xref: /freebsd/sys/kern/subr_capability.c (revision b9f654b163bce26de79705e77b872427c9f2afa1)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2013 FreeBSD Foundation
5  * All rights reserved.
6  *
7  * This software was developed by Pawel Jakub Dawidek under sponsorship from
8  * the FreeBSD Foundation.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 /*
36  * Note that this file is compiled into the kernel and into libc.
37  */
38 
39 #include <sys/types.h>
40 #include <sys/capsicum.h>
41 
42 #ifdef _KERNEL
43 #include <sys/systm.h>
44 #include <sys/kernel.h>
45 #include <machine/stdarg.h>
46 #else	/* !_KERNEL */
47 #include <assert.h>
48 #include <stdarg.h>
49 #include <stdbool.h>
50 #include <stdint.h>
51 #include <string.h>
52 #endif
53 
54 #ifdef _KERNEL
55 #define	assert(exp)	KASSERT((exp), ("%s:%u", __func__, __LINE__))
56 __read_mostly cap_rights_t cap_accept_rights;
57 __read_mostly cap_rights_t cap_bind_rights;
58 __read_mostly cap_rights_t cap_chflags_rights;
59 __read_mostly cap_rights_t cap_connect_rights;
60 __read_mostly cap_rights_t cap_event_rights;
61 __read_mostly cap_rights_t cap_fchdir_rights;
62 __read_mostly cap_rights_t cap_fchflags_rights;
63 __read_mostly cap_rights_t cap_fchmod_rights;
64 __read_mostly cap_rights_t cap_fchown_rights;
65 __read_mostly cap_rights_t cap_fcntl_rights;
66 __read_mostly cap_rights_t cap_fexecve_rights;
67 __read_mostly cap_rights_t cap_flock_rights;
68 __read_mostly cap_rights_t cap_fpathconf_rights;
69 __read_mostly cap_rights_t cap_fstat_rights;
70 __read_mostly cap_rights_t cap_fstatfs_rights;
71 __read_mostly cap_rights_t cap_fsync_rights;
72 __read_mostly cap_rights_t cap_ftruncate_rights;
73 __read_mostly cap_rights_t cap_futimes_rights;
74 __read_mostly cap_rights_t cap_getpeername_rights;
75 __read_mostly cap_rights_t cap_getsockopt_rights;
76 __read_mostly cap_rights_t cap_getsockname_rights;
77 __read_mostly cap_rights_t cap_ioctl_rights;
78 __read_mostly cap_rights_t cap_listen_rights;
79 __read_mostly cap_rights_t cap_linkat_source_rights;
80 __read_mostly cap_rights_t cap_linkat_target_rights;
81 __read_mostly cap_rights_t cap_mmap_rights;
82 __read_mostly cap_rights_t cap_mkdirat_rights;
83 __read_mostly cap_rights_t cap_mkfifoat_rights;
84 __read_mostly cap_rights_t cap_mknodat_rights;
85 __read_mostly cap_rights_t cap_pdgetpid_rights;
86 __read_mostly cap_rights_t cap_pdkill_rights;
87 __read_mostly cap_rights_t cap_pread_rights;
88 __read_mostly cap_rights_t cap_pwrite_rights;
89 __read_mostly cap_rights_t cap_read_rights;
90 __read_mostly cap_rights_t cap_recv_rights;
91 __read_mostly cap_rights_t cap_renameat_source_rights;
92 __read_mostly cap_rights_t cap_renameat_target_rights;
93 __read_mostly cap_rights_t cap_seek_rights;
94 __read_mostly cap_rights_t cap_send_rights;
95 __read_mostly cap_rights_t cap_send_connect_rights;
96 __read_mostly cap_rights_t cap_setsockopt_rights;
97 __read_mostly cap_rights_t cap_shutdown_rights;
98 __read_mostly cap_rights_t cap_symlinkat_rights;
99 __read_mostly cap_rights_t cap_unlinkat_rights;
100 __read_mostly cap_rights_t cap_write_rights;
