BSD 4_3_Reno release

[unix-history] / usr / src / libexec / tftpd / tftpd.c

diff --git a/usr/src/libexec/tftpd/tftpd.c b/usr/src/libexec/tftpd/tftpd.c
index d6ea61f..6e1bd60 100644 (file)
--- a/usr/src/libexec/tftpd/tftpd.c
+++ b/usr/src/libexec/tftpd/tftpd.c
@@ -1,92 +1,168 @@
-/*     tftpd.c 4.6     82/11/15        */
+/*
+ * Copyright (c) 1983 Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that: (1) source distributions retain this entire copyright
+ * notice and comment, and (2) distributions including binaries display
+ * the following acknowledgement:  ``This product includes software
+ * developed by the University of California, Berkeley and its contributors''
+ * in the documentation or other materials provided with the distribution
+ * and in all advertising materials mentioning features or use of this
+ * software. 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#ifndef lint
+char copyright[] =
+"@(#) Copyright (c) 1983 Regents of the University of California.\n\
+ All rights reserved.\n";
+#endif /* not lint */
+
+#ifndef lint
+static char sccsid[] = "@(#)tftpd.c    5.12 (Berkeley) 6/1/90";
+#endif /* not lint */

 
 /*
  * Trivial file transfer protocol server.
 
 /*
  * Trivial file transfer protocol server.

+ *
+ * This version includes many modifications by Jim Guyton <guyton@rand-unix>

  */
  */

+

 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/ioctl.h>
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/ioctl.h>

+#include <sys/wait.h>
+#include <sys/stat.h>
+#include <sys/signal.h>

 
 #include <netinet/in.h>
 
 
 #include <netinet/in.h>
 

-#include <signal.h>
-#include <stat.h>
+#include <arpa/tftp.h>
+
+#include <netdb.h>
+#include <setjmp.h>

 #include <stdio.h>
 #include <stdio.h>

-#include <wait.h>

 #include <errno.h>
 #include <ctype.h>
 #include <errno.h>
 #include <ctype.h>

-#include <netdb.h>
+#include <syslog.h>
+#include <string.h>

 
 

-#include "tftp.h"
+#define        TIMEOUT         5

 
 extern int errno;
 struct sockaddr_in sin = { AF_INET };
 
 extern int errno;
 struct sockaddr_in sin = { AF_INET };

-int    f;
-char   buf[BUFSIZ];
+int    peer;
+int    rexmtval = TIMEOUT;
+int    maxtimeout = 5*TIMEOUT;

 
 

-main(argc, argv)
-       char *argv[];
+#define        PKTSIZE SEGSIZE+4
+char   buf[PKTSIZE];
+char   ackbuf[PKTSIZE];
+struct sockaddr_in from;
+int    fromlen;
+
+#define MAXARG 4
+char   *dirs[MAXARG+1];
+
+main(ac, av)
+       char **av;

 {
 {

-       union wait status;
-       struct sockaddr_in from;

        register struct tftphdr *tp;
        register struct tftphdr *tp;

-       register int n;
-       struct servent *sp;
+       register int n = 0;
+       int on = 1;

 
 

-       sp = getservbyname("tftp", "udp");
-       if (sp == 0) {
-               fprintf(stderr, "tftpd: udp/tftp: unknown service\n");
+       ac--; av++;
+       while (ac-- > 0 && n < MAXARG)
+               dirs[n++] = *av++;
+       openlog("tftpd", LOG_PID, LOG_DAEMON);
+       if (ioctl(0, FIONBIO, &on) < 0) {
+               syslog(LOG_ERR, "ioctl(FIONBIO): %m\n");

                exit(1);
        }
                exit(1);
        }

-       sin.sin_port = htons((u_short)sp->s_port);
-#ifndef DEBUG
-       if (fork())
-               exit(0);
-       for (f = 0; f < 10; f++)
-               (void) close(f);
-       (void) open("/", 0);
-       (void) dup2(0, 1);
-       (void) dup2(0, 2);
-       { int t = open("/dev/tty", 2);
-         if (t >= 0) {
-               ioctl(t, TIOCNOTTY, (char *)0);
-               (void) close(t);
-         }
+       fromlen = sizeof (from);
+       n = recvfrom(0, buf, sizeof (buf), 0,
+           (caddr_t)&from, &fromlen);
+       if (n < 0) {
+               syslog(LOG_ERR, "recvfrom: %m\n");
+               exit(1);

