| 1 |  |  | /*	$OpenBSD: comsat.c,v 1.48 2017/04/03 17:23:39 tedu Exp $	*/ | 
    
    | 2 |  |  |  | 
    
    | 3 |  |  | /* | 
    
    | 4 |  |  |  * Copyright (c) 1980, 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/limits.h> | 
    
    | 33 |  |  | #include <sys/socket.h> | 
    
    | 34 |  |  | #include <sys/stat.h> | 
    
    | 35 |  |  | #include <sys/wait.h> | 
    
    | 36 |  |  |  | 
    
    | 37 |  |  | #include <netinet/in.h> | 
    
    | 38 |  |  |  | 
    
    | 39 |  |  | #include <ctype.h> | 
    
    | 40 |  |  | #include <errno.h> | 
    
    | 41 |  |  | #include <fcntl.h> | 
    
    | 42 |  |  | #include <netdb.h> | 
    
    | 43 |  |  | #include <limits.h> | 
    
    | 44 |  |  | #include <paths.h> | 
    
    | 45 |  |  | #include <pwd.h> | 
    
    | 46 |  |  | #include <signal.h> | 
    
    | 47 |  |  | #include <stdio.h> | 
    
    | 48 |  |  | #include <stdlib.h> | 
    
    | 49 |  |  | #include <string.h> | 
    
    | 50 |  |  | #include <syslog.h> | 
    
    | 51 |  |  | #include <termios.h> | 
    
    | 52 |  |  | #include <unistd.h> | 
    
    | 53 |  |  | #include <utmp.h> | 
    
    | 54 |  |  | #include <vis.h> | 
    
    | 55 |  |  | #include <err.h> | 
    
    | 56 |  |  |  | 
    
    | 57 |  |  | int	debug = 0; | 
    
    | 58 |  |  | #define	dsyslog	if (debug) syslog | 
    
    | 59 |  |  |  | 
    
    | 60 |  |  | #define MAXIDLE	120 | 
    
    | 61 |  |  |  | 
    
    | 62 |  |  | char	hostname[HOST_NAME_MAX+1]; | 
    
    | 63 |  |  | struct	utmp *utmp = NULL; | 
    
    | 64 |  |  | time_t	lastmsgtime; | 
    
    | 65 |  |  | int	nutmp, uf; | 
    
    | 66 |  |  |  | 
    
    | 67 |  |  | void jkfprintf(FILE *, char[], off_t); | 
    
    | 68 |  |  | void mailfor(char *); | 
    
    | 69 |  |  | void notify(struct utmp *, off_t); | 
    
    | 70 |  |  | void readutmp(int); | 
    
    | 71 |  |  | void doreadutmp(void); | 
    
    | 72 |  |  | void reapchildren(int); | 
    
    | 73 |  |  |  | 
    
    | 74 |  |  | volatile sig_atomic_t wantreadutmp; | 
    
    | 75 |  |  |  | 
    
    | 76 |  |  | int | 
    
    | 77 |  |  | main(int argc, char *argv[]) | 
    
    | 78 |  |  | { | 
    
    | 79 |  |  | 	struct sockaddr_storage from; | 
    
    | 80 |  |  | 	struct sigaction sa; | 
    
    | 81 |  |  | 	ssize_t cc; | 
    
    | 82 |  |  | 	socklen_t fromlen; | 
    
    | 83 |  |  | 	char msgbuf[100]; | 
    
    | 84 |  |  | 	sigset_t sigset; | 
    
    | 85 |  |  |  | 
    
    | 86 |  |  | 	/* verify proper invocation */ | 
    
    | 87 |  |  | 	fromlen = sizeof(from); | 
    
    | 88 |  |  | 	if (getsockname(0, (struct sockaddr *)&from, &fromlen) == -1) { | 
    
    | 89 |  |  | 		(void)fprintf(stderr, | 
    
    | 90 |  |  | 		    "comsat: getsockname: %s.\n", strerror(errno)); | 
    
    | 91 |  |  | 		exit(1); | 
    
    | 92 |  |  | 	} | 
    
    | 93 |  |  |  | 
    
    | 94 |  |  | 	if (pledge("stdio rpath wpath proc tty flock cpath", NULL) == -1) | 
    
