1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 1999 Brian Somers <brian@Awfulhak.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/param.h> 30 #include <sys/socket.h> 31 #include <sys/un.h> 32 33 #include <errno.h> 34 #include <fcntl.h> 35 #include <stdio.h> 36 #include <stdlib.h> 37 #include <string.h> 38 #include <sysexits.h> 39 #include <sys/wait.h> 40 #include <sys/stat.h> 41 #include <sys/uio.h> 42 #include <termios.h> 43 #include <unistd.h> 44 45 #include "layer.h" 46 #include "defs.h" 47 #include "mbuf.h" 48 #include "log.h" 49 #include "timer.h" 50 #include "lqr.h" 51 #include "hdlc.h" 52 #include "throughput.h" 53 #include "fsm.h" 54 #include "lcp.h" 55 #include "ccp.h" 56 #include "link.h" 57 #include "async.h" 58 #include "descriptor.h" 59 #include "physical.h" 60 #include "mp.h" 61 #include "chat.h" 62 #include "command.h" 63 #include "auth.h" 64 #include "chap.h" 65 #include "cbcp.h" 66 #include "datalink.h" 67 #include "id.h" 68 #include "main.h" 69 #include "exec.h" 70 71 72 struct execdevice { 73 struct device dev; /* What struct physical knows about */ 74 int fd_out; /* output descriptor */ 75 }; 76 77 #define device2exec(d) ((d)->type == EXEC_DEVICE ? (struct execdevice *)d : NULL) 78 79 unsigned 80 exec_DeviceSize(void) 81 { 82 return sizeof(struct execdevice); 83 } 84 85 static void 86 exec_Free(struct physical *p) 87 { 88 struct execdevice *dev = device2exec(p->handler); 89 90 if (dev->fd_out != -1) 91 close(dev->fd_out); 92 free(dev); 93 } 94 95 static void 96 exec_device2iov(struct device *d, struct iovec *iov, int *niov, 97 int maxiov __unused, int *auxfd, int *nauxfd) 98 { 99 struct execdevice *dev; 100 int sz = physical_MaxDeviceSize(); 101 102 iov[*niov].iov_base = d = realloc(d, sz); 103 if (d == NULL) { 104 log_Printf(LogALERT, "Failed to allocate memory: %d\n", sz); 105 AbortProgram(EX_OSERR); 106 } 107 iov[*niov].iov_len = sz; 108 (*niov)++; 109 110 dev = device2exec(d); 111 if (dev->fd_out >= 0) { 112 *auxfd = dev->fd_out; 113 (*nauxfd)++; 114 } 115 } 116 117 static int 118 exec_RemoveFromSet(struct physical *p, fd_set *r, fd_set *w, fd_set *e) 119 { 120 struct execdevice *dev = device2exec(p->handler); 121 int sets; 122 123 p->handler->removefromset = NULL; 124 sets = physical_RemoveFromSet(p, r, w, e); 125 p->handler->removefromset = exec_RemoveFromSet; 126 127 if (dev->fd_out >= 0) { 128 if (w && FD_ISSET(dev->fd_out, w)) { 129 FD_CLR(dev->fd_out, w); 130 log_Printf(LogTIMER, "%s: fdunset(w) %d\n", p->link.name, dev->fd_out); 131 sets++; 132 } 133 if (e && FD_ISSET(dev->fd_out, e)) { 134 FD_CLR(dev->fd_out, e); 135 log_Printf(LogTIMER, "%s: fdunset(e) %d\n", p->link.name, dev->fd_out); 136 sets++; 137 } 138 } 139 140 return sets; 141 } 142 143 static ssize_t 144 exec_Write(struct physical *p, const void *v, size_t n) 145 { 146 struct execdevice *dev = device2exec(p->handler); 147 int fd = dev->fd_out == -1 ? p->fd : dev->fd_out; 148 149 return write(fd, v, n); 150 } 151 152 static struct device baseexecdevice = { 153 EXEC_DEVICE, 154 "exec", 155 0, 156 { CD_NOTREQUIRED, 0 }, 157 NULL, 158 exec_RemoveFromSet, 159 NULL, 160 NULL, 161 NULL, 162 NULL, 163 NULL, 164 exec_Free, 165 NULL, 166 exec_Write, 167 exec_device2iov, 168 NULL, 169 NULL, 170 NULL 171 }; 172 173 struct