xref: /freebsd/lib/libjail/jail.c (revision 6580f5c38dd5b01aeeaed16b370f1a12423437f0)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2009 James Gritton.
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/jail.h>
31 #include <sys/linker.h>
32 #include <sys/socket.h>
33 #include <sys/sysctl.h>
34 
35 #include <arpa/inet.h>
36 #include <netinet/in.h>
37 
38 #include <errno.h>
39 #include <inttypes.h>
40 #include <stdio.h>
41 #include <stdarg.h>
42 #include <stdlib.h>
43 #include <string.h>
44 
45 #include "jail.h"
46 
47 #define	SJPARAM		"security.jail.param"
48 
49 #define JPS_IN_ADDR	1
50 #define JPS_IN6_ADDR	2
51 
52 #define ARRAY_SANITY	5
53 #define ARRAY_SLOP	5
54 
55 
56 static int jailparam_import_enum(const char **values, int nvalues,
57     const char *valstr, size_t valsize, int *value);
58 static int jailparam_type(struct jailparam *jp);
59 static int kldload_param(const char *name);
60 static char *noname(const char *name);
61 static char *nononame(const char *name);
62 
63 char jail_errmsg[JAIL_ERRMSGLEN];
64 
65 static const char *bool_values[] = { "false", "true" };
66 static const char *jailsys_values[] = { "disable", "new", "inherit" };
67 
68 
69 /*
70  * Import a null-terminated parameter list and set a jail with the flags
71  * and parameters.
72  */
73 int
74 jail_setv(int flags, ...)
75 {
76 	va_list ap, tap;
77 	struct jailparam *jp;
78 	const char *name, *value;
79 	int njp, jid;
80 
81 	/* Create the parameter list and import the parameters. */
82 	va_start(ap, flags);
83 	va_copy(tap, ap);
84 	for (njp = 0; va_arg(tap, char *) != NULL; njp++)
85 		(void)va_arg(tap, char *);
86 	va_end(tap);
87 	jp = alloca(njp * sizeof(struct jailparam));
88 	for (njp = 0; (name = va_arg(ap, char *)) != NULL;) {
89 		value = va_arg(ap, char *);
90 		if (jailparam_init(jp + njp, name) < 0)
91 			goto error;
92 		if (jailparam_import(jp + njp++, value) < 0)
93 			goto error;
94 	}
95 	va_end(ap);
96 	jid = jailparam_set(jp, njp, flags);
97 	jailparam_free(jp, njp);
98 	return (jid);
99 
100  error:
101 	jailparam_free(jp, njp);
102 	va_end(ap);
103 	return (-1);
104 }
105 
106 /*
107  * Read a null-terminated parameter list, get the referenced jail, and export
108  * the parameters to the list.
109  */
110 int
111 jail_getv(int flags, ...)
112 {
113 	va_list ap, tap;
114 	struct jailparam *jp, *jp_lastjid, *jp_jid, *jp_name, *jp_key;
115 	char *valarg, *value;
116 	const char *name, *key_value, *lastjid_value, *jid_value, *name_value;
117 	int njp, i, jid;
118 
119 	/* Create the parameter list and find the key. */
120 	va_start(ap, flags);
121 	va_copy(tap, ap);
122 	for (njp = 0; va_arg(tap, char *) != NULL; njp++)
123 		(void)va_arg(tap, char *);
124 	va_end(tap);
125 
126 	jp = alloca(njp * sizeof(struct jailparam));
127 	va_copy(tap, ap);
128 	jp_lastjid = jp_jid = jp_name = NULL;
129 	lastjid_value = jid_value = name_value = NULL;
130 	for (njp = 0; (name = va_arg(tap, char *)) != NULL; njp++) {
131 		value = va_arg(tap, char *);
132 		if (jailparam_init(jp + njp, name) < 0) {
133 			va_end(tap);
134 			goto error;
135 		}
136 		if (!strcmp(jp[njp].jp_name, "lastjid")) {
137 			jp_lastjid = jp + njp;
138 			lastjid_value = value;
139 		} else if (!strcmp(jp[njp].jp_name, "jid")) {
140 			jp_jid = jp + njp;
141 			jid_value = value;
142 		} if (!strcmp(jp[njp].jp_name, "name")) {
143 			jp_name = jp + njp;
144 			name_value = value;
145 		}
146 	}
147 	va_end(tap);
148 	/* Import the key parameter. */
149 	if (jp_lastjid != NULL) {
150 		jp_key = jp_lastjid;
151 		key_value = lastjid_value;
152 	} else if (jp_jid != NULL && strtol(jid_value, NULL, 10) != 0) {
153 		jp_key = jp_jid;
154 		key_value = jid_value;
155 	} else if (jp_name != NULL) {
156 		jp_key = jp_name;
157 		key_value = name_value;
158 	} else {
159 		strlcpy(jail_errmsg, "no jail specified", JAIL_ERRMSGLEN);
160 		errno = ENOENT;
161 		goto error;
162 	}
163 	if (jailparam_import(jp_key, key_value) < 0)
164 		goto error;
165 	/* Get the jail and export the parameters. */
166 	jid = jailparam_get(jp, njp, flags);
167 	if (jid < 0)
168 		goto error;
169 	for (i = 0; i < njp; i++) {
170 		(void)va_arg(ap, char *);
171 		valarg = va_arg(ap, char *);
172 		if (jp + i != jp_key) {
173 			/* It's up to the caller to ensure there's room. */
174 			if ((jp[i].jp_ctltype & CTLTYPE) == CTLTYPE_STRING)
175 				strcpy(valarg, jp[i].jp_value);
176 			else {
177 				value = jailparam_export(jp + i);
178 				if (value == NULL)
179 					goto error;
180 				strcpy(valarg, value);
181 				free(value);
182 			}
183 		}
184 	}
185 	jailparam_free(jp, njp);
186 	va_end(ap);
187 	return (jid);
188 
189  error:
190 	jailparam_free(jp, njp);
191 	va_end(ap);
192 	return (-1);
193 }
194 
195 /*
196  * Return a list of all known parameters.
