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For open/openat, if the flags parameter does not contain O_CREAT, the
3rd (variadic) mode_t parameter is irrelevant.  Many developers in the past
have passed mode_t (0, 044, 0644, or such), which might lead future people
to copy this broken idiom, and perhaps even believe this parameter has some
meaning or implication or application. Delete them all.
This comes out of a conversation where tb@ noticed that a strange (but
intentional) pledge behaviour is to always knock-out high-bits from
mode_t on a number of system calls as a safety factor, and his bewilderment
that this appeared to be happening against valid modes (at least visually),
but no sorry, they are all irrelevant junk.  They could all be 0xdeafbeef.
ok millert

/*	$OpenBSD: rmpproto.c,v 1.14 2021/10/24 21:24:19 deraadt Exp $	*/
/*	$NetBSD: rmpproto.c,v 1.5.2.1 1995/11/14 08:45:44 thorpej Exp $	*/

/*
 * Copyright (c) 1988, 1992 The University of Utah and the Center
 *	for Software Science (CSS).
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * the Center for Software Science of the University of Utah Computer
 * Science Department.  CSS requests users of this software to return
 * to css-dist@cs.utah.edu any improvements that they make and grant
 * CSS redistribution rights.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. Neither the name of the University 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 REGENTS 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 REGENTS 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.
 *
 *	from: @(#)rmpproto.c	8.1 (Berkeley) 6/4/93
 *
 * From: Utah Hdr: rmpproto.c 3.1 92/07/06
 * Author: Jeff Forys, University of Utah CSS
 */

#include <sys/time.h>

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include "defs.h"

/*
**  ProcessPacket -- determine packet type and do what's required.
**
**	An RMP BOOT packet has been received.  Look at the type field
**	and process Boot Requests, Read Requests, and Boot Complete
**	packets.  Any other type will be dropped with a warning msg.
**
**	Parameters:
**		rconn - the new connection
**		client - list of files available to this host
**
**	Returns:
**		Nothing.
**
**	Side Effects:
**		- If this is a valid boot request, it will be added to
**		  the linked list of outstanding requests (RmpConns).
**		- If this is a valid boot complete, its associated
**		  entry in RmpConns will be deleted.
**		- Also, unless we run out of memory, a reply will be
**		  sent to the host that sent the packet.
*/
void
ProcessPacket(RMPCONN *rconn, CLIENT *client)
{
	struct rmp_packet *rmp = &rconn->rmp;
	RMPCONN *rconnout;

	switch (rmp->r_type) {		/* do what we came here to do */
	case RMP_BOOT_REQ:		/* boot request */
		if ((rconnout = NewConn(rconn)) == NULL)
			return;

		/*
		 *  If the Session ID is 0xffff, this is a "probe"
		 *  packet and we do not want to add the connection
		 *  to the linked list of active connections.  There
		 *  are two types of probe packets, if the Sequence
		 *  Number is 0 they want to know our host name, o/w
		 *  they want the name of the file associated with
		 *  the number spec'd by the Sequence Number.
		 *
		 *  If this is an actual boot request, open the file
		 *  and send a reply.  If SendBootRepl() does not
		 *  return 0, add the connection to the linked list
		 *  of active connections, otherwise delete it since
		 *  an error was encountered.
		 */
		if (ntohs(rmp->r_brq.rmp_session) == RMP_PROBESID) {
			if (WORDZE(rmp->r_brq.rmp_seqno))
				(void) SendServerID(rconnout);
			else
				(void) SendFileNo(rmp, rconnout,
				    client ? client->files : BootFiles);
			FreeConn(rconnout);
		} else {
			if (SendBootRepl(rmp, rconnout,
			    client? client->files: BootFiles))
				AddConn(rconnout);
			else
				FreeConn(rconnout);
		}
		break;

	case RMP_BOOT_REPL:		/* boot reply (not valid) */
		syslog(LOG_WARNING, "%s: sent a boot reply",
		    EnetStr(rconn));
		break;

	case RMP_READ_REQ:		/* read request */
		/*
		 *  Send a portion of the boot file.
		 */
		(void) SendReadRepl(rconn);
		break;

	case RMP_READ_REPL:		/* read reply (not valid) */
		syslog(LOG_WARNING, "%s: sent a read reply",
		    EnetStr(rconn));
		break;

	case RMP_BOOT_DONE:		/* boot complete */
		/*
		 *  Remove the entry from the linked list of active
		 *  connections.
		 */
		(void) BootDone(rconn);
		break;

	default:			/* unknown RMP packet type */
		syslog(LOG_WARNING, "%s: unknown packet type (%u)",
		    EnetStr(rconn), rmp->r_type);
	}
}