    | 95 |  |  | 		err(1, "pledge"); | 
    
    | 96 |  |  |  | 
    
    | 97 |  |  | 	openlog("comsat", LOG_PID, LOG_DAEMON); | 
    
    | 98 |  |  | 	if (chdir(_PATH_MAILDIR)) { | 
    
    | 99 |  |  | 		syslog(LOG_ERR, "chdir: %s: %m", _PATH_MAILDIR); | 
    
    | 100 |  |  | 		(void) recv(0, msgbuf, sizeof(msgbuf) - 1, 0); | 
    
    | 101 |  |  | 		exit(1); | 
    
    | 102 |  |  | 	} | 
    
    | 103 |  |  | 	if ((uf = open(_PATH_UTMP, O_RDONLY)) == -1) { | 
    
    | 104 |  |  | 		syslog(LOG_ERR, "open: %s: %m", _PATH_UTMP); | 
    
    | 105 |  |  | 		(void) recv(0, msgbuf, sizeof(msgbuf) - 1, 0); | 
    
    | 106 |  |  | 		exit(1); | 
    
    | 107 |  |  | 	} | 
    
    | 108 |  |  | 	(void)time(&lastmsgtime); | 
    
    | 109 |  |  | 	(void)gethostname(hostname, sizeof(hostname)); | 
    
    | 110 |  |  | 	doreadutmp(); | 
    
    | 111 |  |  |  | 
    
    | 112 |  |  | 	(void)signal(SIGTTOU, SIG_IGN); | 
    
    | 113 |  |  |  | 
    
    | 114 |  |  | 	bzero(&sa, sizeof sa); | 
    
    | 115 |  |  | 	sigemptyset(&sa.sa_mask); | 
    
    | 116 |  |  | 	sa.sa_handler = readutmp; | 
    
    | 117 |  |  | 	sa.sa_flags = 0;			/* no SA_RESTART */ | 
    
    | 118 |  |  | 	(void)sigaction(SIGALRM, &sa, NULL); | 
    
    | 119 |  |  |  | 
    
    | 120 |  |  | 	sa.sa_handler = reapchildren; | 
    
    | 121 |  |  | 	sa.sa_flags = SA_RESTART; | 
    
    | 122 |  |  | 	(void)sigaction(SIGCHLD, &sa, NULL); | 
    
    | 123 |  |  |  | 
    
    | 124 |  |  | 	for (;;) { | 
    
    | 125 |  |  | 		if (wantreadutmp) { | 
    
    | 126 |  |  | 			wantreadutmp = 0; | 
    
    | 127 |  |  | 			doreadutmp(); | 
    
    | 128 |  |  | 		} | 
    
    | 129 |  |  |  | 
    
    | 130 |  |  | 		cc = recv(0, msgbuf, sizeof(msgbuf) - 1, 0); | 
    
    | 131 |  |  | 		if (cc <= 0) { | 
    
    | 132 |  |  | 			if (errno != EINTR) | 
    
    | 133 |  |  | 				sleep(1); | 
    
    | 134 |  |  | 			continue; | 
    
    | 135 |  |  | 		} | 
    
    | 136 |  |  | 		if (!nutmp)		/* no one has logged in yet */ | 
    
    | 137 |  |  | 			continue; | 
    
    | 138 |  |  | 		sigemptyset(&sigset); | 
    
    | 139 |  |  | 		sigaddset(&sigset, SIGALRM); | 
    
    | 140 |  |  | 		sigprocmask(SIG_SETMASK, &sigset, NULL); | 
    
    | 141 |  |  | 		msgbuf[cc] = '\0'; | 
    
    | 142 |  |  | 		(void)time(&lastmsgtime); | 
    
    | 143 |  |  | 		mailfor(msgbuf); | 
    
    | 144 |  |  | 		sigemptyset(&sigset); | 
    
    | 145 |  |  | 		sigprocmask(SIG_SETMASK, &sigset, NULL); | 
    
    | 146 |  |  | 	} | 
    
    | 147 |  |  | } | 
    
    | 148 |  |  |  | 
    
    | 149 |  |  | /* ARGSUSED */ | 
    
    | 150 |  |  | void | 
    
    | 151 |  |  | reapchildren(int signo) | 
    
    | 152 |  |  | { | 
    
    | 153 |  |  | 	int save_errno = errno; | 
    
    | 154 |  |  |  | 
    
    | 155 |  |  | 	while (wait3(NULL, WNOHANG, NULL) > 0) | 
    
    | 156 |  |  | 		; | 
    