        }
        }

-#endif
-       for (;;) {
-               int fromlen;
-
-               f = socket(AF_INET, SOCK_DGRAM, 0, 0);
-               if (f < 0) {
-                       perror("tftpd: socket");
-                       close(f);
-                       sleep(5);
-                       continue;
-               }
-               while (bind(f, (caddr_t)&sin, sizeof (sin), 0) < 0) {
-                       perror("tftpd: bind");
-                       close(f);
-                       sleep(5);
-                       continue;
+       /*
+        * Now that we have read the message out of the UDP
+        * socket, we fork and exit.  Thus, inetd will go back
+        * to listening to the tftp port, and the next request
+        * to come in will start up a new instance of tftpd.
+        *
+        * We do this so that inetd can run tftpd in "wait" mode.
+        * The problem with tftpd running in "nowait" mode is that
+        * inetd may get one or more successful "selects" on the
+        * tftp port before we do our receive, so more than one
+        * instance of tftpd may be started up.  Worse, if tftpd
+        * break before doing the above "recvfrom", inetd would
+        * spawn endless instances, clogging the system.
+        */
+       {
+               int pid;
+               int i, j;
+
+               for (i = 1; i < 20; i++) {
+                   pid = fork();
+                   if (pid < 0) {
+                               sleep(i);
+                               /*
+                                * flush out to most recently sent request.
+                                *
+                                * This may drop some request, but those
+                                * will be resent by the clients when
+                                * they timeout.  The positive effect of
+                                * this flush is to (try to) prevent more
+                                * than one tftpd being started up to service
+                                * a single request from a single client.
+                                */
+                               j = sizeof from;
+                               i = recvfrom(0, buf, sizeof (buf), 0,
+                                   (caddr_t)&from, &j);
+                               if (i > 0) {
+                                       n = i;
+                                       fromlen = j;
+                               }
+                   } else {
+                               break;
+                   }

                }
                }

-again:
-               fromlen = sizeof (from);
-               n = recvfrom(f, buf, sizeof (buf), 0, (caddr_t)&from, &fromlen);
-               if (n <= 0) {
-                       if (n < 0)
-                               perror("tftpd: recvfrom");
-                       goto again;
+               if (pid < 0) {
+                       syslog(LOG_ERR, "fork: %m\n");
+                       exit(1);
+               } else if (pid != 0) {
+                       exit(0);

                }
                }

-               tp = (struct tftphdr *)buf;
-               tp->th_opcode = ntohs(tp->th_opcode);
-               if (tp->th_opcode == RRQ || tp->th_opcode == WRQ)
-                       if (fork() == 0)
-                               tftp(&from, tp, n);
-               (void) close(f);
-               while (wait3(status, WNOHANG, 0) > 0)
-                       continue;

        }
        }

+       from.sin_family = AF_INET;
+       alarm(0);
+       close(0);
+       close(1);
+       peer = socket(AF_INET, SOCK_DGRAM, 0);
+       if (peer < 0) {
+               syslog(LOG_ERR, "socket: %m\n");
+               exit(1);
+       }
+       if (bind(peer, (caddr_t)&sin, sizeof (sin)) < 0) {
+               syslog(LOG_ERR, "bind: %m\n");
+               exit(1);
+       }
+       if (connect(peer, (caddr_t)&from, sizeof(from)) < 0) {
+               syslog(LOG_ERR, "connect: %m\n");
+               exit(1);
+       }
+       tp = (struct tftphdr *)buf;
+       tp->th_opcode = ntohs(tp->th_opcode);
+       if (tp->th_opcode == RRQ || tp->th_opcode == WRQ)
+               tftp(tp, n);
+       exit(1);

 }
 
 int    validate_access();
 }
 
 int    validate_access();


@@ -97,22 +173,20 @@ struct formats {
        int     (*f_validate)();
        int     (*f_send)();
        int     (*f_recv)();
        int     (*f_validate)();
        int     (*f_send)();
        int     (*f_recv)();

+       int     f_convert;

 } formats[] = {
 } formats[] = {

-       { "netascii",   validate_access,        sendfile,       recvfile },
-       { "octet",      validate_access,        sendfile,       recvfile },
+       { "netascii",   validate_access,        sendfile,       recvfile, 1 },
+       { "octet",      validate_access,        sendfile,       recvfile, 0 },

 #ifdef notdef
 #ifdef notdef

-       { "mail",       validate_user,          sendmail,       recvmail },
+       { "mail",       validate_user,          sendmail,       recvmail, 1 },

 #endif
        { 0 }
 };
 
 #endif
        { 0 }
 };
 

-int    fd;                     /* file being transferred */
-

 /*
  * Handle initial connection protocol.
  */
 /*
  * Handle initial connection protocol.
  */

