xref: /freebsd/lib/libjail/jail.c (revision e75dda31c1eead9ad40580bd8fec17f2bbf55a21)
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 static char *kvname(const char *name);
63 
64 char jail_errmsg[JAIL_ERRMSGLEN];
65 
66 static const char *bool_values[] = { "false", "true" };
67 static const char *jailsys_values[] = { "disable", "new", "inherit" };
68 
69 
70 /*
71  * Import a null-terminated parameter list and set a jail with the flags
72  * and parameters.
73  */
74 int
jail_setv(int flags,...)75 jail_setv(int flags, ...)
76 {
77 	va_list ap, tap;
78 	struct jailparam *jp, *jp_desc;
79 	const char *name;
80 	char *value, *desc_value;
81 	int njp, jid;
82 
83 	/* Create the parameter list and import the parameters. */
84 	va_start(ap, flags);
85 	va_copy(tap, ap);
86 	for (njp = 0; va_arg(tap, char *) != NULL; njp++)
87 		(void)va_arg(tap, char *);
88 	va_end(tap);
89 	jp = alloca(njp * sizeof(struct jailparam));
90 	jp_desc = NULL;
91 	desc_value = NULL;
92 	for (njp = 0; (name = va_arg(ap, char *)) != NULL; njp++) {
93 		value = va_arg(ap, char *);
94 		if (jailparam_init(jp + njp, name) < 0)
95 			goto error;
96 		if (jailparam_import(jp + njp, value) < 0)
97 			goto error;
98 		if (!strcmp(name, "desc") &&
99 		    (flags & (JAIL_GET_DESC | JAIL_OWN_DESC))) {
100 			jp_desc = jp + njp;
101 			desc_value = value;
102 		}
103 	}
104 	va_end(ap);
105 	jid = jailparam_set(jp, njp, flags);
106 	if (jid > 0 && jp_desc != NULL)
107 		sprintf(desc_value, "%d", *(int *)jp_desc->jp_value);
108 	jailparam_free(jp, njp);
109 	return (jid);
110 
111  error:
112 	jailparam_free(jp, njp);
113 	va_end(ap);
114 	return (-1);
115 }
116 
117 /*
118  * Read a null-terminated parameter list, get the referenced jail, and export
119  * the parameters to the list.
120  */
121 int
jail_getv(int flags,...)122 jail_getv(int flags, ...)
123 {
124 	va_list ap, tap;
125 	struct jailparam *jp, *jp_desc, *jp_lastjid, *jp_jid, *jp_name, *jp_key;
126 	char *valarg, *value;
127 	const char *name, *key_value, *desc_value, *lastjid_value, *jid_value;
128 	const char *name_value;
129 	int njp, i, jid;
130 
131 	/* Create the parameter list and find the key. */
132 	va_start(ap, flags);
133 	va_copy(tap, ap);
134 	for (njp = 0; va_arg(tap, char *) != NULL; njp++)
135 		(void)va_arg(tap, char *);
136 	va_end(tap);
137 
138 	jp = alloca(njp * sizeof(struct jailparam));
139 	va_copy(tap, ap);
140 	jp_desc = jp_lastjid = jp_jid = jp_name = NULL;
141 	desc_value = lastjid_value = jid_value = name_value = NULL;
142 	for (njp = 0; (name = va_arg(tap, char *)) != NULL; njp++) {
143 		value = va_arg(tap, char *);
144 		if (jailparam_init(jp + njp, name) < 0) {
145 			va_end(tap);
146 			goto error;
147 		}
148 		if (!strcmp(jp[njp].jp_name, "desc") &&
149 		    (flags & (JAIL_USE_DESC | JAIL_AT_DESC))) {
150 			jp_desc = jp + njp;
151 			desc_value = value;
152 		} else if (!strcmp(jp[njp].jp_name, "lastjid")) {
153 			jp_lastjid = jp + njp;
154 			lastjid_value = value;
155 		} else if (!strcmp(jp[njp].jp_name, "jid")) {
156 			jp_jid = jp + njp;
157 			jid_value = value;
158 		} if (!strcmp(jp[njp].jp_name, "name")) {
159 			jp_name = jp + njp;
160 			name_value = value;
161 		}
162 	}
163 	va_end(tap);
164 	/* Import the key parameter. */
165 	if (jp_desc != NULL && (flags & JAIL_USE_DESC)) {
166 		jp_key = jp_desc;
167 		key_value = desc_value;
168 	} else if (jp_lastjid != NULL) {
169 		jp_key = jp_lastjid;
170 		key_value = lastjid_value;
171 	} else if (jp_jid != NULL && strtol(jid_value, NULL, 10) != 0) {
172 		jp_key = jp_jid;
173 		key_value = jid_value;
174 	} else if (jp_name != NULL) {
175 		jp_key = jp_name;
176 		key_value = name_value;
177 	} else {
178 		strlcpy(jail_errmsg, "no jail specified", JAIL_ERRMSGLEN);
179 		errno = ENOENT;
180 		goto error;
181 	}
182 	if (jailparam_import(jp_key, key_value) < 0)
183 		goto error;
184 	if (jp_desc != NULL && jp_desc != jp_key &&
185 	    jailparam_import(jp_desc, desc_value) < 0)
186 		goto error;
187 	/* Get the jail and export the parameters. */
188 	jid = jailparam_get(jp, njp, flags);
189 	if (jid < 0)
190 		goto error;
191 	for (i = 0; i < njp; i++) {
192 		(void)va_arg(ap, char *);
193 		valarg = va_arg(ap, char *);
194 		if (jp + i != jp_key) {
195 			/* It's up to the caller to ensure there's room. */
196 			if ((jp[i].jp_ctltype & CTLTYPE) == CTLTYPE_STRING)
197 				strcpy(valarg, jp[i].jp_value);
198 			else {
199 				value = jailparam_export(jp + i);
200 				if (value == NULL)
201 					goto error;
202 				strcpy(valarg, value);
203 				free(value);
204 			}
205 		}
206 	}
207 	jailparam_free(jp, njp);
208 	va_end(ap);
209 	return (jid);
210 
211  error:
212 	jailparam_free(jp, njp);
213 	va_end(ap);
214 	return (-1);
215 }
216 
217 /*
218  * Return a list of all known parameters.