    | 157 |  |  | 	errno = save_errno; | 
    
    | 158 |  |  | } | 
    
    | 159 |  |  |  | 
    
    | 160 |  |  | /* ARGSUSED */ | 
    
    | 161 |  |  | void | 
    
    | 162 |  |  | readutmp(int signo) | 
    
    | 163 |  |  | { | 
    
    | 164 |  |  | 	wantreadutmp = 1; | 
    
    | 165 |  |  | } | 
    
    | 166 |  |  |  | 
    
    | 167 |  |  | void | 
    
    | 168 |  |  | doreadutmp(void) | 
    
    | 169 |  |  | { | 
    
    | 170 |  |  | 	static u_int utmpsize;		/* last malloced size for utmp */ | 
    
    | 171 |  |  | 	static time_t utmpmtime;	/* last modification time for utmp */ | 
    
    | 172 |  |  | 	struct stat statbf; | 
    
    | 173 |  |  | 	int n; | 
    
    | 174 |  |  |  | 
    
    | 175 |  |  | 	if (time(NULL) - lastmsgtime >= MAXIDLE) | 
    
    | 176 |  |  | 		exit(0); | 
    
    | 177 |  |  | 	(void)fstat(uf, &statbf); | 
    
    | 178 |  |  | 	if (statbf.st_mtime > utmpmtime) { | 
    
    | 179 |  |  | 		utmpmtime = statbf.st_mtime; | 
    
    | 180 |  |  | 		/* avoid int overflow */ | 
    
    | 181 |  |  | 		if (statbf.st_size > INT_MAX - 10 * sizeof(struct utmp)) { | 
    
    | 182 |  |  | 			syslog(LOG_ALERT, "utmp file excessively large"); | 
    
    | 183 |  |  | 			exit(1); | 
    
    | 184 |  |  | 		} | 
    
    | 185 |  |  | 		if (statbf.st_size > utmpsize) { | 
    
    | 186 |  |  | 			u_int nutmpsize = statbf.st_size + 10 * | 
    
    | 187 |  |  | 			    sizeof(struct utmp); | 
    
    | 188 |  |  | 			struct utmp *u; | 
    
    | 189 |  |  |  | 
    
    | 190 |  |  | 			if ((u = recallocarray(utmp, utmpsize, | 
    
    | 191 |  |  | 			    nutmpsize, 1)) == NULL) { | 
    
    | 192 |  |  | 				free(utmp); | 
    
    | 193 |  |  | 				syslog(LOG_ERR, "%s", strerror(errno)); | 
    
    | 194 |  |  | 				exit(1); | 
    
    | 195 |  |  | 			} | 
    
    | 196 |  |  | 			utmp = u; | 
    
    | 197 |  |  | 			utmpsize = nutmpsize; | 
    
    | 198 |  |  | 		} | 
    
    | 199 |  |  | 		n = pread(uf, utmp, statbf.st_size, 0); | 
    
    | 200 |  |  | 		if (n == -1) | 
    
    | 201 |  |  | 			n = 0; | 
    
    | 202 |  |  | 		nutmp = n / sizeof(struct utmp); | 
    
    | 203 |  |  | 		dsyslog(LOG_DEBUG, "read %d utmp entries", nutmp); | 
    
    | 204 |  |  | 	} | 
    
    | 205 |  |  | 	(void)alarm(15); | 
    
    | 206 |  |  | } | 
    
    | 207 |  |  |  | 
    
    | 208 |  |  | void | 
    
    | 209 |  |  | mailfor(char *name) | 
    
    | 210 |  |  | { | 
    
    | 211 |  |  | 	struct utmp *utp = &utmp[nutmp]; | 
    
    | 212 |  |  | 	char utname[UT_NAMESIZE+1]; | 
    
    | 213 |  |  | 	const char *errstr; | 
    
    | 214 |  |  | 	char *cp; | 
    
    | 215 |  |  | 	off_t offset; | 
    
    | 216 |  |  |  | 
    
    | 217 |  |  | 	dsyslog(LOG_DEBUG, "mail for '%s'", name); | 
    
    | 218 |  |  | 	if (!(cp = strchr(name, '@'))) | 
    
    | 219 |  |  | 		return; | 
    
    | 220 |  |  | 	*cp++ = '\0'; | 
    
