root/usr.sbin/rbootd/rmpproto.c
/*      $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));
}