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      1 /*	$NetBSD: rpc.c,v 1.31 2019/04/05 20:09:29 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1992 Regents of the University of California.
      5  * All rights reserved.
      6  *
      7  * This software was developed by the Computer Systems Engineering group
      8  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
      9  * contributed to Berkeley.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  * 1. Redistributions of source code must retain the above copyright
     15  *    notice, this list of conditions and the following disclaimer.
     16  * 2. Redistributions in binary form must reproduce the above copyright
     17  *    notice, this list of conditions and the following disclaimer in the
     18  *    documentation and/or other materials provided with the distribution.
     19  * 3. All advertising materials mentioning features or use of this software
     20  *    must display the following acknowledgement:
     21  *	This product includes software developed by the University of
     22  *	California, Lawrence Berkeley Laboratory and its contributors.
     23  * 4. Neither the name of the University nor the names of its contributors
     24  *    may be used to endorse or promote products derived from this software
     25  *    without specific prior written permission.
     26  *
     27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     37  * SUCH DAMAGE.
     38  *
     39  * @(#) Header: rpc.c,v 1.12 93/09/28 08:31:56 leres Exp  (LBL)
     40  */
     41 
     42 /*
     43  * RPC functions used by NFS and bootparams.
     44  * Note that bootparams requires the ability to find out the
     45  * address of the server from which its response has come.
     46  * This is supported by keeping the IP/UDP headers in the
     47  * buffer space provided by the caller.  (See rpc_fromaddr)
     48  */
     49 
     50 #include <sys/param.h>
     51 #include <sys/socket.h>
     52 
     53 #include <netinet/in.h>
     54 #include <netinet/in_systm.h>
     55 
     56 #ifdef _STANDALONE
     57 #include <lib/libkern/libkern.h>
     58 #include "stand.h"
     59 #else
     60 #include <string.h>
     61 #include <errno.h>
     62 #include <stdio.h>
     63 #endif
     64 
     65 #include "rpcv2.h"
     66 
     67 #include "net.h"
     68 #include "rpc.h"
     69 
     70 struct auth_info {
     71 	int32_t 	authtype;	/* auth type */
     72 	u_int32_t	authlen;	/* auth length */
     73 };
     74 
     75 struct auth_unix {
     76 	int32_t   ua_time;
     77 	int32_t   ua_hostname;	/* null */
     78 	int32_t   ua_uid;
     79 	int32_t   ua_gid;
     80 	int32_t   ua_gidlist;	/* null */
     81 };
     82 
     83 struct rpc_call {
     84 	u_int32_t	rp_xid;		/* request transaction id */
     85 	int32_t 	rp_direction;	/* call direction (0) */
     86 	u_int32_t	rp_rpcvers;	/* rpc version (2) */
     87 	u_int32_t	rp_prog;	/* program */
     88 	u_int32_t	rp_vers;	/* version */
     89 	u_int32_t	rp_proc;	/* procedure */
     90 };
     91 
     92 struct rpc_reply {
     93 	u_int32_t	rp_xid;		/* request transaction id */
     94 	int32_t 	rp_direction;	/* call direction (1) */
     95 	int32_t 	rp_astatus;	/* accept status (0: accepted) */
     96 	union {
     97 		u_int32_t	rpu_errno;
     98 		struct {
     99 			struct auth_info rok_auth;
    100 			u_int32_t	rok_status;
    101 		} rpu_rok;
    102 	} rp_u;
    103 };
    104 
    105 /* Local forwards */
    106 static	ssize_t recvrpc(struct iodesc *, void *, size_t, saseconds_t);
    107 
    108 int rpc_xid;
    109 int rpc_port = 0x400;	/* predecrement */
    110 
    111 /*
    112  * Make a rpc call; return length of answer
    113  * Note: Caller must leave room for headers.