    | 221 |  |  | 	cp[strcspn(cp, " \t\n")] = '\0'; | 
    
    | 222 |  |  | 	offset = strtonum(cp, 0, LLONG_MAX, &errstr); | 
    
    | 223 |  |  | 	if (errstr) { | 
    
    | 224 |  |  | 		syslog(LOG_ERR, "'%s' is %s", cp + 1, errstr); | 
    
    | 225 |  |  | 		return; | 
    
    | 226 |  |  | 	} | 
    
    | 227 |  |  | 	while (--utp >= utmp) { | 
    
    | 228 |  |  | 		memcpy(utname, utp->ut_name, UT_NAMESIZE); | 
    
    | 229 |  |  | 		utname[UT_NAMESIZE] = '\0'; | 
    
    | 230 |  |  | 		dsyslog(LOG_DEBUG, "check %s against %s", name, utname); | 
    
    | 231 |  |  | 		if (!strncmp(utname, name, UT_NAMESIZE)) | 
    
    | 232 |  |  | 			notify(utp, offset); | 
    
    | 233 |  |  | 	} | 
    
    | 234 |  |  | } | 
    
    | 235 |  |  |  | 
    
    | 236 |  |  | static char *cr; | 
    
    | 237 |  |  |  | 
    
    | 238 |  |  | void | 
    
    | 239 |  |  | notify(struct utmp *utp, off_t offset) | 
    
    | 240 |  |  | { | 
    
    | 241 |  |  | 	int fd; | 
    
    | 242 |  |  | 	FILE *tp; | 
    
    | 243 |  |  | 	struct stat stb; | 
    
    | 244 |  |  | 	struct termios ttybuf; | 
    
    | 245 |  |  | 	char tty[PATH_MAX], name[UT_NAMESIZE + 1]; | 
    
    | 246 |  |  |  | 
    
    | 247 |  |  | 	(void)snprintf(tty, sizeof(tty), "%s%.*s", | 
    
    | 248 |  |  | 	    _PATH_DEV, (int)sizeof(utp->ut_line), utp->ut_line); | 
    
    | 249 |  |  | 	if (strchr(tty + sizeof(_PATH_DEV) - 1, '/')) { | 
    
    | 250 |  |  | 		/* A slash is an attempt to break security... */ | 
    
    | 251 |  |  | 		syslog(LOG_AUTH | LOG_NOTICE, "'/' in \"%s\"", tty); | 
    
    | 252 |  |  | 		return; | 
    
    | 253 |  |  | 	} | 
    
    | 254 |  |  | 	if (stat(tty, &stb) || !(stb.st_mode & S_IEXEC)) { | 
    
    | 255 |  |  | 		dsyslog(LOG_DEBUG, "%.*s: wrong mode on %s", | 
    
    | 256 |  |  | 		    (int)sizeof(utp->ut_name), utp->ut_name, tty); | 
    
    | 257 |  |  | 		return; | 
    
    | 258 |  |  | 	} | 
    
    | 259 |  |  | 	dsyslog(LOG_DEBUG, "notify %.*s on %s", (int)sizeof(utp->ut_name), | 
    
    | 260 |  |  | 	    utp->ut_name, tty); | 
    
    | 261 |  |  | 	if (fork()) | 
    
    | 262 |  |  | 		return; | 
    
    | 263 |  |  | 	(void)signal(SIGALRM, SIG_DFL); | 
    
    | 264 |  |  | 	(void)alarm(30); | 
    
    | 265 |  |  | 	fd = open(tty, O_WRONLY); | 
    
    | 266 |  |  | 	if (fd == -1 || (tp = fdopen(fd, "w")) == NULL) { | 
    
    | 267 |  |  | 		dsyslog(LOG_ERR, "%s: %s", tty, strerror(errno)); | 
    
    | 268 |  |  | 		_exit(1); | 
    
    | 269 |  |  | 	} | 
    
    | 270 |  |  | 	(void)tcgetattr(fileno(tp), &ttybuf); | 
    
    | 271 |  |  | 	cr = (ttybuf.c_oflag & ONLCR) && (ttybuf.c_oflag & OPOST) ? | 
    
    | 272 |  |  | 	    "\n" : "\n\r"; | 
    
    | 273 |  |  | 	memcpy(name, utp->ut_name, UT_NAMESIZE); | 
    
    | 274 |  |  | 	name[UT_NAMESIZE] = '\0'; | 
    
    | 275 |  |  | 	(void)fprintf(tp, "%s\007New mail for %s@%.*s\007 has arrived:%s----%s", | 
    