219  */
220 int
jailparam_all(struct jailparam ** jpp)221 jailparam_all(struct jailparam **jpp)
222 {
223 	struct jailparam *jp, *tjp;
224 	size_t mlen1, mlen2, buflen;
225 	unsigned njp, nlist;
226 	int mib1[CTL_MAXNAME], mib2[CTL_MAXNAME - 2];
227 	char buf[MAXPATHLEN];
228 
229 	njp = 0;
230 	nlist = 32;
231 	jp = malloc(nlist * sizeof(*jp));
232 	if (jp == NULL) {
233 		strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
234 		return (-1);
235 	}
236 	mib1[0] = 0;
237 	mib1[1] = 2;
238 	mlen1 = CTL_MAXNAME - 2;
239 	if (sysctlnametomib(SJPARAM, mib1 + 2, &mlen1) < 0) {
240 		snprintf(jail_errmsg, JAIL_ERRMSGLEN,
241 		    "sysctlnametomib(" SJPARAM "): %s", strerror(errno));
242 		goto error;
243 	}
244 	for (;; njp++) {
245 		/* Get the next parameter. */
246 		mlen2 = sizeof(mib2);
247 		if (sysctl(mib1, mlen1 + 2, mib2, &mlen2, NULL, 0) < 0) {
248 			if (errno == ENOENT) {
249 				/* No more entries. */
250 				break;
251 			}
252 			snprintf(jail_errmsg, JAIL_ERRMSGLEN,
253 			    "sysctl(0.2): %s", strerror(errno));
254 			goto error;
255 		}
256 		if (mib2[0] != mib1[2] ||
257 		    mib2[1] != mib1[3] ||
258 		    mib2[2] != mib1[4])
259 			break;
260 		/* Convert it to an ascii name. */
261 		memcpy(mib1 + 2, mib2, mlen2);
262 		mlen1 = mlen2 / sizeof(int);
263 		mib1[1] = 1;
264 		buflen = sizeof(buf);
265 		if (sysctl(mib1, mlen1 + 2, buf, &buflen, NULL, 0) < 0) {
266 			snprintf(jail_errmsg, JAIL_ERRMSGLEN,
267 			    "sysctl(0.1): %s", strerror(errno));
268 			goto error;
269 		}
270 		if (buf[buflen - 2] == '.')
271 			buf[buflen - 2] = '\0';
272 		/* Add the parameter to the list */
273 		if (njp >= nlist) {
274 			nlist *= 2;
275 			tjp = reallocarray(jp, nlist, sizeof(*jp));
276 			if (tjp == NULL)
277 				goto error;
278 			jp = tjp;
279 		}
280 		if (jailparam_init(jp + njp, buf + sizeof(SJPARAM)) < 0)
281 			goto error;
282 		mib1[1] = 2;
283 	}
284 	/* Just return the untrimmed buffer if reallocarray() somehow fails. */
285 	tjp = reallocarray(jp, njp, sizeof(*jp));
286 	if (tjp != NULL)
287 		jp = tjp;
288 	*jpp = jp;
289 	return (njp);
290 
291  error:
292 	jailparam_free(jp, njp);
293 	free(jp);
294 	return (-1);
295 }
296 
297 /*
298  * Clear a jail parameter and copy in its name.
299  */
300 int
jailparam_init(struct jailparam * jp,const char * name)301 jailparam_init(struct jailparam *jp, const char *name)
302 {
303 
304 	memset(jp, 0, sizeof(*jp));
305 	jp->jp_name = strdup(name);
306 	if (jp->jp_name == NULL) {
307 		strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
308 		return (-1);
309 	}
310 	if (jailparam_type(jp) < 0) {
311 		jailparam_free(jp, 1);
312 		jp->jp_name = NULL;
313 		jp->jp_value = NULL;
314 		return (-1);
315 	}
316 	return (0);
317 }
318 
319 /*
320  * Put a name and value into a jail parameter element, converting the value
321  * to internal form.
322  */
323 int
jailparam_import(struct jailparam * jp,const char * value)324 jailparam_import(struct jailparam *jp, const char *value)
325 {
326 	char *p, *ep, *tvalue;
327 	const char *avalue;
328 	int i, nval, fw;
329 
330 	if (value == NULL)
331 		return (0);
332 	if ((jp->jp_ctltype & CTLTYPE) == CTLTYPE_STRING) {
333 		jp->jp_value = strdup(value);
334 		if (jp->jp_value == NULL) {
335 			strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
336 			return (-1);
337 		}
338 		return (0);
339 	}
340 	nval = 1;
341 	if (jp->jp_elemlen) {
342 		if (value[0] == '\0' || (value[0] == '-' && value[1] == '\0')) {
343 			jp->jp_value = strdup("");
344 			if (jp->jp_value == NULL) {
345 				strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
346 				return (-1);
347 			}
348 			jp->jp_valuelen = 0;
349 			return (0);
350 		}
351 		for (p = strchr(value, ','); p; p = strchr(p + 1, ','))
352 			nval++;
353 		jp->jp_valuelen = jp->jp_elemlen * nval;
354 	}
355 	jp->jp_value = malloc(jp->jp_valuelen);
356 	if (jp->jp_value == NULL) {
357 		strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
358 		return (-1);
359 	}
360 	avalue = value;
361 	for (i = 0; i < nval; i++) {
362 		fw = nval == 1 ? strlen(avalue) : strcspn(avalue, ",");
363 		switch (jp->jp_ctltype & CTLTYPE) {
364 		case CTLTYPE_INT:
365 			if (jp->jp_flags & (JP_BOOL | JP_NOBOOL)) {
366 				if (!jailparam_import_enum(bool_values, 2,
367 				    avalue, fw, &((int *)jp->jp_value)[i])) {
368 					snprintf(jail_errmsg,
369 					    JAIL_ERRMSGLEN, "%s: "
370 					    "unknown boolean value \"%.*s\"",
371 					    jp->jp_name, fw, avalue);
372 					errno = EINVAL;
373 					goto error;
374 				}
375 				break;
376 			}
377 			if (jp->jp_flags & JP_JAILSYS) {
378 				/*
379 				 * Allow setting a jailsys parameter to "new"
380 				 * in a booleanesque fashion.