    114  */
    115 ssize_t
    116 rpc_call(struct iodesc *d, n_long prog, n_long vers, n_long proc,
    117 	void *sdata, size_t slen, void *rdata, size_t rlen)
    118 {
    119 	ssize_t cc;
    120 	struct auth_info *auth;
    121 	struct rpc_call *call;
    122 	struct rpc_reply *reply;
    123 	char *send_head, *send_tail;
    124 	char *recv_head, *recv_tail;
    125 	n_long x;
    126 	int port;	/* host order */
    127 
    128 #ifdef RPC_DEBUG
    129 	if (debug)
    130 		printf("%s: prog=0x%x vers=%d proc=%d\n", __func__,
    131 		    prog, vers, proc);
    132 #endif
    133 
    134 	port = rpc_getport(d, prog, vers);
    135 	if (port == -1)
    136 		return -1;
    137 
    138 	d->destport = htons(port);
    139 
    140 	/*
    141 	 * Prepend authorization stuff and headers.
    142 	 * Note, must prepend things in reverse order.
    143 	 */
    144 	send_head = sdata;
    145 	send_tail = (char *)sdata + slen;
    146 
    147 	/* Auth verifier is always auth_null */
    148 	send_head -= sizeof(*auth);
    149 	auth = (struct auth_info *)send_head;
    150 	auth->authtype = htonl(RPCAUTH_NULL);
    151 	auth->authlen = 0;
    152 
    153 #if 1
    154 	/* Auth credentials: always auth unix (as root) */
    155 	send_head -= sizeof(struct auth_unix);
    156 	(void)memset(send_head, 0, sizeof(struct auth_unix));
    157 	send_head -= sizeof(*auth);
    158 	auth = (struct auth_info *)send_head;
    159 	auth->authtype = htonl(RPCAUTH_UNIX);
    160 	auth->authlen = htonl(sizeof(struct auth_unix));
    161 #else
    162 	/* Auth credentials: always auth_null (XXX OK?) */
    163 	send_head -= sizeof(*auth);
    164 	auth = send_head;
    165 	auth->authtype = htonl(RPCAUTH_NULL);
    166 	auth->authlen = 0;
    167 #endif
    168 
    169 	/* RPC call structure. */
    170 	send_head -= sizeof(*call);
    171 	call = (struct rpc_call *)send_head;
    172 	rpc_xid++;
    173 	call->rp_xid       = htonl(rpc_xid);
    174 	call->rp_direction = htonl(RPC_CALL);
    175 	call->rp_rpcvers   = htonl(RPC_VER2);
    176 	call->rp_prog = htonl(prog);
    177 	call->rp_vers = htonl(vers);
    178 	call->rp_proc = htonl(proc);
    179 
    180 	/* Make room for the rpc_reply header. */
    181 	recv_head = rdata;
    182 	recv_tail = (char *)rdata + rlen;
    183 	recv_head -= sizeof(*reply);
    184 
    185 	cc = sendrecv(d,
    186 	    sendudp, send_head, send_tail - send_head,
    187 	    recvrpc, recv_head, recv_tail - recv_head);
    188 
    189 #ifdef RPC_DEBUG
    190 	if (debug)
    191 		printf("%s: cc=%zd rlen=%zu\n", __func__, cc, rlen);
    192 #endif
    193 	if (cc == -1)
    194 		return -1;
    195 
    196 	if ((size_t)cc <= sizeof(*reply)) {
    197 		errno = EBADRPC;
    198 		return -1;
    199 	}
    200 
    201 	recv_tail = recv_head + cc;
    202 
    203 	/*
    204 	 * Check the RPC reply status.
    205 	 * The xid, dir, astatus were already checked.
    206 	 */
    207 	reply = (struct rpc_reply *)recv_head;
    208 	auth = &reply->rp_u.rpu_rok.rok_auth;
    209 	x = ntohl(auth->authlen);
    210 	if (x != 0) {
    211 #ifdef RPC_DEBUG
    212 		if (debug)
    213 			printf("%s: reply auth != NULL\n", __func__);
    214 #endif
    215 		errno = EBADRPC;
    216 		return -1;
    217 	}
    218 	x = ntohl(reply->rp_u.rpu_rok.rok_status);
    219 	if (x != 0) {
    220 		printf("%s: error = %d\n", __func__, x);
    221 		errno = EBADRPC;
    222 		return -1;
    223 	}
    224 	recv_head += sizeof(*reply);
    225 
    226 	return (ssize_t)(recv_tail - recv_head);
    227 }
    228 
    229 /*
    230  * Returns true if packet is the one we're waiting for.
