xref: /freebsd/sys/kern/subr_capability.c (revision 240c614d48cb0484bfe7876decdf6bbdcc99ba73)
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 <sys/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 const cap_rights_t cap_accept_rights = CAP_RIGHTS_INITIALIZER(CAP_ACCEPT);
54 const cap_rights_t cap_bind_rights = CAP_RIGHTS_INITIALIZER(CAP_BIND);
55 const cap_rights_t cap_connect_rights = CAP_RIGHTS_INITIALIZER(CAP_CONNECT);
56 const cap_rights_t cap_event_rights = CAP_RIGHTS_INITIALIZER(CAP_EVENT);
57 const cap_rights_t cap_fchdir_rights = CAP_RIGHTS_INITIALIZER(CAP_FCHDIR);
58 const cap_rights_t cap_fchflags_rights = CAP_RIGHTS_INITIALIZER(CAP_FCHFLAGS);
59 const cap_rights_t cap_fchmod_rights = CAP_RIGHTS_INITIALIZER(CAP_FCHMOD);
60 const cap_rights_t cap_fchown_rights = CAP_RIGHTS_INITIALIZER(CAP_FCHOWN);
61 const cap_rights_t cap_fchroot_rights = CAP_RIGHTS_INITIALIZER(CAP_FCHROOT);
62 const cap_rights_t cap_fcntl_rights = CAP_RIGHTS_INITIALIZER(CAP_FCNTL);
63 const cap_rights_t cap_fexecve_rights = CAP_RIGHTS_INITIALIZER(CAP_FEXECVE);
64 const cap_rights_t cap_flock_rights = CAP_RIGHTS_INITIALIZER(CAP_FLOCK);
65 const cap_rights_t cap_fpathconf_rights = CAP_RIGHTS_INITIALIZER(CAP_FPATHCONF);
66 const cap_rights_t cap_fstat_rights = CAP_RIGHTS_INITIALIZER(CAP_FSTAT);
67 const cap_rights_t cap_fstatfs_rights = CAP_RIGHTS_INITIALIZER(CAP_FSTATFS);
68 const cap_rights_t cap_fsync_rights = CAP_RIGHTS_INITIALIZER(CAP_FSYNC);
69 const cap_rights_t cap_ftruncate_rights = CAP_RIGHTS_INITIALIZER(CAP_FTRUNCATE);
70 const cap_rights_t cap_futimes_rights = CAP_RIGHTS_INITIALIZER(CAP_FUTIMES);
71 const cap_rights_t cap_getpeername_rights =
72     CAP_RIGHTS_INITIALIZER(CAP_GETPEERNAME);
73 const cap_rights_t cap_getsockopt_rights =
74     CAP_RIGHTS_INITIALIZER(CAP_GETSOCKOPT);
75 const cap_rights_t cap_getsockname_rights =
76     CAP_RIGHTS_INITIALIZER(CAP_GETSOCKNAME);
77 const cap_rights_t cap_inotify_add_rights =
78     CAP_RIGHTS_INITIALIZER(CAP_INOTIFY_ADD);
79 const cap_rights_t cap_inotify_rm_rights =
80     CAP_RIGHTS_INITIALIZER(CAP_INOTIFY_RM);
81 const cap_rights_t cap_ioctl_rights = CAP_RIGHTS_INITIALIZER(CAP_IOCTL);
82 const cap_rights_t cap_listen_rights = CAP_RIGHTS_INITIALIZER(CAP_LISTEN);
83 const cap_rights_t cap_linkat_source_rights =
84     CAP_RIGHTS_INITIALIZER(CAP_LINKAT_SOURCE);
85 const cap_rights_t cap_linkat_target_rights =
86     CAP_RIGHTS_INITIALIZER(CAP_LINKAT_TARGET);
87 const cap_rights_t cap_mmap_rights = CAP_RIGHTS_INITIALIZER(CAP_MMAP);
88 const cap_rights_t cap_mkdirat_rights = CAP_RIGHTS_INITIALIZER(CAP_MKDIRAT);
89 const cap_rights_t cap_mkfifoat_rights = CAP_RIGHTS_INITIALIZER(CAP_MKFIFOAT);
90 const cap_rights_t cap_mknodat_rights = CAP_RIGHTS_INITIALIZER(CAP_MKNODAT);
91 const cap_rights_t cap_pdgetpid_rights = CAP_RIGHTS_INITIALIZER(CAP_PDGETPID);
92 const cap_rights_t cap_pdkill_rights = CAP_RIGHTS_INITIALIZER(CAP_PDKILL);
93 const cap_rights_t cap_pdwait_rights = CAP_RIGHTS_INITIALIZER(CAP_PDWAIT);
94 const cap_rights_t cap_pread_rights = CAP_RIGHTS_INITIALIZER(CAP_PREAD);
95 const cap_rights_t cap_pwrite_rights = CAP_RIGHTS_INITIALIZER(CAP_PWRITE);
96 const cap_rights_t cap_read_rights = CAP_RIGHTS_INITIALIZER(CAP_READ);
97 const cap_rights_t cap_recv_rights = CAP_RIGHTS_INITIALIZER(CAP_RECV);
98 const cap_rights_t cap_renameat_source_rights =
99     CAP_RIGHTS_INITIALIZER(CAP_RENAMEAT_SOURCE);
100 const cap_rights_t cap_renameat_target_rights =
101     CAP_RIGHTS_INITIALIZER(CAP_RENAMEAT_TARGET);
102 const cap_rights_t cap_seek_rights = CAP_RIGHTS_INITIALIZER(CAP_SEEK);
103 const cap_rights_t cap_send_rights = CAP_RIGHTS_INITIALIZER(CAP_SEND);