197  */
198 int
199 jailparam_all(struct jailparam **jpp)
200 {
201 	struct jailparam *jp, *tjp;
202 	size_t mlen1, mlen2, buflen;
203 	unsigned njp, nlist;
204 	int mib1[CTL_MAXNAME], mib2[CTL_MAXNAME - 2];
205 	char buf[MAXPATHLEN];
206 
207 	njp = 0;
208 	nlist = 32;
209 	jp = malloc(nlist * sizeof(*jp));
210 	if (jp == NULL) {
211 		strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
212 		return (-1);
213 	}
214 	mib1[0] = 0;
215 	mib1[1] = 2;
216 	mlen1 = CTL_MAXNAME - 2;
217 	if (sysctlnametomib(SJPARAM, mib1 + 2, &mlen1) < 0) {
218 		snprintf(jail_errmsg, JAIL_ERRMSGLEN,
219 		    "sysctlnametomib(" SJPARAM "): %s", strerror(errno));
220 		goto error;
221 	}
222 	for (;; njp++) {
223 		/* Get the next parameter. */
224 		mlen2 = sizeof(mib2);
225 		if (sysctl(mib1, mlen1 + 2, mib2, &mlen2, NULL, 0) < 0) {
226 			if (errno == ENOENT) {
227 				/* No more entries. */
228 				break;
229 			}
230 			snprintf(jail_errmsg, JAIL_ERRMSGLEN,
231 			    "sysctl(0.2): %s", strerror(errno));
232 			goto error;
233 		}
234 		if (mib2[0] != mib1[2] ||
235 		    mib2[1] != mib1[3] ||
236 		    mib2[2] != mib1[4])
237 			break;
238 		/* Convert it to an ascii name. */
239 		memcpy(mib1 + 2, mib2, mlen2);
240 		mlen1 = mlen2 / sizeof(int);
241 		mib1[1] = 1;
242 		buflen = sizeof(buf);
243 		if (sysctl(mib1, mlen1 + 2, buf, &buflen, NULL, 0) < 0) {
244 			snprintf(jail_errmsg, JAIL_ERRMSGLEN,
245 			    "sysctl(0.1): %s", strerror(errno));
246 			goto error;
247 		}
248 		if (buf[buflen - 2] == '.')
249 			buf[buflen - 2] = '\0';
250 		/* Add the parameter to the list */
251 		if (njp >= nlist) {
252 			nlist *= 2;
253 			tjp = reallocarray(jp, nlist, sizeof(*jp));
254 			if (tjp == NULL)
255 				goto error;
256 			jp = tjp;
257 		}
258 		if (jailparam_init(jp + njp, buf + sizeof(SJPARAM)) < 0)
259 			goto error;
260 		mib1[1] = 2;
261 	}
262 	/* Just return the untrimmed buffer if reallocarray() somehow fails. */
263 	tjp = reallocarray(jp, njp, sizeof(*jp));
264 	if (tjp != NULL)
265 		jp = tjp;
266 	*jpp = jp;
267 	return (njp);
268 
269  error:
270 	jailparam_free(jp, njp);
271 	free(jp);
272 	return (-1);
273 }
274 
275 /*
276  * Clear a jail parameter and copy in its name.
277  */
278 int
279 jailparam_init(struct jailparam *jp, const char *name)
280 {
281 
282 	memset(jp, 0, sizeof(*jp));
283 	jp->jp_name = strdup(name);
284 	if (jp->jp_name == NULL) {
285 		strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
286 		return (-1);
287 	}
288 	if (jailparam_type(jp) < 0) {
289 		jailparam_free(jp, 1);
290 		jp->jp_name = NULL;
291 		jp->jp_value = NULL;
292 		return (-1);
293 	}
294 	return (0);
295 }
296 
297 /*
298  * Put a name and value into a jail parameter element, converting the value
299  * to internal form.
