deskey = *deskey;
	if (!key_call
	    ((u_long) KEY_DECRYPT, (xdrproc_t) xdr_cryptkeyarg, &arg,
	     (xdrproc_t) xdr_cryptkeyres, &res)) {
		return (-1);
	}
	if (res.status != KEY_SUCCESS) {
		debug("decrypt status is nonzero");
		return (-1);
	}
	*deskey = res.cryptkeyres_u.deskey;
	return (0);
}

int
key_gendes(des_block *key)
{
	if (!key_call
	    ((u_long) KEY_GEN, (xdrproc_t) xdr_void, NULL,
	     (xdrproc_t) xdr_des_block, key)) {
		return (-1);
	}
	return (0);
}

int
key_setnet(struct key_netstarg *arg)
{
	keystatus status;

	if (!key_call
	    ((u_long) KEY_NET_PUT, (xdrproc_t) xdr_key_netstarg, arg,
	     (xdrproc_t) xdr_keystatus, &status)) {
		return (-1);
	}

	if (status != KEY_SUCCESS) {
		debug("key_setnet status is nonzero");
		return (-1);
	}
	return (1);
}

int
key_get_conv(char *pkey, des_block *deskey)
{
	cryptkeyres res;

	if (!key_call
	    ((u_long) KEY_GET_CONV, (xdrproc_t) xdr_keybuf, pkey,
	     (xdrproc_t) xdr_cryptkeyres, &res)) {
		return (-1);
	}
	if (res.status != KEY_SUCCESS) {
		debug("get_conv status is nonzero");
		return (-1);
	}
	*deskey = res.cryptkeyres_u.deskey;
	return (0);
}

struct key_call_private {
	CLIENT *client;		/* Client handle */
	pid_t pid;		/* process-id at moment of creation */
	uid_t uid;		/* user-id at last authorization */
};
static struct key_call_private *key_call_private_mainL;

static void
key_call_destroy(void *vp)
{
	struct key_call_private *kcp = (struct key_call_private *)vp;

	if (kcp) {
		if (kcp->client)
			clnt_destroy(kcp->client);
		__free(kcp);
	}
}

/*
 * Keep the handle cached.  This call may be made quite often.
 */
static CLIENT *
getkeyserv_handle(int vers)
{
	void *localhandle;
	struct netconfig *nconf;
	struct netconfig *tpconf;
	struct key_call_private *kcp = key_call_private_main;
	struct timeval wait_time;
	struct utsname u;
	int fd;
	extern thread_key_t key_call_key;
	extern mutex_t tsd_lock;

#define	TOTAL_TIMEOUT	30	/* total timeout talking to keyserver */
#define	TOTAL_TRIES	5	/* Number of tries */

	if (key_call_key == -1) {
		mutex_lock(&tsd_lock);
		if (key_call_key == -1)
			thr_keycreate(&key_call_key, key_call_destroy);
		mutex_unlock(&tsd_lock);
	}
	kcp = (struct key_call_private *)thr_getspecific(key_call_key);
	if (kcp == (struct key_call_private *)NULL) {
		kcp = (struct key_call_private *)mem_alloc(sizeof(*kcp));
		if (kcp == (struct key_call_private *)NULL)
			return ((CLIENT *) NULL);
		thr_setspecific(key_call_key, (void *)kcp);
		kcp->client = NULL;
	}

	/* if pid has changed, destroy client and rebuild */
	if (kcp->client != NULL && kcp->pid != getpid()) {
		clnt_destroy(kcp->client);
		kcp->client = NULL;
	}