381 				 */
382 				if (value[0] == '\0')
383 					((int *)jp->jp_value)[i] = JAIL_SYS_NEW;
384 				else if (!jailparam_import_enum(jailsys_values,
385 				    sizeof(jailsys_values) /
386 				    sizeof(jailsys_values[0]), avalue, fw,
387 				    &((int *)jp->jp_value)[i])) {
388 					snprintf(jail_errmsg,
389 					    JAIL_ERRMSGLEN, "%s: "
390 					    "unknown jailsys value \"%.*s\"",
391 					    jp->jp_name, fw, avalue);
392 					errno = EINVAL;
393 					goto error;
394 				}
395 				break;
396 			}
397 			((int *)jp->jp_value)[i] = strtol(avalue, &ep, 10);
398 		integer_test:
399 			if (ep != avalue + fw) {
400 				snprintf(jail_errmsg, JAIL_ERRMSGLEN,
401 				    "%s: non-integer value \"%.*s\"",
402 				    jp->jp_name, fw, avalue);
403 				errno = EINVAL;
404 				goto error;
405 			}
406 			break;
407 		case CTLTYPE_UINT:
408 			((unsigned *)jp->jp_value)[i] =
409 			    strtoul(avalue, &ep, 10);
410 			goto integer_test;
411 		case CTLTYPE_LONG:
412 			((long *)jp->jp_value)[i] = strtol(avalue, &ep, 10);
413 			goto integer_test;
414 		case CTLTYPE_ULONG:
415 			((unsigned long *)jp->jp_value)[i] =
416 			    strtoul(avalue, &ep, 10);
417 			goto integer_test;
418 		case CTLTYPE_S64:
419 			((int64_t *)jp->jp_value)[i] =
420 			    strtoimax(avalue, &ep, 10);
421 			goto integer_test;
422 		case CTLTYPE_U64:
423 			((uint64_t *)jp->jp_value)[i] =
424 			    strtoumax(avalue, &ep, 10);
425 			goto integer_test;
426 		case CTLTYPE_STRUCT:
427 			tvalue = alloca(fw + 1);
428 			strlcpy(tvalue, avalue, fw + 1);
429 			switch (jp->jp_structtype) {
430 			case JPS_IN_ADDR:
431 				if (inet_pton(AF_INET, tvalue,
432 				    &((struct in_addr *)jp->jp_value)[i]) != 1)
433 				{
434 					snprintf(jail_errmsg,
435 					    JAIL_ERRMSGLEN,
436 					    "%s: not an IPv4 address: %s",
437 					    jp->jp_name, tvalue);
438 					errno = EINVAL;
439 					goto error;
440 				}
441 				break;
442 			case JPS_IN6_ADDR:
443 				if (inet_pton(AF_INET6, tvalue,
444 				    &((struct in6_addr *)jp->jp_value)[i]) != 1)
445 				{
446 					snprintf(jail_errmsg,
447 					    JAIL_ERRMSGLEN,
448 					    "%s: not an IPv6 address: %s",
449 					    jp->jp_name, tvalue);
450 					errno = EINVAL;
451 					goto error;
452 				}
453 				break;
454 			default:
455 				goto unknown_type;
456 			}
457 			break;
458 		default:
459 		unknown_type:
460 			snprintf(jail_errmsg, JAIL_ERRMSGLEN,
461 			    "unknown type for %s", jp->jp_name);
462 			errno = ENOENT;
463 			goto error;
464 		}
465 		avalue += fw + 1;
466 	}
467 	return (0);
468 
469  error:
470 	free(jp->jp_value);
471 	jp->jp_value = NULL;
472 	return (-1);
473 }
474 
475 static int
jailparam_import_enum(const char ** values,int nvalues,const char * valstr,size_t valsize,int * value)476 jailparam_import_enum(const char **values, int nvalues, const char *valstr,
477     size_t valsize, int *value)
478 {
479 	char *ep;
480 	int i;
481 
482 	for (i = 0; i < nvalues; i++)
483 		if (valsize == strlen(values[i]) &&
484 		    !strncasecmp(valstr, values[i], valsize)) {
485 			*value = i;
486 			return 1;
487 		}
488 	*value = strtol(valstr, &ep, 10);
489 	return (ep == valstr + valsize);
490 }
491 
492 /*
493  * Put a name and value into a jail parameter element, copying the value
494  * but not altering it.
495  */
496 int
jailparam_import_raw(struct jailparam * jp,void * value,size_t valuelen)497 jailparam_import_raw(struct jailparam *jp, void *value, size_t valuelen)
498 {
499 
500 	jp->jp_value = value;
501 	jp->jp_valuelen = valuelen;
502 	jp->jp_flags |= JP_RAWVALUE;
503 	return (0);
504 }
505 
506 /*
507  * Run the jail_set and jail_get system calls on a parameter list.
508  */
509 int
jailparam_set(struct jailparam * jp,unsigned njp,int flags)510 jailparam_set(struct jailparam *jp, unsigned njp, int flags)
511 {
512 	struct iovec *jiov;
513 	char *nname;
514 	int i, jid, bool0;
515 	unsigned j;
516 
517 	jiov = alloca(sizeof(struct iovec) * 2 * (njp + 1));
518 	bool0 = 0;
519 	for (i = j = 0; j < njp; j++) {
520 		jiov[i].iov_base = jp[j].jp_name;
521 		jiov[i].iov_len = strlen(jp[j].jp_name) + 1;
522 		i++;
523 		if (jp[j].jp_flags & (JP_BOOL | JP_NOBOOL)) {
524 			/*
525 			 * Set booleans without values.  If one has a value of
526 			 * zero, change it to (or from) its "no" counterpart.