300  */
301 int
302 jailparam_import(struct jailparam *jp, const char *value)
303 {
304 	char *p, *ep, *tvalue;
305 	const char *avalue;
306 	int i, nval, fw;
307 
308 	if (value == NULL)
309 		return (0);
310 	if ((jp->jp_ctltype & CTLTYPE) == CTLTYPE_STRING) {
311 		jp->jp_value = strdup(value);
312 		if (jp->jp_value == NULL) {
313 			strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
314 			return (-1);
315 		}
316 		return (0);
317 	}
318 	nval = 1;
319 	if (jp->jp_elemlen) {
320 		if (value[0] == '\0' || (value[0] == '-' && value[1] == '\0')) {
321 			jp->jp_value = strdup("");
322 			if (jp->jp_value == NULL) {
323 				strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
324 				return (-1);
325 			}
326 			jp->jp_valuelen = 0;
327 			return (0);
328 		}
329 		for (p = strchr(value, ','); p; p = strchr(p + 1, ','))
330 			nval++;
331 		jp->jp_valuelen = jp->jp_elemlen * nval;
332 	}
333 	jp->jp_value = malloc(jp->jp_valuelen);
334 	if (jp->jp_value == NULL) {
335 		strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
336 		return (-1);
337 	}
338 	avalue = value;
339 	for (i = 0; i < nval; i++) {
340 		fw = nval == 1 ? strlen(avalue) : strcspn(avalue, ",");
341 		switch (jp->jp_ctltype & CTLTYPE) {
342 		case CTLTYPE_INT:
343 			if (jp->jp_flags & (JP_BOOL | JP_NOBOOL)) {
344 				if (!jailparam_import_enum(bool_values, 2,
345 				    avalue, fw, &((int *)jp->jp_value)[i])) {
346 					snprintf(jail_errmsg,
347 					    JAIL_ERRMSGLEN, "%s: "
348 					    "unknown boolean value \"%.*s\"",
349 					    jp->jp_name, fw, avalue);
350 					errno = EINVAL;
351 					goto error;
352 				}
353 				break;
354 			}
355 			if (jp->jp_flags & JP_JAILSYS) {
356 				/*
357 				 * Allow setting a jailsys parameter to "new"
358 				 * in a booleanesque fashion.
359 				 */
360 				if (value[0] == '\0')
361 					((int *)jp->jp_value)[i] = JAIL_SYS_NEW;
362 				else if (!jailparam_import_enum(jailsys_values,
363 				    sizeof(jailsys_values) /
364 				    sizeof(jailsys_values[0]), avalue, fw,
365 				    &((int *)jp->jp_value)[i])) {
366 					snprintf(jail_errmsg,
367 					    JAIL_ERRMSGLEN, "%s: "
368 					    "unknown jailsys value \"%.*s\"",
369 					    jp->jp_name, fw, avalue);
370 					errno = EINVAL;
371 					goto error;
372 				}
373 				break;
374 			}
375 			((int *)jp->jp_value)[i] = strtol(avalue, &ep, 10);
376 		integer_test:
377 			if (ep != avalue + fw) {
378 				snprintf(jail_errmsg, JAIL_ERRMSGLEN,
379 				    "%s: non-integer value \"%.*s\"",
380 				    jp->jp_name, fw, avalue);
381 				errno = EINVAL;
382 				goto error;
383 			}
384 			break;
385 		case CTLTYPE_UINT:
386 			((unsigned *)jp->jp_value)[i] =
387 			    strtoul(avalue, &ep, 10);
388 			goto integer_test;
389 		case CTLTYPE_LONG:
390 			((long *)jp->jp_value)[i] = strtol(avalue, &ep, 10);
391 			goto integer_test;
392 		case CTLTYPE_ULONG:
393 			((unsigned long *)jp->jp_value)[i] =
394 			    strtoul(avalue, &ep, 10);
395 			goto integer_test;
396 		case CTLTYPE_S64:
397 			((int64_t *)jp->jp_value)[i] =
398 			    strtoimax(avalue, &ep, 10);
399 			goto integer_test;
400 		case CTLTYPE_U64:
401 			((uint64_t *)jp->jp_value)[i] =
402 			    strtoumax(avalue, &ep, 10);
403 			goto integer_test;
404 		case CTLTYPE_STRUCT:
405 			tvalue = alloca(fw + 1);
406 			strlcpy(tvalue, avalue, fw + 1);
407 			switch (jp->jp_structtype) {
408 			case JPS_IN_ADDR:
409 				if (inet_pton(AF_INET, tvalue,
410 				    &((struct in_addr *)jp->jp_value)[i]) != 1)
411 				{
412 					snprintf(jail_errmsg,
413 					    JAIL_ERRMSGLEN,
414 					    "%s: not an IPv4 address: %s",
415 					    jp->jp_name, tvalue);
416 					errno = EINVAL;
417 					goto error;
418 				}
419 				break;
420 			case JPS_IN6_ADDR:
421 				if (inet_pton(AF_INET6, tvalue,
422 				    &((struct in6_addr *)jp->jp_value)[i]) != 1)
423 				{
424 					snprintf(jail_errmsg,
425 					    JAIL_ERRMSGLEN,
426 					    "%s: not an IPv6 address: %s",
427 					    jp->jp_name, tvalue);
428 					errno = EINVAL;
429 					goto error;
430 				}
431 				break;
432 			default:
433 				goto unknown_type;
434 			}
435 			break;
436 		default:
437 		unknown_type:
438 			snprintf(jail_errmsg, JAIL_ERRMSGLEN,
439 			    "unknown type for %s", jp->jp_name);
440 			errno = ENOENT;
441 			goto error;
442 		}
443 		avalue += fw + 1;
444 	}
445 	return (0);
446 
447  error:
448 	free(jp->jp_value);
449 	jp->jp_value = NULL;
450 	return (-1);
451 }
452 
453 static int
454 jailparam_import_enum(const char **values, int nvalues, const char *valstr,
455     size_t valsize, int *value)
456 {
457 	char *ep;
458 	int i;
459 
460 	for (i = 0; i < nvalues; i++)
461 		if (valsize == strlen(values[i]) &&
462 		    !strncasecmp(valstr, values[i], valsize)) {
463 			*value = i;
464 			return 1;
465 		}
466 	*value = strtol(valstr, &ep, 10);
467 	return (ep == valstr + valsize);
468 }
469 
470 /*
471  * Put a name and value into a jail parameter element, copying the value
472  * but not altering it.
