/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * 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) 1988 by Sun Microsystems, Inc.
 */
/*
 * auth_des.c, client-side implementation of DES authentication
 */

#include "namespace.h"
#include "reentrant.h"
#include <err.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <rpc/des_crypt.h>
#include <syslog.h>
#include <rpc/types.h>
#include <rpc/auth.h>
#include <rpc/auth_des.h>
#include <rpc/clnt.h>
#include <rpc/xdr.h>
#include <sys/socket.h>
#undef NIS
#include <rpcsvc/nis.h>
#include "un-namespace.h"
#include "mt_misc.h"

#define USEC_PER_SEC            1000000
#define RTIME_TIMEOUT           5       /* seconds to wait for sync */

#define AUTH_PRIVATE(auth)      (struct ad_private *) auth->ah_private
#define ALLOC(object_type)      (object_type *) mem_alloc(sizeof(object_type))
#define FREE(ptr, size)         mem_free((char *)(ptr), (int) size)
#define ATTEMPT(xdr_op)         if (!(xdr_op)) return (FALSE)

extern bool_t xdr_authdes_cred( XDR *, struct authdes_cred *);
extern bool_t xdr_authdes_verf( XDR *, struct authdes_verf *);
extern int key_encryptsession_pk(char *, netobj *, des_block *);

extern bool_t __rpc_get_time_offset(struct timeval *, nis_server *, char *,
        char **, char **);

/* 
 * DES authenticator operations vector
 */
static void     authdes_nextverf(AUTH *);
static bool_t   authdes_marshal(AUTH *, XDR *);
static bool_t   authdes_validate(AUTH *, struct opaque_auth *);
static bool_t   authdes_refresh(AUTH *, void *);
static void     authdes_destroy(AUTH *);

static struct auth_ops *authdes_ops(void);

/*
 * This struct is pointed to by the ah_private field of an "AUTH *"
 */
struct ad_private {
        char *ad_fullname;              /* client's full name */
        u_int ad_fullnamelen;           /* length of name, rounded up */
        char *ad_servername;            /* server's full name */
        u_int ad_servernamelen;         /* length of name, rounded up */
        u_int ad_window;                /* client specified window */
        bool_t ad_dosync;               /* synchronize? */              
        struct netbuf ad_syncaddr;      /* remote host to synch with */
        char *ad_timehost;              /* remote host to synch with */
        struct timeval ad_timediff;     /* server's time - client's time */
        u_int ad_nickname;              /* server's nickname for client */
        struct authdes_cred ad_cred;    /* storage for credential */
        struct authdes_verf ad_verf;    /* storage for verifier */
        struct timeval ad_timestamp;    /* timestamp sent */
        des_block ad_xkey;              /* encrypted conversation key */
        u_char ad_pkey[1024];           /* Server's actual public key */
        char *ad_netid;                 /* Timehost netid */
        char *ad_uaddr;                 /* Timehost uaddr */
        nis_server *ad_nis_srvr;        /* NIS+ server struct */
};

AUTH *authdes_pk_seccreate(const char *, netobj *, u_int, const char *,
        const des_block *, nis_server *);
        
/*
 * documented version of authdes_seccreate
 */
/*
        servername:     network name of server
        win:            time to live
        timehost:       optional hostname to sync with
        ckey:           optional conversation key to use
*/

AUTH *
authdes_seccreate(const char *servername, const u_int win,
        const char *timehost, const des_block *ckey)
{
        u_char  pkey_data[1024];
        netobj  pkey;
        AUTH    *dummy;

        if (! getpublickey(servername, (char *) pkey_data)) {
                syslog(LOG_ERR,
                    "authdes_seccreate: no public key found for %s",
                    servername);
                return (NULL);
        }

        pkey.n_bytes = (char *) pkey_data;
        pkey.n_len = (u_int)strlen((char *)pkey_data) + 1;
        dummy = authdes_pk_seccreate(servername, &pkey, win, timehost,
            ckey, NULL);
        return (dummy);
}

/*
 * Slightly modified version of authdessec_create which takes the public key
 * of the server principal as an argument. This spares us a call to
 * getpublickey() which in the nameserver context can cause a deadlock.
 */
AUTH *
authdes_pk_seccreate(const char *servername, netobj *pkey, u_int window,
        const char *timehost, const des_block *ckey, nis_server *srvr)
{
        AUTH *auth;
        struct ad_private *ad;
        char namebuf[MAXNETNAMELEN+1];