527 			 */
528 			jiov[i].iov_base = NULL;
529 			jiov[i].iov_len = 0;
530 			if (jp[j].jp_value != NULL &&
531 			    jp[j].jp_valuelen == sizeof(int) &&
532 			    !*(int *)jp[j].jp_value) {
533 				bool0 = 1;
534 				nname = jp[j].jp_flags & JP_BOOL
535 				    ? noname(jp[j].jp_name)
536 				    : nononame(jp[j].jp_name);
537 				if (nname == NULL) {
538 					njp = j;
539 					jid = -1;
540 					goto done;
541 				}
542 				jiov[i - 1].iov_base = nname;
543 				jiov[i - 1].iov_len = strlen(nname) + 1;
544 
545 			}
546 		} else if (jp[j].jp_flags & JP_KEYVALUE &&
547 		    jp[j].jp_value == NULL) {
548 			/* No value means key removal. */
549 			jiov[i].iov_base = NULL;
550 			jiov[i].iov_len = 0;
551 		} else {
552 			/*
553 			 * Try to fill in missing values with an empty string.
554 			 */
555 			if (jp[j].jp_value == NULL && jp[j].jp_valuelen > 0 &&
556 			    jailparam_import(jp + j, "") < 0) {
557 				njp = j;
558 				jid = -1;
559 				goto done;
560 			}
561 			jiov[i].iov_base = jp[j].jp_value;
562 			jiov[i].iov_len =
563 			    (jp[j].jp_ctltype & CTLTYPE) == CTLTYPE_STRING
564 			    ? strlen(jp[j].jp_value) + 1
565 			    : jp[j].jp_valuelen;
566 		}
567 		i++;
568 	}
569 	jiov[i].iov_base = __DECONST(char *, "errmsg");
570 	jiov[i].iov_len = sizeof("errmsg");
571 	i++;
572 	jiov[i].iov_base = jail_errmsg;
573 	jiov[i].iov_len = JAIL_ERRMSGLEN;
574 	i++;
575 	jail_errmsg[0] = 0;
576 	jid = jail_set(jiov, i, flags);
577 	if (jid < 0 && !jail_errmsg[0])
578 		snprintf(jail_errmsg, sizeof(jail_errmsg), "jail_set: %s",
579 		    strerror(errno));
580  done:
581 	if (bool0)
582 		for (j = 0; j < njp; j++)
583 			if ((jp[j].jp_flags & (JP_BOOL | JP_NOBOOL)) &&
584 			    jp[j].jp_value != NULL &&
585 			    jp[j].jp_valuelen == sizeof(int) &&
586 			    !*(int *)jp[j].jp_value)
587 				free(jiov[j * 2].iov_base);
588 	return (jid);
589 }
590 
591 int
jailparam_get(struct jailparam * jp,unsigned njp,int flags)592 jailparam_get(struct jailparam *jp, unsigned njp, int flags)
593 {
594 	struct iovec *jiov;
595 	struct jailparam *jp_desc, *jp_lastjid, *jp_jid, *jp_name, *jp_key;
596 	int i, ai, ki, jid, arrays, sanity;
597 	unsigned j;
598 
599 	/*
600 	 * Get the types for all parameters.
601 	 * Find the key and any array parameters.
602 	 */
603 	jiov = alloca(sizeof(struct iovec) * 2 * (njp + 1));
604 	jp_desc = jp_lastjid = jp_jid = jp_name = NULL;
605 	arrays = 0;
606 	for (ai = j = 0; j < njp; j++) {
607 		if (!strcmp(jp[j].jp_name, "desc") &&
608 		    (flags & (JAIL_USE_DESC | JAIL_AT_DESC)))
609 			jp_desc = jp + j;
610 		else if (!strcmp(jp[j].jp_name, "lastjid"))
611 			jp_lastjid = jp + j;
612 		else if (!strcmp(jp[j].jp_name, "jid"))
613 			jp_jid = jp + j;
614 		else if (!strcmp(jp[j].jp_name, "name"))
615 			jp_name = jp + j;
616 		else if (jp[j].jp_elemlen && !(jp[j].jp_flags & JP_RAWVALUE)) {
617 			arrays = 1;
618 			jiov[ai].iov_base = jp[j].jp_name;
619 			jiov[ai].iov_len = strlen(jp[j].jp_name) + 1;
620 			ai++;
621 			jiov[ai].iov_base = NULL;
622 			jiov[ai].iov_len = 0;
623 			ai++;
624 		}
625 	}
626 	jp_key = jp_desc && jp_desc->jp_valuelen == sizeof(int) &&
627 	    jp_desc->jp_value && (flags & JAIL_USE_DESC) ? jp_desc :
628 	    jp_lastjid ? jp_lastjid :
629 	    jp_jid && jp_jid->jp_valuelen == sizeof(int) &&
630 	    jp_jid->jp_value && *(int *)jp_jid->jp_value ? jp_jid : jp_name;
631 	if (jp_key == NULL || jp_key->jp_value == NULL) {
632 		strlcpy(jail_errmsg, "no jail specified", JAIL_ERRMSGLEN);
633 		errno = ENOENT;
634 		return (-1);
635 	}
636 	ki = ai;
637 	jiov[ki].iov_base = jp_key->jp_name;
638 	jiov[ki].iov_len = strlen(jp_key->jp_name) + 1;
639 	ki++;
640 	jiov[ki].iov_base = jp_key->jp_value;
641 	jiov[ki].iov_len = (jp_key->jp_ctltype & CTLTYPE) == CTLTYPE_STRING
642 	    ? strlen(jp_key->jp_value) + 1 : jp_key->jp_valuelen;
643 	ki++;
644 	jiov[ki].iov_base = __DECONST(char *, "errmsg");