101 __read_mostly cap_rights_t cap_no_rights;
102 
103 static void
104 __cap_rights_sysinit1(void *arg)
105 {
106 	cap_rights_init(&cap_accept_rights, CAP_ACCEPT);
107 	cap_rights_init(&cap_bind_rights, CAP_BIND);
108 	cap_rights_init(&cap_connect_rights, CAP_CONNECT);
109 	cap_rights_init(&cap_event_rights, CAP_EVENT);
110 	cap_rights_init(&cap_fchdir_rights, CAP_FCHDIR);
111 	cap_rights_init(&cap_fchflags_rights, CAP_FCHFLAGS);
112 	cap_rights_init(&cap_fchmod_rights, CAP_FCHMOD);
113 	cap_rights_init(&cap_fchown_rights, CAP_FCHOWN);
114 	cap_rights_init(&cap_fcntl_rights, CAP_FCNTL);
115 	cap_rights_init(&cap_fexecve_rights, CAP_FEXECVE);
116 	cap_rights_init(&cap_flock_rights, CAP_FLOCK);
117 	cap_rights_init(&cap_fpathconf_rights, CAP_FPATHCONF);
118 	cap_rights_init(&cap_fstat_rights, CAP_FSTAT);
119 	cap_rights_init(&cap_fstatfs_rights, CAP_FSTATFS);
120 	cap_rights_init(&cap_fsync_rights, CAP_FSYNC);
121 	cap_rights_init(&cap_ftruncate_rights, CAP_FTRUNCATE);
122 	cap_rights_init(&cap_futimes_rights, CAP_FUTIMES);
123 	cap_rights_init(&cap_getpeername_rights, CAP_GETPEERNAME);
124 	cap_rights_init(&cap_getsockname_rights, CAP_GETSOCKNAME);
125 	cap_rights_init(&cap_getsockopt_rights, CAP_GETSOCKOPT);
126 	cap_rights_init(&cap_ioctl_rights, CAP_IOCTL);
127 	cap_rights_init(&cap_linkat_source_rights, CAP_LINKAT_SOURCE);
128 	cap_rights_init(&cap_linkat_target_rights, CAP_LINKAT_TARGET);
129 	cap_rights_init(&cap_listen_rights, CAP_LISTEN);
130 	cap_rights_init(&cap_mkdirat_rights, CAP_MKDIRAT);
131 	cap_rights_init(&cap_mkfifoat_rights, CAP_MKFIFOAT);
132 	cap_rights_init(&cap_mknodat_rights, CAP_MKNODAT);
133 	cap_rights_init(&cap_mmap_rights, CAP_MMAP);
134 	cap_rights_init(&cap_pdgetpid_rights, CAP_PDGETPID);
135 	cap_rights_init(&cap_pdkill_rights, CAP_PDKILL);
136 	cap_rights_init(&cap_pread_rights, CAP_PREAD);
137 	cap_rights_init(&cap_pwrite_rights, CAP_PWRITE);
138 	cap_rights_init(&cap_read_rights, CAP_READ);
139 	cap_rights_init(&cap_recv_rights, CAP_RECV);
140 	cap_rights_init(&cap_renameat_source_rights, CAP_RENAMEAT_SOURCE);
141 	cap_rights_init(&cap_renameat_target_rights, CAP_RENAMEAT_TARGET);
142 	cap_rights_init(&cap_seek_rights, CAP_SEEK);
143 	cap_rights_init(&cap_send_rights, CAP_SEND);
144 	cap_rights_init(&cap_send_connect_rights, CAP_SEND, CAP_CONNECT);
145 	cap_rights_init(&cap_setsockopt_rights, CAP_SETSOCKOPT);
146 	cap_rights_init(&cap_shutdown_rights, CAP_SHUTDOWN);
147 	cap_rights_init(&cap_symlinkat_rights, CAP_SYMLINKAT);
148 	cap_rights_init(&cap_unlinkat_rights, CAP_UNLINKAT);
149 	cap_rights_init(&cap_write_rights, CAP_WRITE);
150 	cap_rights_init(&cap_no_rights);
151 }
152 SYSINIT(cap_rights1_sysinit, SI_SUB_COPYRIGHT, SI_ORDER_ANY,	\
153 		    __cap_rights_sysinit1, NULL);
154 
155 #endif
156 
157 #define	CAPARSIZE_MIN	(CAP_RIGHTS_VERSION_00 + 2)
158 #define	CAPARSIZE_MAX	(CAP_RIGHTS_VERSION + 2)
159 
160 static __inline int
161 right_to_index(uint64_t right)
162 {
163 	static const int bit2idx[] = {
164 		-1, 0, 1, -1, 2, -1, -1, -1, 3, -1, -1, -1, -1, -1, -1, -1,