-tftp(client, tp, size)
-       struct sockaddr_in *client;
+tftp(tp, size)

        struct tftphdr *tp;
        int size;
 {
        struct tftphdr *tp;
        int size;
 {


@@ -121,10 +195,6 @@ tftp(client, tp, size)
        register struct formats *pf;
        char *filename, *mode;
 
        register struct formats *pf;
        char *filename, *mode;
 

-       if (connect(f, (caddr_t)client, sizeof (*client), 0) < 0) {
-               perror("connect");
-               exit(1);
-       }

        filename = cp = tp->th_stuff;
 again:
        while (cp < buf + size) {
        filename = cp = tp->th_stuff;
 again:
        while (cp < buf + size) {


@@ -151,7 +221,7 @@ again:
                nak(EBADOP);
                exit(1);
        }
                nak(EBADOP);
                exit(1);
        }

-       ecode = (*pf->f_validate)(filename, client, tp->th_opcode);
+       ecode = (*pf->f_validate)(filename, tp->th_opcode);

        if (ecode) {
                nak(ecode);
                exit(1);
        if (ecode) {
                nak(ecode);
                exit(1);


@@ -163,24 +233,42 @@ again:
        exit(0);
 }
 
        exit(0);
 }
 

+
+FILE *file;
+

 /*
  * Validate file access.  Since we
  * have no uid or gid, for now require
  * file to exist and be publicly
  * readable/writable.
 /*
  * Validate file access.  Since we
  * have no uid or gid, for now require
  * file to exist and be publicly
  * readable/writable.

+ * If we were invoked with arguments
+ * from inetd then the file must also be
+ * in one of the given directory prefixes.

  * Note also, full path name must be
  * given as we have no login directory.
  */
  * Note also, full path name must be
  * given as we have no login directory.
  */

-validate_access(file, client, mode)
-       char *file;
-       struct sockaddr_in *client;
+validate_access(filename, mode)
+       char *filename;

        int mode;
 {
        struct stat stbuf;
        int mode;
 {
        struct stat stbuf;

+       int     fd;
+       char *cp, **dirp;

 
 

-       if (*file != '/')
+       if (*filename != '/')

                return (EACCESS);
                return (EACCESS);

-       if (stat(file, &stbuf) < 0)
+       /*
+        * prevent tricksters from getting around the directory restrictions
+        */
+       for (cp = filename + 1; *cp; cp++)
+               if(*cp == '.' && strncmp(cp-1, "/../", 4) == 0)
+                       return(EACCESS);
+       for (dirp = dirs; *dirp; dirp++)
+               if (strncmp(filename, *dirp, strlen(*dirp)) == 0)
+                       break;
+       if (*dirp==0 && dirp!=dirs)
+               return (EACCESS);
+       if (stat(filename, &stbuf) < 0)

                return (errno == ENOENT ? ENOTFOUND : EACCESS);
        if (mode == RRQ) {
                if ((stbuf.st_mode&(S_IREAD >> 6)) == 0)
                return (errno == ENOENT ? ENOTFOUND : EACCESS);
        if (mode == RRQ) {
                if ((stbuf.st_mode&(S_IREAD >> 6)) == 0)


@@ -189,125 +277,169 @@ validate_access(file, client, mode)
                if ((stbuf.st_mode&(S_IWRITE >> 6)) == 0)
                        return (EACCESS);
        }
                if ((stbuf.st_mode&(S_IWRITE >> 6)) == 0)
                        return (EACCESS);
        }

-       fd = open(file, mode == RRQ ? 0 : 1);
+       fd = open(filename, mode == RRQ ? 0 : 1);

        if (fd < 0)
                return (errno + 100);
        if (fd < 0)
                return (errno + 100);

+       file = fdopen(fd, (mode == RRQ)? "r":"w");
+       if (file == NULL) {
+               return errno+100;
+       }

        return (0);
 }
 
        return (0);
 }
 

-int timeout;
+int    timeout;
+jmp_buf        timeoutbuf;

 
 timer()
 {
 
 timer()
 {

-       timeout += TIMEOUT;
-       if (timeout >= MAXTIMEOUT)
+
+       timeout += rexmtval;
+       if (timeout >= maxtimeout)

                exit(1);
                exit(1);

-       alarm(TIMEOUT);
+       longjmp(timeoutbuf, 1);

 }
 
 /*
  * Send the requested file.
  */
 sendfile(pf)
 }
 
 /*
  * Send the requested file.
  */
 sendfile(pf)

-       struct format *pf;
+       struct formats *pf;

