fingerd.c revision 1.39
1/* $OpenBSD: fingerd.c,v 1.39 2015/11/13 01:26:33 deraadt Exp $ */ 2 3/* 4 * Copyright (c) 1983, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32#include <sys/socket.h> 33#include <netinet/in.h> 34#include <arpa/inet.h> 35#include <errno.h> 36 37#include <err.h> 38#include <unistd.h> 39#include <syslog.h> 40#include <netdb.h> 41#include <stdio.h> 42#include <stdlib.h> 43#include <string.h> 44#include <stdarg.h> 45#include <limits.h> 46#include "pathnames.h" 47 48__dead void logerr(const char *, ...); 49__dead void usage(void); 50 51void 52usage(void) 53{ 54 syslog(LOG_ERR, 55 "usage: fingerd [-lMmpSsu] [-P filename]"); 56 exit(2); 57} 58 59 60int 61main(int argc, char *argv[]) 62{ 63 FILE *fp; 64 int ch, ac = 2; 65 int p[2], logging, secure, user_required, short_list; 66#define ENTRIES 50 67 char **comp, *prog; 68 char **ap, *av[ENTRIES + 1], line[8192], *lp, *hname; 69 char hostbuf[HOST_NAME_MAX+1]; 70 71 if (pledge("stdio inet dns proc exec", NULL) == -1) 72 err(1, "pledge"); 73 74 prog = _PATH_FINGER; 75 logging = secure = user_required = short_list = 0; 76 openlog("fingerd", LOG_PID, LOG_DAEMON); 77 opterr = 0; 78 while ((ch = getopt(argc, argv, "sluSmMpP:")) != -1) 79 switch (ch) { 80 case 'l': 81 logging = 1; 82 break; 83 case 'P': 84 prog = optarg; 85 break; 86 case 's': 87 secure = 1; 88 break; 89 case 'u': 90 user_required = 1; 91 break; 92 case 'S': 93 if (ac < ENTRIES) { 94 short_list = 1; 95 av[ac++] = "-s"; 96 } 97 break; 98 case 'm': 99 if (ac < ENTRIES) 100 av[ac++] = "-m"; 101 break; 102 case 'M': 103 if (ac < ENTRIES) 104 av[ac++] = "-M"; 105 break; 106 case 'p': 107 if (ac < ENTRIES) 108 av[ac++] = "-p"; 109 break; 110 default: 111 usage(); 112 } 113 114 if (logging) { 115 struct sockaddr_storage ss; 116 struct sockaddr *sa; 117 socklen_t sval; 118 119 sval = sizeof(ss); 120 if (getpeername(0, (struct sockaddr *)&ss, &sval) < 0) 121 err(1, "getpeername"); 122 sa = (struct sockaddr *)&ss; 123 124 if (pledge("stdio dns proc exec", NULL) == -1) 125 err(1, "pledge"); 126 127 if (getnameinfo(sa, sa->sa_len, hostbuf, sizeof(hostbuf), 128 NULL, 0, 0) != 0) { 129 strlcpy(hostbuf, "?", sizeof(hostbuf)); 130 } 131 hname = hostbuf; 132 } 133 134 if (pledge("stdio proc exec", NULL) == -1) 135 err(1, "pledge"); 136 137 if (fgets(line, sizeof(line), stdin) == NULL) { 138 if (logging) 139 syslog(LOG_NOTICE, "query from %s: %s", hname, 140 feof(stdin) ? "EOF" : strerror(errno)); 141 exit(1); 142 } 143 144 if (logging) 145 syslog(LOG_NOTICE, "query from %s: `%.*s'", hname, 146 (int)strcspn(line, "\r\n"), line); 147 148 /* 149 * Note: we assume that finger(1) will treat "--" as end of 150 * command args (ie: that it uses getopt(3)). 151 */ 152 av[ac++] = "--"; 153 comp = &av[1]; 154 for (lp = line, ap = &av[ac]; ac < ENTRIES;) { 155 size_t len; 156 157 if ((*ap = strtok(lp, " \t\r\n")) == NULL) 158 break; 159 lp = NULL; 160 if (secure && strchr(*ap, '@')) { 161 (void) puts("forwarding service denied\r"); 162 exit(1); 163 } 164 165 len = strlen(*ap); 166 while (len > 0 && (*ap)[len - 1] == '@') 167 (*ap)[--len] = '\0'; 168 if (**ap == '\0') 169 continue; 170 171 /* RFC1196: "/[Ww]" == "-l" */ 172 if ((*ap)[0] == '/' && ((*ap)[1] == 'W' || (*ap)[1] == 'w')) { 173 if (!short_list) { 174 av[1] = "-l"; 175 comp = &av[0]; 176 } 177 } else { 178 ap++; 179 ac++; 180 } 181 } 182 av[ENTRIES - 1] = NULL; 183 184 if ((lp = strrchr(prog, '/'))) 185 *comp = ++lp; 186 else 187 *comp = prog; 188 189 if (user_required) { 190 for (ap = comp + 1; strcmp("--", *(ap++)); ) 191 ; 192 if (*ap == NULL) { 193 (void) puts("must provide username\r"); 194 exit(1); 195 } 196 } 197 198 if (pipe(p) < 0) 199 logerr("pipe: %s", strerror(errno)); 200 201 switch (vfork()) { 202 case 0: 203 (void) close(p[0]); 204 if (p[1] != 1) { 205 (void) dup2(p[1], 1); 206 (void) close(p[1]); 207 } 208 execv(prog, comp); 209 syslog(LOG_ERR, "execv: %s: %s", prog, strerror(errno)); 210 _exit(1); 211 case -1: 212 logerr("fork: %s", strerror(errno)); 213 } 214 if (pledge("stdio", NULL) == -1) 215 err(1, "pledge"); 216 217 (void) close(p[1]); 218 if (!(fp = fdopen(p[0], "r"))) 219 logerr("fdopen: %s", strerror(errno)); 220 while ((ch = getc(fp)) != EOF) { 221 if (ch == '\n') 222 putchar('\r'); 223 putchar(ch); 224 } 225 exit(0); 226} 227 228void 229logerr(const char *fmt, ...) 230{ 231 va_list ap; 232 233 va_start(ap, fmt); 234 (void) vsyslog(LOG_ERR, fmt, ap); 235 va_end(ap); 236 exit(1); 237} 238