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  * @(#)fingerd.c        8.1 (Berkeley) 6/4/93
  34  * $FreeBSD: src/libexec/fingerd/fingerd.c,v 1.26 2008/08/04 01:25:48 cperciva Exp $
  35  * $DragonFly: src/libexec/fingerd/fingerd.c,v 1.3 2003/11/14 03:54:29 dillon Exp $
  36  */
  37
  38 #include <sys/types.h>
  39 #include <sys/param.h>
  40 #include <sys/socket.h>
  41 #include <netinet/in.h>
  42 #include <netinet/tcp.h>
  43 #include <arpa/inet.h>
  44 #include <errno.h>
  45
  46 #include <unistd.h>
  47 #include <syslog.h>
  48 #include <libutil.h>
  49 #include <netdb.h>
  50 #include <stdio.h>
  51 #include <stdlib.h>
  52 #include <string.h>
  53 #include "pathnames.h"
  54
  55 void logerr(const char *, ...) __printflike(1, 2) __dead2;
  56
  57 int
  58 main(int argc, char *argv[])
  59 {
  60         FILE *fp;
  61         int ch;
  62         char *lp;
  63         struct sockaddr_storage ss;
  64         socklen_t sval;
  65         int p[2], logging, pflag, secure;
  66 #define ENTRIES 50
  67         char **ap, *av[ENTRIES + 1], **comp, line[1024], *prog;
  68         char rhost[MAXHOSTNAMELEN];
  69
  70         prog = _PATH_FINGER;
  71         logging = pflag = secure = 0;
  72         openlog("fingerd", LOG_PID | LOG_CONS, LOG_DAEMON);
  73         opterr = 0;
  74         while ((ch = getopt(argc, argv, "lp:s")) != -1)
  75                 switch (ch) {
  76                 case 'l':
  77                         logging = 1;
  78                         break;
  79                 case 'p':
  80                         prog = optarg;
  81                         pflag = 1;
  82                         break;
  83                 case 's':
  84                         secure = 1;
  85                         break;
  86                 case '?':
  87                 default:
  88                         logerr("illegal option -- %c", optopt);
  89                 }
  90
  91         /*
  92          * Enable server-side Transaction TCP.
  93          */
  94         {
  95                 int one = 1;
  96                 if (setsockopt(STDOUT_FILENO, IPPROTO_TCP, TCP_NOPUSH, &one,
  97                                sizeof one) < 0) {
  98                         logerr("setsockopt(TCP_NOPUSH) failed: %m");
  99                 }
 100         }
 101
 102         if (!fgets(line, sizeof(line), stdin))
 103                 exit(1);
 104
 105         if (logging || pflag) {
 106                 sval = sizeof(ss);
 107                 if (getpeername(0, (struct sockaddr *)&ss, &sval) < 0)
 108                         logerr("getpeername: %s", strerror(errno));
 109                 realhostname_sa(rhost, sizeof rhost - 1,
 110                                 (struct sockaddr *)&ss, sval);
 111                 rhost[sizeof(rhost) - 1] = '\0';
 112                 if (pflag)
 113                         setenv("FINGERD_REMOTE_HOST", rhost, 1);
 114         }
 115
 116         if (logging) {
 117                 char *t;
 118                 char *end;
 119
 120                 end = memchr(line, 0, sizeof(line));
 121                 if (end == NULL) {
 122                         if ((t = malloc(sizeof(line) + 1)) == NULL)
 123                                 logerr("malloc: %s", strerror(errno));
 124                         memcpy(t, line, sizeof(line));
 125                         t[sizeof(line)] = 0;
 126                 } else {
 127                         if ((t = strdup(line)) == NULL)
 128                                 logerr("strdup: %s", strerror(errno));
 129                 }
 130                 for (end = t; *end; end++)
 131                         if (*end == '\n' || *end == '\r')
 132                                 *end = ' ';
 133                 syslog(LOG_NOTICE, "query from %s: `%s'", rhost, t);
 134         }
 135
 136         comp = &av[1];
 137         av[2] = "--";
 138         for (lp = line, ap = &av[3];;) {
 139                 *ap = strtok(lp, " \t\r\n");
 140                 if (!*ap) {
 141                         if (secure && ap == &av[3]) {
 142                                 puts("must provide username\r\n");
 143                                 exit(1);
 144                         }
 145                         break;
 146                 }
 147                 if (secure && strchr(*ap, '@')) {
 148                         puts("forwarding service denied\r\n");
 149                         exit(1);
 150                 }
 151
 152                 /* RFC742: "/[Ww]" == "-l" */
 153                 if ((*ap)[0] == '/' && ((*ap)[1] == 'W' || (*ap)[1] == 'w')) {
 154                         av[1] = "-l";
 155                         comp = &av[0];
 156                 }
 157                 else if (++ap == av + ENTRIES) {
 158                         *ap = NULL;
 159                         break;
 160                 }
 161                 lp = NULL;
 162         }
 163
 164         if ((lp = strrchr(prog, '/')) != NULL)
 165                 *comp = ++lp;
 166         else
 167                 *comp = prog;
 168         if (pipe(p) < 0)
 169                 logerr("pipe: %s", strerror(errno));
 170
 171         switch(vfork()) {
 172         case 0:
 173                 close(p[0]);
 174                 if (p[1] != STDOUT_FILENO) {
 175                         dup2(p[1], STDOUT_FILENO);
 176                         close(p[1]);
 177                 }
 178                 dup2(STDOUT_FILENO, STDERR_FILENO);
 179
 180                 execv(prog, comp);
 181                 write(STDERR_FILENO, prog, strlen(prog));
 182 #define MSG ": cannot execute\n"
 183                 write(STDERR_FILENO, MSG, strlen(MSG));
 184 #undef MSG
 185                 _exit(1);
 186         case -1:
 187                 logerr("fork: %s", strerror(errno));
 188         }
 189         close(p[1]);
 190         if (!(fp = fdopen(p[0], "r")))
 191                 logerr("fdopen: %s", strerror(errno));
 192         while ((ch = getc(fp)) != EOF) {
 193                 if (ch == '\n')
 194                         putchar('\r');
 195                 putchar(ch);
 196         }
 197         exit(0);
 198 }
 199
 200 #include <stdarg.h>
 201
 202 void
 203 logerr(const char *fmt, ...)
 204 {
 205         va_list ap;
 206         va_start(ap, fmt);
 207         vsyslog(LOG_ERR, fmt, ap);
 208         va_end(ap);
 209         exit(1);
 210         /* NOTREACHED */
 211 }