 {
 {

-       register struct tftphdr *tp;
+       struct tftphdr *dp, *r_init();
+       register struct tftphdr *ap;    /* ack packet */

        register int block = 1, size, n;
 
        register int block = 1, size, n;
 

-       sigset(SIGALRM, timer);
-       tp = (struct tftphdr *)buf;
+       signal(SIGALRM, timer);
+       dp = r_init();
+       ap = (struct tftphdr *)ackbuf;

        do {
        do {

-               size = read(fd, tp->th_data, SEGSIZE);
+               size = readit(file, &dp, pf->f_convert);

                if (size < 0) {
                        nak(errno + 100);
                if (size < 0) {
                        nak(errno + 100);

-                       break;
+                       goto abort;

                }
                }

-               tp->th_opcode = htons((u_short)DATA);
-               tp->th_block = htons((u_short)block);
+               dp->th_opcode = htons((u_short)DATA);
+               dp->th_block = htons((u_short)block);

                timeout = 0;
                timeout = 0;

-               alarm(TIMEOUT);
-rexmt:
-               if (write(f, buf, size + 4) != size + 4) {
-                       perror("send");
-                       break;
+               (void) setjmp(timeoutbuf);
+
+send_data:
+               if (send(peer, dp, size + 4, 0) != size + 4) {
+                       syslog(LOG_ERR, "tftpd: write: %m\n");
+                       goto abort;

                }
                }

-again:
-               n = read(f, buf, sizeof (buf));
-               if (n <= 0) {
-                       if (n == 0)
-                               goto again;
-                       if (errno == EINTR)
-                               goto rexmt;
+               read_ahead(file, pf->f_convert);
+               for ( ; ; ) {
+                       alarm(rexmtval);        /* read the ack */
+                       n = recv(peer, ackbuf, sizeof (ackbuf), 0);

                        alarm(0);
                        alarm(0);

-                       perror("receive");
-                       break;
+                       if (n < 0) {
+                               syslog(LOG_ERR, "tftpd: read: %m\n");
+                               goto abort;
+                       }
+                       ap->th_opcode = ntohs((u_short)ap->th_opcode);
+                       ap->th_block = ntohs((u_short)ap->th_block);
+
+                       if (ap->th_opcode == ERROR)
+                               goto abort;
+                       
+                       if (ap->th_opcode == ACK) {
+                               if (ap->th_block == block) {
+                                       break;
+                               }
+                               /* Re-synchronize with the other side */
+                               (void) synchnet(peer);
+                               if (ap->th_block == (block -1)) {
+                                       goto send_data;
+                               }
+                       }
+

                }
                }

-               alarm(0);
-#if vax || pdp11
-               tp->th_opcode = ntohs((u_short)tp->th_opcode);
-               tp->th_block = ntohs((u_short)tp->th_block);
-#endif
-               if (tp->th_opcode == ERROR)
-                       break;
-               if (tp->th_opcode != ACK || tp->th_block != block)
-                       goto again;

                block++;
        } while (size == SEGSIZE);
                block++;
        } while (size == SEGSIZE);

-       (void) close(fd);
+abort:
+       (void) fclose(file);
+}
+
+justquit()
+{
+       exit(0);

 }
 
 }
 

+

 /*
  * Receive a file.
  */
 recvfile(pf)
 /*
  * Receive a file.
  */
 recvfile(pf)

-       struct format *pf;
+       struct formats *pf;

 {
 {

-       register struct tftphdr *tp;
+       struct tftphdr *dp, *w_init();
+       register struct tftphdr *ap;    /* ack buffer */

        register int block = 0, n, size;
 
        register int block = 0, n, size;
 

-       sigset(SIGALRM, timer);
-       tp = (struct tftphdr *)buf;
+       signal(SIGALRM, timer);
+       dp = w_init();
+       ap = (struct tftphdr *)ackbuf;

        do {
                timeout = 0;
        do {
                timeout = 0;

-               alarm(TIMEOUT);
-               tp->th_opcode = htons((u_short)ACK);
-               tp->th_block = htons((u_short)block);
+               ap->th_opcode = htons((u_short)ACK);
+               ap->th_block = htons((u_short)block);

                block++;
                block++;

-rexmt:
-               if (write(f, buf, 4) != 4) {
-                       perror("ack");
-                       break;
+               (void) setjmp(timeoutbuf);
+send_ack:
+               if (send(peer, ackbuf, 4, 0) != 4) {
+                       syslog(LOG_ERR, "tftpd: write: %m\n");
+                       goto abort;