104 const cap_rights_t cap_send_connect_rights =
105     CAP_RIGHTS_INITIALIZER2(CAP_SEND, CAP_CONNECT);
106 const cap_rights_t cap_setsockopt_rights =
107     CAP_RIGHTS_INITIALIZER(CAP_SETSOCKOPT);
108 const cap_rights_t cap_shutdown_rights = CAP_RIGHTS_INITIALIZER(CAP_SHUTDOWN);
109 const cap_rights_t cap_symlinkat_rights = CAP_RIGHTS_INITIALIZER(CAP_SYMLINKAT);
110 const cap_rights_t cap_unlinkat_rights = CAP_RIGHTS_INITIALIZER(CAP_UNLINKAT);
111 const cap_rights_t cap_write_rights = CAP_RIGHTS_INITIALIZER(CAP_WRITE);
112 const cap_rights_t cap_no_rights = CAP_RIGHTS_INITIALIZER(0ULL);
113 #endif
114 
115 #define	CAPARSIZE_MIN	(CAP_RIGHTS_VERSION_00 + 2)
116 #define	CAPARSIZE_MAX	(CAP_RIGHTS_VERSION + 2)
117 
118 static __inline int
119 right_to_index(uint64_t right)
120 {
121 	static const int bit2idx[] = {
122 		-1, 0, 1, -1, 2, -1, -1, -1, 3, -1, -1, -1, -1, -1, -1, -1,
123 		4, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
124 	};
125 	int idx;
126 
127 	idx = CAPIDXBIT(right);
128 	assert(idx >= 0 && idx < sizeof(bit2idx) / sizeof(bit2idx[0]));
129 	return (bit2idx[idx]);
130 }
131 
132 static void
133 cap_rights_vset(cap_rights_t *rights, va_list ap)
134 {
135 	uint64_t right;
136 	int i, n __unused;
137 
138 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
139 
140 	n = CAPARSIZE(rights);
141 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
142 
143 	for (;;) {
144 		right = (uint64_t)va_arg(ap, unsigned long long);
145 		if (right == 0)
146 			break;
147 		assert(CAPRVER(right) == 0);
148 		i = right_to_index(right);
149 		assert(i >= 0);
150 		assert(i < n);
151 		assert(CAPIDXBIT(rights->cr_rights[i]) == CAPIDXBIT(right));
152 		rights->cr_rights[i] |= right;
153 		assert(CAPIDXBIT(rights->cr_rights[i]) == CAPIDXBIT(right));
154 	}
155 }
156 
157 static void
158 cap_rights_vclear(cap_rights_t *rights, va_list ap)
159 {
160 	uint64_t right;
161 	int i, n __unused;
162 
163 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
164 
165 	n = CAPARSIZE(rights);
166 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
167 
168 	for (;;) {
169 		right = (uint64_t)va_arg(ap, unsigned long long);
170 		if (right == 0)
171 			break;
172 		assert(CAPRVER(right) == 0);
173 		i = right_to_index(right);
174 		assert(i >= 0);
175 		assert(i < n);
176 		assert(CAPIDXBIT(rights->cr_rights[i]) == CAPIDXBIT(right));
177 		rights->cr_rights[i] &= ~(right & 0x01FFFFFFFFFFFFFFULL);
178 		assert(CAPIDXBIT(rights->cr_rights[i]) == CAPIDXBIT(right));
179 	}
180 }
181 
182 static bool
183 cap_rights_is_vset(const cap_rights_t *rights, va_list ap)
184 {
185 	uint64_t right;
186 	int i, n __unused;
187 
188 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
189 
190 	n = CAPARSIZE(rights);
191 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
192 
193 	for (;;) {
194 		right = (uint64_t)va_arg(ap, unsigned long long);
195 		if (right == 0)
196 			break;
197 		assert(CAPRVER(right) == 0);
198 		i = right_to_index(right);
199 		assert(i >= 0);
200 		assert(i < n);
201 		assert(CAPIDXBIT(rights->cr_rights[i]) == CAPIDXBIT(right));
202 		if ((rights->cr_rights[i] & right) != right)
203 			return (false);
204 	}
205 
206 	return (true);
207 }
208 
209 cap_rights_t *
210 __cap_rights_init(int version, cap_rights_t *rights, ...)
211 {
212 	unsigned int n __unused;
213 	va_list ap;
214 
215 	assert(version == CAP_RIGHTS_VERSION_00);
216 
217 	n = version + 2;
218 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
219 	CAP_NONE(rights);
220 	va_start(ap, rights);
221 	cap_rights_vset(rights, ap);
222 	va_end(ap);
223 
224 	return (rights);
225 }
226 
227 cap_rights_t *
228 __cap_rights_set(cap_rights_t *rights, ...)