    | 276 |  |  | 	    cr, name, (int)sizeof(hostname), hostname, cr, cr); | 
    
    | 277 |  |  | 	jkfprintf(tp, name, offset); | 
    
    | 278 |  |  | 	(void)fclose(tp); | 
    
    | 279 |  |  | 	_exit(0); | 
    
    | 280 |  |  | } | 
    
    | 281 |  |  |  | 
    
    | 282 |  |  | void | 
    
    | 283 |  |  | jkfprintf(FILE *tp, char name[], off_t offset) | 
    
    | 284 |  |  | { | 
    
    | 285 |  |  | 	char *cp, ch; | 
    
    | 286 |  |  | 	char visout[5], *s2; | 
    
    | 287 |  |  | 	FILE *fi; | 
    
    | 288 |  |  | 	int linecnt, charcnt, inheader; | 
    
    | 289 |  |  | 	char line[BUFSIZ]; | 
    
    | 290 |  |  |  | 
    
    | 291 |  |  | 	if ((fi = fopen(name, "r")) == NULL) | 
    
    | 292 |  |  | 		return; | 
    
    | 293 |  |  |  | 
    
    | 294 |  |  | 	(void)fseeko(fi, offset, SEEK_SET); | 
    
    | 295 |  |  | 	/* | 
    
    | 296 |  |  | 	 * Print the first 7 lines or 560 characters of the new mail | 
    
    | 297 |  |  | 	 * (whichever comes first).  Skip header crap other than | 
    
    | 298 |  |  | 	 * From, Subject, To, and Date. | 
    
    | 299 |  |  | 	 */ | 
    
    | 300 |  |  | 	linecnt = 7; | 
    
    | 301 |  |  | 	charcnt = 560; | 
    
    | 302 |  |  | 	inheader = 1; | 
    
    | 303 |  |  | 	while (fgets(line, sizeof(line), fi) != NULL) { | 
    
    | 304 |  |  | 		if (inheader) { | 
    
    | 305 |  |  | 			if (line[0] == '\n') { | 
    
    | 306 |  |  | 				inheader = 0; | 
    
    | 307 |  |  | 				continue; | 
    
    | 308 |  |  | 			} | 
    
    | 309 |  |  | 			if (line[0] == ' ' || line[0] == '\t' || | 
    
    | 310 |  |  | 			    (strncmp(line, "From:", 5) && | 
    
    | 311 |  |  | 			    strncmp(line, "Subject:", 8))) | 
    
    | 312 |  |  | 				continue; | 
    
    | 313 |  |  | 		} | 
    
    | 314 |  |  | 		if (linecnt <= 0 || charcnt <= 0) { | 
    
    | 315 |  |  | 			(void)fprintf(tp, "...more...%s", cr); | 
    
    | 316 |  |  | 			(void)fclose(fi); | 
    
    | 317 |  |  | 			return; | 
    
    | 318 |  |  | 		} | 
    
    | 319 |  |  | 		/* strip weird stuff so can't trojan horse stupid terminals */ | 
    
    | 320 |  |  | 		for (cp = line; (ch = *cp) && ch != '\n'; ++cp, --charcnt) { | 
    
    | 321 |  |  | 			ch = toascii(ch); | 
    
    | 322 |  |  | 			vis(visout, ch, VIS_SAFE|VIS_NOSLASH, cp[1]); | 
    
    | 323 |  |  | 			for (s2 = visout; *s2; s2++) | 
    
    | 324 |  |  | 				(void)fputc(*s2, tp); | 
    
    | 325 |  |  | 		} | 
    
    | 326 |  |  | 		(void)fputs(cr, tp); | 
    
    | 327 |  |  | 		--linecnt; | 
    
    | 328 |  |  | 	} | 
    
    | 329 |  |  | 	(void)fprintf(tp, "----%s\n", cr); | 
    
    | 330 |  |  | 	(void)fclose(fi); | 
    
    | 331 |  |  | } |