/*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1983, 1993 The Regents of the University of California. * Copyright (c) 2013 Mariusz Zaborski * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define UNPRIV_USER "daemon" #define UNPRIV_GROUP "daemon" #define NO_MULTICAST 0 /* multicast modes */ #define PER_INTERFACE_MULTICAST 1 #define SCOPED_MULTICAST 2 #define MAX_MULTICAST_SCOPE 32 /* "site-wide", by convention */ #define INADDR_WHOD_GROUP (u_long)0xe0000103 /* 224.0.1.3 */ /* (belongs in protocols/rwhod.h) */ int insecure_mode; int quiet_mode; int iff_flag = IFF_POINTOPOINT; int multicast_mode = NO_MULTICAST; int multicast_scope; struct sockaddr_in multicast_addr = { sizeof(multicast_addr), AF_INET, 0, { 0 }, { 0 } }; /* * Sleep interval. Don't forget to change the down time check in ruptime * if this is changed. */ #define SL_INTERVAL (3 * 60) char myname[MAXHOSTNAMELEN]; /* * We communicate with each neighbor in a list constructed at the time we're * started up. Neighbors are currently directly connected via a hardware * interface. */ struct neighbor { struct neighbor *n_next; char *n_name; /* interface name */ struct sockaddr *n_addr; /* who to send to */ int n_addrlen; /* size of address */ int n_flags; /* should forward?, interface flags */ }; struct neighbor *neighbors; struct whod mywd; struct servent *sp; int s; int fdp; pid_t pid_child_receiver; #define WHDRSIZE (int)(sizeof(mywd) - sizeof(mywd.wd_we)) int configure(int so); void getboottime(int signo __unused); void receiver_process(void); void rt_xaddrs(caddr_t cp, caddr_t cplim, struct rt_addrinfo *rtinfo); void run_as(uid_t *uid, gid_t *gid); void quit(const char *msg); void sender_process(void); int verify(char *name, int maxlen); static void usage(void) __dead2; #ifdef DEBUG char *interval(int time, char *updown); void Sendto(int s, const void *buf, size_t cc, int flags, const struct sockaddr *to, int tolen); #define sendto Sendto #endif /* * This version of Berkeley's rwhod has been modified to use IP multicast * datagrams, under control of a new command-line option: * * rwhod -m causes rwhod to use IP multicast (instead of * broadcast or unicast) on all interfaces that have * the IFF_MULTICAST flag set in their "ifnet" structs * (excluding the loopback interface). The multicast * reports are sent with a time-to-live of 1, to prevent * forwarding beyond the directly-connected subnet(s). * * rwhod -m causes rwhod to send IP multicast datagrams with a * time-to-live of , via a SINGLE interface rather * than all interfaces. must be between 0 and * MAX_MULTICAST_SCOPE, defined below. Note that "-m 1" * is different than "-m", in that "-m 1" specifies * transmission on one interface only. * * When "-m" is used without a argument, the program accepts multicast * rwhod reports from all multicast-capable interfaces. If a argument * is given, it accepts multicast reports from only one interface, the one * on which reports are sent (which may be controlled via the host's routing * table). Regardless of the "-m" option, the program accepts broadcast or * unicast reports from all interfaces. Thus, this program will hear the * reports of old, non-multicasting rwhods, but, if multicasting is used, * those old rwhods won't hear the reports generated by this program. * * -- Steve Deering, Stanford University, February 1989 */ int main(int argc, char *argv[]) { int on; char *cp; struct sockaddr_in soin; uid_t unpriv_uid; gid_t unpriv_gid; on = 1; if (getuid()) errx(1, "not super user"); run_as(&unpriv_uid, &unpriv_gid); argv++; argc--; while (argc > 0 && *argv[0] == '-') { if (strcmp(*argv, "-m") == 0) { if (argc > 1 && isdigit(*(argv + 1)[0])) { argv++; argc--; multicast_mode = SCOPED_MULTICAST; multicast_scope = atoi(*argv); if (multicast_scope > MAX_MULTICAST_SCOPE) { errx(1, "ttl must not exceed %u", MAX_MULTICAST_SCOPE); } } else { multicast_mode = PER_INTERFACE_MULTICAST; } } else if (strcmp(*argv, "-i") == 0) { insecure_mode = 1; } else if (strcmp(*argv, "-l") == 0) { quiet_mode = 1; } else if (strcmp(*argv, "-p") == 0) { iff_flag = 0; } else { usage(); } argv++; argc--; } if (argc > 0) usage(); #ifndef DEBUG daemon(1, 0); #endif (void) signal(SIGHUP, getboottime); openlog("rwhod", LOG_PID | LOG_NDELAY, LOG_DAEMON); sp = getservbyname("who", "udp"); if (sp == NULL) { syslog(LOG_ERR, "who/udp: unknown service"); exit(1); } if (chdir(_PATH_RWHODIR) < 0) { syslog(LOG_ERR, "%s: %m", _PATH_RWHODIR); exit(1); } /* * Establish host name as returned by system. */ if (gethostname(myname, sizeof(myname) - 1) < 0) { syslog(LOG_ERR, "gethostname: %m"); exit(1); } if ((cp = strchr(myname, '.')) != NULL) *cp = '\0'; strlcpy(mywd.wd_hostname, myname, sizeof(mywd.wd_hostname)); getboottime(0); if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { syslog(LOG_ERR, "socket: %m"); exit(1); } if (setsockopt(s, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on)) < 0) { syslog(LOG_ERR, "setsockopt SO_BROADCAST: %m"); exit(1); } memset(&soin, 0, sizeof(soin)); soin.sin_len = sizeof(soin); soin.sin_family = AF_INET; soin.sin_port = sp->s_port; if (bind(s, (struct sockaddr *)&soin, sizeof(soin)) < 0) { syslog(LOG_ERR, "bind: %m"); exit(1); } if (setgid(unpriv_gid) != 0) { syslog(LOG_ERR, "setgid: %m"); exit(1); } if (setgroups(1, &unpriv_gid) != 0) { /* XXX BOGUS groups[0] = egid */ syslog(LOG_ERR, "setgroups: %m"); exit(1); } if (setuid(unpriv_uid) != 0) { syslog(LOG_ERR, "setuid: %m"); exit(1); } if (!configure(s)) exit(1); if (!quiet_mode) { pid_child_receiver = pdfork(&fdp, 0); if (pid_child_receiver == 0) { receiver_process(); } else if (pid_child_receiver > 0) { sender_process(); } else if (pid_child_receiver == -1) { if (errno == ENOSYS) { syslog(LOG_ERR, "The pdfork(2) system call is not available - kernel too old."); } else { syslog(LOG_ERR, "pdfork: %m"); } exit(1); } } else { receiver_process(); } } static void usage(void) { fprintf(stderr, "usage: rwhod [-i] [-p] [-l] [-m [ttl]]\n"); exit(1); } void run_as(uid_t *uid, gid_t *gid) { struct passwd *pw; struct group *gr; pw = getpwnam(UNPRIV_USER); if (pw == NULL) { syslog(LOG_ERR, "getpwnam(%s): %m", UNPRIV_USER); exit(1); } *uid = pw->pw_uid; gr = getgrnam(UNPRIV_GROUP); if (gr == NULL) { syslog(LOG_ERR, "getgrnam(%s): %m", UNPRIV_GROUP); exit(1); } *gid = gr->gr_gid; } /* * Check out host name for unprintables * and other funnies before allowing a file * to be created. Sorry, but blanks aren't allowed. */ int verify(char *name, int maxlen) { int size; size = 0; while (*name != '\0' && size < maxlen - 1) { if (!isascii((unsigned char)*name) || !