                }
                }

-again:
-               n = read(f, buf, sizeof (buf));
-               if (n <= 0) {
-                       if (n == 0)
-                               goto again;
-                       if (errno == EINTR)
-                               goto rexmt;
+               write_behind(file, pf->f_convert);
+               for ( ; ; ) {
+                       alarm(rexmtval);
+                       n = recv(peer, dp, PKTSIZE, 0);

                        alarm(0);
                        alarm(0);

-                       perror("receive");
-                       break;
+                       if (n < 0) {            /* really? */
+                               syslog(LOG_ERR, "tftpd: read: %m\n");
+                               goto abort;
+                       }
+                       dp->th_opcode = ntohs((u_short)dp->th_opcode);
+                       dp->th_block = ntohs((u_short)dp->th_block);
+                       if (dp->th_opcode == ERROR)
+                               goto abort;
+                       if (dp->th_opcode == DATA) {
+                               if (dp->th_block == block) {
+                                       break;   /* normal */
+                               }
+                               /* Re-synchronize with the other side */
+                               (void) synchnet(peer);
+                               if (dp->th_block == (block-1))
+                                       goto send_ack;          /* rexmit */
+                       }

                }
                }

-               alarm(0);
-#if vax || pdp11
-               tp->th_opcode = ntohs((u_short)tp->th_opcode);
-               tp->th_block = ntohs((u_short)tp->th_block);
-#endif
-               if (tp->th_opcode == ERROR)
-                       break;
-               if (tp->th_opcode != DATA || block != tp->th_block)
-                       goto again;
-               size = write(fd, tp->th_data, n - 4);
-               if (size < 0) {
-                       nak(errno + 100);
-                       break;
+               /*  size = write(file, dp->th_data, n - 4); */
+               size = writeit(file, &dp, n - 4, pf->f_convert);
+               if (size != (n-4)) {                    /* ahem */
+                       if (size < 0) nak(errno + 100);
+                       else nak(ENOSPACE);
+                       goto abort;

                }
        } while (size == SEGSIZE);
                }
        } while (size == SEGSIZE);

-       tp->th_opcode = htons((u_short)ACK);
-       tp->th_block = htons((u_short)(block));
-       (void) write(f, buf, 4);
-       (void) close(fd);
+       write_behind(file, pf->f_convert);
+       (void) fclose(file);            /* close data file */
+
+       ap->th_opcode = htons((u_short)ACK);    /* send the "final" ack */
+       ap->th_block = htons((u_short)(block));
+       (void) send(peer, ackbuf, 4, 0);
+
+       signal(SIGALRM, justquit);      /* just quit on timeout */
+       alarm(rexmtval);
+       n = recv(peer, buf, sizeof (buf), 0); /* normally times out and quits */
+       alarm(0);
+       if (n >= 4 &&                   /* if read some data */
+           dp->th_opcode == DATA &&    /* and got a data block */
+           block == dp->th_block) {    /* then my last ack was lost */
+               (void) send(peer, ackbuf, 4, 0);     /* resend final ack */
+       }
+abort:
+       return;

 }
 
 struct errmsg {
 }
 
 struct errmsg {


@@ -337,7 +469,6 @@ nak(error)
        register struct tftphdr *tp;
        int length;
        register struct errmsg *pe;
        register struct tftphdr *tp;
        int length;
        register struct errmsg *pe;

-       extern char *sys_errlist[];

 
        tp = (struct tftphdr *)buf;
        tp->th_opcode = htons((u_short)ERROR);
 
        tp = (struct tftphdr *)buf;
        tp->th_opcode = htons((u_short)ERROR);


@@ -345,12 +476,14 @@ nak(error)
        for (pe = errmsgs; pe->e_code >= 0; pe++)
                if (pe->e_code == error)
                        break;
        for (pe = errmsgs; pe->e_code >= 0; pe++)
                if (pe->e_code == error)
                        break;

-       if (pe->e_code < 0)
-               pe->e_msg = sys_errlist[error - 100];
+       if (pe->e_code < 0) {
+               pe->e_msg = strerror(error - 100);
+               tp->th_code = EUNDEF;   /* set 'undef' errorcode */
+       }

        strcpy(tp->th_msg, pe->e_msg);
        length = strlen(pe->e_msg);
        tp->th_msg[length] = '\0';
        length += 5;
        strcpy(tp->th_msg, pe->e_msg);
        length = strlen(pe->e_msg);
        tp->th_msg[length] = '\0';
        length += 5;

-       if (write(f, buf, length) != length)
-               perror("nak");
+       if (send(peer, buf, length, 0) != length)
+               syslog(LOG_ERR, "nak: %m\n");

 }
 }