    231  * This just checks the XID, direction, acceptance.
    232  * Remaining checks are done by callrpc
    233  */
    234 static ssize_t
    235 recvrpc(struct iodesc *d, void *pkt, size_t len, saseconds_t tleft)
    236 {
    237 	struct rpc_reply *reply;
    238 	ssize_t	n;
    239 	int	x;
    240 
    241 	errno = 0;
    242 #ifdef RPC_DEBUG
    243 	if (debug)
    244 		printf("%s: called len=%zu\n", __func__, len);
    245 #endif
    246 
    247 	n = readudp(d, pkt, len, tleft);
    248 	if (n <= (4 * 4))
    249 		return -1;
    250 
    251 	reply = (struct rpc_reply *)pkt;
    252 
    253 	x = ntohl(reply->rp_xid);
    254 	if (x != rpc_xid) {
    255 #ifdef RPC_DEBUG
    256 		if (debug)
    257 			printf("%s: rp_xid %d != xid %d\n",
    258 			    __func__, x, rpc_xid);
    259 #endif
    260 		return -1;
    261 	}
    262 
    263 	x = ntohl(reply->rp_direction);
    264 	if (x != RPC_REPLY) {
    265 #ifdef RPC_DEBUG
    266 		if (debug)
    267 			printf("%s: rp_direction %d != REPLY\n", __func__, x);
    268 #endif
    269 		return -1;
    270 	}
    271 
    272 	x = ntohl(reply->rp_astatus);
    273 	if (x != RPC_MSGACCEPTED) {
    274 		errno = ntohl(reply->rp_u.rpu_errno);
    275 		printf("%s: reject, astat=%d, errno=%d\n", __func__, x, errno);
    276 		return -1;
    277 	}
    278 
    279 	/* Return data count (thus indicating success) */
    280 	return n;
    281 }
    282 
    283 /*
    284  * Given a pointer to a reply just received,
    285  * dig out the IP address/port from the headers.
    286  */
    287 void
    288 rpc_fromaddr(void *pkt, struct in_addr *addr, u_short *port)
    289 {
    290 	struct hackhdr {
    291 		/* Tail of IP header: just IP addresses */
    292 		n_long ip_src;
    293 		n_long ip_dst;
    294 		/* UDP header: */
    295 		u_int16_t uh_sport;		/* source port */
    296 		u_int16_t uh_dport;		/* destination port */
    297 		int16_t	  uh_ulen;		/* udp length */
    298 		u_int16_t uh_sum;		/* udp checksum */
    299 		/* RPC reply header: */
    300 		struct rpc_reply rpc;
    301 	} *hhdr;
    302 
    303 	hhdr = ((struct hackhdr *)pkt) - 1;
    304 	addr->s_addr = hhdr->ip_src;
    305 	*port = hhdr->uh_sport;
    306 }
    307 
    308 #ifdef NO_PMAP_CACHE
    309 #define rpc_pmap_getcache(addr, prog, vers) (-1)
    310 #define rpc_pmap_putcache(addr, prog, vers, port)
    311 #else
    312 
    313 /*
    314  * RPC Portmapper cache
    315  */
    316 #define PMAP_NUM 8			/* need at most 5 pmap entries */
    317 
    318 int rpc_pmap_num;
    319 struct pmap_list {
    320 	struct in_addr	addr;	/* server, net order */
    321 	u_int	prog;		/* host order */
    322 	u_int	vers;		/* host order */
    323 	int 	port;		/* host order */
    324 } rpc_pmap_list[PMAP_NUM];
    325 
    326 /*
    327  * return port number in host order, or -1.