        /*
         * Allocate everything now
         */
        auth = ALLOC(AUTH);
        if (auth == NULL) {
                syslog(LOG_ERR, "authdes_pk_seccreate: out of memory");
                return (NULL);
        }
        ad = ALLOC(struct ad_private);
        if (ad == NULL) {
                syslog(LOG_ERR, "authdes_pk_seccreate: out of memory");
                goto failed;
        }
        ad->ad_fullname = ad->ad_servername = NULL; /* Sanity reasons */
        ad->ad_timehost = NULL;
        ad->ad_netid = NULL;
        ad->ad_uaddr = NULL;
        ad->ad_nis_srvr = NULL;
        ad->ad_timediff.tv_sec = 0;
        ad->ad_timediff.tv_usec = 0;
        memcpy(ad->ad_pkey, pkey->n_bytes, pkey->n_len);
        if (!getnetname(namebuf))
                goto failed;
        ad->ad_fullnamelen = RNDUP((u_int) strlen(namebuf));
        ad->ad_fullname = (char *)mem_alloc(ad->ad_fullnamelen + 1);
        ad->ad_servernamelen = strlen(servername);
        ad->ad_servername = (char *)mem_alloc(ad->ad_servernamelen + 1);

        if (ad->ad_fullname == NULL || ad->ad_servername == NULL) {
                syslog(LOG_ERR, "authdes_seccreate: out of memory");
                goto failed;
        }
        if (timehost != NULL) {
                ad->ad_timehost = (char *)mem_alloc(strlen(timehost) + 1);
                if (ad->ad_timehost == NULL) {
                        syslog(LOG_ERR, "authdes_seccreate: out of memory");
                        goto failed;
                }
                memcpy(ad->ad_timehost, timehost, strlen(timehost) + 1);
                ad->ad_dosync = TRUE;
        } else if (srvr != NULL) {
                ad->ad_nis_srvr = srvr; /* transient */
                ad->ad_dosync = TRUE;
        } else {
                ad->ad_dosync = FALSE;
        }
        memcpy(ad->ad_fullname, namebuf, ad->ad_fullnamelen + 1);
        memcpy(ad->ad_servername, servername, ad->ad_servernamelen + 1);
        ad->ad_window = window;
        if (ckey == NULL) {
                if (key_gendes(&auth->ah_key) < 0) {
                        syslog(LOG_ERR,
            "authdes_seccreate: keyserv(1m) is unable to generate session key");
                        goto failed;
                }
        } else {
                auth->ah_key = *ckey;
        }

        /*
         * Set up auth handle
         */
        auth->ah_cred.oa_flavor = AUTH_DES;
        auth->ah_verf.oa_flavor = AUTH_DES;
        auth->ah_ops = authdes_ops();
        auth->ah_private = (caddr_t)ad;

        if (!authdes_refresh(auth, NULL)) {
                goto failed;
        }
        ad->ad_nis_srvr = NULL; /* not needed any longer */
        return (auth);

failed:
        if (auth)
                FREE(auth, sizeof (AUTH));
        if (ad) {
                if (ad->ad_fullname)
                        FREE(ad->ad_fullname, ad->ad_fullnamelen + 1);
                if (ad->ad_servername)
                        FREE(ad->ad_servername, ad->ad_servernamelen + 1);
                if (ad->ad_timehost)
                        FREE(ad->ad_timehost, strlen(ad->ad_timehost) + 1);
                if (ad->ad_netid)
                        FREE(ad->ad_netid, strlen(ad->ad_netid) + 1);
                if (ad->ad_uaddr)
                        FREE(ad->ad_uaddr, strlen(ad->ad_uaddr) + 1);
                FREE(ad, sizeof (struct ad_private));
        }
        return (NULL);
}

/*
 * Implement the five authentication operations
 */


/*
 * 1. Next Verifier
 */     
/*ARGSUSED*/
static void
authdes_nextverf(AUTH *auth __unused)
{
        /* what the heck am I supposed to do??? */
}


/*
 * 2. Marshal
 */
static bool_t
authdes_marshal(AUTH *auth, XDR *xdrs)
{
/* LINTED pointer alignment */
        struct ad_private *ad = AUTH_PRIVATE(auth);
        struct authdes_cred *cred = &ad->ad_cred;
        struct authdes_verf *verf = &ad->ad_verf;
        des_block cryptbuf[2];  
        des_block ivec;
        int status;
        int len;
        rpc_inline_t *ixdr;

