1 /* $OpenBSD: control.c,v 1.15 2019/12/18 09:18:27 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 <net/route.h> 26 27 #include <errno.h> 28 #include <event.h> 29 #include <imsg.h> 30 #include <stdlib.h> 31 #include <string.h> 32 #include <unistd.h> 33 34 #include "log.h" 35 #include "unwind.h" 36 #include "control.h" 37 #include "frontend.h" 38 #include "resolver.h" 39 40 #define CONTROL_BACKLOG 5 41 42 struct ctl_conn *control_connbyfd(int); 43 struct ctl_conn *control_connbypid(pid_t); 44 void control_close(int); 45 46 int 47 control_init(char *path) 48 { 49 struct sockaddr_un sun; 50 int fd; 51 mode_t old_umask; 52 53 if ((fd = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 54 0)) == -1) { 55 log_warn("%s: socket", __func__); 56 return (-1); 57 } 58 59 memset(&sun, 0, sizeof(sun)); 60 sun.sun_family = AF_UNIX; 61 strlcpy(sun.sun_path, path, sizeof(sun.sun_path)); 62 63 if (unlink(path) == -1) 64 if (errno != ENOENT) { 65 log_warn("%s: unlink %s", __func__, path); 66 close(fd); 67 return (-1); 68 } 69 70 old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH); 71 if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) { 72 log_warn("%s: bind: %s", __func__, path); 73 close(fd); 74 umask(old_umask); 75 return (-1); 76 } 77 umask(old_umask); 78 79 if (chmod(path, 80 S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH) == -1) { 81 log_warn("%s: chmod", __func__); 82 close(fd); 83 (void)unlink(path); 84 return (-1); 85 } 86 87 return (fd); 88 } 89 90 int 91 control_listen(void) 92 { 93 if (listen(control_state.fd, CONTROL_BACKLOG) == -1) { 94 log_warn("%s: listen", __func__); 95 return (-1); 96 } 97 98 event_set(&control_state.ev, control_state.fd, EV_READ, 99 control_accept, NULL); 100 event_add(&control_state.ev, NULL); 101 evtimer_set(&control_state.evt, control_accept, NULL); 102 103 return (0); 104 } 105 106 void 107 control_accept(int listenfd, short event, void *bula) 108 { 109 int connfd; 110 socklen_t len; 111 struct sockaddr_un sun; 112 struct ctl_conn *c; 113 114 event_add(&control_state.ev, NULL); 115 if ((event & EV_TIMEOUT)) 116 return; 117 118 len = sizeof(sun); 119 if ((connfd = accept4(listenfd, (struct sockaddr *)&sun, &len, 120 SOCK_CLOEXEC | SOCK_NONBLOCK)) == -1) { 121 /* 122 * Pause accept if we are out of file descriptors, or 123 * libevent will haunt us here too. 124 */ 125 if (errno == ENFILE || errno == EMFILE) { 126 struct timeval evtpause = { 1, 0 }; 127 128 event_del(&control_state.ev); 129 evtimer_add(&control_state.evt, &evtpause); 130 } else if (errno != EWOULDBLOCK && errno != EINTR && 131 errno != ECONNABORTED) 132 log_warn("%s: accept4", __func__); 133 return; 134 } 135 136 if ((c = calloc(1, sizeof(struct ctl_conn))) == NULL) { 137 log_warn("%s: calloc", __func__); 138 close(connfd); 139 return; 140 } 141 142 imsg_init(&c->iev.ibuf, connfd); 143 c->iev.handler = control_dispatch_imsg; 144 c->iev.events = EV_READ; 145 event_set(&c->iev.ev, c->iev.ibuf.fd, c->iev.events, c->iev.handler, 146 &c->iev); 147 event_add(&c->iev.ev, NULL); 148 149 TAILQ_INSERT_TAIL(&ctl_conns, c, entry); 150 } 151 152 struct ctl_conn * 153 control_connbyfd(int fd) 154 { 155 struct