tftpd.c.test

ks8695的SOHO应用中的tftp部分

{
	static char b_ret[4];
	unsigned long to = atol(val);

	if ( to < 1 || to > 255 )
	  return 0;

	timeout    = to;
	rexmtval   = to;
	maxtimeout = TIMEOUT_LIMIT*to;

	sprintf(*ret = b_ret, "%lu", to);
	return(1);
}

/*
 * Parse RFC2347 style options
 */
void
do_opt(char *opt, char *val, char **ap)
{
     struct options *po;
     char *ret;

     /* Global option-parsing variables initialization */
     blksize_set = 0;
     
     if ( !*opt )
	  return;

     for (po = options; po->o_opt; po++)
	  if (!strcasecmp(po->o_opt, opt)) {
	       if (po->o_fnc(val, &ret)) {
		    if (*ap + strlen(opt) + strlen(ret) + 2 >=
			ackbuf + sizeof(ackbuf)) {
			 nak(ENOSPACE);	/* EOPTNEG? */
			 exit(0);
		    }
		    *ap = strrchr(strcpy(strrchr(strcpy(*ap, opt),'\0') + 1,
					 ret),'\0') + 1;
	       } else {
		    nak(EOPTNEG);
		    exit(0);
	       }
	       break;
	  }
     return;
}


FILE *file;

/*
 * 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.
 *
 * for soho router, strict rule applied,
 * only certain files in certain directories 
 * can be created, read, written
 */
int
validate_access(char *filename, int mode, struct formats *pf)
{
	struct stat stbuf;
	int	fd, wmode;
	char *cp, **dirp;

	tsize_ok = 0;

printf("validate_access:\n");
#if KAM_LATER
	if (!secure) {
		if (*filename != '/')
			return (EACCESS);
		/*
		 * 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);
	}
#endif
	/*
	 * We use different a different permissions scheme if `cancreate' is
	 * set.
	 */
	wmode = O_TRUNC;
	if (stat(filename, &stbuf) < 0) {
		if (!cancreate)
			return (errno == ENOENT ? ENOTFOUND : EACCESS);
		else {
			if ((errno == ENOENT) && (mode != RRQ))
				wmode |= O_CREAT;
			else
				return(EACCESS);
		}
	} else {
		if (mode == RRQ) {
			if ((stbuf.st_mode&(S_IREAD >> 6)) == 0)
				return (EACCESS);
			tsize = stbuf.st_size;
			/* We don't know the tsize if conversion is needed */
			tsize_ok = !pf->f_convert;
		} else {
			if ((stbuf.st_mode&(S_IWRITE >> 6)) == 0)
				return (EACCESS);
			tsize = 0;
			tsize_ok = 1;
		}
	}
	fd = open(filename, mode == RRQ ? O_RDONLY : (O_WRONLY|wmode), 0666);
printf("validate_access: fd=%d filename=%s\n",fd, filename);
	if (fd < 0)
		return (errno + 100);
	/*
	 * If the file was created, set default permissions.
	 */
	if ((wmode & O_CREAT) && fchmod(fd, 0666) < 0) {
		int serrno = errno;

		close(fd);
		unlink(filename);

		return (serrno + 100);
	}
	file = fdopen(fd, (mode == RRQ)? "r":"w");
	if (file == NULL) {
printf("validate_access: fdopen fail\n");
		return (errno + 100);
	}
printf("validate_access: fdopen OK\n");
	return (0);
}

int	timeout;
sigjmp_buf	timeoutbuf;

void
timer(int sig)
{

	timeout += rexmtval;
	if (timeout >= maxtimeout)
		exit(0);
	siglongjmp(timeoutbuf, 1);
}

