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
exec_DeviceSize(void)80 exec_DeviceSize(void)
81 {
82 return sizeof(struct execdevice);
83 }
84
85 static void
exec_Free(struct physical * p)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
exec_device2iov(struct device * d,struct iovec * iov,int * niov,int maxiov __unused,int * auxfd,int * nauxfd)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
exec_RemoveFromSet(struct physical * p,fd_set * r,fd_set * w,fd_set * e)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
exec_Write(struct physical * p,const void * v,size_t n)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 *
exec_iov2device(int type,struct physical * p,struct iovec * iov,int * niov,int maxiov __unused,int * auxfd,int * nauxfd)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
exec_UpdateSet(struct fdescriptor * d,fd_set * r,fd_set * w,fd_set * e,int * n)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
exec_IsSet(struct fdescriptor * d,const fd_set * fdset)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 *
exec_Create(struct physical * p)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