xref: /freebsd/sys/kern/subr_capability.c (revision a7100ae23aca07976926bd8d50223c45149f65d6)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2013 FreeBSD Foundation
5  *
6  * This software was developed by Pawel Jakub Dawidek under sponsorship from
7  * the FreeBSD Foundation.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  */
30 
31 #include <sys/cdefs.h>
32 /*
33  * Note that this file is compiled into the kernel and into libc.
34  */
35 
36 #include <sys/types.h>
37 #include <sys/capsicum.h>
38 
39 #ifdef _KERNEL
40 #include <sys/systm.h>
41 #include <sys/kernel.h>
42 #include <machine/stdarg.h>
43 #else	/* !_KERNEL */
44 #include <assert.h>
45 #include <stdarg.h>
46 #include <stdbool.h>
47 #include <stdint.h>
48 #include <string.h>
49 #endif
50 
51 #ifdef _KERNEL
52 #define	assert(exp)	KASSERT((exp), ("%s:%u", __func__, __LINE__))
53 __read_mostly cap_rights_t cap_accept_rights;
54 __read_mostly cap_rights_t cap_bind_rights;
55 __read_mostly cap_rights_t cap_chflags_rights;
56 __read_mostly cap_rights_t cap_connect_rights;
57 __read_mostly cap_rights_t cap_event_rights;
58 __read_mostly cap_rights_t cap_fchdir_rights;
59 __read_mostly cap_rights_t cap_fchflags_rights;
60 __read_mostly cap_rights_t cap_fchmod_rights;
61 __read_mostly cap_rights_t cap_fchown_rights;
62 __read_mostly cap_rights_t cap_fcntl_rights;
63 __read_mostly cap_rights_t cap_fexecve_rights;
64 __read_mostly cap_rights_t cap_flock_rights;
65 __read_mostly cap_rights_t cap_fpathconf_rights;
66 __read_mostly cap_rights_t cap_fstat_rights;
67 __read_mostly cap_rights_t cap_fstatfs_rights;
68 __read_mostly cap_rights_t cap_fsync_rights;
69 __read_mostly cap_rights_t cap_ftruncate_rights;
70 __read_mostly cap_rights_t cap_futimes_rights;
71 __read_mostly cap_rights_t cap_getpeername_rights;
72 __read_mostly cap_rights_t cap_getsockopt_rights;
73 __read_mostly cap_rights_t cap_getsockname_rights;
74 __read_mostly cap_rights_t cap_ioctl_rights;
75 __read_mostly cap_rights_t cap_listen_rights;
76 __read_mostly cap_rights_t cap_linkat_source_rights;
77 __read_mostly cap_rights_t cap_linkat_target_rights;
78 __read_mostly cap_rights_t cap_mmap_rights;
79 __read_mostly cap_rights_t cap_mkdirat_rights;
80 __read_mostly cap_rights_t cap_mkfifoat_rights;
81 __read_mostly cap_rights_t cap_mknodat_rights;
82 __read_mostly cap_rights_t cap_pdgetpid_rights;
83 __read_mostly cap_rights_t cap_pdkill_rights;
84 __read_mostly cap_rights_t cap_pread_rights;
85 __read_mostly cap_rights_t cap_pwrite_rights;
86 __read_mostly cap_rights_t cap_read_rights;
87 __read_mostly cap_rights_t cap_recv_rights;
88 __read_mostly cap_rights_t cap_renameat_source_rights;
89 __read_mostly cap_rights_t cap_renameat_target_rights;
90 __read_mostly cap_rights_t cap_seek_rights;
91 __read_mostly cap_rights_t cap_send_rights;
92 __read_mostly cap_rights_t cap_send_connect_rights;
93 __read_mostly cap_rights_t cap_setsockopt_rights;
94 __read_mostly cap_rights_t cap_shutdown_rights;
95 __read_mostly cap_rights_t cap_symlinkat_rights;
96 __read_mostly cap_rights_t cap_unlinkat_rights;
97 __read_mostly cap_rights_t cap_write_rights;
98 __read_mostly cap_rights_t cap_no_rights;
99 
100 static void
cap_rights_sysinit(void * arg)101 cap_rights_sysinit(void *arg)
102 {
103 	cap_rights_init_one(&cap_accept_rights, CAP_ACCEPT);