(isalnum((unsigned char)*name) || ispunct((unsigned char)*name))) { return (0); } name++; size++; } *name = '\0'; return (size > 0); } void receiver_process(void) { struct sockaddr_in from; struct stat st; cap_rights_t rights; char path[64]; int dirfd; struct whod wd; socklen_t len; int cc, whod; time_t t; len = sizeof(from); dirfd = open(".", O_RDONLY | O_DIRECTORY); if (dirfd < 0) { syslog(LOG_WARNING, "%s: %m", _PATH_RWHODIR); exit(1); } cap_rights_init(&rights, CAP_CREATE, CAP_FSTAT, CAP_FTRUNCATE, CAP_LOOKUP, CAP_SEEK, CAP_WRITE); if (caph_rights_limit(dirfd, &rights) < 0) { syslog(LOG_WARNING, "cap_rights_limit: %m"); exit(1); } if (caph_enter() < 0) { syslog(LOG_ERR, "cap_enter: %m"); exit(1); } for (;;) { cc = recvfrom(s, &wd, sizeof(wd), 0, (struct sockaddr *)&from, &len); if (cc <= 0) { if (cc < 0 && errno != EINTR) syslog(LOG_WARNING, "recv: %m"); continue; } if (from.sin_port != sp->s_port && !insecure_mode) { syslog(LOG_WARNING, "%d: bad source port from %s", ntohs(from.sin_port), inet_ntoa(from.sin_addr)); continue; } if (cc < WHDRSIZE) { syslog(LOG_WARNING, "short packet from %s", inet_ntoa(from.sin_addr)); continue; } if (wd.wd_vers != WHODVERSION) continue; if (wd.wd_type != WHODTYPE_STATUS) continue; if (!verify(wd.wd_hostname, sizeof(wd.wd_hostname))) { syslog(LOG_WARNING, "malformed host name from %s", inet_ntoa(from.sin_addr)); continue; } (void) snprintf(path, sizeof(path), "whod.%s", wd.wd_hostname); /* * Rather than truncating and growing the file each time, * use ftruncate if size is less than previous size. */ whod = openat(dirfd, path, O_WRONLY | O_CREAT, 0644); if (whod < 0) { syslog(LOG_WARNING, "%s: %m", path); continue; } cap_rights_init(&rights, CAP_FSTAT, CAP_FTRUNCATE, CAP_WRITE); if (caph_rights_limit(whod, &rights) < 0) { syslog(LOG_WARNING, "cap_rights_limit: %m"); exit(1); } #if ENDIAN != BIG_ENDIAN { struct whoent *we; int i, n; n = (cc - WHDRSIZE) / sizeof(struct whoent); /* undo header byte swapping before writing to file */ wd.wd_sendtime = ntohl(wd.wd_sendtime); for (i = 0; i < 3; i++) wd.wd_loadav[i] = ntohl(wd.wd_loadav[i]); wd.wd_boottime = ntohl(wd.wd_boottime); we = wd.wd_we; for (i = 0; i < n; i++) { we->we_idle = ntohl(we->we_idle); we->we_utmp.out_time = ntohl(we->we_utmp.out_time); we++; } } #endif (void) time(&t); wd.wd_recvtime = _time_to_int(t); (void) write(whod, (char *)&wd, cc); if (fstat(whod, &st) < 0 || st.st_size > cc) ftruncate(whod, cc); (void) close(whod); } (void) close(dirfd); } void sender_process(void) { int sendcount; double avenrun[3]; time_t now; int i, cc, status; struct utmpx *ut; struct stat stb; struct neighbor *np; struct whoent *we, *wend; sendcount = 0; for (;;) { we = mywd.wd_we; now = time(NULL); if (sendcount % 10 == 0) getboottime(0); sendcount++; wend = &mywd.wd_we[1024 / sizeof(struct whoent)]; setutxent(); while ((ut = getutxent()) != NULL && we < wend) { if (ut->ut_type != USER_PROCESS) continue; strncpy(we->we_utmp.out_line, ut->ut_line, sizeof(we->we_utmp.out_line)); strncpy(we->we_utmp.out_name, ut->ut_user, sizeof(we->we_utmp.out_name)); we->we_utmp.out_time = htonl(_time_to_time32(ut->ut_tv.tv_sec)); we++; } endutxent(); if (chdir(_PATH_DEV) < 0) { syslog(LOG_ERR, "chdir(%s): %m", _PATH_DEV); exit(1); } wend = we; for (we = mywd.wd_we; we < wend; we++) { if (stat(we->we_utmp.out_line, &stb) >= 0) we->we_idle = htonl(now - stb.st_atime); } (void) getloadavg(avenrun, nitems(avenrun)); for (i = 0; i < 3; i++) mywd.wd_loadav[i] = htonl((u_long)(avenrun[i] * 100)); cc = (char *)wend - (char *)&mywd; mywd.wd_sendtime = htonl(_time_to_time32(time(NULL))); mywd.wd_vers = WHODVERSION; mywd.wd_type = WHODTYPE_STATUS; if (multicast_mode == SCOPED_MULTICAST) { (void) sendto(s, (char *)&mywd, cc, 0, (struct sockaddr *)&multicast_addr, sizeof(multicast_addr)); } else { for (np = neighbors; np != NULL; np = np->n_next) { if (multicast_mode == PER_INTERFACE_MULTICAST && (np->n_flags & IFF_MULTICAST) != 0) { /* * Select the outgoing interface for the * multicast. */ if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF, &(((struct sockaddr_in *)np->n_addr)->sin_addr), sizeof(struct in_addr)) < 0) { syslog(LOG_ERR, "setsockopt IP_MULTICAST_IF: %m"); exit(1); } (void) sendto(s, (char *)&mywd, cc, 0, (struct sockaddr *)&multicast_addr, sizeof(multicast_addr)); } else { (void) sendto(s, (char *)&mywd, cc, 0, np->n_addr, np->n_addrlen); } } } if (chdir(_PATH_RWHODIR) < 0) { syslog(LOG_ERR, "chdir(%s): %m", _PATH_RWHODIR); exit(1); } if (waitpid(pid_child_receiver, &status, WNOHANG) == pid_child_receiver) { break; } sleep(SL_INTERVAL); } } void getboottime(int signo __unused) { int mib[2]; size_t size; struct timeval tm; mib[0] = CTL_KERN; mib[1] = KERN_BOOTTIME; size = sizeof(tm); if (sysctl(mib, nitems(mib), &tm, &size, NULL, 0) == -1) { syslog(LOG_ERR, "cannot get boottime: %m"); exit(1); } mywd.wd_boottime = htonl(_time_to_time32(tm.tv_sec)); } void quit(const char *msg) { syslog(LOG_ERR, "%s", msg); exit(1); } void rt_xaddrs(caddr_t cp, caddr_t cplim, struct rt_addrinfo *rtinfo) { struct sockaddr *sa; int i; memset(rtinfo->rti_info, 0, sizeof(rtinfo->rti_info)); for (i = 0; i < RTAX_MAX && cp < cplim; i++) { if ((rtinfo->rti_addrs & (1 << i)) == 0) continue; sa = (struct sockaddr *)cp; rtinfo->rti_info[i] = sa; cp += SA_SIZE(sa); } } /* * Figure out device configuration and select * networks which deserve status information. */ int configure(int so) { struct neighbor *np; struct if_msghdr *ifm; struct ifa_msghdr *ifam; struct sockaddr_dl *sdl; size_t needed; int mib[6], flags, lflags, len; char *buf, *lim, *next; struct rt_addrinfo info; flags = 0; if (multicast_mode != NO_MULTICAST) { multicast_addr.sin_addr.s_addr = htonl(INADDR_WHOD_GROUP); multicast_addr.sin_port = sp->s_port; } if (multicast_mode == SCOPED_MULTICAST) { struct ip_mreq mreq; unsigned char ttl; mreq.imr_multiaddr.s_addr = htonl(INADDR_WHOD_GROUP); mreq.imr_interface.s_addr = htonl(INADDR_ANY); if (setsockopt(so, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0) { syslog(LOG_ERR, "setsockopt IP_ADD_MEMBERSHIP: %m"); return (0); } ttl = multicast_scope; if (setsockopt(so, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)) < 0) { syslog(LOG_ERR, "setsockopt IP_MULTICAST_TTL: %m"); return (0); } return (1); } mib[0] = CTL_NET; mib[1] = PF_ROUTE; mib[2] = 0; mib[3] = AF_INET; mib[4] = NET_RT_IFLIST; mib[5] = 0; if (sysctl(mib, nitems(mib), NULL, &needed, NULL, 0) < 0) quit("route-sysctl-estimate"); if ((buf = malloc(needed)) == NULL) quit("malloc"); if (sysctl(mib, nitems(mib), buf, &needed, NULL, 0) < 0) quit("actual retrieval of interface table"); lim = buf + needed; sdl = NULL; /* XXX just to keep gcc -Wall happy */ for (next = buf; next < lim; next += ifm->ifm_msglen) { ifm = (struct if_msghdr *)next; if (ifm->ifm_type == RTM_IFINFO) { sdl = (struct sockaddr_dl *)(ifm + 1); flags = ifm->ifm_flags; continue; } if ((flags & IFF_UP) == 0) continue; lflags = IFF_BROADCAST | iff_flag; if (multicast_mode == PER_INTERFACE_MULTICAST) lflags |= IFF_MULTICAST; if ((flags & lflags) == 0) continue; if (ifm->ifm_type != RTM_NEWADDR) quit("out of sync parsing NET_RT_IFLIST"); ifam = (struct ifa_msghdr *)ifm; info.rti_addrs = ifam->ifam_addrs; rt_xaddrs((char *)(ifam + 1), ifam->ifam_msglen + (char *)ifam, &info); /* gag, wish we could get rid of Internet dependencies */ #define dstaddr info.rti_info[RTAX_BRD] #define ifaddr info.rti_info[RTAX_IFA] #define IPADDR_SA(x) ((struct sockaddr_in *)(x))->sin_addr.s_addr #define PORT_SA(x) ((struct sockaddr_in *)(x))->sin_port if (dstaddr == 0 || dstaddr->sa_family != AF_INET) continue; PORT_SA(dstaddr) = sp->s_port; for (np = neighbors; np != NULL; np = np->n_next) { if (memcmp(sdl->sdl_data, np->n_name, sdl->sdl_nlen) == 0 && IPADDR_SA(np->n_addr) == IPADDR_SA(dstaddr)) { break; } } if (np != NULL) continue; len = sizeof(*np) + dstaddr->sa_len + sdl->sdl_nlen + 1; np = malloc(len); if (np == NULL) quit("malloc of neighbor structure"); memset(np, 0, len); np->n_flags = flags; np->n_addr = (struct sockaddr *)(np + 1); np->n_addrlen = dstaddr->sa_len; np->n_name = np->n_addrlen + (char *)np->n_addr; memcpy((char *)np->n_addr, (char *)dstaddr, np->n_addrlen); memcpy(np->n_name, sdl->sdl_data, sdl->sdl_nlen); if (multicast_mode == PER_INTERFACE_MULTICAST && (flags & IFF_MULTICAST) != 0 && (flags & IFF_LOOPBACK) == 0) { struct ip_mreq mreq; memcpy((char *)np->n_addr, (char *)ifaddr, np->n_addrlen); mreq.imr_multiaddr.s_addr = htonl(INADDR_WHOD_GROUP); mreq.imr_interface.s_addr = ((struct sockaddr_in *)np->n_addr)->sin_addr.s_addr; if (setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0) { syslog(LOG_ERR, "setsockopt IP_ADD_MEMBERSHIP: %m"); #if 0 /* Fall back to broadcast on this if. */ np->n_flags &= ~IFF_MULTICAST; #else free(np); continue; #endif } } np->n_next = neighbors; neighbors = np; } free(buf); return (1); } #ifdef DEBUG void Sendto(int s, const void *buf, size_t cc, int flags, const struct sockaddr *to, int tolen) { struct whod *w; struct whoent *we; struct sockaddr_in *sin; w = (struct whod *)buf; sin = (struct sockaddr_in *)to; printf("sendto %x.%d\n", ntohl(sin->sin_addr.s_addr), ntohs(sin->sin_port)); printf("hostname %s %s\n", w->wd_hostname, interval(ntohl(w->wd_sendtime) - ntohl(w->wd_boottime), " up")); printf("load %4.2f, %4.2f, %4.2f\n", ntohl(w->wd_loadav[0]) / 100.0, ntohl(w->wd_loadav[1]) / 100.0, ntohl(w->wd_loadav[2]) / 100.0); cc -= WHDRSIZE; for (we = w->wd_we, cc /= sizeof(struct whoent); cc > 0; cc--, we++) { time_t t = _time32_to_time(ntohl(we->we_utmp.out_time)); printf("%-8.8s %s:%s %.12s", we->we_utmp.out_name, w->wd_hostname, we->we_utmp.out_line, ctime(&t) + 4); we->we_idle = ntohl(we->we_idle) / 60; if (we->we_idle != 0) { if (we->we_idle >= 100 * 60) we->we_idle = 100 * 60 - 1; if (we->we_idle >= 60) printf(" %2d", we->we_idle / 60); else printf(" "); printf(":%02d", we->we_idle % 60); } printf("\n"); } } char * interval(int time, char *updown) { static char resbuf[32]; int days, hours, minutes; if (time < 0 || time > 3 * 30 * 24 * 60 * 60) { (void) sprintf(resbuf, " %s ??:??", updown); return (resbuf); } minutes = (time + 59) / 60; /* round to minutes */ hours = minutes / 60; minutes %= 60; days = hours / 24; hours %= 24; if (days > 0) { (void) sprintf(resbuf, "%s %2d+%02d:%02d", updown, days, hours, minutes); } else { (void) sprintf(resbuf, "%s %2d:%02d", updown, hours, minutes); } return (resbuf); } #endif