229 {
230 	va_list ap;
231 
232 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
233 
234 	va_start(ap, rights);
235 	cap_rights_vset(rights, ap);
236 	va_end(ap);
237 
238 	return (rights);
239 }
240 
241 cap_rights_t *
242 __cap_rights_clear(cap_rights_t *rights, ...)
243 {
244 	va_list ap;
245 
246 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
247 
248 	va_start(ap, rights);
249 	cap_rights_vclear(rights, ap);
250 	va_end(ap);
251 
252 	return (rights);
253 }
254 
255 bool
256 __cap_rights_is_set(const cap_rights_t *rights, ...)
257 {
258 	va_list ap;
259 	bool ret;
260 
261 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
262 
263 	va_start(ap, rights);
264 	ret = cap_rights_is_vset(rights, ap);
265 	va_end(ap);
266 
267 	return (ret);
268 }
269 
270 bool
271 cap_rights_is_empty(const cap_rights_t *rights)
272 {
273 #ifndef _KERNEL
274 	cap_rights_t cap_no_rights;
275 	cap_rights_init(&cap_no_rights);
276 #endif
277 
278 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
279 	assert(CAPVER(&cap_no_rights) == CAP_RIGHTS_VERSION_00);
280 
281 	for (int i = 0; i < CAPARSIZE(rights); i++) {
282 		if (rights->cr_rights[i] != cap_no_rights.cr_rights[i])
283 			return (false);
284 	}
285 
286 	return (true);
287 }
288 
289 bool
290 cap_rights_is_valid(const cap_rights_t *rights)
291 {
292 	cap_rights_t allrights;
293 	int i, j;
294 
295 	if (CAPVER(rights) != CAP_RIGHTS_VERSION_00)
296 		return (false);
297 	if (CAPARSIZE(rights) < CAPARSIZE_MIN ||
298 	    CAPARSIZE(rights) > CAPARSIZE_MAX) {
299 		return (false);
300 	}
301 	CAP_ALL(&allrights);
302 	if (!cap_rights_contains(&allrights, rights))
303 		return (false);
304 	for (i = 0; i < CAPARSIZE(rights); i++) {
305 		j = right_to_index(rights->cr_rights[i]);
306 		if (i != j)
307 			return (false);
308 		if (i > 0) {
309 			if (CAPRVER(rights->cr_rights[i]) != 0)
310 				return (false);
311 		}
312 	}
313 
314 	return (true);
315 }
316 
317 cap_rights_t *
318 cap_rights_merge(cap_rights_t *dst, const cap_rights_t *src)
319 {
320 	unsigned int i, n;
321 
322 	assert(CAPVER(dst) == CAP_RIGHTS_VERSION_00);
323 	assert(CAPVER(src) == CAP_RIGHTS_VERSION_00);
324 	assert(CAPVER(dst) == CAPVER(src));
325 	assert(cap_rights_is_valid(src));
326 	assert(cap_rights_is_valid(dst));
327 
328 	n = CAPARSIZE(dst);
329 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
330 
331 	for (i = 0; i < n; i++)
332 		dst->cr_rights[i] |= src->cr_rights[i];
333 
334 	assert(cap_rights_is_valid(src));
335 	assert(cap_rights_is_valid(dst));
336 
337 	return (dst);
338 }
339 
340 cap_rights_t *
341 cap_rights_remove(cap_rights_t *dst, const cap_rights_t *src)
342 {
343 	unsigned int i, n;
344 
345 	assert(CAPVER(dst) == CAP_RIGHTS_VERSION_00);
346 	assert(CAPVER(src) == CAP_RIGHTS_VERSION_00);
347 	assert(CAPVER(dst) == CAPVER(src));
348 	assert(cap_rights_is_valid(src));
349 	assert(cap_rights_is_valid(dst));
350 
351 	n = CAPARSIZE(dst);
352 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
353 
354 	for (i = 0; i < n; i++) {
355 		dst->cr_rights[i] &=
356 		    ~(src->cr_rights[i] & 0x01FFFFFFFFFFFFFFULL);
357 	}
358 
359 	assert(cap_rights_is_valid(src));
360 	assert(cap_rights_is_valid(dst));
361 
362 	return (dst);
363 }
364 
365 #ifndef _KERNEL
366 bool
367 cap_rights_contains(const cap_rights_t *big, const cap_rights_t *little)
368 {
369 	unsigned int i, n;
370 
371 	assert(CAPVER(big) == CAP_RIGHTS_VERSION_00);
372 	assert(CAPVER(little) == CAP_RIGHTS_VERSION_00);
373 	assert(CAPVER(big) == CAPVER(little));
374 
375 	n = CAPARSIZE(big);
376 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
377 
378 	for (i = 0; i < n; i++) {
379 		if ((big->cr_rights[i] & little->cr_rights[i]) !=
380 		    little->cr_rights[i]) {
381 			return (false);
382 		}
383 	}
384 
385 	return (true);
386 }
387 #endif
388