1 /* $OpenBSD: control.c,v 1.6 2016/01/10 10:01:07 jsg Exp $ */ 2 3 /* 4 * Copyright (c) 2010-2015 Reyk Floeter <reyk@openbsd.org> 5 * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org> 6 * 7 * Permission to use, copy, modify, and distribute this software for any 8 * purpose with or without fee is hereby granted, provided that the above 9 * copyright notice and this permission notice appear in all copies. 10 * 11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 18 */ 19 20 #include <sys/param.h> 21 #include <sys/queue.h> 22 #include <sys/stat.h> 23 #include <sys/socket.h> 24 #include <sys/un.h> 25 #include <sys/tree.h> 26 27 #include <net/if.h> 28 29 #include <errno.h> 30 #include <event.h> 31 #include <fcntl.h> 32 #include <stdlib.h> 33 #include <string.h> 34 #include <unistd.h> 35 #include <signal.h> 36 37 #include "proc.h" 38 #include "vmd.h" 39 40 #define CONTROL_BACKLOG 5 41 42 struct ctl_connlist ctl_conns; 43 44 void 45 control_accept(int, short, void *); 46 struct ctl_conn 47 *control_connbyfd(int); 48 void control_close(int, struct control_sock *); 49 void control_dispatch_imsg(int, short, void *); 50 int control_dispatch_vmm(int, struct privsep_proc *, struct imsg *); 51 void control_imsg_forward(struct imsg *); 52 void control_run(struct privsep *, struct privsep_proc *, void *); 53 54 static struct privsep_proc procs[] = { 55 { "parent", PROC_PARENT, control_dispatch_vmm } 56 }; 57 58 pid_t 59 control(struct privsep *ps, struct privsep_proc *p) 60 { 61 return (proc_run(ps, p, procs, nitems(procs), control_run, NULL)); 62 } 63 64 void 65 control_run(struct privsep *ps, struct privsep_proc *p, void *arg) 66 { 67 /* 68 * pledge in the control process: 69 * stdio - for malloc and basic I/O including events. 70 * unix - for the control socket. 71 */ 72 if (pledge("stdio unix", NULL) == -1) 73 fatal("pledge"); 74 } 75 76 int 77 control_dispatch_vmm(int fd, struct privsep_proc *p, struct imsg *imsg) 78 { 79 struct ctl_conn *c; 80 81 if ((c = control_connbyfd(imsg->hdr.peerid)) == NULL) { 82 log_warnx("%s: fd %d: not found", __func__, imsg->hdr.peerid); 83 return (-1); 84 } 85 86 switch (imsg->hdr.type) { 87 case IMSG_VMDOP_START_VM_RESPONSE: 88 case IMSG_VMDOP_TERMINATE_VM_RESPONSE: 89 case IMSG_VMDOP_GET_INFO_VM_DATA: 90 case IMSG_VMDOP_GET_INFO_VM_END_DATA: 91 imsg_compose_event(&c->iev, imsg->hdr.type, 92 0, 0, -1, imsg->data, IMSG_DATA_SIZE(imsg)); 93 break; 94 default: 95 return (-1); 96 } 97 98 return (0); 99 } 100 101 int 102 control_init(struct privsep *ps, struct control_sock *cs) 103 { 104 struct sockaddr_un sun; 105 int fd; 106 mode_t old_umask, mode; 107 108 if (cs->cs_name == NULL) 109 return (0); 110 111 if ((fd = socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK, 0)) == -1) { 112 log_warn("%s: socket", __func__); 113 return (-1); 114 } 115 116 sun.sun_family = AF_UNIX; 117 if (strlcpy(sun.sun_path, cs->cs_name, 118 sizeof(sun.sun_path)) >= sizeof(sun.sun_path)) { 119 log_warn("%s: %s name too long", __func__, cs->cs_name); 120 close(fd); 121 return (-1); 122 } 123 124 if (unlink(cs->cs_name) == -1) 125 if (errno != ENOENT) { 126 log_warn("%s: unlink %s", __func__, cs->cs_name); 127 close(fd); 128 return (-1); 129 } 130 131 if (cs->cs_restricted) { 132 old_umask = umask(S_IXUSR|S_IXGRP|S_IXOTH); 133 mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH; 134 } else { 135 old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH); 136 mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP; 137 } 138 139 if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) { 140 log_warn("%s: bind: %s", __func__, cs->cs_name); 141 close(fd); 142 (void)umask(old_umask); 143 return (-1); 144 } 145 (void)umask(old_umask); 146 147 if (chmod(cs->cs_name, mode) == -1) { 148 log_warn("%s: chmod", __func__); 149 close(fd); 150 (void)unlink(cs->cs_name); 151 return (-1); 152 } 153 154 cs->cs_fd = fd; 155 cs->cs_env = ps; 156 157 return (0); 158 } 159 160 int 161 control_listen(struct control_sock *cs) 162 { 163 if (cs->cs_name == NULL) 164 return (0); 165 166 if (listen(cs->cs_fd, CONTROL_BACKLOG) == -1) { 167 log_warn("%s: listen", __func__); 168 return (-1); 169 } 170 171 event_set(&cs->cs_ev, cs->cs_fd, EV_READ, 172 control_accept, cs); 173 event_add(&cs->cs_ev, NULL); 174 evtimer_set(&cs->cs_evt, control_accept, cs); 175 176 return (0); 177 } 178 179 void 180 control_cleanup(struct control_sock *cs) 181 { 182 if (cs->cs_name == NULL) 183 return; 184 event_del(&cs->cs_ev); 185 event_del(&cs->cs_evt); 186 } 187 188 /* ARGSUSED */ 189 void 190 control_accept(int listenfd, short event, void *arg) 191 { 192 struct control_sock *cs = arg; 193 int connfd; 194 socklen_t len; 195 struct sockaddr_un sun; 196 struct ctl_conn *c; 197 198 event_add(&cs->cs_ev, NULL); 199 if ((event & EV_TIMEOUT)) 200 return; 201 202 len = sizeof(sun); 203 if ((connfd = accept4(listenfd, 204 (struct sockaddr *)&sun, &len, SOCK_NONBLOCK)) == -1) { 205 /* 206 * Pause accept if we are out of file descriptors, or 207 * libevent will haunt us here too. 208 */ 209 if (errno == ENFILE || errno == EMFILE) { 210 struct timeval evtpause = { 1, 0 }; 211 212 event_del(&cs->cs_ev); 213 evtimer_add(&cs->cs_evt, &evtpause); 214 } else if (errno != EWOULDBLOCK && errno != EINTR && 215 errno != ECONNABORTED) 216 log_warn("%s: accept", __func__); 217 return; 218 } 219 220 if ((c = calloc(1, sizeof(struct ctl_conn))) == NULL) { 221 log_warn("%s", __func__); 222 close(connfd); 223 return; 224 } 225 226 if (getsockopt(connfd, SOL_SOCKET, SO_PEERCRED, 227 &c->peercred, &len) != 0) { 228 log_warn("%s: failed to get peer credentials", __func__); 229 close(connfd); 230 free(c); 231 return; 232 } 233 234 imsg_init(&c->iev.ibuf, connfd); 235 c->iev.handler = control_dispatch_imsg; 236 c->iev.events = EV_READ; 237 c->iev.data = cs; 238 event_set(&c->iev.ev, c->iev.ibuf.fd, c->iev.events, 239 c->iev.handler, c->iev.data); 240 event_add(&c->iev.ev, NULL); 241 242 TAILQ_INSERT_TAIL(&ctl_conns, c, entry); 243 } 244 245 struct ctl_conn * 246 control_connbyfd(int fd) 247 { 248 struct ctl_conn *c; 249 250 for (c = TAILQ_FIRST(&ctl_conns); c != NULL && c->iev.ibuf.fd != fd; 251 c = TAILQ_NEXT(c, entry)) 252 ; /* nothing */ 253 254 return (c); 255 } 256 257 void 258 control_close(int fd, struct control_sock *cs) 259 { 260 struct ctl_conn *c; 261 262 if ((c = control_connbyfd(fd)) == NULL) { 263 log_warn("%s: fd %d: not found", __func__, fd); 264 return; 265 } 266 267 msgbuf_clear(&c->iev.ibuf.w); 268 TAILQ_REMOVE(&ctl_conns, c, entry); 269 270 event_del(&c->iev.ev); 271 close(c->iev.ibuf.fd); 272 273 /* Some file descriptors are available again. */ 274 if (evtimer_pending(&cs->cs_evt, NULL)) { 275 evtimer_del(&cs->cs_evt); 276 event_add(&cs->cs_ev, NULL); 277 } 278 279 free(c); 280 } 281 282 /* ARGSUSED */ 283 void 284 control_dispatch_imsg(int fd, short event, void *arg) 285 { 286 struct control_sock *cs = arg; 287 struct privsep *ps = cs->cs_env; 288 struct ctl_conn *c; 289 struct imsg imsg; 290 int n, v, ret = 0; 291 292 if ((c = control_connbyfd(fd)) == NULL) { 293 log_warn("%s: fd %d: not found", __func__, fd); 294 return; 295 } 296 297 if (event & EV_READ) { 298 if (((n = imsg_read(&c->iev.ibuf)) == -1 && errno != EAGAIN) || 299 n == 0) { 300 control_close(fd, cs); 301 return; 302 } 303 } 304 if (event & EV_WRITE) { 305 if (msgbuf_write(&c->iev.ibuf.w) <= 0 && errno != EAGAIN) { 306 control_close(fd, cs); 307 return; 308 } 309 } 310 311 for (;;) { 312 if ((n = imsg_get(&c->iev.ibuf, &imsg)) == -1) { 313 control_close(fd, cs); 314 return; 315 } 316 317 if (n == 0) 318 break; 319 320 switch (imsg.hdr.type) { 321 case IMSG_VMDOP_GET_INFO_VM_REQUEST: 322 break; 323 default: 324 if (c->peercred.uid != 0) { 325 log_warnx("denied request %d from uid %d", 326 imsg.hdr.type, c->peercred.uid); 327 ret = EPERM; 328 goto fail; 329 } 330 break; 331 } 332 333 control_imsg_forward(&imsg); 334 335 switch (imsg.hdr.type) { 336 case IMSG_CTL_NOTIFY: 337 if (c->flags & CTL_CONN_NOTIFY) { 338 log_debug("%s: " 339 "client requested notify more than once", 340 __func__); 341 ret = EINVAL; 342 goto fail; 343 } 344 c->flags |= CTL_CONN_NOTIFY; 345 break; 346 case IMSG_CTL_VERBOSE: 347 IMSG_SIZE_CHECK(&imsg, &v); 348 349 memcpy(&v, imsg.data, sizeof(v)); 350 log_verbose(v); 351 352 proc_forward_imsg(ps, &imsg, PROC_PARENT, -1); 353 break; 354 case IMSG_VMDOP_START_VM_REQUEST: 355 case IMSG_VMDOP_TERMINATE_VM_REQUEST: 356 case IMSG_VMDOP_GET_INFO_VM_REQUEST: 357 imsg.hdr.peerid = fd; 358 359 if (proc_compose_imsg(ps, PROC_PARENT, -1, 360 imsg.hdr.type, imsg.hdr.peerid, -1, 361 imsg.data, IMSG_DATA_SIZE(&imsg)) == -1) { 362 control_close(fd, cs); 363 return; 364 } 365 break; 366 case IMSG_VMDOP_LOAD: 367 case IMSG_VMDOP_RELOAD: 368 proc_forward_imsg(ps, &imsg, PROC_PARENT, -1); 369 break; 370 default: 371 log_debug("%s: error handling imsg %d", 372 __func__, imsg.hdr.type); 373 control_close(fd, cs); 374 break; 375 } 376 imsg_free(&imsg); 377 } 378 379 imsg_event_add(&c->iev); 380 return; 381 382 fail: 383 imsg_compose_event(&c->iev, IMSG_CTL_FAIL, 384 0, 0, -1, &ret, sizeof(ret)); 385 imsg_flush(&c->iev.ibuf); 386 control_close(fd, cs); 387 } 388 389 void 390 control_imsg_forward(struct imsg *imsg) 391 { 392 struct ctl_conn *c; 393 394 TAILQ_FOREACH(c, &ctl_conns, entry) 395 if (c->flags & CTL_CONN_NOTIFY) 396 imsg_compose_event(&c->iev, imsg->hdr.type, 397 imsg->hdr.peerid, imsg->hdr.pid, -1, imsg->data, 398 imsg->hdr.len - IMSG_HEADER_SIZE); 399 } 400