104 	cap_rights_init_one(&cap_bind_rights, CAP_BIND);
105 	cap_rights_init_one(&cap_connect_rights, CAP_CONNECT);
106 	cap_rights_init_one(&cap_event_rights, CAP_EVENT);
107 	cap_rights_init_one(&cap_fchdir_rights, CAP_FCHDIR);
108 	cap_rights_init_one(&cap_fchflags_rights, CAP_FCHFLAGS);
109 	cap_rights_init_one(&cap_fchmod_rights, CAP_FCHMOD);
110 	cap_rights_init_one(&cap_fchown_rights, CAP_FCHOWN);
111 	cap_rights_init_one(&cap_fcntl_rights, CAP_FCNTL);
112 	cap_rights_init_one(&cap_fexecve_rights, CAP_FEXECVE);
113 	cap_rights_init_one(&cap_flock_rights, CAP_FLOCK);
114 	cap_rights_init_one(&cap_fpathconf_rights, CAP_FPATHCONF);
115 	cap_rights_init_one(&cap_fstat_rights, CAP_FSTAT);
116 	cap_rights_init_one(&cap_fstatfs_rights, CAP_FSTATFS);
117 	cap_rights_init_one(&cap_fsync_rights, CAP_FSYNC);
118 	cap_rights_init_one(&cap_ftruncate_rights, CAP_FTRUNCATE);
119 	cap_rights_init_one(&cap_futimes_rights, CAP_FUTIMES);
120 	cap_rights_init_one(&cap_getpeername_rights, CAP_GETPEERNAME);
121 	cap_rights_init_one(&cap_getsockname_rights, CAP_GETSOCKNAME);
122 	cap_rights_init_one(&cap_getsockopt_rights, CAP_GETSOCKOPT);
123 	cap_rights_init_one(&cap_ioctl_rights, CAP_IOCTL);
124 	cap_rights_init_one(&cap_linkat_source_rights, CAP_LINKAT_SOURCE);
125 	cap_rights_init_one(&cap_linkat_target_rights, CAP_LINKAT_TARGET);
126 	cap_rights_init_one(&cap_listen_rights, CAP_LISTEN);
127 	cap_rights_init_one(&cap_mkdirat_rights, CAP_MKDIRAT);
128 	cap_rights_init_one(&cap_mkfifoat_rights, CAP_MKFIFOAT);
129 	cap_rights_init_one(&cap_mknodat_rights, CAP_MKNODAT);
130 	cap_rights_init_one(&cap_mmap_rights, CAP_MMAP);
131 	cap_rights_init_one(&cap_pdgetpid_rights, CAP_PDGETPID);
132 	cap_rights_init_one(&cap_pdkill_rights, CAP_PDKILL);
133 	cap_rights_init_one(&cap_pread_rights, CAP_PREAD);
134 	cap_rights_init_one(&cap_pwrite_rights, CAP_PWRITE);
135 	cap_rights_init_one(&cap_read_rights, CAP_READ);
136 	cap_rights_init_one(&cap_recv_rights, CAP_RECV);
137 	cap_rights_init_one(&cap_renameat_source_rights, CAP_RENAMEAT_SOURCE);
138 	cap_rights_init_one(&cap_renameat_target_rights, CAP_RENAMEAT_TARGET);
139 	cap_rights_init_one(&cap_seek_rights, CAP_SEEK);
140 	cap_rights_init_one(&cap_send_rights, CAP_SEND);
141 	cap_rights_init(&cap_send_connect_rights, CAP_SEND, CAP_CONNECT);
142 	cap_rights_init_one(&cap_setsockopt_rights, CAP_SETSOCKOPT);
143 	cap_rights_init_one(&cap_shutdown_rights, CAP_SHUTDOWN);
144 	cap_rights_init_one(&cap_symlinkat_rights, CAP_SYMLINKAT);
145 	cap_rights_init_one(&cap_unlinkat_rights, CAP_UNLINKAT);
146 	cap_rights_init_one(&cap_write_rights, CAP_WRITE);
147 	cap_rights_init(&cap_no_rights);
148 }
149 SYSINIT(cap_rights_sysinit, SI_SUB_COPYRIGHT, SI_ORDER_ANY, cap_rights_sysinit,
150     NULL);
151 
152 #endif
153 
154 #define	CAPARSIZE_MIN	(CAP_RIGHTS_VERSION_00 + 2)
155 #define	CAPARSIZE_MAX	(CAP_RIGHTS_VERSION + 2)
156 
157 static __inline int
right_to_index(uint64_t right)158 right_to_index(uint64_t right)
159 {
160 	static const int bit2idx[] = {
161 		-1, 0, 1, -1, 2, -1, -1, -1, 3, -1, -1, -1, -1, -1, -1, -1,
162 		4, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
163 	};
164 	int idx;
165 
166 	idx = CAPIDXBIT(right);
167 	assert(idx >= 0 && idx < sizeof(bit2idx) / sizeof(bit2idx[0]));
168 	return (bit2idx[idx]);
169 }
170 
171 static void
