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/*

 * Copyright (c) 1988 by Sun Microsystems, Inc.

 */

/*

 * Sun RPC is a product of Sun Microsystems, Inc. and is provided for

 * unrestricted use provided that this legend is included on all tape

 * media and as a part of the software program in whole or part.  Users

 * may copy or modify Sun RPC without charge, but are not authorized

 * to license or distribute it to anyone else except as part of a product or

 * program developed by the user.

 *

 * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE

 * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.

 *

 * Sun RPC is provided with no support and without any obligation on the

 * part of Sun Microsystems, Inc. to assist in its use, correction,

 * modification or enhancement.

 *

 * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE

 * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC

 * OR ANY PART THEREOF.

 *

 * In no event will Sun Microsystems, Inc. be liable for any lost revenue

 * or profits or other special, indirect and consequential damages, even if

 * Sun has been advised of the possibility of such damages.

 *

 * Sun Microsystems, Inc.

 * 2550 Garcia Avenue

 * Mountain View, California  94043

 */

/*

 * svcauth_des.c, server-side des authentication

 *

 * We insure for the service the following:

 * (1) The timestamp microseconds do not exceed 1 million.

 * (2) The timestamp plus the window is less than the current time.

 * (3) The timestamp is not less than the one previously

 *     seen in the current session.

 *

 * It is up to the server to determine if the window size is

 * too small .

 *

 */

#include <string.h>

#include <stdlib.h>

#include <unistd.h>

#include <rpc/des_crypt.h>

#include <sys/param.h>

#include <netinet/in.h>

#include <rpc/types.h>

#include <rpc/xdr.h>

#include <rpc/auth.h>

#include <rpc/auth_des.h>

#include <rpc/svc.h>

#include <rpc/rpc_msg.h>

#include <rpc/svc_auth.h>

#if defined(LIBC_SCCS) && !defined(lint)

/* from: static char sccsid[] =         "@(#)svcauth_des.c      2.3 89/07/11 4.0 RPCSRC; from 1.15 88/02/08 SMI"; */

static const char rcsid[] = "$FreeBSD: src/lib/libc/rpc/svc_auth_des.c,v 1.3 1999/08/28 00:00:48 peter Exp $";

#endif

#define debug(msg)       printf("svcauth_des: %s\n", msg) 

#define USEC_PER_SEC ((u_long) 1000000L)

#define BEFORE(t1, t2) timercmp(t1, t2, <)

/*

 * LRU cache of conversation keys and some other useful items.

 */

#define AUTHDES_CACHESZ 64

struct cache_entry {

        des_block key;          /* conversation key */

        char *rname;            /* client's name */

        u_int window;           /* credential lifetime window */

        struct timeval laststamp;       /* detect replays of creds */

        char *localcred;        /* generic local credential */

};

static struct cache_entry *authdes_cache/* [AUTHDES_CACHESZ] */;

static short *authdes_lru/* [AUTHDES_CACHESZ] */;

static void cache_init();       /* initialize the cache */

static short cache_spot();      /* find an entry in the cache */

static void cache_ref(/*short sid*/);   /* note that sid was ref'd */

static void invalidate();       /* invalidate entry in cache */

/*

 * cache statistics

 */

static struct {

        u_long ncachehits;      /* times cache hit, and is not replay */

        u_long ncachereplays;   /* times cache hit, and is replay */

        u_long ncachemisses;    /* times cache missed */

} svcauthdes_stats;

/*

 * Service side authenticator for AUTH_DES

 */

enum auth_stat

_svcauth_des(rqst, msg)

        register struct svc_req *rqst;

        register struct rpc_msg *msg;

{

        register long *ixdr;

        des_block cryptbuf[2];

        register struct authdes_cred *cred;

        struct authdes_verf verf;

        int status;

        register struct cache_entry *entry;

        short sid = 0;

        des_block *sessionkey;

        des_block ivec;

        u_int window;

        struct timeval timestamp;

        u_long namelen;

        struct area {

                struct authdes_cred area_cred;

                char area_netname[MAXNETNAMELEN+1];

        } *area;

        if (authdes_cache == NULL) {

                cache_init();

        }

        area = (struct area *)rqst->rq_clntcred;

        cred = (struct authdes_cred *)&area->area_cred;