473  */
474 int
475 jailparam_import_raw(struct jailparam *jp, void *value, size_t valuelen)
476 {
477 
478 	jp->jp_value = value;
479 	jp->jp_valuelen = valuelen;
480 	jp->jp_flags |= JP_RAWVALUE;
481 	return (0);
482 }
483 
484 /*
485  * Run the jail_set and jail_get system calls on a parameter list.
486  */
487 int
488 jailparam_set(struct jailparam *jp, unsigned njp, int flags)
489 {
490 	struct iovec *jiov;
491 	char *nname;
492 	int i, jid, bool0;
493 	unsigned j;
494 
495 	jiov = alloca(sizeof(struct iovec) * 2 * (njp + 1));
496 	bool0 = 0;
497 	for (i = j = 0; j < njp; j++) {
498 		jiov[i].iov_base = jp[j].jp_name;
499 		jiov[i].iov_len = strlen(jp[j].jp_name) + 1;
500 		i++;
501 		if (jp[j].jp_flags & (JP_BOOL | JP_NOBOOL)) {
502 			/*
503 			 * Set booleans without values.  If one has a value of
504 			 * zero, change it to (or from) its "no" counterpart.
505 			 */
506 			jiov[i].iov_base = NULL;
507 			jiov[i].iov_len = 0;
508 			if (jp[j].jp_value != NULL &&
509 			    jp[j].jp_valuelen == sizeof(int) &&
510 			    !*(int *)jp[j].jp_value) {
511 				bool0 = 1;
512 				nname = jp[j].jp_flags & JP_BOOL
513 				    ? noname(jp[j].jp_name)
514 				    : nononame(jp[j].jp_name);
515 				if (nname == NULL) {
516 					njp = j;
517 					jid = -1;
518 					goto done;
519 				}
520 				jiov[i - 1].iov_base = nname;
521 				jiov[i - 1].iov_len = strlen(nname) + 1;
522 
523 			}
524 		} else {
525 			/*
526 			 * Try to fill in missing values with an empty string.
527 			 */
528 			if (jp[j].jp_value == NULL && jp[j].jp_valuelen > 0 &&
529 			    jailparam_import(jp + j, "") < 0) {
530 				njp = j;
531 				jid = -1;
532 				goto done;
533 			}
534 			jiov[i].iov_base = jp[j].jp_value;
535 			jiov[i].iov_len =
536 			    (jp[j].jp_ctltype & CTLTYPE) == CTLTYPE_STRING
537 			    ? strlen(jp[j].jp_value) + 1
538 			    : jp[j].jp_valuelen;
539 		}
540 		i++;
541 	}
542 	jiov[i].iov_base = __DECONST(char *, "errmsg");
543 	jiov[i].iov_len = sizeof("errmsg");
544 	i++;
545 	jiov[i].iov_base = jail_errmsg;
546 	jiov[i].iov_len = JAIL_ERRMSGLEN;
547 	i++;
548 	jail_errmsg[0] = 0;
549 	jid = jail_set(jiov, i, flags);
550 	if (jid < 0 && !jail_errmsg[0])
551 		snprintf(jail_errmsg, sizeof(jail_errmsg), "jail_set: %s",
552 		    strerror(errno));
553  done:
554 	if (bool0)
555 		for (j = 0; j < njp; j++)
556 			if ((jp[j].jp_flags & (JP_BOOL | JP_NOBOOL)) &&
557 			    jp[j].jp_value != NULL &&
558 			    jp[j].jp_valuelen == sizeof(int) &&
559 			    !*(int *)jp[j].jp_value)
560 				free(jiov[j * 2].iov_base);
561 	return (jid);
562 }
563 
564 int
565 jailparam_get(struct jailparam *jp, unsigned njp, int flags)
566 {
567 	struct iovec *jiov;
568 	struct jailparam *jp_lastjid, *jp_jid, *jp_name, *jp_key;
569 	int i, ai, ki, jid, arrays, sanity;
570 	unsigned j;
571 
572 	/*
573 	 * Get the types for all parameters.
574 	 * Find the key and any array parameters.