device * 174 exec_iov2device(int type, struct physical *p, struct iovec *iov, 175 int *niov, int maxiov __unused, int *auxfd, int *nauxfd) 176 { 177 if (type == EXEC_DEVICE) { 178 struct execdevice *dev = (struct execdevice *)iov[(*niov)++].iov_base; 179 180 dev = realloc(dev, sizeof *dev); /* Reduce to the correct size */ 181 if (dev == NULL) { 182 log_Printf(LogALERT, "Failed to allocate memory: %d\n", 183 (int)(sizeof *dev)); 184 AbortProgram(EX_OSERR); 185 } 186 187 if (*nauxfd) { 188 dev->fd_out = *auxfd; 189 (*nauxfd)--; 190 } else 191 dev->fd_out = -1; 192 193 /* Refresh function pointers etc */ 194 memcpy(&dev->dev, &baseexecdevice, sizeof dev->dev); 195 196 physical_SetupStack(p, dev->dev.name, PHYSICAL_NOFORCE); 197 return &dev->dev; 198 } 199 200 return NULL; 201 } 202 203 static int 204 exec_UpdateSet(struct fdescriptor *d, fd_set *r, fd_set *w, fd_set *e, int *n) 205 { 206 struct physical *p = descriptor2physical(d); 207 struct execdevice *dev = device2exec(p->handler); 208 int result = 0; 209 210 if (w && dev->fd_out >= 0) { 211 FD_SET(dev->fd_out, w); 212 log_Printf(LogTIMER, "%s: fdset(w) %d\n", p->link.name, dev->fd_out); 213 result++; 214 w = NULL; 215 } 216 217 if (e && dev->fd_out >= 0) { 218 FD_SET(dev->fd_out, e); 219 log_Printf(LogTIMER, "%s: fdset(e) %d\n", p->link.name, dev->fd_out); 220 result++; 221 } 222 223 if (result && *n <= dev->fd_out) 224 *n = dev->fd_out + 1; 225 226 return result + physical_doUpdateSet(d, r, w, e, n, 0); 227 } 228 229 static int 230 exec_IsSet(struct fdescriptor *d, const fd_set *fdset) 231 { 232 struct physical *p = descriptor2physical(d); 233 struct execdevice *dev = device2exec(p->handler); 234 int result = dev->fd_out >= 0 && FD_ISSET(dev->fd_out, fdset); 235 result += physical_IsSet(d, fdset); 236 237 return result; 238 } 239 240 struct device * 241 exec_Create(struct physical *p) 242 { 243 struct execdevice *dev; 244 245 dev = NULL; 246 if (p->fd < 0) { 247 if (*p->name.full == '!') { 248 int fids[2], type; 249 250 if ((dev = malloc(sizeof *dev)) == NULL) { 251 log_Printf(LogWARN, "%s: Cannot allocate an exec device: %s\n", 252 p->link.name, strerror(errno)); 253 return NULL; 254 } 255 dev->fd_out = -1; 256 257 p->fd--; /* We own the device but maybe can't use it - change fd */ 258 type = physical_IsSync(p) ? SOCK_DGRAM : SOCK_STREAM; 259 260 if (socketpair(AF_UNIX, type, PF_UNSPEC, fids) < 0) { 261 log_Printf(LogPHASE, "Unable to create pipe for line exec: %s\n", 262 strerror(errno)); 263 free(dev); 264 dev = NULL; 265 } else { 266 static int child_status; /* This variable is abused ! */ 267 int stat, argc, i, ret, wret, pidpipe[2]; 268 pid_t pid, realpid; 269 char *argv[MAXARGS]; 270 271 stat = fcntl(fids[0], F_GETFL, 0); 272 if (stat > 0) { 273 stat |= O_NONBLOCK; 274 fcntl(fids[0], F_SETFL, stat); 275 } 276 realpid = getpid(); 277 if (pipe(pidpipe) == -1) { 278 log_Printf(LogPHASE, "Unable to pipe for line exec: %s\n", 279 strerror(errno)); 280 close(fids[1]); 281 close(fids[0]); 282 free(dev); 283 dev = NULL; 284 } else switch ((pid = fork())) { 285 case -1: 286 log_Printf(LogPHASE, "Unable to fork for line exec: %s\n", 287 strerror(errno)); 288 close(pidpipe[0]); 289 close(pidpipe[1]); 290 close(fids[1]); 291 close(fids[0]); 292 break; 293 294 