    328  * arguments are:
    329  *  addr .. server, net order.
    330  *  prog .. host order.
    331  *  vers .. host order.
    332  */
    333 int
    334 rpc_pmap_getcache(struct in_addr addr, u_int prog, u_int vers)
    335 {
    336 	struct pmap_list *pl;
    337 
    338 	for (pl = rpc_pmap_list; pl < &rpc_pmap_list[rpc_pmap_num]; pl++) {
    339 		if (pl->addr.s_addr == addr.s_addr &&
    340 			pl->prog == prog && pl->vers == vers )
    341 		{
    342 			return pl->port;
    343 		}
    344 	}
    345 	return -1;
    346 }
    347 
    348 /*
    349  * arguments are:
    350  *  addr .. server, net order.
    351  *  prog .. host order.
    352  *  vers .. host order.
    353  *  port .. host order.
    354  */
    355 void
    356 rpc_pmap_putcache(struct in_addr addr, u_int prog, u_int vers, int port)
    357 {
    358 	struct pmap_list *pl;
    359 
    360 	/* Don't overflow cache... */
    361 	if (rpc_pmap_num >= PMAP_NUM) {
    362 		/* ... just re-use the last entry. */
    363 		rpc_pmap_num = PMAP_NUM - 1;
    364 #ifdef	RPC_DEBUG
    365 		printf("%s: cache overflow\n", __func__);
    366 #endif
    367 	}
    368 
    369 	pl = &rpc_pmap_list[rpc_pmap_num];
    370 	rpc_pmap_num++;
    371 
    372 	/* Cache answer */
    373 	pl->addr = addr;
    374 	pl->prog = prog;
    375 	pl->vers = vers;
    376 	pl->port = port;
    377 }
    378 #endif
    379 
    380 /*
    381  * Request a port number from the port mapper.
    382  * Returns the port in host order.
    383  * prog and vers are host order.
    384  */
    385 int
    386 rpc_getport(struct iodesc *d, n_long prog, n_long vers)
    387 {
    388 	struct args {
    389 		n_long	prog;		/* call program */
    390 		n_long	vers;		/* call version */
    391 		n_long	proto;		/* call protocol */
    392 		n_long	port;		/* call port (unused) */
    393 	} *args;
    394 	struct res {
    395 		n_long port;
    396 	} *res;
    397 	struct {
    398 		n_long	h[RPC_HEADER_WORDS];
    399 		struct args d;
    400 	} sdata;
    401 	struct {
    402 		n_long	h[RPC_HEADER_WORDS];
    403 		struct res d;
    404 		n_long  pad;
    405 	} rdata;
    406 	ssize_t cc;
    407 	int port;
    408 
    409 #ifdef RPC_DEBUG
    410 	if (debug)
    411 		printf("%s: prog=0x%x vers=%d\n", __func__, prog, vers);
    412 #endif
    413 
    414 	/* This one is fixed forever. */
    415 	if (prog == PMAPPROG)
    416 		return PMAPPORT;
    417 
    418 	/* Try for cached answer first */
    419 	port = rpc_pmap_getcache(d->destip, prog, vers);
    420 	if (port != -1)
    421 		return port;
    422 
    423 	args = &sdata.d;
    424 	args->prog = htonl(prog);
    425 	args->vers = htonl(vers);
    426 	args->proto = htonl(IPPROTO_UDP);
    427 	args->port = 0;
    428 	res = &rdata.d;
    429 
    430 	cc = rpc_call(d, PMAPPROG, PMAPVERS, PMAPPROC_GETPORT,
    431 		args, sizeof(*args), res, sizeof(*res));
    432 	if ((size_t)cc < sizeof(*res)) {
    433 		printf("%s: %s", __func__, strerror(errno));
    434 		errno = EBADRPC;
    435 		return -1;
    436 	}
    437 	port = (int)ntohl(res->port);
    438 
    439 	rpc_pmap_putcache(d->destip, prog, vers, port);
    440 
    441 	return port;
    442 }
    443