ctl_conn *c; 156 157 TAILQ_FOREACH(c, &ctl_conns, entry) { 158 if (c->iev.ibuf.fd == fd) 159 break; 160 } 161 162 return (c); 163 } 164 165 struct ctl_conn * 166 control_connbypid(pid_t pid) 167 { 168 struct ctl_conn *c; 169 170 TAILQ_FOREACH(c, &ctl_conns, entry) { 171 if (c->iev.ibuf.pid == pid) 172 break; 173 } 174 175 return (c); 176 } 177 178 void 179 control_close(int fd) 180 { 181 struct ctl_conn *c; 182 183 if ((c = control_connbyfd(fd)) == NULL) { 184 log_warnx("%s: fd %d: not found", __func__, fd); 185 return; 186 } 187 188 msgbuf_clear(&c->iev.ibuf.w); 189 TAILQ_REMOVE(&ctl_conns, c, entry); 190 191 event_del(&c->iev.ev); 192 close(c->iev.ibuf.fd); 193 194 /* Some file descriptors are available again. */ 195 if (evtimer_pending(&control_state.evt, NULL)) { 196 evtimer_del(&control_state.evt); 197 event_add(&control_state.ev, NULL); 198 } 199 200 free(c); 201 } 202 203 void 204 control_dispatch_imsg(int fd, short event, void *bula) 205 { 206 struct ctl_conn *c; 207 struct imsg imsg; 208 ssize_t n; 209 int verbose; 210 uid_t euid; 211 gid_t egid; 212 213 if ((c = control_connbyfd(fd)) == NULL) { 214 log_warnx("%s: fd %d: not found", __func__, fd); 215 return; 216 } 217 218 if (event & EV_READ) { 219 if (((n = imsg_read(&c->iev.ibuf)) == -1 && errno != EAGAIN) || 220 n == 0) { 221 control_close(fd); 222 return; 223 } 224 } 225 if (event & EV_WRITE) { 226 if (msgbuf_write(&c->iev.ibuf.w) <= 0 && errno != EAGAIN) { 227 control_close(fd); 228 return; 229 } 230 } 231 232 if (getpeereid(fd, &euid, &egid) == -1) { 233 control_close(fd); 234 return; 235 } 236 237 for (;;) { 238 if ((n = imsg_get(&c->iev.ibuf, &imsg)) == -1) { 239 control_close(fd); 240 return; 241 } 242 if (n == 0) 243 break; 244 245 switch (imsg.hdr.type) { 246 case IMSG_CTL_LOG_VERBOSE: 247 case IMSG_CTL_RELOAD: 248 if (euid != 0) { 249 imsg_free(&imsg); 250 control_close(fd); 251 return; 252 } 253 break; 254 default: 255 break; 256 } 257 258 switch (imsg.hdr.type) { 259 case IMSG_CTL_RELOAD: 260 frontend_imsg_compose_main(imsg.hdr.type, 0, NULL, 0); 261 break; 262 case IMSG_CTL_LOG_VERBOSE: 263 if (IMSG_DATA_SIZE(imsg) != sizeof(verbose)) 264 break; 265 266 /* Forward to all other processes. */ 267 frontend_imsg_compose_main(imsg.hdr.type, imsg.hdr.pid, 268 imsg.data, IMSG_DATA_SIZE(imsg)); 269 frontend_imsg_compose_resolver(imsg.hdr.type, 270 imsg.hdr.pid, imsg.data, IMSG_DATA_SIZE(imsg)); 271 272 memcpy(&verbose, imsg.data, sizeof(verbose)); 273 log_setverbose(verbose); 274 break; 275 case IMSG_CTL_STATUS: 276 case IMSG_CTL_AUTOCONF: 277 case IMSG_CTL_MEM: 278 if (IMSG_DATA_SIZE(imsg) != 0) 279 break; 280 frontend_imsg_compose_resolver(imsg.hdr.type, 0, NULL, 281 0); 282 break; 283 default: 284 log_debug("%s: error handling imsg %d", __func__, 285 imsg.hdr.type); 286 break; 287 } 288 imsg_free(&imsg); 289 } 290 291 imsg_event_add(&c->iev); 292 } 293 294 int 295 control_imsg_relay(struct imsg *imsg) 296 { 297 struct ctl_conn *c; 298 299 if ((c = control_connbypid(imsg->hdr.pid)) == NULL) 300 return (0); 301 302 return (imsg_compose_event(&c->iev, imsg->hdr.type, 0, imsg->hdr.pid, 303 -1, imsg->data, IMSG_DATA_SIZE(*imsg))); 304 } 305