        /*
         * Figure out the "time", accounting for any time difference
         * with the server if necessary.
         */
        (void)gettimeofday(&ad->ad_timestamp, NULL);
        ad->ad_timestamp.tv_sec += ad->ad_timediff.tv_sec;
        ad->ad_timestamp.tv_usec += ad->ad_timediff.tv_usec;
        while (ad->ad_timestamp.tv_usec >= USEC_PER_SEC) {
                ad->ad_timestamp.tv_usec -= USEC_PER_SEC;
                ad->ad_timestamp.tv_sec++;
        }

        /*
         * XDR the timestamp and possibly some other things, then
         * encrypt them.
         */
        ixdr = (rpc_inline_t *)cryptbuf;
        IXDR_PUT_INT32(ixdr, ad->ad_timestamp.tv_sec);
        IXDR_PUT_INT32(ixdr, ad->ad_timestamp.tv_usec);
        if (ad->ad_cred.adc_namekind == ADN_FULLNAME) {
                IXDR_PUT_U_INT32(ixdr, ad->ad_window);
                IXDR_PUT_U_INT32(ixdr, ad->ad_window - 1);
                ivec.key.high = ivec.key.low = 0;       
                status = cbc_crypt((char *)&auth->ah_key, (char *)cryptbuf, 
                        (u_int) 2 * sizeof (des_block),
                        DES_ENCRYPT | DES_HW, (char *)&ivec);
        } else {
                status = ecb_crypt((char *)&auth->ah_key, (char *)cryptbuf, 
                        (u_int) sizeof (des_block),
                        DES_ENCRYPT | DES_HW);
        }
        if (DES_FAILED(status)) {
                syslog(LOG_ERR, "authdes_marshal: DES encryption failure");
                return (FALSE);
        }
        ad->ad_verf.adv_xtimestamp = cryptbuf[0];
        if (ad->ad_cred.adc_namekind == ADN_FULLNAME) {
                ad->ad_cred.adc_fullname.window = cryptbuf[1].key.high;
                ad->ad_verf.adv_winverf = cryptbuf[1].key.low;
        } else {
                ad->ad_cred.adc_nickname = ad->ad_nickname;
                ad->ad_verf.adv_winverf = 0;
        }

        /*
         * Serialize the credential and verifier into opaque
         * authentication data.
         */
        if (ad->ad_cred.adc_namekind == ADN_FULLNAME) {
                len = ((1 + 1 + 2 + 1)*BYTES_PER_XDR_UNIT + ad->ad_fullnamelen);
        } else {
                len = (1 + 1)*BYTES_PER_XDR_UNIT;
        }

        if ((ixdr = xdr_inline(xdrs, 2*BYTES_PER_XDR_UNIT))) {
                IXDR_PUT_INT32(ixdr, AUTH_DES);
                IXDR_PUT_INT32(ixdr, len);
        } else {
                ATTEMPT(xdr_putint32(xdrs, (int *)&auth->ah_cred.oa_flavor));
                ATTEMPT(xdr_putint32(xdrs, &len));
        }
        ATTEMPT(xdr_authdes_cred(xdrs, cred));

        len = (2 + 1)*BYTES_PER_XDR_UNIT; 
        if ((ixdr = xdr_inline(xdrs, 2*BYTES_PER_XDR_UNIT))) {
                IXDR_PUT_INT32(ixdr, AUTH_DES);
                IXDR_PUT_INT32(ixdr, len);
        } else {
                ATTEMPT(xdr_putint32(xdrs, (int *)&auth->ah_verf.oa_flavor));
                ATTEMPT(xdr_putint32(xdrs, &len));
        }
        ATTEMPT(xdr_authdes_verf(xdrs, verf));
        return (TRUE);
}


/*
 * 3. Validate
 */
static bool_t
authdes_validate(AUTH *auth, struct opaque_auth *rverf)
{
/* LINTED pointer alignment */
        struct ad_private *ad = AUTH_PRIVATE(auth);
        struct authdes_verf verf;
        int status;
        uint32_t *ixdr;
        des_block buf;

        if (rverf->oa_length != (2 + 1) * BYTES_PER_XDR_UNIT) {
                return (FALSE);
        }
/* LINTED pointer alignment */
        ixdr = (uint32_t *)rverf->oa_base;
        buf.key.high = (uint32_t)*ixdr++;
        buf.key.low = (uint32_t)*ixdr++;
        verf.adv_int_u = (uint32_t)*ixdr++;

