libexec/fingerd/fingerd.c

   1 /*
   2  * Copyright (c) 1983, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * @(#) Copyright (c) 1983, 1993 The Regents of the University of California.  All rights reserved.
  34  * @(#)fingerd.c        8.1 (Berkeley) 6/4/93
  35  * $FreeBSD: src/libexec/fingerd/fingerd.c,v 1.16.2.3 2002/04/03 09:05:23 mike Exp $
  36  * $DragonFly: src/libexec/fingerd/fingerd.c,v 1.3 2003/11/14 03:54:29 dillon Exp $
  37  */
  38
  39 #include <sys/types.h>
  40 #include <sys/param.h>
  41 #include <sys/socket.h>
  42 #include <netinet/in.h>
  43 #include <netinet/tcp.h>
  44 #include <arpa/inet.h>
  45 #include <errno.h>
  46
  47 #include <unistd.h>
  48 #include <syslog.h>
  49 #include <libutil.h>
  50 #include <netdb.h>
  51 #include <stdio.h>
  52 #include <stdlib.h>
  53 #include <strings.h>
  54 #include "pathnames.h"
  55
  56 void logerr (const char *, ...);
  57
  58 int
  59 main(argc, argv)
  60         int argc;
  61         char *argv[];
  62 {
  63         register FILE *fp;
  64         register int ch;
  65         register char *lp;
  66         struct sockaddr_storage ss;
  67         int p[2], logging, secure, sval;
  68 #define ENTRIES 50
  69         char **ap, *av[ENTRIES + 1], **comp, line[1024], *prog;
  70         char rhost[MAXHOSTNAMELEN];
  71
  72         prog = _PATH_FINGER;
  73         logging = secure = 0;
  74         openlog("fingerd", LOG_PID | LOG_CONS, LOG_DAEMON);
  75         opterr = 0;
  76         while ((ch = getopt(argc, argv, "slp:")) != -1)
  77                 switch (ch) {
  78                 case 'l':
  79                         logging = 1;
  80                         break;
  81                 case 'p':
  82                         prog = optarg;
  83                         break;
  84                 case 's':
  85                         secure = 1;
  86                         break;
  87                 case '?':
  88                 default:
  89                         logerr("illegal option -- %c", optopt);
  90                 }
  91
  92         /*
  93          * Enable server-side Transaction TCP.
  94          */
  95         {
  96                 int one = 1;
  97                 if (setsockopt(STDOUT_FILENO, IPPROTO_TCP, TCP_NOPUSH, &one,
  98                                sizeof one) < 0) {
  99                         logerr("setsockopt(TCP_NOPUSH) failed: %m");
 100                 }
 101         }
 102
 103         if (!fgets(line, sizeof(line), stdin))
 104                 exit(1);
 105
 106         if (logging) {
 107                 char *t;
 108                 char *end;
 109
 110                 end = memchr(line, 0, sizeof(line));
 111                 if (end == NULL) {
 112                         if ((t = malloc(sizeof(line) + 1)) == NULL)
 113                                 logerr("malloc: %s", strerror(errno));
 114                         memcpy(t, line, sizeof(line));
 115                         t[sizeof(line)] = 0;
 116                 } else {
 117                         if ((t = strdup(line)) == NULL)
 118                                 logerr("strdup: %s", strerror(errno));
 119                 }
 120                 for (end = t; *end; end++)
 121                         if (*end == '\n' || *end == '\r')
 122                                 *end = ' ';
 123                 sval = sizeof(ss);
 124                 if (getpeername(0, (struct sockaddr *)&ss, &sval) < 0)
 125                         logerr("getpeername: %s", strerror(errno));
 126                 realhostname_sa(rhost, sizeof rhost - 1,
 127                                 (struct sockaddr *)&ss, sval);
 128                 rhost[sizeof(rhost) - 1] = '\0';
 129                 syslog(LOG_NOTICE, "query from %s: `%s'", rhost, t);
 130         }
 131
 132         comp = &av[1];
 133         av[2] = "--";
 134         for (lp = line, ap = &av[3];;) {
 135                 *ap = strtok(lp, " \t\r\n");
 136                 if (!*ap) {
 137                         if (secure && ap == &av[3]) {
 138                                 puts("must provide username\r\n");
 139                                 exit(1);
 140                         }
 141                         break;
 142                 }
 143                 if (secure && strchr(*ap, '@')) {
 144                         puts("forwarding service denied\r\n");
 145                         exit(1);
 146                 }
 147
 148                 /* RFC742: "/[Ww]" == "-l" */
 149                 if ((*ap)[0] == '/' && ((*ap)[1] == 'W' || (*ap)[1] == 'w')) {
 150                         av[1] = "-l";
 151                         comp = &av[0];
 152                 }
 153                 else if (++ap == av + ENTRIES) {
 154                         *ap = NULL;
 155                         break;
 156                 }
 157                 lp = NULL;
 158         }
 159
 160         if (lp = strrchr(prog, '/'))
 161                 *comp = ++lp;
 162         else
 163                 *comp = prog;
 164         if (pipe(p) < 0)
 165                 logerr("pipe: %s", strerror(errno));
 166
 167         switch(vfork()) {
 168         case 0:
 169                 (void)close(p[0]);
 170                 if (p[1] != 1) {
 171                         (void)dup2(p[1], 1);
 172                         (void)close(p[1]);
 173                 }
 174                 execv(prog, comp);
 175                 logerr("execv: %s: %s", prog, strerror(errno));
 176                 _exit(1);
 177         case -1:
 178                 logerr("fork: %s", strerror(errno));
 179         }
 180         (void)close(p[1]);
 181         if (!(fp = fdopen(p[0], "r")))
 182                 logerr("fdopen: %s", strerror(errno));
 183         while ((ch = getc(fp)) != EOF) {
 184                 if (ch == '\n')
 185                         putchar('\r');
 186                 putchar(ch);
 187         }
 188         exit(0);
 189 }
 190
 191 #if __STDC__
 192 #include <stdarg.h>
 193 #else
 194 #include <varargs.h>
 195 #endif
 196
 197 void
 198 #if __STDC__
 199 logerr(const char *fmt, ...)
 200 #else
 201 logerr(fmt, va_alist)
 202         char *fmt;
 203         va_dcl
 204 #endif
 205 {
 206         va_list ap;
 207 #if __STDC__
 208         va_start(ap, fmt);
 209 #else
 210         va_start(ap);
 211 #endif
 212         (void)vsyslog(LOG_ERR, fmt, ap);
 213         va_end(ap);
 214         exit(1);
 215         /* NOTREACHED */
 216 }