case 0: 295 close(pidpipe[0]); 296 close(fids[0]); 297 timer_TermService(); 298 #ifndef NOSUID 299 setuid(ID0realuid()); 300 #endif 301 302 child_status = 0; 303 switch ((pid = vfork())) { 304 case 0: 305 close(pidpipe[1]); 306 break; 307 308 case -1: 309 ret = errno; 310 log_Printf(LogPHASE, "Unable to vfork to drop parent: %s\n", 311 strerror(errno)); 312 close(pidpipe[1]); 313 _exit(ret); 314 315 default: 316 write(pidpipe[1], &pid, sizeof pid); 317 close(pidpipe[1]); 318 _exit(child_status); /* The error from exec() ! */ 319 } 320 321 log_Printf(LogDEBUG, "Exec'ing ``%s''\n", p->name.base); 322 323 if ((argc = MakeArgs(p->name.base, argv, VECSIZE(argv), 324 PARSE_REDUCE|PARSE_NOHASH)) < 0) { 325 log_Printf(LogWARN, "Syntax error in exec command\n"); 326 _exit(ESRCH); 327 } 328 329 command_Expand(argv, argc, (char const *const *)argv, 330 p->dl->bundle, 0, realpid); 331 332 dup2(fids[1], STDIN_FILENO); 333 dup2(fids[1], STDOUT_FILENO); 334 dup2(fids[1], STDERR_FILENO); 335 for (i = getdtablesize(); i > STDERR_FILENO; i--) 336 fcntl(i, F_SETFD, 1); 337 338 execvp(*argv, argv); 339 child_status = errno; /* Only works for vfork() */ 340 printf("execvp failed: %s: %s\r\n", *argv, strerror(child_status)); 341 _exit(child_status); 342 break; 343 344 default: 345 close(pidpipe[1]); 346 close(fids[1]); 347 if (read(pidpipe[0], &p->session_owner, sizeof p->session_owner) != 348 sizeof p->session_owner) 349 p->session_owner = (pid_t)-1; 350 close(pidpipe[0]); 351 while ((wret = waitpid(pid, &stat, 0)) == -1 && errno == EINTR) 352 ; 353 if (wret == -1) { 354 log_Printf(LogWARN, "Waiting for child process: %s\n", 355 strerror(errno)); 356 close(fids[0]); 357 p->session_owner = (pid_t)-1; 358 break; 359 } else if (WIFSIGNALED(stat)) { 360 log_Printf(LogWARN, "Child process received sig %d !\n", 361 WTERMSIG(stat)); 362 close(fids[0]); 363 p->session_owner = (pid_t)-1; 364 break; 365 } else if (WIFSTOPPED(stat)) { 366 log_Printf(LogWARN, "Child process received stop sig %d !\n", 367 WSTOPSIG(stat)); 368 /* I guess that's ok.... */ 369 } else if ((ret = WEXITSTATUS(stat))) { 370 log_Printf(LogWARN, "Cannot exec \"%s\": %s\n", p->name.base, 371 strerror(ret)); 372 close(fids[0]); 373 p->session_owner = (pid_t)-1; 374 break; 375 } 376 p->fd = fids[0]; 377 log_Printf(LogDEBUG, "Using descriptor %d for child\n", p->fd); 378 } 379 } 380 } 381 } else { 382 struct stat st; 383 384 if (fstat(p->fd, &st) != -1 && (st.st_mode & S_IFIFO)) { 385 if ((dev = malloc(sizeof *dev)) == NULL) 386 log_Printf(LogWARN, "%s: Cannot allocate an exec device: %s\n", 387 p->link.name, strerror(errno)); 388 else if (p->fd == STDIN_FILENO) { 389 log_Printf(LogPHASE, "%s: Using stdin/stdout to communicate with " 390 "parent (pipe mode)\n", p->link.name); 391 dev->fd_out = dup(STDOUT_FILENO); 392 393 /* Hook things up so that we monitor dev->fd_out */ 394 p->desc.UpdateSet = exec_UpdateSet; 395 p->desc.IsSet = exec_IsSet; 396 } else 397 dev->fd_out = -1; 398 } 399 } 400 401 if (dev) { 402 memcpy(&dev->dev, &baseexecdevice, sizeof dev->dev); 403 physical_SetupStack(p, dev->dev.name, PHYSICAL_NOFORCE); 404 if (p->cfg.cd.necessity != CD_DEFAULT) 405 log_Printf(LogWARN, "Carrier settings ignored\n"); 406 return &dev->dev; 407 } 408 409 return NULL; 410 } 411