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. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * @(#)fingerd.c        8.1 (Berkeley) 6/4/93
  30  * $FreeBSD: src/libexec/fingerd/fingerd.c,v 1.26 2008/08/04 01:25:48 cperciva Exp $
  31  * $DragonFly: src/libexec/fingerd/fingerd.c,v 1.3 2003/11/14 03:54:29 dillon Exp $
  32  */
  33
  34 #include <sys/types.h>
  35 #include <sys/param.h>
  36 #include <sys/socket.h>
  37 #include <netinet/in.h>
  38 #include <netinet/tcp.h>
  39 #include <arpa/inet.h>
  40 #include <errno.h>
  41
  42 #include <unistd.h>
  43 #include <syslog.h>
  44 #include <libutil.h>
  45 #include <netdb.h>
  46 #include <stdio.h>
  47 #include <stdlib.h>
  48 #include <string.h>
  49 #include "pathnames.h"
  50
  51 void logerr(const char *, ...) __printflike(1, 2) __dead2;
  52
  53 int
  54 main(int argc, char *argv[])
  55 {
  56         FILE *fp;
  57         int ch;
  58         char *lp;
  59         struct sockaddr_storage ss;
  60         socklen_t sval;
  61         int p[2], logging, pflag, secure;
  62 #define ENTRIES 50
  63         char **ap, *av[ENTRIES + 1], **comp, line[1024], *prog;
  64         char rhost[MAXHOSTNAMELEN];
  65
  66         prog = _PATH_FINGER;
  67         logging = pflag = secure = 0;
  68         openlog("fingerd", LOG_PID | LOG_CONS, LOG_DAEMON);
  69         opterr = 0;
  70         while ((ch = getopt(argc, argv, "lp:s")) != -1)
  71                 switch (ch) {
  72                 case 'l':
  73                         logging = 1;
  74                         break;
  75                 case 'p':
  76                         prog = optarg;
  77                         pflag = 1;
  78                         break;
  79                 case 's':
  80                         secure = 1;
  81                         break;
  82                 case '?':
  83                 default:
  84                         logerr("illegal option -- %c", optopt);
  85                 }
  86
  87         /*
  88          * Enable server-side Transaction TCP.
  89          */
  90         {
  91                 int one = 1;
  92                 if (setsockopt(STDOUT_FILENO, IPPROTO_TCP, TCP_NOPUSH, &one,
  93                                sizeof one) < 0) {
  94                         logerr("setsockopt(TCP_NOPUSH) failed: %m");
  95                 }
  96         }
  97
  98         if (!fgets(line, sizeof(line), stdin))
  99                 exit(1);
 100
 101         if (logging || pflag) {
 102                 sval = sizeof(ss);
 103                 if (getpeername(0, (struct sockaddr *)&ss, &sval) < 0)
 104                         logerr("getpeername: %s", strerror(errno));
 105                 realhostname_sa(rhost, sizeof rhost - 1,
 106                                 (struct sockaddr *)&ss, sval);
 107                 rhost[sizeof(rhost) - 1] = '\0';
 108                 if (pflag)
 109                         setenv("FINGERD_REMOTE_HOST", rhost, 1);
 110         }
 111
 112         if (logging) {
 113                 char *t;
 114                 char *end;
 115
 116                 end = memchr(line, 0, sizeof(line));
 117                 if (end == NULL) {
 118                         if ((t = malloc(sizeof(line) + 1)) == NULL)
 119                                 logerr("malloc: %s", strerror(errno));
 120                         memcpy(t, line, sizeof(line));
 121                         t[sizeof(line)] = 0;
 122                 } else {
 123                         if ((t = strdup(line)) == NULL)
 124                                 logerr("strdup: %s", strerror(errno));
 125                 }
 126                 for (end = t; *end; end++)
 127                         if (*end == '\n' || *end == '\r')
 128                                 *end = ' ';
 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, '/')) != NULL)
 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                 close(p[0]);
 170                 if (p[1] != STDOUT_FILENO) {
 171                         dup2(p[1], STDOUT_FILENO);
 172                         close(p[1]);
 173                 }
 174                 dup2(STDOUT_FILENO, STDERR_FILENO);
 175
 176                 execv(prog, comp);
 177                 write(STDERR_FILENO, prog, strlen(prog));
 178 #define MSG ": cannot execute\n"
 179                 write(STDERR_FILENO, MSG, strlen(MSG));
 180 #undef MSG
 181                 _exit(1);
 182         case -1:
 183                 logerr("fork: %s", strerror(errno));
 184         }
 185         close(p[1]);
 186         if (!(fp = fdopen(p[0], "r")))
 187                 logerr("fdopen: %s", strerror(errno));
 188         while ((ch = getc(fp)) != EOF) {
 189                 if (ch == '\n')
 190                         putchar('\r');
 191                 putchar(ch);
 192         }
 193         exit(0);
 194 }
 195
 196 #include <stdarg.h>
 197
 198 void
 199 logerr(const char *fmt, ...)
 200 {
 201         va_list ap;
 202         va_start(ap, fmt);
 203         vsyslog(LOG_ERR, fmt, ap);
 204         va_end(ap);
 205         exit(1);
 206         /* NOTREACHED */
 207 }