1 /* $OpenBSD: ypldap_dns.c,v 1.8 2015/01/16 06:40:22 deraadt 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/param.h> 21 #include <sys/socket.h> 22 #include <sys/stat.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 #include <limits.h> 41 42 #include "ypldap.h" 43 44 volatile sig_atomic_t quit_dns = 0; 45 struct imsgev *iev_dns; 46 47 void dns_dispatch_imsg(int, short, void *); 48 void dns_sig_handler(int, short, void *); 49 void dns_shutdown(void); 50 int host_dns(const char *, struct ypldap_addr_list *); 51 52 void 53 dns_sig_handler(int sig, short event, void *p) 54 { 55 switch (sig) { 56 case SIGINT: 57 case SIGTERM: 58 dns_shutdown(); 59 break; 60 default: 61 fatalx("unexpected signal"); 62 } 63 } 64 65 void 66 dns_shutdown(void) 67 { 68 log_info("dns engine exiting"); 69 _exit(0); 70 } 71 72 pid_t 73 ypldap_dns(int pipe_ntp[2], struct passwd *pw) 74 { 75 pid_t pid; 76 struct event ev_sigint; 77 struct event ev_sigterm; 78 struct event ev_sighup; 79 struct env env; 80 81 switch (pid = fork()) { 82 case -1: 83 fatal("cannot fork"); 84 break; 85 case 0: 86 break; 87 default: 88 return (pid); 89 } 90 91 setproctitle("dns engine"); 92 close(pipe_ntp[0]); 93 94 if (setgroups(1, &pw->pw_gid) || 95 setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) || 96 setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid)) 97 fatal("can't drop privileges"); 98 endservent(); 99 100 event_init(); 101 signal_set(&ev_sigint, SIGINT, dns_sig_handler, NULL); 102 signal_set(&ev_sigterm, SIGTERM, dns_sig_handler, NULL); 103 signal_set(&ev_sighup, SIGHUP, dns_sig_handler, NULL); 104 signal_add(&ev_sigint, NULL); 105 signal_add(&ev_sigterm, NULL); 106 signal_add(&ev_sighup, NULL); 107 108 if ((env.sc_iev = calloc(1, sizeof(*env.sc_iev))) == NULL) 109 fatal(NULL); 110 111 env.sc_iev->events = EV_READ; 112 env.sc_iev->data = &env; 113 imsg_init(&env.sc_iev->ibuf, pipe_ntp[1]); 114 env.sc_iev->handler = dns_dispatch_imsg; 115 event_set(&env.sc_iev->ev, env.sc_iev->ibuf.fd, env.sc_iev->events, 116 env.sc_iev->handler, &env); 117 event_add(&env.sc_iev->ev, NULL); 118 119 event_dispatch(); 120 dns_shutdown(); 121 122 return (0); 123 } 124 125 void 126 dns_dispatch_imsg(int fd, short events, void *p) 127 { 128 struct imsg imsg; 129 int n, cnt; 130 char *name; 131 struct ypldap_addr_list hn = TAILQ_HEAD_INITIALIZER(hn); 132 struct ypldap_addr *h; 133 struct ibuf *buf; 134 struct env *env = p; 135 struct imsgev *iev = env->sc_iev; 136 struct imsgbuf *ibuf = &iev->ibuf; 137 int shut = 0; 138 139 if ((events & (EV_READ | EV_WRITE)) == 0) 140 fatalx("unknown event"); 141 142 if (events & EV_READ) { 143 if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN) 144 fatal("imsg_read error"); 145 if (n == 0) 146 shut = 1; 147 } 148 if (events & EV_WRITE) { 149 if ((n = msgbuf_write(&ibuf->w)) == -1 && errno != EAGAIN) 150 fatal("msgbuf_write"); 151 if (n == 0) 152 shut = 1; 153 goto done; 154 } 155 156 for (;;) { 157 if ((n = imsg_get(ibuf, &imsg)) == -1) 158 fatal("client_dispatch_imsg: imsg_get error"); 159 if (n == 0) 160 break; 161 162 switch (imsg.hdr.type) { 163 case IMSG_HOST_DNS: 164 name = imsg.data; 165 if (imsg.hdr.len < 1 + IMSG_HEADER_SIZE) 166 fatalx("invalid IMSG_HOST_DNS received"); 167 imsg.hdr.len -= 1 + IMSG_HEADER_SIZE; 168 if (name[imsg.hdr.len] != '\0' || 169 strlen(name) != imsg.hdr.len) 170 fatalx("invalid IMSG_HOST_DNS received"); 171 if ((cnt = host_dns(name, &hn)) == -1) 172 break; 173 buf = imsg_create(ibuf, IMSG_HOST_DNS, 174 imsg.hdr.peerid, 0, 175 cnt * sizeof(struct sockaddr_storage)); 176 if (buf == NULL) 177 break; 178 if (cnt > 0) { 179 while(!TAILQ_EMPTY(&hn)) { 180 h = TAILQ_FIRST(&hn); 181 TAILQ_REMOVE(&hn, h, next); 182 imsg_add(buf, &h->ss, sizeof(h->ss)); 183 free(h); 184 } 185 } 186 187 imsg_close(ibuf, buf); 188 break; 189 default: 190 break; 191 } 192 imsg_free(&imsg); 193 } 194 195 done: 196 if (!shut) 197 imsg_event_add(iev); 198 else { 199 /* this pipe is dead, so remove the event handler */ 200 event_del(&iev->ev); 201 event_loopexit(NULL); 202 } 203 } 204 205 int 206 host_dns(const char *s, struct ypldap_addr_list *hn) 207 { 208 struct addrinfo hints, *res0, *res; 209 int error, cnt = 0; 210 struct sockaddr_in *sa_in; 211 struct sockaddr_in6 *sa_in6; 212 struct ypldap_addr *h; 213 214 memset(&hints, 0, sizeof(hints)); 215 hints.ai_family = PF_UNSPEC; 216 hints.ai_socktype = SOCK_DGRAM; /* DUMMY */ 217 error = getaddrinfo(s, NULL, &hints, &res0); 218 if (error == EAI_AGAIN || error == EAI_NONAME) 219 return (0); 220 if (error) { 221 log_warnx("could not parse \"%s\": %s", s, 222 gai_strerror(error)); 223 return (-1); 224 } 225 226 for (res = res0; res && cnt < MAX_SERVERS_DNS; res = res->ai_next) { 227 if (res->ai_family != AF_INET && 228 res->ai_family != AF_INET6) 229 continue; 230 if ((h = calloc(1, sizeof(struct ypldap_addr))) == NULL) 231 fatal(NULL); 232 h->ss.ss_family = res->ai_family; 233 if (res->ai_family == AF_INET) { 234 sa_in = (struct sockaddr_in *)&h->ss; 235 sa_in->sin_len = sizeof(struct sockaddr_in); 236 sa_in->sin_addr.s_addr = ((struct sockaddr_in *) 237 res->ai_addr)->sin_addr.s_addr; 238 } else { 239 sa_in6 = (struct sockaddr_in6 *)&h->ss; 240 sa_in6->sin6_len = sizeof(struct sockaddr_in6); 241 memcpy(&sa_in6->sin6_addr, &((struct sockaddr_in6 *) 242 res->ai_addr)->sin6_addr, sizeof(struct in6_addr)); 243 } 244 245 TAILQ_INSERT_HEAD(hn, h, next); 246 cnt++; 247 } 248 freeaddrinfo(res0); 249 return (cnt); 250 } 251