1 /* $OpenBSD: control.c,v 1.10 2019/03/01 08:02:25 florian Exp $ */ 2 3 /* 4 * Copyright (c) 2003, 2004 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 USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 #include <sys/types.h> 19 #include <sys/queue.h> 20 #include <sys/stat.h> 21 #include <sys/socket.h> 22 #include <sys/time.h> 23 #include <sys/un.h> 24 25 #include <errno.h> 26 #include <event.h> 27 #include <imsg.h> 28 #include <stdlib.h> 29 #include <string.h> 30 #include <unistd.h> 31 32 #include "log.h" 33 #include "unwind.h" 34 #include "control.h" 35 #include "frontend.h" 36 #include "resolver.h" 37 38 #define CONTROL_BACKLOG 5 39 40 struct ctl_conn *control_connbyfd(int); 41 struct ctl_conn *control_connbypid(pid_t); 42 void control_close(int); 43 44 int 45 control_init(char *path) 46 { 47 struct sockaddr_un sun; 48 int fd; 49 mode_t old_umask; 50 51 if ((fd = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 52 0)) == -1) { 53 log_warn("%s: socket", __func__); 54 return (-1); 55 } 56 57 memset(&sun, 0, sizeof(sun)); 58 sun.sun_family = AF_UNIX; 59 strlcpy(sun.sun_path, path, sizeof(sun.sun_path)); 60 61 if (unlink(path) == -1) 62 if (errno != ENOENT) { 63 log_warn("%s: unlink %s", __func__, path); 64 close(fd); 65 return (-1); 66 } 67 68 old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH); 69 if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) { 70 log_warn("%s: bind: %s", __func__, path); 71 close(fd); 72 umask(old_umask); 73 return (-1); 74 } 75 umask(old_umask); 76 77 if (chmod(path, 78 S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH) == -1) { 79 log_warn("%s: chmod", __func__); 80 close(fd); 81 (void)unlink(path); 82 return (-1); 83 } 84 85 return (fd); 86 } 87 88 int 89 control_listen(void) 90 { 91 if (listen(control_state.fd, CONTROL_BACKLOG) == -1) { 92 log_warn("%s: listen", __func__); 93 return (-1); 94 } 95 96 event_set(&control_state.ev, control_state.fd, EV_READ, 97 control_accept, NULL); 98 event_add(&control_state.ev, NULL); 99 evtimer_set(&control_state.evt, control_accept, NULL); 100 101 return (0); 102 } 103 104 void 105 control_accept(int listenfd, short event, void *bula) 106 { 107 int connfd; 108 socklen_t len; 109 struct sockaddr_un sun; 110 struct ctl_conn *c; 111 112 event_add(&control_state.ev, NULL); 113 if ((event & EV_TIMEOUT)) 114 return; 115 116 len = sizeof(sun); 117 if ((connfd = accept4(listenfd, (struct sockaddr *)&sun, &len, 118 SOCK_CLOEXEC | SOCK_NONBLOCK)) == -1) { 119 /* 120 * Pause accept if we are out of file descriptors, or 121 * libevent will haunt us here too. 122 */ 123 if (errno == ENFILE || errno == EMFILE) { 124 struct timeval evtpause = { 1, 0 }; 125 126 event_del(&control_state.ev); 127 evtimer_add(&control_state.evt, &evtpause); 128 } else if (errno != EWOULDBLOCK && errno != EINTR && 129 errno != ECONNABORTED) 130 log_warn("%s: accept4", __func__); 131 return; 132 } 133 134 if ((c = calloc(1, sizeof(struct ctl_conn))) == NULL) { 135 log_warn("%s: calloc", __func__); 136 close(connfd); 137 return; 138 } 139 140 imsg_init(&c->iev.ibuf, connfd); 141 c->iev.handler = control_dispatch_imsg; 142 c->iev.events = EV_READ; 143 event_set(&c->iev.ev, c->iev.ibuf.fd, c->iev.events, c->iev.handler, 144 &c->iev); 145 event_add(&c->iev.ev, NULL); 146 147 TAILQ_INSERT_TAIL(&ctl_conns, c, entry); 148 } 149 150 struct ctl_conn * 151 control_connbyfd(int fd) 152 { 153 struct