/*
 * Send the requested file.
 */
void
sendfile(struct formats *pf, struct tftphdr *oap, int oacklen)
{
	struct tftphdr *dp;
	struct tftphdr *ap;    /* ack packet */
	int block = 1, size, n;

	ap = (struct tftphdr *)ackbuf;

        if (oap) {
	     timeout = 0;
	     (void)sigsetjmp(timeoutbuf,1);
oack:
	     if (send(peer, oap, oacklen, 0) != oacklen) {
		  syslog(LOG_ERR, "tftpd: oack: %m\n");
		  goto abort;
	     }
	     for ( ; ; ) {
	          bsd_signal(SIGALRM, timer);
		  alarm(rexmtval);
		  n = recv(peer, ackbuf, sizeof(ackbuf), 0);
		  alarm(0);
		  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) {
		       syslog(LOG_ERR, "tftp: client does not accept "
			      "options\n");
		       goto abort;
		  }
		  if (ap->th_opcode == ACK) {
		       if (ap->th_block == 0)
			    break;
		       /* Resynchronize with the other side */
		       (void)synchnet(peer);
		       goto oack;
		  }
	     }
        }

	dp = r_init();
	do {
		size = readit(file, &dp, pf->f_convert);
		if (size < 0) {
			nak(errno + 100);
			goto abort;
		}
		dp->th_opcode = htons((u_short)DATA);
		dp->th_block = htons((u_short)block);
		timeout = 0;
		(void) sigsetjmp(timeoutbuf,1);

send_data:
		if (send(peer, dp, size + 4, 0) != size + 4) {
			syslog(LOG_ERR, "tftpd: write: %m");
			goto abort;
		}
		read_ahead(file, pf->f_convert);
		for ( ; ; ) {
		        bsd_signal(SIGALRM, timer);
			alarm(rexmtval);	/* read the ack */
			n = recv(peer, ackbuf, sizeof (ackbuf), 0);
			alarm(0);
			if (n < 0) {
				syslog(LOG_ERR, "tftpd: read(ack): %m");
				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;
				}
			}

		}
		block++;
	} while (size == segsize);
abort:
	(void) fclose(file);
}

void
justquit(int sig)
{
	exit(0);
}


/*
 * Receive a file.
 */
void
recvfile(struct formats *pf, struct tftphdr *oap, int oacklen)
{
	struct tftphdr *dp;
	struct tftphdr *ap;    /* ack buffer */
	int block = 0, acksize, n, size;
	int written=0;

printf("recvfile\n");
	dp = w_init();
	do {
		timeout = 0;
		
		if (!block && oap) {
		     ap = (struct tftphdr *)ackbuf;
		     acksize = oacklen;
		} else {
		     ap = (struct tftphdr *)ackbuf;
		     ap->th_opcode = htons((u_short)ACK);
		     ap->th_block = htons((u_short)block);
		     acksize = 4;
		}
		block++;
		(void) sigsetjmp(timeoutbuf,1);
		bsd_signal(SIGALRM, timer);
send_ack:
		if (send(peer, ackbuf, acksize, 0) != acksize) {
			syslog(LOG_ERR, "tftpd: write(ack): %m");
			kd_Log("abort1");
			goto abort;
		}
		written = write_behind(file, pf->f_convert);
		// kd_Log("written4 %d",written);
		if (written < 0) {
			if (written == -1) nak(errno + 100);
			else nak(ENOSPACE);
			kd_Log("tftpd:remove %s errno=0x%x size=%d",pf->filename,errno,size);
			fclose(file);
			unlink(pf->filename);
			kd_Log("abort2");
			goto abort;
		}

		for ( ; ; ) {
		        bsd_signal(SIGALRM, timer);
		  	alarm(rexmtval);
			n = recv(peer, dp, PKTSIZE, 0);
			alarm(0);
			if (n < 0) {		/* really? */
			        kd_Log("tftpd:remove %s errno=0x%x size=%d",
				       pf->filename,errno,size);
			        nak(EUNDEF);
				fclose(file);
				unlink(pf->filename);
				syslog(LOG_ERR, "tftpd: read: %m");
				kd_Log("abort3");
				goto abort;
			}
			//printf("recv %d\n",n);
			dp->th_opcode = ntohs((u_short)dp->th_opcode);
			dp->th_block = ntohs((u_short)dp->th_block);
			if (dp->th_opcode == ERROR) {
			        kd_Log("abort4");
				goto abort;
			}
			if (dp->th_opcode == DATA) {
				if (dp->th_block == block) {
					break;   /* normal */
				}
				kd_Log("synchnet");
				/* Re-synchronize with the other side */
				(void) synchnet(peer);
				if (dp->th_block == (block-1))
					goto send_ack;		/* rexmit */
			}
		}
		/*  size = write(file, dp->th_data, n - 4); */
		size = writeit(file, &dp, n - 4, pf->f_convert);
	  	// kd_Log("size=%d @ %d",size,n-4);
		if (size != (n-4)) {			/* ahem */
			if (size < 0) nak(errno + 100);
			else nak(ENOSPACE);
			kd_Log("abort5");
			goto abort;
		}
	} while (size == segsize);
	written = write_behind(file, pf->f_convert);
	// kd_Log("written3 %d",written);
	(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);