645 	jiov[ki].iov_len = sizeof("errmsg");
646 	ki++;
647 	jiov[ki].iov_base = jail_errmsg;
648 	jiov[ki].iov_len = JAIL_ERRMSGLEN;
649 	ki++;
650 	jail_errmsg[0] = 0;
651 	if (jp_desc != NULL && jp_desc != jp_key) {
652 		jiov[ki].iov_base = jp_desc->jp_name;
653 		jiov[ki].iov_len = strlen(jp_desc->jp_name) + 1;
654 		ki++;
655 		jiov[ki].iov_base = jp_desc->jp_value;
656 		jiov[ki].iov_len = jp_desc->jp_valuelen;
657 		ki++;
658 	}
659 	if (arrays && jail_get(jiov, ki, flags) < 0) {
660 		if (!jail_errmsg[0])
661 			snprintf(jail_errmsg, sizeof(jail_errmsg),
662 			    "jail_get: %s", strerror(errno));
663 		return (-1);
664 	}
665 	/* Allocate storage for all parameters. */
666 	for (ai = j = 0, i = ki; j < njp; j++) {
667 		if (jp[j].jp_elemlen && !(jp[j].jp_flags & JP_RAWVALUE)) {
668 			ai++;
669 			jiov[ai].iov_len += jp[j].jp_elemlen * ARRAY_SLOP;
670 			if (jp[j].jp_valuelen >= jiov[ai].iov_len)
671 				jiov[ai].iov_len = jp[j].jp_valuelen;
672 			else {
673 				jp[j].jp_valuelen = jiov[ai].iov_len;
674 				if (jp[j].jp_value != NULL)
675 					free(jp[j].jp_value);
676 				jp[j].jp_value = malloc(jp[j].jp_valuelen);
677 				if (jp[j].jp_value == NULL) {
678 					strerror_r(errno, jail_errmsg,
679 					    JAIL_ERRMSGLEN);
680 					return (-1);
681 				}
682 			}
683 			jiov[ai].iov_base = jp[j].jp_value;
684 			memset(jiov[ai].iov_base, 0, jiov[ai].iov_len);
685 			ai++;
686 		} else if (jp + j != jp_key && jp + j != jp_desc) {
687 			jiov[i].iov_base = jp[j].jp_name;
688 			jiov[i].iov_len = strlen(jp[j].jp_name) + 1;
689 			i++;
690 			if (jp[j].jp_value == NULL &&
691 			    !(jp[j].jp_flags & JP_RAWVALUE)) {
692 				jp[j].jp_value = malloc(jp[j].jp_valuelen);
693 				if (jp[j].jp_value == NULL) {
694 					strerror_r(errno, jail_errmsg,
695 					    JAIL_ERRMSGLEN);
696 					return (-1);
697 				}
698 			}
699 			jiov[i].iov_base = jp[j].jp_value;
700 			jiov[i].iov_len = jp[j].jp_valuelen;
701 			memset(jiov[i].iov_base, 0, jiov[i].iov_len);
702 			i++;
703 		}
704 	}
705 	/*
706 	 * Get the prison.  If there are array elements, retry a few times
707 	 * in case their sizes changed from under us.
708 	 */
709 	for (sanity = 0;; sanity++) {
710 		jid = jail_get(jiov, i, flags);
711 		if (jid >= 0 || !arrays || sanity == ARRAY_SANITY ||
712 		    errno != EINVAL || jail_errmsg[0])
713 			break;
714 		for (ai = j = 0; j < njp; j++) {
715 			if (jp[j].jp_elemlen &&
716 			    !(jp[j].jp_flags & JP_RAWVALUE)) {
717 				ai++;
718 				jiov[ai].iov_base = NULL;
719 				jiov[ai].iov_len = 0;
720 				ai++;
721 			}
722 		}
723 		if (jail_get(jiov, ki, flags) < 0)
724 			break;
725 		for (ai = j = 0; j < njp; j++) {
726 			if (jp[j].jp_elemlen &&
727 			    !(jp[j].jp_flags & JP_RAWVALUE)) {
728 				ai++;
729 				jiov[ai].iov_len +=
730 				    jp[j].jp_elemlen * ARRAY_SLOP;
731 				if (jp[j].jp_valuelen >= jiov[ai].iov_len)
732 					jiov[ai].iov_len = jp[j].jp_valuelen;
733 				else {
734 					jp[j].jp_valuelen = jiov[ai].iov_len;
735 					if (jp[j].jp_value != NULL)
736 						free(jp[j].jp_value);
737 					jp[j].jp_value =
738 					    malloc(jiov[ai].iov_len);
739 					if (jp[j].jp_value == NULL) {
740 						strerror_r(errno, jail_errmsg,
741 						    JAIL_ERRMSGLEN);
742 						return (-1);
743 					}
744 				}
745 				jiov[ai].iov_base = jp[j].jp_value;
746 				memset(jiov[ai].iov_base, 0, jiov[ai].iov_len);
747 				ai++;
748 			}
749 		}
750 	}
751 	if (jid < 0 && !jail_errmsg[0])
752 		snprintf(jail_errmsg, sizeof(jail_errmsg),
753 		    "jail_get: %s", strerror(errno));
754 	for (ai = j = 0, i = ki; j < njp; j++) {
755 		if (jp[j].jp_elemlen && !(jp[j].jp_flags & JP_RAWVALUE)) {
756 			ai++;
757 			jp[j].jp_valuelen = jiov[ai].iov_len;
758 			ai++;
759 		} else if (jp + j != jp_key) {
760 			i++;
761 			jp[j].jp_valuelen = jiov[i].iov_len;
762 			i++;
763 		}
764 	}
765 	return (jid);
766 }
767 
768 /*
769  * Convert a jail parameter's value to external form.