/*
**  SendServerID -- send our host name to who ever requested it.
**
**	Parameters:
**		rconn - the reply packet to be formatted.
**
**	Returns:
**		1 on success, 0 on failure.
**
**	Side Effects:
**		none.
*/
int
SendServerID(RMPCONN *rconn)
{
	struct rmp_packet *rpl;
	char *src, *dst;
	u_int8_t *size;

	rpl = &rconn->rmp;			/* cache ptr to RMP packet */

	/*
	 *  Set up assorted fields in reply packet.
	 */
	rpl->r_brpl.rmp_type = RMP_BOOT_REPL;
	rpl->r_brpl.rmp_retcode = RMP_E_OKAY;
	ZEROWORD(rpl->r_brpl.rmp_seqno);
	rpl->r_brpl.rmp_session = 0;
	rpl->r_brpl.rmp_version = htons(RMP_VERSION);

	size = &rpl->r_brpl.rmp_flnmsize;	/* ptr to length of host name */

	/*
	 *  Copy our host name into the reply packet incrementing the
	 *  length as we go.  Stop at RMP_HOSTLEN or the first dot.
	 */
	src = MyHost;
	dst = (char *) &rpl->r_brpl.rmp_flnm;
	for (*size = 0; *size < RMP_HOSTLEN; (*size)++) {
		if (*src == '.' || *src == '\0')
			break;
		*dst++ = *src++;
	}

	rconn->rmplen = RMPBOOTSIZE(*size);	/* set packet length */

	return(SendPacket(rconn));		/* send packet */
}

/*
**  SendFileNo -- send the name of a bootable file to the requester.
**
**	Parameters:
**		req - RMP BOOT packet containing the request.
**		rconn - the reply packet to be formatted.
**		filelist - list of files available to the requester.
**
**	Returns:
**		1 on success, 0 on failure.
**
**	Side Effects:
**		none.
*/
int
SendFileNo(struct rmp_packet *req, RMPCONN *rconn, char *filelist[])
{
	struct rmp_packet *rpl;
	char *src, *dst;
	u_int8_t *size;
	int i;

	GETWORD(req->r_brpl.rmp_seqno, i);	/* SeqNo is really FileNo */
	rpl = &rconn->rmp;			/* cache ptr to RMP packet */

	/*
	 *  Set up assorted fields in reply packet.
	 */
	rpl->r_brpl.rmp_type = RMP_BOOT_REPL;
	PUTWORD(i, rpl->r_brpl.rmp_seqno);
	i--;
	rpl->r_brpl.rmp_session = 0;
	rpl->r_brpl.rmp_version = htons(RMP_VERSION);

	size = &rpl->r_brpl.rmp_flnmsize;	/* ptr to length of filename */
	*size = 0;				/* init length to zero */

	/*
	 *  Copy the file name into the reply packet incrementing the
	 *  length as we go.  Stop at end of string or when RMPBOOTDATA
	 *  characters have been copied.  Also, set return code to
	 *  indicate success or "no more files".
	 */
	if (i < C_MAXFILE && filelist[i] != NULL) {
		src = filelist[i];
		dst = (char *)&rpl->r_brpl.rmp_flnm;
		for (; *src && *size < RMPBOOTDATA; (*size)++) {
			if (*src == '\0')
				break;
			*dst++ = *src++;
		}
		rpl->r_brpl.rmp_retcode = RMP_E_OKAY;
	} else
		rpl->r_brpl.rmp_retcode = RMP_E_NODFLT;

	rconn->rmplen = RMPBOOTSIZE(*size);	/* set packet length */

	return(SendPacket(rconn));		/* send packet */
}

/*
**  SendBootRepl -- open boot file and respond to boot request.
**
**	Parameters:
**		req - RMP BOOT packet containing the request.
**		rconn - the reply packet to be formatted.
**		filelist - list of files available to the requester.
**
**	Returns:
**		1 on success, 0 on failure.
**
**	Side Effects:
**		none.
*/
int
SendBootRepl(struct rmp_packet *req, RMPCONN *rconn, char *filelist[])
{
	int retval;
	char *filename, filepath[RMPBOOTDATA+1];
	RMPCONN *oldconn;
	struct rmp_packet *rpl;
	char *src, *dst1, *dst2;
	u_int8_t i;

	/*
	 *  If another connection already exists, delete it since we
	 *  are obviously starting again.
	 */
	if ((oldconn = FindConn(rconn)) != NULL) {
		syslog(LOG_WARNING, "%s: dropping existing connection",
		    EnetStr(oldconn));
		RemoveConn(oldconn);
	}

	rpl = &rconn->rmp;			/* cache ptr to RMP packet */

	/*
	 *  Set up assorted fields in reply packet.
	 */
	rpl->r_brpl.rmp_type = RMP_BOOT_REPL;
	COPYWORD(req->r_brq.rmp_seqno, rpl->r_brpl.rmp_seqno);
	rpl->r_brpl.rmp_session = htons(GenSessID());
	rpl->r_brpl.rmp_version = htons(RMP_VERSION);
	rpl->r_brpl.rmp_flnmsize = req->r_brq.rmp_flnmsize;