	bsd_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:
	kd_Log("abort_Final");
	return;
}

struct errmsg {
	int	e_code;
	char	*e_msg;
} errmsgs[] = {
	{ EUNDEF,	"Undefined error code" },
	{ ENOTFOUND,	"File not found" },
	{ EACCESS,	"Access violation" },
	{ ENOSPACE,	"Disk full or allocation exceeded" },
	{ EBADOP,	"Illegal TFTP operation" },
	{ EBADID,	"Unknown transfer ID" },
	{ EEXISTS,	"File already exists" },
	{ ENOUSER,	"No such user" },
	{ EOPTNEG,	"Failure to negotiate RFC2347 options" },
	{ -1,		0 }
};

/*
 * Send a nak packet (error message).
 * Error code passed in is one of the
 * standard TFTP codes, or a UNIX errno
 * offset by 100.
 */
void
nak(int error)
{
	struct tftphdr *tp;
	int length;
	struct errmsg *pe;

	tp = (struct tftphdr *)buf;
	tp->th_opcode = htons((u_short)ERROR);
	tp->th_code = htons((u_short)error);
	for (pe = errmsgs; pe->e_code >= 0; pe++)
		if (pe->e_code == error)
			break;
	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;
	if (send(peer, buf, length, 0) != length)
		syslog(LOG_ERR, "nak: %m");
}


#if KAM_LATER    // inetd only
int
main(int argc, char **argv)
{
	struct tftphdr *tp;
	struct passwd *pw;
	struct options *opt;
	struct sockaddr_in myaddr;
	int n = 0;
	int on = 1;
	int fd = 0;
	int pid;
	int c;
	int setrv;
	int timeout = 900;	/* Default timeout */
	char *user = "nobody";	/* Default user */

	__progname = basename(argv[0]);

	openlog(__progname, LOG_PID | LOG_NDELAY, LOG_DAEMON);

	while ((c = getopt(argc, argv, "csu:r:t:")) != -1)
		switch (c) {
		case 'c':
			cancreate = 1;
			break;
		case 's':
			secure = 1;
			break;
		case 't':
		  timeout = atoi(optarg);
		  break;
		case 'u':
		  user = optarg;
		  break;
		case 'r':
		  for ( opt = options ; opt->o_opt ; opt++ ) {
		    if ( !strcasecmp(optarg, opt->o_opt) ) {
		      opt->o_opt = ""; /* Don't support this option */
		      break;
		    }
		  }
		  if ( !opt->o_opt ) {
		        syslog(LOG_ERR, "Unknown option: %s", optarg);
			exit(1);
		  }
		  break;

		default:
			usage();
			break;
		}

	for (; optind != argc; optind++) {
		if (dirs)
			dirs = realloc(dirs, (ndirs+2) * sizeof (char *));
		else
			dirs = calloc(ndirs+2, sizeof(char *));
		if (dirs == NULL) {
			syslog(LOG_ERR, "malloc: %m");
			exit(1);
		}			
		dirs[n++] = argv[optind];
		dirs[n] = NULL;
		ndirs++;
	}

	if (secure) {
		if (ndirs == 0) {
			syslog(LOG_ERR, "no -s directory");
			exit(1);
		}
		if (ndirs > 1) {
			syslog(LOG_ERR, "too many -s directories");
			exit(1);
		}
		if (chdir(dirs[0])) {
			syslog(LOG_ERR, "%s: %m", dirs[0]);
			exit(1);
		}
	}

	pw = getpwnam(user);
	if (!pw) {
		syslog(LOG_ERR, "no user %s: %m", user);
		exit(1);
	}

	if (ioctl(fd, FIONBIO, &on) < 0) {
		syslog(LOG_ERR, "ioctl(FIONBIO): %m");
		exit(1);
	}