770  */
771 char *
jailparam_export(struct jailparam * jp)772 jailparam_export(struct jailparam *jp)
773 {
774 	size_t *valuelens;
775 	char *value, *tvalue, **values;
776 	size_t valuelen;
777 	int i, nval, ival;
778 	char valbuf[INET6_ADDRSTRLEN];
779 
780 	if (jp->jp_value == NULL) {
781 		snprintf(jail_errmsg, JAIL_ERRMSGLEN,
782 		    "parameter %s was not imported", jp->jp_name);
783 		errno = EINVAL;
784 		return (NULL);
785 	}
786 	if ((jp->jp_ctltype & CTLTYPE) == CTLTYPE_STRING) {
787 		value = strdup(jp->jp_value);
788 		if (value == NULL)
789 			strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
790 		return (value);
791 	}
792 	nval = jp->jp_elemlen ? jp->jp_valuelen / jp->jp_elemlen : 1;
793 	if (nval == 0) {
794 		value = strdup("");
795 		if (value == NULL)
796 			strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
797 		return (value);
798 	}
799 	values = alloca(nval * sizeof(char *));
800 	valuelens = alloca(nval * sizeof(size_t));
801 	valuelen = 0;
802 	for (i = 0; i < nval; i++) {
803 		switch (jp->jp_ctltype & CTLTYPE) {
804 		case CTLTYPE_INT:
805 			ival = ((int *)jp->jp_value)[i];
806 			if ((jp->jp_flags & (JP_BOOL | JP_NOBOOL)) &&
807 			    (unsigned)ival < 2) {
808 				strlcpy(valbuf, bool_values[ival],
809 				    sizeof(valbuf));
810 				break;
811 			}
812 			if ((jp->jp_flags & JP_JAILSYS) &&
813 			    (unsigned)ival < sizeof(jailsys_values) /
814 			    sizeof(jailsys_values[0])) {
815 				strlcpy(valbuf, jailsys_values[ival],
816 				    sizeof(valbuf));
817 				break;
818 			}
819 			snprintf(valbuf, sizeof(valbuf), "%d", ival);
820 			break;
821 		case CTLTYPE_UINT:
822 			snprintf(valbuf, sizeof(valbuf), "%u",
823 			    ((unsigned *)jp->jp_value)[i]);
824 			break;
825 		case CTLTYPE_LONG:
826 			snprintf(valbuf, sizeof(valbuf), "%ld",
827 			    ((long *)jp->jp_value)[i]);
828 			break;
829 		case CTLTYPE_ULONG:
830 			snprintf(valbuf, sizeof(valbuf), "%lu",
831 			    ((unsigned long *)jp->jp_value)[i]);
832 			break;
833 		case CTLTYPE_S64:
834 			snprintf(valbuf, sizeof(valbuf), "%jd",
835 			    (intmax_t)((int64_t *)jp->jp_value)[i]);
836 			break;
837 		case CTLTYPE_U64:
838 			snprintf(valbuf, sizeof(valbuf), "%ju",
839 			    (uintmax_t)((uint64_t *)jp->jp_value)[i]);
840 			break;
841 		case CTLTYPE_STRUCT:
842 			switch (jp->jp_structtype) {
843 			case JPS_IN_ADDR:
844 				if (inet_ntop(AF_INET,
845 				    &((struct in_addr *)jp->jp_value)[i],
846 				    valbuf, sizeof(valbuf)) == NULL) {
847 					strerror_r(errno, jail_errmsg,
848 					    JAIL_ERRMSGLEN);
849 					return (NULL);
850 				}
851 				break;
852 			case JPS_IN6_ADDR:
853 				if (inet_ntop(AF_INET6,
854 				    &((struct in6_addr *)jp->jp_value)[i],
855 				    valbuf, sizeof(valbuf)) == NULL) {
856 					strerror_r(errno, jail_errmsg,
857 					    JAIL_ERRMSGLEN);
858 					return (NULL);
859 				}
860 				break;
861 			default:
862 				goto unknown_type;
863 			}
864 			break;
865 		default:
866 		unknown_type:
867 			snprintf(jail_errmsg, JAIL_ERRMSGLEN,
868 			    "unknown type for %s", jp->jp_name);
869 			errno = ENOENT;
870 			return (NULL);
871 		}
872 		valuelens[i] = strlen(valbuf) + 1;
873 		valuelen += valuelens[i];
874 		values[i] = alloca(valuelens[i]);
875 		strcpy(values[i], valbuf);
876 	}
877 	value = malloc(valuelen);
878 	if (value == NULL)
879 		strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
880 	else {
881 		tvalue = value;
882 		for (i = 0; i < nval; i++) {
883 			strcpy(tvalue, values[i]);
884 			if (i < nval - 1) {
885 				tvalue += valuelens[i];
886 				tvalue[-1] = ',';
887 			}
888 		}
889 	}
890 	return (value);
891 }
892 
893 /*
894  * Free the contents of a jail parameter list (but not the list itself).
895  */
896 void
jailparam_free(struct jailparam * jp,unsigned njp)897 jailparam_free(struct jailparam *jp, unsigned njp)
898 {
899 	unsigned j;
900 
901 	for (j = 0; j < njp; j++) {
902 		free(jp[j].jp_name);
903 		if (!(jp[j].jp_flags & JP_RAWVALUE))
904 			free(jp[j].jp_value);
905 	}
906 }
907 
908 /*
909  * Find a parameter's type and size from its MIB.
910  */
911 static int
jailparam_type(struct jailparam * jp)912 jailparam_type(struct jailparam *jp)
913 {
914 	char *p, *name, *nname;
915 	size_t miblen, desclen;
916 	int i, isarray;
917 	struct {
918 	    int i;
919 	    char s[MAXPATHLEN];
920 	} desc;
921 	int mib[CTL_MAXNAME];
922 
923 	/*
924 	 * Some pseudo-parameters don't show up in the sysctl
925 	 * parameter list.