165 		4, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
166 	};
167 	int idx;
168 
169 	idx = CAPIDXBIT(right);
170 	assert(idx >= 0 && idx < sizeof(bit2idx) / sizeof(bit2idx[0]));
171 	return (bit2idx[idx]);
172 }
173 
174 static void
175 cap_rights_vset(cap_rights_t *rights, va_list ap)
176 {
177 	uint64_t right;
178 	int i, n __unused;
179 
180 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
181 
182 	n = CAPARSIZE(rights);
183 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
184 
185 	for (;;) {
186 		right = (uint64_t)va_arg(ap, unsigned long long);
187 		if (right == 0)
188 			break;
189 		assert(CAPRVER(right) == 0);
190 		i = right_to_index(right);
191 		assert(i >= 0);
192 		assert(i < n);
193 		assert(CAPIDXBIT(rights->cr_rights[i]) == CAPIDXBIT(right));
194 		rights->cr_rights[i] |= right;
195 		assert(CAPIDXBIT(rights->cr_rights[i]) == CAPIDXBIT(right));
196 	}
197 }
198 
199 static void
200 cap_rights_vclear(cap_rights_t *rights, va_list ap)
201 {
202 	uint64_t right;
203 	int i, n __unused;
204 
205 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
206 
207 	n = CAPARSIZE(rights);
208 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
209 
210 	for (;;) {
211 		right = (uint64_t)va_arg(ap, unsigned long long);
212 		if (right == 0)
213 			break;
214 		assert(CAPRVER(right) == 0);
215 		i = right_to_index(right);
216 		assert(i >= 0);
217 		assert(i < n);
218 		assert(CAPIDXBIT(rights->cr_rights[i]) == CAPIDXBIT(right));
219 		rights->cr_rights[i] &= ~(right & 0x01FFFFFFFFFFFFFFULL);
220 		assert(CAPIDXBIT(rights->cr_rights[i]) == CAPIDXBIT(right));
221 	}
222 }
223 
224 static bool
225 cap_rights_is_vset(const cap_rights_t *rights, va_list ap)
226 {
227 	uint64_t right;
228 	int i, n __unused;
229 
230 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
231 
232 	n = CAPARSIZE(rights);
233 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
234 
235 	for (;;) {
236 		right = (uint64_t)va_arg(ap, unsigned long long);
237 		if (right == 0)
238 			break;
239 		assert(CAPRVER(right) == 0);
240 		i = right_to_index(right);
241 		assert(i >= 0);
242 		assert(i < n);
243 		assert(CAPIDXBIT(rights->cr_rights[i]) == CAPIDXBIT(right));
244 		if ((rights->cr_rights[i] & right) != right)
245 			return (false);
246 	}
247 
248 	return (true);
249 }
250 
251 void
252 __cap_rights_sysinit(void *arg)
253 {
254 	struct cap_rights_init_args *cria = arg;
255 	cap_rights_t *rights = cria->cria_rights;
256 
257 	__cap_rights_init(CAP_RIGHTS_VERSION, rights, cria->cria_value1,
258        cria->cria_value2, cria->cria_value3, cria->cria_value4, 0ULL);
259 }
260 
261 cap_rights_t *
262 __cap_rights_init(int version, cap_rights_t *rights, ...)
263 {
264 	unsigned int n __unused;
265 	va_list ap;
266 
267 	assert(version == CAP_RIGHTS_VERSION_00);
268 
269 	n = version + 2;
270 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
271 	CAP_NONE(rights);
272 	va_start(ap, rights);
273 	cap_rights_vset(rights, ap);
274 	va_end(ap);
275 
276 	return (rights);
277 }
278 
279 cap_rights_t *
280 __cap_rights_set(cap_rights_t *rights, ...)