575 	 */
576 	jiov = alloca(sizeof(struct iovec) * 2 * (njp + 1));
577 	jp_lastjid = jp_jid = jp_name = NULL;
578 	arrays = 0;
579 	for (ai = j = 0; j < njp; j++) {
580 		if (!strcmp(jp[j].jp_name, "lastjid"))
581 			jp_lastjid = jp + j;
582 		else if (!strcmp(jp[j].jp_name, "jid"))
583 			jp_jid = jp + j;
584 		else if (!strcmp(jp[j].jp_name, "name"))
585 			jp_name = jp + j;
586 		else if (jp[j].jp_elemlen && !(jp[j].jp_flags & JP_RAWVALUE)) {
587 			arrays = 1;
588 			jiov[ai].iov_base = jp[j].jp_name;
589 			jiov[ai].iov_len = strlen(jp[j].jp_name) + 1;
590 			ai++;
591 			jiov[ai].iov_base = NULL;
592 			jiov[ai].iov_len = 0;
593 			ai++;
594 		}
595 	}
596 	jp_key = jp_lastjid ? jp_lastjid :
597 	    jp_jid && jp_jid->jp_valuelen == sizeof(int) &&
598 	    jp_jid->jp_value && *(int *)jp_jid->jp_value ? jp_jid : jp_name;
599 	if (jp_key == NULL || jp_key->jp_value == NULL) {
600 		strlcpy(jail_errmsg, "no jail specified", JAIL_ERRMSGLEN);
601 		errno = ENOENT;
602 		return (-1);
603 	}
604 	ki = ai;
605 	jiov[ki].iov_base = jp_key->jp_name;
606 	jiov[ki].iov_len = strlen(jp_key->jp_name) + 1;
607 	ki++;
608 	jiov[ki].iov_base = jp_key->jp_value;
609 	jiov[ki].iov_len = (jp_key->jp_ctltype & CTLTYPE) == CTLTYPE_STRING
610 	    ? strlen(jp_key->jp_value) + 1 : jp_key->jp_valuelen;
611 	ki++;
612 	jiov[ki].iov_base = __DECONST(char *, "errmsg");
613 	jiov[ki].iov_len = sizeof("errmsg");
614 	ki++;
615 	jiov[ki].iov_base = jail_errmsg;
616 	jiov[ki].iov_len = JAIL_ERRMSGLEN;
617 	ki++;
618 	jail_errmsg[0] = 0;
619 	if (arrays && jail_get(jiov, ki, flags) < 0) {
620 		if (!jail_errmsg[0])
621 			snprintf(jail_errmsg, sizeof(jail_errmsg),
622 			    "jail_get: %s", strerror(errno));
623 		return (-1);
624 	}
625 	/* Allocate storage for all parameters. */
626 	for (ai = j = 0, i = ki; j < njp; j++) {
627 		if (jp[j].jp_elemlen && !(jp[j].jp_flags & JP_RAWVALUE)) {
628 			ai++;
629 			jiov[ai].iov_len += jp[j].jp_elemlen * ARRAY_SLOP;
630 			if (jp[j].jp_valuelen >= jiov[ai].iov_len)
631 				jiov[ai].iov_len = jp[j].jp_valuelen;
632 			else {
633 				jp[j].jp_valuelen = jiov[ai].iov_len;
634 				if (jp[j].jp_value != NULL)
635 					free(jp[j].jp_value);
636 				jp[j].jp_value = malloc(jp[j].jp_valuelen);
637 				if (jp[j].jp_value == NULL) {
638 					strerror_r(errno, jail_errmsg,
639 					    JAIL_ERRMSGLEN);
640 					return (-1);
641 				}
642 			}
643 			jiov[ai].iov_base = jp[j].jp_value;
644 			memset(jiov[ai].iov_base, 0, jiov[ai].iov_len);
645 			ai++;
646 		} else if (jp + j != jp_key) {
647 			jiov[i].iov_base = jp[j].jp_name;
648 			jiov[i].iov_len = strlen(jp[j].jp_name) + 1;
649 			i++;
650 			if (jp[j].jp_value == NULL &&
651 			    !(jp[j].jp_flags & JP_RAWVALUE)) {
652 				jp[j].jp_value = malloc(jp[j].jp_valuelen);
653 				if (jp[j].jp_value == NULL) {
654 					strerror_r(errno, jail_errmsg,
655 					    JAIL_ERRMSGLEN);
656 					return (-1);
657 				}
658 			}
659 			jiov[i].iov_base = jp[j].jp_value;
660 			jiov[i].iov_len = jp[j].jp_valuelen;
661 			memset(jiov[i].iov_base, 0, jiov[i].iov_len);
662 			i++;
663 		}
664 	}
665 	/*
666 	 * Get the prison.  If there are array elements, retry a few times
667 	 * in case their sizes changed from under us.
668 	 */
669 	for (sanity = 0;; sanity++) {
670 		jid = jail_get(jiov, i, flags);
671 		if (jid >= 0 || !arrays || sanity == ARRAY_SANITY ||
672 		    errno != EINVAL || jail_errmsg[0])
673 			break;
674 		for (ai = j = 0; j < njp; j++) {
675 			if (jp[j].jp_elemlen &&
676 			    !(jp[j].jp_flags & JP_RAWVALUE)) {
677 				ai++;
678 				jiov[ai].iov_base = NULL;
679 				jiov[ai].iov_len = 0;
680 				ai++;
681 			}
682 		}
683 		if (jail_get(jiov, ki, flags) < 0)
684 			break;
685 		for (ai = j = 0; j < njp; j++) {
686 			if (jp[j].jp_elemlen &&
687 			    !(jp[j].jp_flags & JP_RAWVALUE)) {
688 				ai++;
689 				jiov[ai].iov_len +=
690 				    jp[j].jp_elemlen * ARRAY_SLOP;
691 				if (jp[j].jp_valuelen >= jiov[ai].iov_len)
692 					jiov[ai].iov_len = jp[j].jp_valuelen;
693 				else {
694 					jp[j].jp_valuelen = jiov[ai].iov_len;
695 					if (jp[j].jp_value != NULL)
696 						free(jp[j].jp_value);
697 					jp[j].jp_value =
698 					    malloc(jiov[ai].iov_len);
699 					if (jp[j].jp_value == NULL) {
700 						strerror_r(errno, jail_errmsg,
701 						    JAIL_ERRMSGLEN);
702 						return (-1);
703 					}
704 				}
705 				jiov[ai].iov_base = jp[j].jp_value;
706 				memset(jiov[ai].iov_base, 0, jiov[ai].iov_len);
707 				ai++;
708 			}
709 		}
710 	}
711 	if (jid < 0 && !jail_errmsg[0])
712 		snprintf(jail_errmsg, sizeof(jail_errmsg),
713 		    "jail_get: %s", strerror(errno));
714 	for (ai = j = 0, i = ki; j < njp; j++) {
715 		if (jp[j].jp_elemlen && !(jp[j].jp_flags & JP_RAWVALUE)) {
716 			ai++;
717 			jp[j].jp_valuelen = jiov[ai].iov_len;
718 			ai++;
719 		} else if (jp + j != jp_key) {
720 			i++;
721 			jp[j].jp_valuelen = jiov[i].iov_len;
722 			i++;
723 		}
724 	}
725 	return (jid);
726 }
727 
728 /*
729  * Convert a jail parameter's value to external form.
