1 /* $OpenBSD: ypldap_dns.c,v 1.7 2014/07/13 15:38:09 krw Exp $ */ 2 3 /* 4 * Copyright (c) 2003-2008 Henning Brauer <henning@openbsd.org> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER 15 * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING 16 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include <sys/types.h> 20 #include <sys/socket.h> 21 #include <sys/stat.h> 22 #include <sys/param.h> 23 #include <sys/time.h> 24 #include <sys/tree.h> 25 #include <sys/queue.h> 26 27 #include <netinet/in.h> 28 #include <arpa/nameser.h> 29 30 #include <netdb.h> 31 #include <pwd.h> 32 #include <errno.h> 33 #include <event.h> 34 #include <resolv.h> 35 #include <poll.h> 36 #include <signal.h> 37 #include <stdlib.h> 38 #include <string.h> 39 #include <unistd.h> 40 41 #include "ypldap.h" 42 43 volatile sig_atomic_t quit_dns = 0; 44 struct imsgev *iev_dns; 45 46 void dns_dispatch_imsg(int, short, void *); 47 void dns_sig_handler(int, short, void *); 48 void dns_shutdown(void); 49 int host_dns(const char *s, struct ypldap_addr **hn); 50 51 void 52 dns_sig_handler(int sig, short event, void *p) 53 { 54 switch (sig) { 55 case SIGINT: 56 case SIGTERM: 57 dns_shutdown(); 58 break; 59 default: 60 fatalx("unexpected signal"); 61 } 62 } 63 64 void 65 dns_shutdown(void) 66 { 67 log_info("dns engine exiting"); 68 _exit(0); 69 } 70 71 pid_t 72 ypldap_dns(int pipe_ntp[2], struct passwd *pw) 73 { 74 pid_t pid; 75 struct event ev_sigint; 76 struct event ev_sigterm; 77 struct event ev_sighup; 78 struct env env; 79 80 switch (pid = fork()) { 81 case -1: 82 fatal("cannot fork"); 83 break; 84 case 0: 85 break; 86 default: 87 return (pid); 88 } 89 90 setproctitle("dns engine"); 91 close(pipe_ntp[0]); 92 93 if (setgroups(1, &pw->pw_gid) || 94 setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) || 95 setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid)) 96 fatal("can't drop privileges"); 97 endservent(); 98 99 event_init(); 100 signal_set(&ev_sigint, SIGINT, dns_sig_handler, NULL); 101 signal_set(&ev_sigterm, SIGTERM, dns_sig_handler, NULL); 102 signal_set(&ev_sighup, SIGHUP, dns_sig_handler, NULL); 103 signal_add(&ev_sigint, NULL); 104 signal_add(&ev_sigterm, NULL); 105 signal_add(&ev_sighup, NULL); 106 107 if ((env.sc_iev = calloc(1, sizeof(*env.sc_iev))) == NULL) 108 fatal(NULL); 109 110 env.sc_iev->events = EV_READ; 111 env.sc_iev->data = &env; 112 imsg_init(&env.sc_iev->ibuf, pipe_ntp[1]); 113 env.sc_iev->handler = dns_dispatch_imsg; 114 event_set(&env.sc_iev->ev, env.sc_iev->ibuf.fd, env.sc_iev->events, 115 env.sc_iev->handler, &env); 116 event_add(&env.sc_iev->ev, NULL); 117 118 event_dispatch(); 119 dns_shutdown(); 120 121 return (0); 122 } 123 124 void 125 dns_dispatch_imsg(int fd, short events, void *p) 126 { 127 struct imsg imsg; 128 int n, cnt; 129 char *name; 130 struct ypldap_addr *h, *hn; 131 struct ibuf *buf; 132 struct env *env = p; 133 struct imsgev *iev = env->sc_iev; 134 struct imsgbuf *ibuf = &iev->ibuf; 