281 {
282 	va_list ap;
283 
284 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
285 
286 	va_start(ap, rights);
287 	cap_rights_vset(rights, ap);
288 	va_end(ap);
289 
290 	return (rights);
291 }
292 
293 cap_rights_t *
294 __cap_rights_clear(cap_rights_t *rights, ...)
295 {
296 	va_list ap;
297 
298 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
299 
300 	va_start(ap, rights);
301 	cap_rights_vclear(rights, ap);
302 	va_end(ap);
303 
304 	return (rights);
305 }
306 
307 bool
308 __cap_rights_is_set(const cap_rights_t *rights, ...)
309 {
310 	va_list ap;
311 	bool ret;
312 
313 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
314 
315 	va_start(ap, rights);
316 	ret = cap_rights_is_vset(rights, ap);
317 	va_end(ap);
318 
319 	return (ret);
320 }
321 
322 bool
323 cap_rights_is_valid(const cap_rights_t *rights)
324 {
325 	cap_rights_t allrights;
326 	int i, j;
327 
328 	if (CAPVER(rights) != CAP_RIGHTS_VERSION_00)
329 		return (false);
330 	if (CAPARSIZE(rights) < CAPARSIZE_MIN ||
331 	    CAPARSIZE(rights) > CAPARSIZE_MAX) {
332 		return (false);
333 	}
334 	CAP_ALL(&allrights);
335 	if (!cap_rights_contains(&allrights, rights))
336 		return (false);
337 	for (i = 0; i < CAPARSIZE(rights); i++) {
338 		j = right_to_index(rights->cr_rights[i]);
339 		if (i != j)
340 			return (false);
341 		if (i > 0) {
342 			if (CAPRVER(rights->cr_rights[i]) != 0)
343 				return (false);
344 		}
345 	}
346 
347 	return (true);
348 }
349 
350 cap_rights_t *
351 cap_rights_merge(cap_rights_t *dst, const cap_rights_t *src)
352 {
353 	unsigned int i, n;
354 
355 	assert(CAPVER(dst) == CAP_RIGHTS_VERSION_00);
356 	assert(CAPVER(src) == CAP_RIGHTS_VERSION_00);
357 	assert(CAPVER(dst) == CAPVER(src));
358 	assert(cap_rights_is_valid(src));
359 	assert(cap_rights_is_valid(dst));
360 
361 	n = CAPARSIZE(dst);
362 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
363 
364 	for (i = 0; i < n; i++)
365 		dst->cr_rights[i] |= src->cr_rights[i];
366 
367 	assert(cap_rights_is_valid(src));
368 	assert(cap_rights_is_valid(dst));
369 
370 	return (dst);
371 }
372 
373 cap_rights_t *
374 cap_rights_remove(cap_rights_t *dst, const cap_rights_t *src)
375 {
376 	unsigned int i, n;
377 
378 	assert(CAPVER(dst) == CAP_RIGHTS_VERSION_00);
379 	assert(CAPVER(src) == CAP_RIGHTS_VERSION_00);
380 	assert(CAPVER(dst) == CAPVER(src));
381 	assert(cap_rights_is_valid(src));
382 	assert(cap_rights_is_valid(dst));
383 
384 	n = CAPARSIZE(dst);
385 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
386 
387 	for (i = 0; i < n; i++) {
388 		dst->cr_rights[i] &=
389 		    ~(src->cr_rights[i] & 0x01FFFFFFFFFFFFFFULL);
390 	}
391 
392 	assert(cap_rights_is_valid(src));
393 	assert(cap_rights_is_valid(dst));
394 
395 	return (dst);
396 }
397 
398 bool
399 cap_rights_contains(const cap_rights_t *big, const cap_rights_t *little)
400 {
401 	unsigned int i, n;
402 
403 	assert(CAPVER(big) == CAP_RIGHTS_VERSION_00);
404 	assert(CAPVER(little) == CAP_RIGHTS_VERSION_00);
405 	assert(CAPVER(big) == CAPVER(little));
406 
407 	n = CAPARSIZE(big);
408 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
409 
410 	for (i = 0; i < n; i++) {
411 		if ((big->cr_rights[i] & little->cr_rights[i]) !=
412 		    little->cr_rights[i]) {
413 			return (false);
414 		}
415 	}
416 
417 	return (true);
418 }
419