730  */
731 char *
732 jailparam_export(struct jailparam *jp)
733 {
734 	size_t *valuelens;
735 	char *value, *tvalue, **values;
736 	size_t valuelen;
737 	int i, nval, ival;
738 	char valbuf[INET6_ADDRSTRLEN];
739 
740 	if (jp->jp_value == NULL) {
741 		snprintf(jail_errmsg, JAIL_ERRMSGLEN,
742 		    "parameter %s was not imported", jp->jp_name);
743 		errno = EINVAL;
744 		return (NULL);
745 	}
746 	if ((jp->jp_ctltype & CTLTYPE) == CTLTYPE_STRING) {
747 		value = strdup(jp->jp_value);
748 		if (value == NULL)
749 			strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
750 		return (value);
751 	}
752 	nval = jp->jp_elemlen ? jp->jp_valuelen / jp->jp_elemlen : 1;
753 	if (nval == 0) {
754 		value = strdup("");
755 		if (value == NULL)
756 			strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
757 		return (value);
758 	}
759 	values = alloca(nval * sizeof(char *));
760 	valuelens = alloca(nval * sizeof(size_t));
761 	valuelen = 0;
762 	for (i = 0; i < nval; i++) {
763 		switch (jp->jp_ctltype & CTLTYPE) {
764 		case CTLTYPE_INT:
765 			ival = ((int *)jp->jp_value)[i];
766 			if ((jp->jp_flags & (JP_BOOL | JP_NOBOOL)) &&
767 			    (unsigned)ival < 2) {
768 				strlcpy(valbuf, bool_values[ival],
769 				    sizeof(valbuf));
770 				break;
771 			}
772 			if ((jp->jp_flags & JP_JAILSYS) &&
773 			    (unsigned)ival < sizeof(jailsys_values) /
774 			    sizeof(jailsys_values[0])) {
775 				strlcpy(valbuf, jailsys_values[ival],
776 				    sizeof(valbuf));
777 				break;
778 			}
779 			snprintf(valbuf, sizeof(valbuf), "%d", ival);
780 			break;
781 		case CTLTYPE_UINT:
782 			snprintf(valbuf, sizeof(valbuf), "%u",
783 			    ((unsigned *)jp->jp_value)[i]);
784 			break;
785 		case CTLTYPE_LONG:
786 			snprintf(valbuf, sizeof(valbuf), "%ld",
787 			    ((long *)jp->jp_value)[i]);
788 			break;
789 		case CTLTYPE_ULONG:
790 			snprintf(valbuf, sizeof(valbuf), "%lu",
791 			    ((unsigned long *)jp->jp_value)[i]);
792 			break;
793 		case CTLTYPE_S64:
794 			snprintf(valbuf, sizeof(valbuf), "%jd",
795 			    (intmax_t)((int64_t *)jp->jp_value)[i]);
796 			break;
797 		case CTLTYPE_U64:
798 			snprintf(valbuf, sizeof(valbuf), "%ju",
799 			    (uintmax_t)((uint64_t *)jp->jp_value)[i]);
800 			break;
801 		case CTLTYPE_STRUCT:
802 			switch (jp->jp_structtype) {
803 			case JPS_IN_ADDR:
804 				if (inet_ntop(AF_INET,
805 				    &((struct in_addr *)jp->jp_value)[i],
806 				    valbuf, sizeof(valbuf)) == NULL) {
807 					strerror_r(errno, jail_errmsg,
808 					    JAIL_ERRMSGLEN);
809 					return (NULL);
810 				}
811 				break;
812 			case JPS_IN6_ADDR:
813 				if (inet_ntop(AF_INET6,
814 				    &((struct in6_addr *)jp->jp_value)[i],
815 				    valbuf, sizeof(valbuf)) == NULL) {
816 					strerror_r(errno, jail_errmsg,
817 					    JAIL_ERRMSGLEN);
818 					return (NULL);
819 				}
820 				break;
821 			default:
822 				goto unknown_type;
823 			}
824 			break;
825 		default:
826 		unknown_type:
827 			snprintf(jail_errmsg, JAIL_ERRMSGLEN,
828 			    "unknown type for %s", jp->jp_name);
829 			errno = ENOENT;
830 			return (NULL);
831 		}
832 		valuelens[i] = strlen(valbuf) + 1;
833 		valuelen += valuelens[i];
834 		values[i] = alloca(valuelens[i]);
835 		strcpy(values[i], valbuf);
836 	}
837 	value = malloc(valuelen);
838 	if (value == NULL)
839 		strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
840 	else {
841 		tvalue = value;
842 		for (i = 0; i < nval; i++) {
843 			strcpy(tvalue, values[i]);
844 			if (i < nval - 1) {
845 				tvalue += valuelens[i];
846 				tvalue[-1] = ',';
847 			}
848 		}
849 	}
850 	return (value);
851 }
852 
853 /*
854  * Free the contents of a jail parameter list (but not the list itself).