	/* This means we don't want to wait() for children */
	bsd_signal(SIGCHLD, SIG_IGN);

	do {
	  fd_set readset;
	  struct timeval tv_timeout;
	  

	  FD_ZERO(&readset);
	  FD_SET(fd, &readset);
	  tv_timeout.tv_sec = timeout;
	  tv_timeout.tv_usec = 0;

	  /* when fired up by inetd or xinetd, descriptors 0, 1 & 2 are
	     sockets to the client */
	  if ( select(fd+1, &readset, NULL, NULL, &tv_timeout) == 0 )
	    exit(0);		/* Timeout, return to inetd */

	  fromlen = sizeof (from);
	  n = myrecvfrom(fd, buf, sizeof (buf), 0,
			 (struct sockaddr *)&from, &fromlen,
			 &myaddr);

	  if (n < 0) {
	    syslog(LOG_ERR, "recvfrom: %m");
	    exit(1);
	  }

#ifdef HAVE_TCPWRAPPERS
	/* Verify if this was a legal request for us.  This has to be
	   done before the chroot, while /etc is still accessible. */
	  request_init(&wrap_request,
		       RQ_DAEMON, __progname,
		       RQ_FILE, fd,
		       RQ_CLIENT_SIN, &from,
		       RQ_SERVER_SIN, &myaddr,
		       0);
	  sock_methods(&wrap_request);
	  if ( hosts_access(&wrap_request) == 0 ) {
	    if ( deny_severity != -1 )
	      syslog(deny_severity, "connection refused from %s",
		     inet_ntoa(from.sin_addr));
	    exit(1);		/* Access denied */
	  } else if ( allow_severity != -1 ) {
	    syslog(allow_severity, "connect from %s",
		   inet_ntoa(from.sin_addr));
	  }
#endif

	/*
	 * Now that we have read the message out of the UDP
	 * socket, we fork and go back to listening to the
	 * socket.
	 */
	  pid = fork();
	  if (pid < 0) {
	    syslog(LOG_ERR, "fork: %m");
	    exit(1);		/* Return to inetd, just in case */
	  }
	} while ( pid > 0 );	/* Parent process continues... */

	/* Child process: handle the actual request here */

	/* Chroot and drop privileges */

	if (secure && chroot(".")) {
		syslog(LOG_ERR, "chroot: %m");
		exit(1);
	}

#ifdef HAVE_SETREGID
	setrv = setregid(pw->pw_gid, pw->pw_gid);
#else
	setrv = setegid(pw->pw_gid) || setgid(pw->pw_gid);
#endif

#ifdef HAVE_SETREUID
	setrv = setrv || setreuid(pw->pw_uid, pw->pw_uid);
#else
	/* Important: setuid() must come first */
	setrv = setrv || setuid(pw->pw_uid) ||
	  (geteuid() != pw->pw_uid && seteuid(pw->pw_uid));
#endif

	if ( setrv ) {
	  syslog(LOG_ERR, "cannot drop privileges: %m");
	  exit(1);
	}

	/* Close file descriptors we don't need */

	from.sin_family = AF_INET;
	alarm(0);
	close(fd);
	close(1);

	/* Process the request... */

	peer = socket(AF_INET, SOCK_DGRAM, 0);
	if (peer < 0) {
		syslog(LOG_ERR, "socket: %m");
		exit(1);
	}
	myaddr.sin_port = htons(0); /* We want a new local port */
	if (bind(peer, (struct sockaddr *)&myaddr, sizeof (myaddr)) < 0) {
		syslog(LOG_ERR, "bind: %m");
		exit(1);
	}
	if (connect(peer, (struct sockaddr *)&from, sizeof(from)) < 0) {
		syslog(LOG_ERR, "connect: %m");
		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(0);
}
#endif