        /*

         * Get the credential

         */

        ixdr = (long *)msg->rm_call.cb_cred.oa_base;

        cred->adc_namekind = IXDR_GET_ENUM(ixdr, enum authdes_namekind);

        switch (cred->adc_namekind) {

        case ADN_FULLNAME:

                namelen = IXDR_GET_U_LONG(ixdr);

                if (namelen > MAXNETNAMELEN) {

                        return (AUTH_BADCRED);

                }

                cred->adc_fullname.name = area->area_netname;

                bcopy((char *)ixdr, cred->adc_fullname.name,

                        (u_int)namelen);

                cred->adc_fullname.name[namelen] = 0;

                ixdr += (RNDUP(namelen) / BYTES_PER_XDR_UNIT);

                cred->adc_fullname.key.key.high = (u_long)*ixdr++;

                cred->adc_fullname.key.key.low = (u_long)*ixdr++;

                cred->adc_fullname.window = (u_long)*ixdr++;

                break;

        case ADN_NICKNAME:

                cred->adc_nickname = (u_long)*ixdr++;

                break;

        default:

                return (AUTH_BADCRED);

        }

        /*

         * Get the verifier

         */

        ixdr = (long *)msg->rm_call.cb_verf.oa_base;

        verf.adv_xtimestamp.key.high = (u_long)*ixdr++;

        verf.adv_xtimestamp.key.low =  (u_long)*ixdr++;

        verf.adv_int_u = (u_long)*ixdr++;

        /*

         * Get the conversation key

         */

        if (cred->adc_namekind == ADN_FULLNAME) {

                netobj pkey;

                char pkey_data[1024];

                sessionkey = &cred->adc_fullname.key;

                if (! getpublickey(cred->adc_fullname.name, pkey_data)) {

                        debug("getpublickey");

                        return(AUTH_BADCRED);

                }

                pkey.n_bytes = pkey_data;

                pkey.n_len = strlen(pkey_data) + 1;

                if (key_decryptsession_pk(cred->adc_fullname.name, &pkey,

                                       sessionkey) < 0) {

                        debug("decryptsessionkey");

                        return (AUTH_BADCRED); /* key not found */

                }

        } else { /* ADN_NICKNAME */

                sid = (short)cred->adc_nickname;

                if (sid >= AUTHDES_CACHESZ) {

                        debug("bad nickname");

                        return (AUTH_BADCRED);  /* garbled credential */

                }

                sessionkey = &authdes_cache[sid].key;

        }

        /*

         * Decrypt the timestamp

         */

        cryptbuf[0] = verf.adv_xtimestamp;

        if (cred->adc_namekind == ADN_FULLNAME) {

                cryptbuf[1].key.high = cred->adc_fullname.window;

                cryptbuf[1].key.low = verf.adv_winverf;

                ivec.key.high = ivec.key.low = 0;

                status = cbc_crypt((char *)sessionkey, (char *)cryptbuf,

                        2*sizeof(des_block), DES_DECRYPT | DES_HW,

                        (char *)&ivec);

        } else {

                status = ecb_crypt((char *)sessionkey, (char *)cryptbuf,

                        sizeof(des_block), DES_DECRYPT | DES_HW);

        }

        if (DES_FAILED(status)) {

                debug("decryption failure");

                return (AUTH_FAILED);   /* system error */

        }

        /*

         * XDR the decrypted timestamp

         */

        ixdr = (long *)cryptbuf;

        timestamp.tv_sec = IXDR_GET_LONG(ixdr);

        timestamp.tv_usec = IXDR_GET_LONG(ixdr);

        /*

         * Check for valid credentials and verifiers.

         * They could be invalid because the key was flushed

         * out of the cache, and so a new session should begin.

         * Be sure and send AUTH_REJECTED{CRED, VERF} if this is the case.