cap_rights_vset(cap_rights_t * rights,va_list ap)172 cap_rights_vset(cap_rights_t *rights, va_list ap)
173 {
174 	uint64_t right;
175 	int i, n __unused;
176 
177 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
178 
179 	n = CAPARSIZE(rights);
180 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
181 
182 	for (;;) {
183 		right = (uint64_t)va_arg(ap, unsigned long long);
184 		if (right == 0)
185 			break;
186 		assert(CAPRVER(right) == 0);
187 		i = right_to_index(right);
188 		assert(i >= 0);
189 		assert(i < n);
190 		assert(CAPIDXBIT(rights->cr_rights[i]) == CAPIDXBIT(right));
191 		rights->cr_rights[i] |= right;
192 		assert(CAPIDXBIT(rights->cr_rights[i]) == CAPIDXBIT(right));
193 	}
194 }
195 
196 static void
cap_rights_vclear(cap_rights_t * rights,va_list ap)197 cap_rights_vclear(cap_rights_t *rights, va_list ap)
198 {
199 	uint64_t right;
200 	int i, n __unused;
201 
202 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
203 
204 	n = CAPARSIZE(rights);
205 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
206 
207 	for (;;) {
208 		right = (uint64_t)va_arg(ap, unsigned long long);
209 		if (right == 0)
210 			break;
211 		assert(CAPRVER(right) == 0);
212 		i = right_to_index(right);
213 		assert(i >= 0);
214 		assert(i < n);
215 		assert(CAPIDXBIT(rights->cr_rights[i]) == CAPIDXBIT(right));
216 		rights->cr_rights[i] &= ~(right & 0x01FFFFFFFFFFFFFFULL);
217 		assert(CAPIDXBIT(rights->cr_rights[i]) == CAPIDXBIT(right));
218 	}
219 }
220 
221 static bool
cap_rights_is_vset(const cap_rights_t * rights,va_list ap)222 cap_rights_is_vset(const cap_rights_t *rights, va_list ap)
223 {
224 	uint64_t right;
225 	int i, n __unused;
226 
227 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
228 
229 	n = CAPARSIZE(rights);
230 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
231 
232 	for (;;) {
233 		right = (uint64_t)va_arg(ap, unsigned long long);
234 		if (right == 0)
235 			break;
236 		assert(CAPRVER(right) == 0);
237 		i = right_to_index(right);
238 		assert(i >= 0);
239 		assert(i < n);
240 		assert(CAPIDXBIT(rights->cr_rights[i]) == CAPIDXBIT(right));
241 		if ((rights->cr_rights[i] & right) != right)
242 			return (false);
243 	}
244 
245 	return (true);
246 }
247 
248 cap_rights_t *
__cap_rights_init(int version,cap_rights_t * rights,...)249 __cap_rights_init(int version, cap_rights_t *rights, ...)
250 {
251 	unsigned int n __unused;
252 	va_list ap;
253 
254 	assert(version == CAP_RIGHTS_VERSION_00);
255 
256 	n = version + 2;
257 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
258 	CAP_NONE(rights);
259 	va_start(ap, rights);
260 	cap_rights_vset(rights, ap);
261 	va_end(ap);
262 
263 	return (rights);
264 }
265 
266 cap_rights_t *
__cap_rights_set(cap_rights_t * rights,...)267 __cap_rights_set(cap_rights_t *rights, ...)
268 {
269 	va_list ap;
270 
271 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
272 
273 	va_start(ap, rights);
274 	cap_rights_vset(rights, ap);
275 	va_end(ap);
276 
277 	return (rights);
278 }
279 
280 cap_rights_t *
__cap_rights_clear(cap_rights_t * rights,...)281 __cap_rights_clear(cap_rights_t *rights, ...)
282 {
283 	va_list ap;
284 
285 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
286 
287 	va_start(ap, rights);
288 	cap_rights_vclear(rights, ap);
289 	va_end(ap);
290 
291 	return (rights);