926 	 */
927 	name = jp->jp_name;
928 	if (!strcmp(name, "lastjid")) {
929 		jp->jp_valuelen = sizeof(int);
930 		jp->jp_ctltype = CTLTYPE_INT | CTLFLAG_WR;
931 		return (0);
932 	}
933 	if (!strcmp(name, "desc")) {
934 		jp->jp_valuelen = sizeof(int);
935 		jp->jp_ctltype = CTLTYPE_INT | CTLFLAG_RW;
936 		return (0);
937 	}
938 
939 	/* Find the sysctl that describes the parameter. */
940 	mib[0] = 0;
941 	mib[1] = 3;
942 	snprintf(desc.s, sizeof(desc.s), SJPARAM ".%s", name);
943 	miblen = sizeof(mib) - 2 * sizeof(int);
944 	if (sysctl(mib, 2, mib + 2, &miblen, desc.s, strlen(desc.s)) < 0) {
945 		if (errno != ENOENT) {
946 			snprintf(jail_errmsg, JAIL_ERRMSGLEN,
947 			    "sysctl(0.3.%s): %s", name, strerror(errno));
948 			return (-1);
949 		}
950 		if (kldload_param(name) >= 0 && sysctl(mib, 2, mib + 2, &miblen,
951 		    desc.s, strlen(desc.s)) >= 0)
952 			goto mib_desc;
953 		/*
954 		 * The parameter probably doesn't exist.  But it might be
955 		 * the "no" counterpart to a boolean.
956 		 */
957 		nname = nononame(name);
958 		if (nname != NULL) {
959 			snprintf(desc.s, sizeof(desc.s), SJPARAM ".%s", nname);
960 			miblen = sizeof(mib) - 2 * sizeof(int);
961 			if (sysctl(mib, 2, mib + 2, &miblen, desc.s,
962 			    strlen(desc.s)) >= 0) {
963 				name = alloca(strlen(nname) + 1);
964 				strcpy(name, nname);
965 				free(nname);
966 				jp->jp_flags |= JP_NOBOOL;
967 				goto mib_desc;
968 			}
969 			free(nname);
970 		}
971 		/*
972 		 * It might be an assumed sub-node of a fmt='A,keyvalue' sysctl.
973 		 */
974 		nname = kvname(name);
975 		if (nname != NULL) {
976 			snprintf(desc.s, sizeof(desc.s), SJPARAM ".%s", nname);
977 			miblen = sizeof(mib) - 2 * sizeof(int);
978 			if (sysctl(mib, 2, mib + 2, &miblen, desc.s,
979 			    strlen(desc.s)) >= 0) {
980 				name = alloca(strlen(nname) + 1);
981 				strcpy(name, nname);
982 				free(nname);
983 				jp->jp_flags |= JP_KEYVALUE;
984 				goto mib_desc;
985 			}
986 			free(nname);
987 		}
988 unknown_parameter:
989 		snprintf(jail_errmsg, JAIL_ERRMSGLEN,
990 		    "unknown parameter: %s", jp->jp_name);
991 		errno = ENOENT;
992 		return (-1);
993 	}
994  mib_desc:
995 	mib[1] = 4;
996 	desclen = sizeof(desc);
997 	if (sysctl(mib, (miblen / sizeof(int)) + 2, &desc, &desclen,
998 	    NULL, 0) < 0) {
999 		snprintf(jail_errmsg, JAIL_ERRMSGLEN,
1000 		    "sysctl(0.4.%s): %s", name, strerror(errno));
1001 		return (-1);
1002 	}
1003 	jp->jp_ctltype = desc.i;
1004 	/* If this came from removing a "no", it better be a boolean. */
1005 	if (jp->jp_flags & JP_NOBOOL) {
1006 		if ((desc.i & CTLTYPE) == CTLTYPE_INT && desc.s[0] == 'B') {
1007 			jp->jp_valuelen = sizeof(int);
1008 			return (0);
1009 		}
1010 		else if ((desc.i & CTLTYPE) != CTLTYPE_NODE)
1011 			goto unknown_parameter;
1012 	}
1013 	/* Make sure it is a valid keyvalue param. */
1014 	if (jp->jp_flags & JP_KEYVALUE) {
1015 		if ((desc.i & CTLTYPE) != CTLTYPE_STRING ||
1016 		    strcmp(desc.s, "A,keyvalue") != 0)
1017 			goto unknown_parameter;
1018 	}
1019 	/* See if this is an array type. */
1020 	p = strchr(desc.s, '\0');
1021 	isarray  = 0;
1022 	if (p - 2 < desc.s || strcmp(p - 2, ",a"))
1023 		isarray = 0;
1024 	else {
1025 		isarray = 1;
1026 		p[-2] = 0;
1027 	}
1028 	/* Look for types we understand. */
1029 	switch (desc.i & CTLTYPE) {
1030 	case CTLTYPE_INT:
1031 		if (desc.s[0] == 'B')
1032 			jp->jp_flags |= JP_BOOL;
1033 		else if (!strcmp(desc.s, "E,jailsys"))
1034 			jp->jp_flags |= JP_JAILSYS;
1035 	case CTLTYPE_UINT:
1036 		jp->jp_valuelen = sizeof(int);
1037 		break;
1038 	case CTLTYPE_LONG:
1039 	case CTLTYPE_ULONG:
1040 		jp->jp_valuelen = sizeof(long);
1041 		break;
1042 	case CTLTYPE_S64:
1043 	case CTLTYPE_U64:
1044 		jp->jp_valuelen = sizeof(int64_t);
1045 		break;
1046 	case CTLTYPE_STRING:
1047 		desc.s[0] = 0;
1048 		desclen = sizeof(desc.s);
1049 		if (sysctl(mib + 2, miblen / sizeof(int), desc.s, &desclen,
1050 		    NULL, 0) < 0) {
1051 			snprintf(jail_errmsg, JAIL_ERRMSGLEN,
1052 			    "sysctl(" SJPARAM ".%s): %s", name,
1053 			    strerror(errno));
1054 			return (-1);
1055 		}
1056 		jp->jp_valuelen = strtoul(desc.s, NULL, 10);
1057 		break;
1058 	case CTLTYPE_STRUCT:
1059 		if (!strcmp(desc.s, "S,in_addr")) {
1060 			jp->jp_structtype = JPS_IN_ADDR;
1061 			jp->jp_valuelen = sizeof(struct in_addr);
1062 		} else if (!strcmp(desc.s, "S,in6_addr")) {
1063 			jp->jp_structtype = JPS_IN6_ADDR;
1064 			jp->jp_valuelen = sizeof(struct in6_addr);
1065 		} else {
1066 			desclen = 0;
1067 			if (sysctl(mib + 2, miblen / sizeof(int),
1068 			    NULL, &jp->jp_valuelen, NULL, 0) < 0) {
1069 				snprintf(jail_errmsg, JAIL_ERRMSGLEN,
1070 				    "sysctl(" SJPARAM ".%s): %s", name,
1071 				    strerror(errno));
1072 				return (-1);
1073 			}
1074 		}
1075 		break;
1076 	case CTLTYPE_NODE:
1077 		/*
1078 		 * A node might be described by an empty-named child,
1079 		 * which would be immediately before or after the node itself.