        /*
         * Decrypt the timestamp
         */
        status = ecb_crypt((char *)&auth->ah_key, (char *)&buf,
                (u_int)sizeof (des_block), DES_DECRYPT | DES_HW);

        if (DES_FAILED(status)) {
                syslog(LOG_ERR, "authdes_validate: DES decryption failure");
                return (FALSE);
        }

        /*
         * xdr the decrypted timestamp
         */
/* LINTED pointer alignment */
        ixdr = (uint32_t *)buf.c;
        verf.adv_timestamp.tv_sec = IXDR_GET_INT32(ixdr) + 1;
        verf.adv_timestamp.tv_usec = IXDR_GET_INT32(ixdr);

        /*
         * validate
         */
        if (bcmp((char *)&ad->ad_timestamp, (char *)&verf.adv_timestamp,
                 sizeof(struct timeval)) != 0) {
                syslog(LOG_DEBUG, "authdes_validate: verifier mismatch");
                return (FALSE);
        }

        /*
         * We have a nickname now, let's use it
         */
        ad->ad_nickname = verf.adv_nickname;
        ad->ad_cred.adc_namekind = ADN_NICKNAME;
        return (TRUE);
}

/*
 * 4. Refresh
 */
/*ARGSUSED*/
static bool_t
authdes_refresh(AUTH *auth, void *dummy __unused)
{
/* LINTED pointer alignment */
        struct ad_private *ad = AUTH_PRIVATE(auth);
        struct authdes_cred *cred = &ad->ad_cred;
        int             ok;
        netobj          pkey;

        if (ad->ad_dosync) {
                ok = __rpc_get_time_offset(&ad->ad_timediff, ad->ad_nis_srvr,
                    ad->ad_timehost, &(ad->ad_uaddr),
                    &(ad->ad_netid));
                if (! ok) {
                        /*
                         * Hope the clocks are synced!
                         */
                        ad->ad_dosync = 0;
                        syslog(LOG_DEBUG,
                            "authdes_refresh: unable to synchronize clock");
                 }
        }
        ad->ad_xkey = auth->ah_key;
        pkey.n_bytes = (char *)(ad->ad_pkey);
        pkey.n_len = (u_int)strlen((char *)ad->ad_pkey) + 1;
        if (key_encryptsession_pk(ad->ad_servername, &pkey, &ad->ad_xkey) < 0) {
                syslog(LOG_INFO,
                    "authdes_refresh: keyserv(1m) is unable to encrypt session key");
                return (FALSE);
        }
        cred->adc_fullname.key = ad->ad_xkey;
        cred->adc_namekind = ADN_FULLNAME;
        cred->adc_fullname.name = ad->ad_fullname;
        return (TRUE);
}


/*
 * 5. Destroy
 */
static void
authdes_destroy(AUTH *auth)
{
/* LINTED pointer alignment */
        struct ad_private *ad = AUTH_PRIVATE(auth);

        FREE(ad->ad_fullname, ad->ad_fullnamelen + 1);
        FREE(ad->ad_servername, ad->ad_servernamelen + 1);
        if (ad->ad_timehost)
                FREE(ad->ad_timehost, strlen(ad->ad_timehost) + 1);
        if (ad->ad_netid)
                FREE(ad->ad_netid, strlen(ad->ad_netid) + 1);
        if (ad->ad_uaddr)
                FREE(ad->ad_uaddr, strlen(ad->ad_uaddr) + 1);
        FREE(ad, sizeof (struct ad_private));
        FREE(auth, sizeof(AUTH));
}

static struct auth_ops *
authdes_ops(void)
{
        static struct auth_ops ops;

        /* VARIABLES PROTECTED BY ops_lock: ops */
 
        mutex_lock(&authdes_ops_lock);
        if (ops.ah_nextverf == NULL) {
                ops.ah_nextverf = authdes_nextverf;
                ops.ah_marshal = authdes_marshal;
                ops.ah_validate = authdes_validate;
                ops.ah_refresh = authdes_refresh;
                ops.ah_destroy = authdes_destroy;
        }
        mutex_unlock(&authdes_ops_lock);
        return (&ops);
}