         */

        {

                struct timeval current;

                int nick;

                int winverf;

                if (cred->adc_namekind == ADN_FULLNAME) {

                        window = IXDR_GET_U_LONG(ixdr);

                        winverf = IXDR_GET_U_LONG(ixdr);

                        if (winverf != window - 1) {

                                debug("window verifier mismatch");

                                return (AUTH_BADCRED);  /* garbled credential */

                        }

                        sid = cache_spot(sessionkey, cred->adc_fullname.name,

                            &timestamp);

                        if (sid < 0) {

                                debug("replayed credential");

                                return (AUTH_REJECTEDCRED);     /* replay */

                        }

                        nick = 0;

                } else {        /* ADN_NICKNAME */

                        window = authdes_cache[sid].window;

                        nick = 1;

                }

                if ((u_long)timestamp.tv_usec >= USEC_PER_SEC) {

                        debug("invalid usecs");

                        /* cached out (bad key), or garbled verifier */

                        return (nick ? AUTH_REJECTEDVERF : AUTH_BADVERF);

                }

                if (nick && BEFORE(&timestamp,

                                   &authdes_cache[sid].laststamp)) {

                        debug("timestamp before last seen");

                        return (AUTH_REJECTEDVERF);     /* replay */

                }

                (void) gettimeofday(&current, (struct timezone *)NULL);

                current.tv_sec -= window;       /* allow for expiration */

                if (!BEFORE(&current, &timestamp)) {

                        debug("timestamp expired");

                        /* replay, or garbled credential */

                        return (nick ? AUTH_REJECTEDVERF : AUTH_BADCRED);

                }

        }

        /*

         * Set up the reply verifier

         */

        verf.adv_nickname = (u_long)sid;

        /*

         * xdr the timestamp before encrypting

         */

        ixdr = (long *)cryptbuf;

        IXDR_PUT_LONG(ixdr, timestamp.tv_sec - 1);

        IXDR_PUT_LONG(ixdr, timestamp.tv_usec);

        /*

         * encrypt the timestamp

         */

        status = ecb_crypt((char *)sessionkey, (char *)cryptbuf,

            sizeof(des_block), DES_ENCRYPT | DES_HW);

        if (DES_FAILED(status)) {

                debug("encryption failure");

                return (AUTH_FAILED);   /* system error */

        }

        verf.adv_xtimestamp = cryptbuf[0];

        /*

         * Serialize the reply verifier, and update rqst

         */

        ixdr = (long *)msg->rm_call.cb_verf.oa_base;

        *ixdr++ = (long)verf.adv_xtimestamp.key.high;

        *ixdr++ = (long)verf.adv_xtimestamp.key.low;

        *ixdr++ = (long)verf.adv_int_u;

        rqst->rq_xprt->xp_verf.oa_flavor = AUTH_DES;

        rqst->rq_xprt->xp_verf.oa_base = msg->rm_call.cb_verf.oa_base;

        rqst->rq_xprt->xp_verf.oa_length =

                (char *)ixdr - msg->rm_call.cb_verf.oa_base;

        /*

         * We succeeded, commit the data to the cache now and

         * finish cooking the credential.

         */

        entry = &authdes_cache[sid];

        entry->laststamp = timestamp;

        cache_ref(sid);

        if (cred->adc_namekind == ADN_FULLNAME) {

                cred->adc_fullname.window = window;

                cred->adc_nickname = (u_long)sid;       /* save nickname */

                if (entry->rname != NULL) {

                        mem_free(entry->rname, strlen(entry->rname) + 1);

                }

                entry->rname = (char *)mem_alloc((u_int)strlen(cred->adc_fullname.name)

                                         + 1);

                if (entry->rname != NULL) {

                        (void) strcpy(entry->rname, cred->adc_fullname.name);

                } else {

                        debug("out of memory");

                }

                entry->key = *sessionkey;

                entry->window = window;

                invalidate(entry->localcred); /* mark any cached cred invalid */

        } else { /* ADN_NICKNAME */

                /*

                 * nicknames are cooked into fullnames

                 */

                cred->adc_namekind = ADN_FULLNAME;

                cred->adc_fullname.name = entry->rname;

                cred->adc_fullname.key = entry->key;

                cred->adc_fullname.window = entry->window;

        }

        return (AUTH_OK);       /* we made it!*/

}

/*

 * Initialize the cache

 */

static void

cache_init()

{

        register int i;

        authdes_cache = (struct cache_entry *)

                mem_alloc(sizeof(struct cache_entry) * AUTHDES_CACHESZ);

        bzero((char *)authdes_cache,

                sizeof(struct cache_entry) * AUTHDES_CACHESZ);

        authdes_lru = (short *)mem_alloc(sizeof(short) * AUTHDES_CACHESZ);

        /*

         * Initialize the lru list

         */

        for (i = 0; i < AUTHDES_CACHESZ; i++) {

                authdes_lru[i] = i;

        }

}

/*

 * Find the lru victim

 */

static short

cache_victim()

{

        return (authdes_lru[AUTHDES_CACHESZ-1]);

}

/*

 * Note that sid was referenced

 */

static void

cache_ref(sid)

        register short sid;

{

        register int i;

        register short curr;

        register short prev;

        prev = authdes_lru[0];

        authdes_lru[0] = sid;

        for (i = 1; prev != sid; i++) {

                curr = authdes_lru[i];

                authdes_lru[i] = prev;

                prev = curr;

        }

}

/*

 * Find a spot in the cache for a credential containing

 * the items given.  Return -1 if a replay is detected, otherwise

 * return the spot in the cache.