ctl_conn *c; 154 155 TAILQ_FOREACH(c, &ctl_conns, entry) { 156 if (c->iev.ibuf.fd == fd) 157 break; 158 } 159 160 return (c); 161 } 162 163 struct ctl_conn * 164 control_connbypid(pid_t pid) 165 { 166 struct ctl_conn *c; 167 168 TAILQ_FOREACH(c, &ctl_conns, entry) { 169 if (c->iev.ibuf.pid == pid) 170 break; 171 } 172 173 return (c); 174 } 175 176 void 177 control_close(int fd) 178 { 179 struct ctl_conn *c; 180 181 if ((c = control_connbyfd(fd)) == NULL) { 182 log_warnx("%s: fd %d: not found", __func__, fd); 183 return; 184 } 185 186 msgbuf_clear(&c->iev.ibuf.w); 187 TAILQ_REMOVE(&ctl_conns, c, entry); 188 189 event_del(&c->iev.ev); 190 close(c->iev.ibuf.fd); 191 192 /* Some file descriptors are available again. */ 193 if (evtimer_pending(&control_state.evt, NULL)) { 194 evtimer_del(&control_state.evt); 195 event_add(&control_state.ev, NULL); 196 } 197 198 free(c); 199 } 200 201 void 202 control_dispatch_imsg(int fd, short event, void *bula) 203 { 204 struct ctl_conn *c; 205 struct imsg imsg; 206 ssize_t n; 207 int verbose; 208 uid_t euid; 209 gid_t egid; 210 211 if ((c = control_connbyfd(fd)) == NULL) { 212 log_warnx("%s: fd %d: not found", __func__, fd); 213 return; 214 } 215 216 if (event & EV_READ) { 217 if (((n = imsg_read(&c->iev.ibuf)) == -1 && errno != EAGAIN) || 218 n == 0) { 219 control_close(fd); 220 return; 221 } 222 } 223 if (event & EV_WRITE) { 224 if (msgbuf_write(&c->iev.ibuf.w) <= 0 && errno != EAGAIN) { 225 control_close(fd); 226 return; 227 } 228 } 229 230 if (getpeereid(fd, &euid, &egid) == -1) { 231 control_close(fd); 232 return; 233 } 234 235 for (;;) { 236 if ((n = imsg_get(&c->iev.ibuf, &imsg)) == -1) { 237 control_close(fd); 238 return; 239 } 240 if (n == 0) 241 break; 242 243 switch (imsg.hdr.type) { 244 case IMSG_CTL_LOG_VERBOSE: 245 case IMSG_CTL_RELOAD: 246 if (euid != 0) { 247 imsg_free(&imsg); 248 control_close(fd); 249 return; 250 } 251 break; 252 default: 253 break; 254 } 255 256 switch (imsg.hdr.type) { 257 case IMSG_CTL_RELOAD: 258 frontend_imsg_compose_main(imsg.hdr.type, 0, NULL, 0); 259 break; 260 case IMSG_CTL_RECHECK_CAPTIVEPORTAL: 261 frontend_imsg_compose_resolver(imsg.hdr.type, 262 imsg.hdr.pid, NULL, 0); 263 break; 264 case IMSG_CTL_LOG_VERBOSE: 265 if (IMSG_DATA_SIZE(imsg) != sizeof(verbose)) 266 break; 267 268 /* Forward to all other processes. */ 269 frontend_imsg_compose_main(imsg.hdr.type, imsg.hdr.pid, 270 imsg.data, IMSG_DATA_SIZE(imsg)); 271 frontend_imsg_compose_resolver(imsg.hdr.type, 272 imsg.hdr.pid, imsg.data, IMSG_DATA_SIZE(imsg)); 273 frontend_imsg_compose_captiveportal(imsg.hdr.type, 274 imsg.hdr.pid, imsg.data, IMSG_DATA_SIZE(imsg)); 275 276 memcpy(&verbose, imsg.data, sizeof(verbose)); 277 log_setverbose(verbose); 278 break; 279 case IMSG_CTL_STATUS: 280 if (IMSG_DATA_SIZE(imsg) != 281 sizeof(enum uw_resolver_type)) 282 break; 283 frontend_imsg_compose_resolver(imsg.hdr.type, 0, 284 imsg.data, IMSG_DATA_SIZE(imsg)); 285 break; 286 default: 287 log_debug("%s: error handling imsg %d", __func__, 288 imsg.hdr.type); 289 break; 290 } 291 imsg_free(&imsg); 292 } 293 294 imsg_event_add(&c->iev); 295 } 296 297 int 298 control_imsg_relay(struct imsg *imsg) 299 { 300 struct ctl_conn *c; 301 302 if ((c = control_connbypid(imsg->hdr.pid)) == NULL) 303 return (0); 304 305 return (imsg_compose_event(&c->iev, imsg->hdr.type, 0, imsg->hdr.pid, 306 -1, imsg->data, IMSG_DATA_SIZE(*imsg))); 307 } 308