855  */
856 void
857 jailparam_free(struct jailparam *jp, unsigned njp)
858 {
859 	unsigned j;
860 
861 	for (j = 0; j < njp; j++) {
862 		free(jp[j].jp_name);
863 		if (!(jp[j].jp_flags & JP_RAWVALUE))
864 			free(jp[j].jp_value);
865 	}
866 }
867 
868 /*
869  * Find a parameter's type and size from its MIB.
870  */
871 static int
872 jailparam_type(struct jailparam *jp)
873 {
874 	char *p, *name, *nname;
875 	size_t miblen, desclen;
876 	int i, isarray;
877 	struct {
878 	    int i;
879 	    char s[MAXPATHLEN];
880 	} desc;
881 	int mib[CTL_MAXNAME];
882 
883 	/* The "lastjid" parameter isn't real. */
884 	name = jp->jp_name;
885 	if (!strcmp(name, "lastjid")) {
886 		jp->jp_valuelen = sizeof(int);
887 		jp->jp_ctltype = CTLTYPE_INT | CTLFLAG_WR;
888 		return (0);
889 	}
890 
891 	/* Find the sysctl that describes the parameter. */
892 	mib[0] = 0;
893 	mib[1] = 3;
894 	snprintf(desc.s, sizeof(desc.s), SJPARAM ".%s", name);
895 	miblen = sizeof(mib) - 2 * sizeof(int);
896 	if (sysctl(mib, 2, mib + 2, &miblen, desc.s, strlen(desc.s)) < 0) {
897 		if (errno != ENOENT) {
898 			snprintf(jail_errmsg, JAIL_ERRMSGLEN,
899 			    "sysctl(0.3.%s): %s", name, strerror(errno));
900 			return (-1);
901 		}
902 		if (kldload_param(name) >= 0 && sysctl(mib, 2, mib + 2, &miblen,
903 		    desc.s, strlen(desc.s)) >= 0)
904 			goto mib_desc;
905 		/*
906 		 * The parameter probably doesn't exist.  But it might be
907 		 * the "no" counterpart to a boolean.
908 		 */
909 		nname = nononame(name);
910 		if (nname == NULL) {
911 		unknown_parameter:
912 			snprintf(jail_errmsg, JAIL_ERRMSGLEN,
913 			    "unknown parameter: %s", jp->jp_name);
914 			errno = ENOENT;
915 			return (-1);
916 		}
917 		name = alloca(strlen(nname) + 1);
918 		strcpy(name, nname);
919 		free(nname);
920 		snprintf(desc.s, sizeof(desc.s), SJPARAM ".%s", name);
921 		miblen = sizeof(mib) - 2 * sizeof(int);
922 		if (sysctl(mib, 2, mib + 2, &miblen, desc.s,
923 		    strlen(desc.s)) < 0)
924 			goto unknown_parameter;
925 		jp->jp_flags |= JP_NOBOOL;
926 	}
927  mib_desc:
928 	mib[1] = 4;
929 	desclen = sizeof(desc);
930 	if (sysctl(mib, (miblen / sizeof(int)) + 2, &desc, &desclen,
931 	    NULL, 0) < 0) {
932 		snprintf(jail_errmsg, JAIL_ERRMSGLEN,
933 		    "sysctl(0.4.%s): %s", name, strerror(errno));
934 		return (-1);
935 	}
936 	jp->jp_ctltype = desc.i;
937 	/* If this came from removing a "no", it better be a boolean. */
938 	if (jp->jp_flags & JP_NOBOOL) {
939 		if ((desc.i & CTLTYPE) == CTLTYPE_INT && desc.s[0] == 'B') {
940 			jp->jp_valuelen = sizeof(int);
941 			return (0);
942 		}
943 		else if ((desc.i & CTLTYPE) != CTLTYPE_NODE)
944 			goto unknown_parameter;
945 	}
946 	/* See if this is an array type. */
947 	p = strchr(desc.s, '\0');
948 	isarray  = 0;
949 	if (p - 2 < desc.s || strcmp(p - 2, ",a"))
950 		isarray = 0;
951 	else {
952 		isarray = 1;
953 		p[-2] = 0;
954 	}
955 	/* Look for types we understand. */
956 	switch (desc.i & CTLTYPE) {
957 	case CTLTYPE_INT:
958 		if (desc.s[0] == 'B')
959 			jp->jp_flags |= JP_BOOL;
960 		else if (!strcmp(desc.s, "E,jailsys"))
961 			jp->jp_flags |= JP_JAILSYS;
962 	case CTLTYPE_UINT:
963 		jp->jp_valuelen = sizeof(int);
964 		break;
965 	case CTLTYPE_LONG:
966 	case CTLTYPE_ULONG:
967 		jp->jp_valuelen = sizeof(long);
968 		break;
969 	case CTLTYPE_S64:
970 	case CTLTYPE_U64:
971 		jp->jp_valuelen = sizeof(int64_t);
972 		break;
973 	case CTLTYPE_STRING:
974 		desc.s[0] = 0;
975 		desclen = sizeof(desc.s);
976 		if (sysctl(mib + 2, miblen / sizeof(int), desc.s, &desclen,
977 		    NULL, 0) < 0) {
978 			snprintf(jail_errmsg, JAIL_ERRMSGLEN,
979 			    "sysctl(" SJPARAM ".%s): %s", name,
980 			    strerror(errno));
981 			return (-1);
982 		}
983 		jp->jp_valuelen = strtoul(desc.s, NULL, 10);
984 		break;
985 	case CTLTYPE_STRUCT:
986 		if (!strcmp(desc.s, "S,in_addr")) {
987 			jp->jp_structtype = JPS_IN_ADDR;
988 			jp->jp_valuelen = sizeof(struct in_addr);
989 		} else if (!strcmp(desc.s, "S,in6_addr")) {
990 			jp->jp_structtype = JPS_IN6_ADDR;
991 			jp->jp_valuelen = sizeof(struct in6_addr);
992 		} else {
993 			desclen = 0;
994 			if (sysctl(mib + 2, miblen / sizeof(int),
995 			    NULL, &jp->jp_valuelen, NULL, 0) < 0) {
996 				snprintf(jail_errmsg, JAIL_ERRMSGLEN,
997 				    "sysctl(" SJPARAM ".%s): %s", name,
998 				    strerror(errno));
999 				return (-1);
1000 			}
1001 		}
1002 		break;
1003 	case CTLTYPE_NODE:
1004 		/*
1005 		 * A node might be described by an empty-named child,
1006 		 * which would be immediately before or after the node itself.