	/*
	 *  Copy file name to `filepath' string, and into reply packet.
	 */
	dst1 = filepath;
	dst2 = &rpl->r_brpl.rmp_flnm;
	if (req->r_brq.rmp_flnmsize)
		src = &req->r_brq.rmp_flnm;
	else {
		/* no file supplied, substitute the first one */
		src = filelist[0];
		req->r_brq.rmp_flnmsize = strlen(src);
	}
	for (i = 0; i < req->r_brq.rmp_flnmsize; i++)
		*dst1++ = *dst2++ = *src++;
	*dst1 = '\0';

	/*
	 *  If we are booting HP-UX machines, their secondary loader will
	 *  ask for files like "/hp-ux".  As a security measure, we do not
	 *  allow boot files to lay outside the boot directory (unless they
	 *  are purposely link'd out.  So, make `filename' become the path-
	 *  stripped file name and spoof the client into thinking that it
	 *  really got what it wanted.
	 */
	if ((filename = strrchr(filepath,'/')) != NULL)
		filename++;
	else
		filename = filepath;

	/*
	 *  Check that this is a valid boot file name.
	 */
	for (i = 0; i < C_MAXFILE && filelist[i] != NULL; i++)
		if (STREQN(filename, filelist[i]))
			goto match;

	/*
	 *  Invalid boot file name, set error and send reply packet.
	 */
	rpl->r_brpl.rmp_retcode = RMP_E_NOFILE;
	retval = 0;
	goto sendpkt;

match:
	/*
	 *  This is a valid boot file.  Open the file and save the file
	 *  descriptor associated with this connection and set success
	 *  indication.  If the file couldnt be opened, set error:
	 *  	"no such file or dir" - RMP_E_NOFILE
	 *	"file table overflow" - RMP_E_BUSY
	 *	"too many open files" - RMP_E_BUSY
	 *	anything else         - RMP_E_OPENFILE
	 */
	if ((rconn->bootfd = open(filename, O_RDONLY)) == -1) {
		rpl->r_brpl.rmp_retcode = (errno == ENOENT)? RMP_E_NOFILE:
			(errno == EMFILE || errno == ENFILE)? RMP_E_BUSY:
			RMP_E_OPENFILE;
		retval = 0;
	} else {
		rpl->r_brpl.rmp_retcode = RMP_E_OKAY;
		retval = 1;
	}

sendpkt:
	syslog(LOG_INFO, "%s: request to boot %s (%s)",
	    EnetStr(rconn), filename, retval? "granted": "denied");

	rconn->rmplen = RMPBOOTSIZE(rpl->r_brpl.rmp_flnmsize);

	return (retval & SendPacket(rconn));
}

/*
**  SendReadRepl -- send a portion of the boot file to the requester.
**
**	Parameters:
**		rconn - the reply packet to be formatted.
**
**	Returns:
**		1 on success, 0 on failure.
**
**	Side Effects:
**		none.
*/
int
SendReadRepl(RMPCONN *rconn)
{
	int retval = 0;
	RMPCONN *oldconn;
	struct rmp_packet *rpl, *req;
	int size = 0;
	int madeconn = 0;

	/*
	 *  Find the old connection.  If one doesnt exist, create one only
	 *  to return the error code.
	 */
	if ((oldconn = FindConn(rconn)) == NULL) {
		if ((oldconn = NewConn(rconn)) == NULL)
			return(0);
		syslog(LOG_ERR, "SendReadRepl: no active connection (%s)",
		    EnetStr(rconn));
		madeconn++;
	}

	req = &rconn->rmp;		/* cache ptr to request packet */
	rpl = &oldconn->rmp;		/* cache ptr to reply packet */

	if (madeconn) {			/* no active connection above; abort */
		rpl->r_rrpl.rmp_retcode = RMP_E_ABORT;
		retval = 1;
		goto sendpkt;
	}

	/*
	 *  Make sure Session ID's match.
	 */
	if (ntohs(req->r_rrq.rmp_session) !=
	    ((rpl->r_type == RMP_BOOT_REPL)? ntohs(rpl->r_brpl.rmp_session):
	    ntohs(rpl->r_rrpl.rmp_session))) {
		syslog(LOG_ERR, "SendReadRepl: bad session id (%s)",
		    EnetStr(rconn));
		rpl->r_rrpl.rmp_retcode = RMP_E_BADSID;
		retval = 1;
		goto sendpkt;
	}