135 int shut = 0; 136 137 if ((events & (EV_READ | EV_WRITE)) == 0) 138 fatalx("unknown event"); 139 140 if (events & EV_READ) { 141 if ((n = imsg_read(ibuf)) == -1) 142 fatal("imsg_read error"); 143 if (n == 0) 144 shut = 1; 145 } 146 if (events & EV_WRITE) { 147 if ((n = msgbuf_write(&ibuf->w)) == -1 && errno != EAGAIN) 148 fatal("msgbuf_write"); 149 if (n == 0) 150 shut = 1; 151 goto done; 152 } 153 154 for (;;) { 155 if ((n = imsg_get(ibuf, &imsg)) == -1) 156 fatal("client_dispatch_imsg: imsg_get error"); 157 if (n == 0) 158 break; 159 160 switch (imsg.hdr.type) { 161 case IMSG_HOST_DNS: 162 name = imsg.data; 163 if (imsg.hdr.len < 1 + IMSG_HEADER_SIZE) 164 fatalx("invalid IMSG_HOST_DNS received"); 165 imsg.hdr.len -= 1 + IMSG_HEADER_SIZE; 166 if (name[imsg.hdr.len] != '\0' || 167 strlen(name) != imsg.hdr.len) 168 fatalx("invalid IMSG_HOST_DNS received"); 169 if ((cnt = host_dns(name, &hn)) == -1) 170 break; 171 buf = imsg_create(ibuf, IMSG_HOST_DNS, 172 imsg.hdr.peerid, 0, 173 cnt * sizeof(struct sockaddr_storage)); 174 if (buf == NULL) 175 break; 176 if (cnt > 0) { 177 h = hn; 178 while (h != NULL) { 179 imsg_add(buf, &h->ss, sizeof(h->ss)); 180 hn = h->next; 181 free(h); 182 h = hn; 183 } 184 } 185 186 imsg_close(ibuf, buf); 187 break; 188 default: 189 break; 190 } 191 imsg_free(&imsg); 192 } 193 194 done: 195 if (!shut) 196 imsg_event_add(iev); 197 else { 198 /* this pipe is dead, so remove the event handler */ 199 event_del(&iev->ev); 200 event_loopexit(NULL); 201 } 202 } 203 204 int 205 host_dns(const char *s, struct ypldap_addr **hn) 206 { 207 struct addrinfo hints, *res0, *res; 208 int error, cnt = 0; 209 struct sockaddr_in *sa_in; 210 struct sockaddr_in6 *sa_in6; 211 struct ypldap_addr *h, *hh = NULL; 212 213 bzero(&hints, sizeof(hints)); 214 hints.ai_family = PF_UNSPEC; 215 hints.ai_socktype = SOCK_DGRAM; /* DUMMY */ 216 error = getaddrinfo(s, NULL, &hints, &res0); 217 if (error == EAI_AGAIN || error == EAI_NODATA || error == EAI_NONAME) 218 return (0); 219 if (error) { 220 log_warnx("could not parse \"%s\": %s", s, 221 gai_strerror(error)); 222 return (-1); 223 } 224 225 for (res = res0; res && cnt < MAX_SERVERS_DNS; res = res->ai_next) { 226 if (res->ai_family != AF_INET && 227 res->ai_family != AF_INET6) 228 continue; 229 if ((h = calloc(1, sizeof(struct ypldap_addr))) == NULL) 230 fatal(NULL); 231 h->ss.ss_family = res->ai_family; 232 if (res->ai_family == AF_INET) { 233 sa_in = (struct sockaddr_in *)&h->ss; 234 sa_in->sin_len = sizeof(struct sockaddr_in); 235 sa_in->sin_addr.s_addr = ((struct sockaddr_in *) 236 res->ai_addr)->sin_addr.s_addr; 237 } else { 238 sa_in6 = (struct sockaddr_in6 *)&h->ss; 239 sa_in6->sin6_len = sizeof(struct sockaddr_in6); 240 memcpy(&sa_in6->sin6_addr, &((struct sockaddr_in6 *) 241 res->ai_addr)->sin6_addr, sizeof(struct in6_addr)); 242 } 243 244 h->next = hh; 245 hh = h; 246 cnt++; 247 } 248 freeaddrinfo(res0); 249 250 *hn = hh; 251 return (cnt); 252 } 253