1007 		 */
1008 		mib[1] = 1;
1009 		miblen += sizeof(int);
1010 		for (i = -1; i <= 1; i += 2) {
1011 			mib[(miblen / sizeof(int)) + 1] =
1012 			    mib[(miblen / sizeof(int))] + i;
1013 			desclen = sizeof(desc.s);
1014 			if (sysctl(mib, (miblen / sizeof(int)) + 2, desc.s,
1015 			    &desclen, NULL, 0) < 0) {
1016 				if (errno == ENOENT)
1017 					continue;
1018 				snprintf(jail_errmsg, JAIL_ERRMSGLEN,
1019 				    "sysctl(0.1): %s", strerror(errno));
1020 				return (-1);
1021 			}
1022 			if (desclen == sizeof(SJPARAM) + strlen(name) + 2 &&
1023 			    memcmp(SJPARAM ".", desc.s, sizeof(SJPARAM)) == 0 &&
1024 			    memcmp(name, desc.s + sizeof(SJPARAM),
1025 			    desclen - sizeof(SJPARAM) - 2) == 0 &&
1026 			    desc.s[desclen - 2] == '.')
1027 				goto mib_desc;
1028 		}
1029 		goto unknown_parameter;
1030 	default:
1031 		snprintf(jail_errmsg, JAIL_ERRMSGLEN,
1032 		    "unknown type for %s", jp->jp_name);
1033 		errno = ENOENT;
1034 		return (-1);
1035 	}
1036 	if (isarray) {
1037 		jp->jp_elemlen = jp->jp_valuelen;
1038 		jp->jp_valuelen = 0;
1039 	}
1040 	return (0);
1041 }
1042 
1043 /*
1044  * Attempt to load a kernel module matching an otherwise nonexistent parameter.
1045  */
1046 static int
1047 kldload_param(const char *name)
1048 {
1049 	int kl;
1050 
1051 	if (strcmp(name, "linux") == 0 || strncmp(name, "linux.", 6) == 0)
1052 		kl = kldload("linux");
1053 	else if (strcmp(name, "sysvmsg") == 0 || strcmp(name, "sysvsem") == 0 ||
1054 	    strcmp(name, "sysvshm") == 0)
1055 		kl = kldload(name);
1056 	else if (strncmp(name, "allow.mount.", 12) == 0) {
1057 		/* Load the matching filesystem */
1058 		const char *modname = name + 12;
1059 
1060 		kl = kldload(modname);
1061 		if (kl < 0 && errno == ENOENT &&
1062 		    strncmp(modname, "no", 2) == 0)
1063 			kl = kldload(modname + 2);
1064 	} else {
1065 		errno = ENOENT;
1066 		return (-1);
1067 	}
1068 	if (kl < 0 && errno == EEXIST) {
1069 		/*
1070 		 * In the module is already loaded, then it must not contain
1071 		 * the parameter.
1072 		 */
1073 		errno = ENOENT;
1074 	}
1075 	return kl;
1076 }
1077 
1078 /*
1079  * Change a boolean parameter name into its "no" counterpart or vice versa.
1080  */
1081 static char *
1082 noname(const char *name)
1083 {
1084 	char *nname, *p;
1085 
1086 	nname = malloc(strlen(name) + 3);
1087 	if (nname == NULL) {
1088 		strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
1089 		return (NULL);
1090 	}
1091 	p = strrchr(name, '.');
1092 	if (p != NULL)
1093 		sprintf(nname, "%.*s.no%s", (int)(p - name), name, p + 1);
1094 	else
1095 		sprintf(nname, "no%s", name);
1096 	return (nname);
1097 }
1098 
1099 static char *
1100 nononame(const char *name)
1101 {
1102 	char *p, *nname;
1103 
1104 	p = strrchr(name, '.');
1105 	if (strncmp(p ? p + 1 : name, "no", 2)) {
1106 		snprintf(jail_errmsg, sizeof(jail_errmsg),
1107 		    "mismatched boolean: %s", name);
1108 		errno = EINVAL;
1109 		return (NULL);
1110 	}
1111 	nname = malloc(strlen(name) - 1);
1112 	if (nname == NULL) {
1113 		strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
1114 		return (NULL);
1115 	}
1116 	if (p != NULL)
1117 		sprintf(nname, "%.*s.%s", (int)(p - name), name, p + 3);
1118 	else
1119 		strcpy(nname, name + 2);
1120 	return (nname);
1121 }
1122