292 }
293 
294 bool
__cap_rights_is_set(const cap_rights_t * rights,...)295 __cap_rights_is_set(const cap_rights_t *rights, ...)
296 {
297 	va_list ap;
298 	bool ret;
299 
300 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
301 
302 	va_start(ap, rights);
303 	ret = cap_rights_is_vset(rights, ap);
304 	va_end(ap);
305 
306 	return (ret);
307 }
308 
309 bool
cap_rights_is_empty(const cap_rights_t * rights)310 cap_rights_is_empty(const cap_rights_t *rights)
311 {
312 #ifndef _KERNEL
313 	cap_rights_t cap_no_rights;
314 	cap_rights_init(&cap_no_rights);
315 #endif
316 
317 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
318 	assert(CAPVER(&cap_no_rights) == CAP_RIGHTS_VERSION_00);
319 
320 	for (int i = 0; i < CAPARSIZE(rights); i++) {
321 		if (rights->cr_rights[i] != cap_no_rights.cr_rights[i])
322 			return (false);
323 	}
324 
325 	return (true);
326 }
327 
328 bool
cap_rights_is_valid(const cap_rights_t * rights)329 cap_rights_is_valid(const cap_rights_t *rights)
330 {
331 	cap_rights_t allrights;
332 	int i, j;
333 
334 	if (CAPVER(rights) != CAP_RIGHTS_VERSION_00)
335 		return (false);
336 	if (CAPARSIZE(rights) < CAPARSIZE_MIN ||
337 	    CAPARSIZE(rights) > CAPARSIZE_MAX) {
338 		return (false);
339 	}
340 	CAP_ALL(&allrights);
341 	if (!cap_rights_contains(&allrights, rights))
342 		return (false);
343 	for (i = 0; i < CAPARSIZE(rights); i++) {
344 		j = right_to_index(rights->cr_rights[i]);
345 		if (i != j)
346 			return (false);
347 		if (i > 0) {
348 			if (CAPRVER(rights->cr_rights[i]) != 0)
349 				return (false);
350 		}
351 	}
352 
353 	return (true);
354 }
355 
356 cap_rights_t *
cap_rights_merge(cap_rights_t * dst,const cap_rights_t * src)357 cap_rights_merge(cap_rights_t *dst, const cap_rights_t *src)
358 {
359 	unsigned int i, n;
360 
361 	assert(CAPVER(dst) == CAP_RIGHTS_VERSION_00);
362 	assert(CAPVER(src) == CAP_RIGHTS_VERSION_00);
363 	assert(CAPVER(dst) == CAPVER(src));
364 	assert(cap_rights_is_valid(src));
365 	assert(cap_rights_is_valid(dst));
366 
367 	n = CAPARSIZE(dst);
368 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
369 
370 	for (i = 0; i < n; i++)
371 		dst->cr_rights[i] |= src->cr_rights[i];
372 
373 	assert(cap_rights_is_valid(src));
374 	assert(cap_rights_is_valid(dst));
375 
376 	return (dst);
377 }
378 
379 cap_rights_t *
cap_rights_remove(cap_rights_t * dst,const cap_rights_t * src)380 cap_rights_remove(cap_rights_t *dst, const cap_rights_t *src)
381 {
382 	unsigned int i, n;
383 
384 	assert(CAPVER(dst) == CAP_RIGHTS_VERSION_00);
385 	assert(CAPVER(src) == CAP_RIGHTS_VERSION_00);
386 	assert(CAPVER(dst) == CAPVER(src));
387 	assert(cap_rights_is_valid(src));
388 	assert(cap_rights_is_valid(dst));
389 
390 	n = CAPARSIZE(dst);
391 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
392 
393 	for (i = 0; i < n; i++) {
394 		dst->cr_rights[i] &=
395 		    ~(src->cr_rights[i] & 0x01FFFFFFFFFFFFFFULL);
396 	}
397 
398 	assert(cap_rights_is_valid(src));
399 	assert(cap_rights_is_valid(dst));
400 
401 	return (dst);
402 }
403 
404 #ifndef _KERNEL
405 bool
cap_rights_contains(const cap_rights_t * big,const cap_rights_t * little)406 cap_rights_contains(const cap_rights_t *big, const cap_rights_t *little)
407 {
408 	unsigned int i, n;
409 
410 	assert(CAPVER(big) == CAP_RIGHTS_VERSION_00);
411 	assert(CAPVER(little) == CAP_RIGHTS_VERSION_00);
412 	assert(CAPVER(big) == CAPVER(little));
413 
414 	n = CAPARSIZE(big);
415 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
416 
417 	for (i = 0; i < n; i++) {
418 		if ((big->cr_rights[i] & little->cr_rights[i]) !=
419 		    little->cr_rights[i]) {
420 			return (false);
421 		}
422 	}
423 
424 	return (true);
425 }
426 #endif
427