 */

static short

cache_spot(key, name, timestamp)

        register des_block *key;

        char *name;

        struct timeval *timestamp;

{

        register struct cache_entry *cp;

        register int i;

        register u_long hi;

        hi = key->key.high;

        for (cp = authdes_cache, i = 0; i < AUTHDES_CACHESZ; i++, cp++) {

                if (cp->key.key.high == hi &&

                    cp->key.key.low == key->key.low &&

                    cp->rname != NULL &&

                    bcmp(cp->rname, name, strlen(name) + 1) == 0) {

                        if (BEFORE(timestamp, &cp->laststamp)) {

                                svcauthdes_stats.ncachereplays++;

                                return (-1); /* replay */

                        }

                        svcauthdes_stats.ncachehits++;

                        return (i);     /* refresh */

                }

        }

        svcauthdes_stats.ncachemisses++;

        return (cache_victim());        /* new credential */

}

#if (defined(sun) || defined(vax) || defined(__FreeBSD__))

/*

 * Local credential handling stuff.

 * NOTE: bsd unix dependent.

 * Other operating systems should put something else here.

 */

#define UNKNOWN         -2      /* grouplen, if cached cred is unknown user */

#define INVALID         -1      /* grouplen, if cache entry is invalid */

struct bsdcred {

        short uid;              /* cached uid */

        short gid;              /* cached gid */

        short grouplen; /* length of cached groups */

        short groups[NGROUPS];  /* cached groups */

};

/*

 * Map a des credential into a unix cred.

 * We cache the credential here so the application does

 * not have to make an rpc call every time to interpret

 * the credential.

 */

int

authdes_getucred(adc, uid, gid, grouplen, groups)

        struct authdes_cred *adc;

        uid_t *uid;

        gid_t *gid;

        int *grouplen;

        register gid_t *groups;

{

        unsigned sid;

        register int i;

        uid_t i_uid;

        gid_t i_gid;

        int i_grouplen;

        struct bsdcred *cred;

        sid = adc->adc_nickname;

        if (sid >= AUTHDES_CACHESZ) {

                debug("invalid nickname");

                return (0);

        }

        cred = (struct bsdcred *)authdes_cache[sid].localcred;

        if (cred == NULL) {

                cred = (struct bsdcred *)mem_alloc(sizeof(struct bsdcred));

                authdes_cache[sid].localcred = (char *)cred;

                cred->grouplen = INVALID;

        }

        if (cred->grouplen == INVALID) {

                /*

                 * not in cache: lookup

                 */

                if (!netname2user(adc->adc_fullname.name, &i_uid, &i_gid,

                        &i_grouplen, groups))

                {

                        debug("unknown netname");

                        cred->grouplen = UNKNOWN;       /* mark as lookup up, but not found */

                        return (0);

                }

                debug("missed ucred cache");

                *uid = cred->uid = i_uid;

                *gid = cred->gid = i_gid;

                *grouplen = cred->grouplen = i_grouplen;

                for (i = i_grouplen - 1; i >= 0; i--) {

                        cred->groups[i] = groups[i]; /* int to short */

                }

                return (1);

        } else if (cred->grouplen == UNKNOWN) {

                /*

                 * Already lookup up, but no match found

                 */

                return (0);

        }

        /*

         * cached credentials

         */

        *uid = cred->uid;

        *gid = cred->gid;

        *grouplen = cred->grouplen;

        for (i = cred->grouplen - 1; i >= 0; i--) {

                groups[i] = cred->groups[i];    /* short to int */

        }

        return (1);

}

static void

invalidate(cred)

        char *cred;

{

        if (cred == NULL) {

                return;

        }

        ((struct bsdcred *)cred)->grouplen = INVALID;

}

#endif