	if (kcp->client != NULL) {
		/* if uid has changed, build client handle again */
		if (kcp->uid != geteuid()) {
			kcp->uid = geteuid();
			auth_destroy(kcp->client->cl_auth);
			kcp->client->cl_auth =
			    authsys_create("", kcp->uid, 0, 0, NULL);
			if (kcp->client->cl_auth == NULL) {
				clnt_destroy(kcp->client);
				kcp->client = NULL;
				return ((CLIENT *) NULL);
			}
		}
		/* Change the version number to the new one */
		clnt_control(kcp->client, CLSET_VERS, (void *)&vers);
		return (kcp->client);
	}
	localhandle = setnetconfig();
	if (!localhandle)
		return ((CLIENT *) NULL);
	tpconf = NULL;
#if defined(__FreeBSD__)
	if (uname(&u) == -1)
#else
#if defined(i386)
	if (uname(&u) == -1)
#elif defined(sparc)
	if (uname(&u) == -1)
#else
#error Unknown architecture!
#endif
#endif
	{
		endnetconfig(localhandle);
		return ((CLIENT *) NULL);
	}
	while ((nconf = getnetconfig(localhandle)) != NULL) {
		if (strcmp(nconf->nc_protofmly, NC_LOOPBACK) == 0) {
			/*
			 * We use COTS_ORD here so that the caller can
			 * find out immediately if the server is dead.
			 */
			if (nconf->nc_semantics == NC_TPI_COTS_ORD) {
				kcp->client =
				    clnt_tp_create(u.nodename, KEY_PROG, vers,
						   nconf);
				if (kcp->client)
					break;
			} else {
				tpconf = nconf;
			}
		}
	}
	if ((kcp->client == (CLIENT *) NULL) && (tpconf))
		/* Now, try the CLTS or COTS loopback transport */
		kcp->client =
		    clnt_tp_create(u.nodename, KEY_PROG, vers, tpconf);
	endnetconfig(localhandle);

	if (kcp->client == (CLIENT *) NULL)
		return ((CLIENT *) NULL);
	kcp->uid = geteuid();
	kcp->pid = getpid();
	kcp->client->cl_auth = authsys_create("", kcp->uid, 0, 0, NULL);
	if (kcp->client->cl_auth == NULL) {
		clnt_destroy(kcp->client);
		kcp->client = NULL;
		return ((CLIENT *) NULL);
	}

	wait_time.tv_sec = TOTAL_TIMEOUT / TOTAL_TRIES;
	wait_time.tv_usec = 0;
	(void)clnt_control(kcp->client, CLSET_RETRY_TIMEOUT,
			   (char *)&wait_time);
	if (clnt_control(kcp->client, CLGET_FD, (char *)&fd))
		fcntl(fd, F_SETFD, 1);	/* make it "close on exec" */

	return (kcp->client);
}

/* returns  0 on failure, 1 on success */

static int
key_call(u_long proc, xdrproc_t xdr_arg, void *arg,
	 xdrproc_t xdr_rslt, void *rslt)
{
	CLIENT *clnt;
	struct timeval wait_time;

	if (proc == KEY_ENCRYPT_PK && __key_encryptsession_pk_LOCAL) {
		cryptkeyres *res;
		res = (*__key_encryptsession_pk_LOCAL) (geteuid(), arg);
		*(cryptkeyres *) rslt = *res;
		return (1);
	} else if (proc == KEY_DECRYPT_PK && __key_decryptsession_pk_LOCAL) {
		cryptkeyres *res;
		res = (*__key_decryptsession_pk_LOCAL) (geteuid(), arg);
		*(cryptkeyres *) rslt = *res;
		return (1);
	} else if (proc == KEY_GEN && __key_gendes_LOCAL) {
		des_block *res;
		res = (*__key_gendes_LOCAL) (geteuid(), 0);
		*(des_block *) rslt = *res;
		return (1);
	}

	if ((proc == KEY_ENCRYPT_PK) || (proc == KEY_DECRYPT_PK)
	    || (proc == KEY_NET_GET) || (proc == KEY_NET_PUT)
	    || (proc == KEY_GET_CONV))
		clnt = getkeyserv_handle(2);	/* talk to version 2 */
	else
		clnt = getkeyserv_handle(1);	/* talk to version 1 */

	if (clnt == NULL)
		return (0);

	wait_time.tv_sec = TOTAL_TIMEOUT;
	wait_time.tv_usec = 0;

	if (clnt_call(clnt, proc, xdr_arg, arg, xdr_rslt, rslt, wait_time) ==
	    RPC_SUCCESS)
		return (1);
	else
		return (0);
}