1080 		 */
1081 		mib[1] = 1;
1082 		miblen += sizeof(int);
1083 		for (i = -1; i <= 1; i += 2) {
1084 			mib[(miblen / sizeof(int)) + 1] =
1085 			    mib[(miblen / sizeof(int))] + i;
1086 			desclen = sizeof(desc.s);
1087 			if (sysctl(mib, (miblen / sizeof(int)) + 2, desc.s,
1088 			    &desclen, NULL, 0) < 0) {
1089 				if (errno == ENOENT)
1090 					continue;
1091 				snprintf(jail_errmsg, JAIL_ERRMSGLEN,
1092 				    "sysctl(0.1): %s", strerror(errno));
1093 				return (-1);
1094 			}
1095 			if (desclen == sizeof(SJPARAM) + strlen(name) + 2 &&
1096 			    memcmp(SJPARAM ".", desc.s, sizeof(SJPARAM)) == 0 &&
1097 			    memcmp(name, desc.s + sizeof(SJPARAM),
1098 			    desclen - sizeof(SJPARAM) - 2) == 0 &&
1099 			    desc.s[desclen - 2] == '.')
1100 				goto mib_desc;
1101 		}
1102 		goto unknown_parameter;
1103 	default:
1104 		snprintf(jail_errmsg, JAIL_ERRMSGLEN,
1105 		    "unknown type for %s", jp->jp_name);
1106 		errno = ENOENT;
1107 		return (-1);
1108 	}
1109 	if (isarray) {
1110 		jp->jp_elemlen = jp->jp_valuelen;
1111 		jp->jp_valuelen = 0;
1112 	}
1113 	return (0);
1114 }
1115 
1116 /*
1117  * Attempt to load a kernel module matching an otherwise nonexistent parameter.
1118  */
1119 static int
kldload_param(const char * name)1120 kldload_param(const char *name)
1121 {
1122 	int kl;
1123 
1124 	if (strcmp(name, "linux") == 0 || strncmp(name, "linux.", 6) == 0)
1125 		kl = kldload("linux");
1126 	else if (strcmp(name, "sysvmsg") == 0 || strcmp(name, "sysvsem") == 0 ||
1127 	    strcmp(name, "sysvshm") == 0)
1128 		kl = kldload(name);
1129 	else if (strncmp(name, "allow.mount.", 12) == 0) {
1130 		/* Load the matching filesystem */
1131 		const char *modname = name + 12;
1132 
1133 		kl = kldload(modname);
1134 		if (kl < 0 && errno == ENOENT &&
1135 		    strncmp(modname, "no", 2) == 0)
1136 			kl = kldload(modname + 2);
1137 	} else {
1138 		errno = ENOENT;
1139 		return (-1);
1140 	}
1141 	if (kl < 0 && errno == EEXIST) {
1142 		/*
1143 		 * In the module is already loaded, then it must not contain
1144 		 * the parameter.
1145 		 */
1146 		errno = ENOENT;
1147 	}
1148 	return kl;
1149 }
1150 
1151 /*
1152  * Change a boolean parameter name into its "no" counterpart or vice versa.
1153  */
1154 static char *
noname(const char * name)1155 noname(const char *name)
1156 {
1157 	char *nname, *p;
1158 
1159 	nname = malloc(strlen(name) + 3);
1160 	if (nname == NULL) {
1161 		strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
1162 		return (NULL);
1163 	}
1164 	p = strrchr(name, '.');
1165 	if (p != NULL)
1166 		sprintf(nname, "%.*s.no%s", (int)(p - name), name, p + 1);
1167 	else
1168 		sprintf(nname, "no%s", name);
1169 	return (nname);
1170 }
1171 
1172 static char *
nononame(const char * name)1173 nononame(const char *name)
1174 {
1175 	char *p, *nname;
1176 
1177 	p = strrchr(name, '.');
1178 	if (strncmp(p ? p + 1 : name, "no", 2)) {
1179 		snprintf(jail_errmsg, sizeof(jail_errmsg),
1180 		    "mismatched boolean: %s", name);
1181 		errno = EINVAL;
1182 		return (NULL);
1183 	}
1184 	nname = malloc(strlen(name) - 1);
1185 	if (nname == NULL) {
1186 		strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
1187 		return (NULL);
1188 	}
1189 	if (p != NULL)
1190 		sprintf(nname, "%.*s.%s", (int)(p - name), name, p + 3);
1191 	else
1192 		strcpy(nname, name + 2);
1193 	return (nname);
1194 }
1195 
1196 static char *
kvname(const char * name)1197 kvname(const char *name)
1198 {
1199 	const char *p;
1200 	char *kvname;
1201 	size_t len;
1202 
1203 	p = strchr(name, '.');
1204 	if (p == NULL)
1205 		return (NULL);
1206 
1207 	len = p - name;
1208 	kvname = malloc(len + 1);
1209 	if (kvname == NULL) {
1210 		strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
1211 		return (NULL);
1212 	}
1213 	strncpy(kvname, name, len);
1214 	kvname[len] = '\0';
1215 
1216 	return (kvname);
1217 }
1218