	/*
	 *  If the requester asks for more data than we can fit,
	 *  silently clamp the request size down to RMPREADDATA.
	 *
	 *  N.B. I do not know if this is "legal", however it seems
	 *  to work.  This is necessary for bpfwrite() on machines
	 *  with MCLBYTES less than 1514.
	 */
	if (ntohs(req->r_rrq.rmp_size) > RMPREADDATA)
		req->r_rrq.rmp_size = htons(RMPREADDATA);

	/*
	 *  Position read head on file according to info in request packet.
	 */
	GETWORD(req->r_rrq.rmp_offset, size);
	if (lseek(oldconn->bootfd, (off_t)size, SEEK_SET) == -1) {
		syslog(LOG_ERR, "SendReadRepl: lseek: %m (%s)",
		    EnetStr(rconn));
		rpl->r_rrpl.rmp_retcode = RMP_E_ABORT;
		retval = 1;
		goto sendpkt;
	}

	/*
	 *  Read data directly into reply packet.
	 */
	if ((size = read(oldconn->bootfd, &rpl->r_rrpl.rmp_data,
	    (int) ntohs(req->r_rrq.rmp_size))) <= 0) {
		if (size == -1) {
			syslog(LOG_ERR, "SendReadRepl: read: %m (%s)",
			    EnetStr(rconn));
			rpl->r_rrpl.rmp_retcode = RMP_E_ABORT;
		} else {
			rpl->r_rrpl.rmp_retcode = RMP_E_EOF;
		}
		retval = 1;
		goto sendpkt;
	}

	/*
	 *  Set success indication.
	 */
	rpl->r_rrpl.rmp_retcode = RMP_E_OKAY;

sendpkt:
	/*
	 *  Set up assorted fields in reply packet.
	 */
	rpl->r_rrpl.rmp_type = RMP_READ_REPL;
	COPYWORD(req->r_rrq.rmp_offset, rpl->r_rrpl.rmp_offset);
	rpl->r_rrpl.rmp_session = req->r_rrq.rmp_session;

	oldconn->rmplen = RMPREADSIZE(size);	/* set size of packet */

	retval &= SendPacket(oldconn);		/* send packet */

	if (madeconn)				/* clean up after ourself */
		FreeConn(oldconn);

	return (retval);
}

/*
**  BootDone -- free up memory allocated for a connection.
**
**	Parameters:
**		rconn - incoming boot complete packet.
**
**	Returns:
**		1 on success, 0 on failure.
**
**	Side Effects:
**		none.
*/
int
BootDone(RMPCONN *rconn)
{
	RMPCONN *oldconn;
	struct rmp_packet *rpl;

	/*
	 *  If we cant find the connection, ignore the request.
	 */
	if ((oldconn = FindConn(rconn)) == NULL) {
		syslog(LOG_ERR, "BootDone: no existing connection (%s)",
		    EnetStr(rconn));
		return(0);
	}

	rpl = &oldconn->rmp;			/* cache ptr to RMP packet */

	/*
	 *  Make sure Session ID's match.
	 */
	if (ntohs(rconn->rmp.r_rrq.rmp_session) !=
	    ((rpl->r_type == RMP_BOOT_REPL)? ntohs(rpl->r_brpl.rmp_session):
	    ntohs(rpl->r_rrpl.rmp_session))) {
		syslog(LOG_ERR, "BootDone: bad session id (%s)",
		    EnetStr(rconn));
		return(0);
	}

	RemoveConn(oldconn);			/* remove connection */

	syslog(LOG_INFO, "%s: boot complete", EnetStr(rconn));

	return(1);
}

/*
**  SendPacket -- send an RMP packet to a remote host.
**
**	Parameters:
**		rconn - packet to be sent.
**
**	Returns:
**		1 on success, 0 on failure.
**
**	Side Effects:
**		none.
*/
int
SendPacket(RMPCONN *rconn)
{
	/*
	 *  Set Ethernet Destination address to Source (BPF and the enet
	 *  driver will take care of getting our source address set).
	 */
	bcopy((char *)&rconn->rmp.hp_hdr.saddr[0],
	    (char *)&rconn->rmp.hp_hdr.daddr[0], RMP_ADDRLEN);
	rconn->rmp.hp_hdr.len = htons(rconn->rmplen - sizeof(struct hp_hdr));

	/*
	 *  Reverse 802.2/HP Extended Source & Destination Access Pts.
	 */
	rconn->rmp.hp_llc.dxsap = htons(HPEXT_SXSAP);
	rconn->rmp.hp_llc.sxsap = htons(HPEXT_DXSAP);

	/*
	 *  Last time this connection was active.
	 */
	(void) gettimeofday(&rconn->tstamp, NULL);

	if (DbgFp != NULL)			/* display packet */
		DispPkt(rconn,DIR_SENT);

	/*
	 *  Send RMP packet to remote host.
	 */
	return(BpfWrite(rconn));
}