xref: /freebsd/sys/kern/subr_capability.c (revision e453e498cbb88570a3ff7b3679de65c88707da95)
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_ioctl_rights = CAP_RIGHTS_INITIALIZER(CAP_IOCTL);
78 const cap_rights_t cap_listen_rights = CAP_RIGHTS_INITIALIZER(CAP_LISTEN);
79 const cap_rights_t cap_linkat_source_rights =
80     CAP_RIGHTS_INITIALIZER(CAP_LINKAT_SOURCE);
81 const cap_rights_t cap_linkat_target_rights =
82     CAP_RIGHTS_INITIALIZER(CAP_LINKAT_TARGET);
83 const cap_rights_t cap_mmap_rights = CAP_RIGHTS_INITIALIZER(CAP_MMAP);
84 const cap_rights_t cap_mkdirat_rights = CAP_RIGHTS_INITIALIZER(CAP_MKDIRAT);
85 const cap_rights_t cap_mkfifoat_rights = CAP_RIGHTS_INITIALIZER(CAP_MKFIFOAT);
86 const cap_rights_t cap_mknodat_rights = CAP_RIGHTS_INITIALIZER(CAP_MKNODAT);
87 const cap_rights_t cap_pdgetpid_rights = CAP_RIGHTS_INITIALIZER(CAP_PDGETPID);
88 const cap_rights_t cap_pdkill_rights = CAP_RIGHTS_INITIALIZER(CAP_PDKILL);
89 const cap_rights_t cap_pread_rights = CAP_RIGHTS_INITIALIZER(CAP_PREAD);
90 const cap_rights_t cap_pwrite_rights = CAP_RIGHTS_INITIALIZER(CAP_PWRITE);
91 const cap_rights_t cap_read_rights = CAP_RIGHTS_INITIALIZER(CAP_READ);
92 const cap_rights_t cap_recv_rights = CAP_RIGHTS_INITIALIZER(CAP_RECV);
93 const cap_rights_t cap_renameat_source_rights =
94     CAP_RIGHTS_INITIALIZER(CAP_RENAMEAT_SOURCE);
95 const cap_rights_t cap_renameat_target_rights =
96     CAP_RIGHTS_INITIALIZER(CAP_RENAMEAT_TARGET);
97 const cap_rights_t cap_seek_rights = CAP_RIGHTS_INITIALIZER(CAP_SEEK);
98 const cap_rights_t cap_send_rights = CAP_RIGHTS_INITIALIZER(CAP_SEND);
99 const cap_rights_t cap_send_connect_rights =
100     CAP_RIGHTS_INITIALIZER2(CAP_SEND, CAP_CONNECT);
101 const cap_rights_t cap_setsockopt_rights =
102     CAP_RIGHTS_INITIALIZER(CAP_SETSOCKOPT);
103 const cap_rights_t cap_shutdown_rights = CAP_RIGHTS_INITIALIZER(CAP_SHUTDOWN);
104 const cap_rights_t cap_symlinkat_rights = CAP_RIGHTS_INITIALIZER(CAP_SYMLINKAT);
105 const cap_rights_t cap_unlinkat_rights = CAP_RIGHTS_INITIALIZER(CAP_UNLINKAT);
106 const cap_rights_t cap_write_rights = CAP_RIGHTS_INITIALIZER(CAP_WRITE);
107 const cap_rights_t cap_no_rights = CAP_RIGHTS_INITIALIZER(0ULL);
108 #endif
109 
110 #define	CAPARSIZE_MIN	(CAP_RIGHTS_VERSION_00 + 2)
111 #define	CAPARSIZE_MAX	(CAP_RIGHTS_VERSION + 2)
112 
113 static __inline int
right_to_index(uint64_t right)114 right_to_index(uint64_t right)
115 {
116 	static const int bit2idx[] = {
117 		-1, 0, 1, -1, 2, -1, -1, -1, 3, -1, -1, -1, -1, -1, -1, -1,
118 		4, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
119 	};
120 	int idx;
121 
122 	idx = CAPIDXBIT(right);
123 	assert(idx >= 0 && idx < sizeof(bit2idx) / sizeof(bit2idx[0]));
124 	return (bit2idx[idx]);
125 }
126 
127 static void
cap_rights_vset(cap_rights_t * rights,va_list ap)128 cap_rights_vset(cap_rights_t *rights, va_list ap)
129 {
130 	uint64_t right;
131 	int i, n __unused;
132 
133 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
134 
135 	n = CAPARSIZE(rights);
136 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
137 
138 	for (;;) {
139 		right = (uint64_t)va_arg(ap, unsigned long long);
140 		if (right == 0)
141 			break;
142 		assert(CAPRVER(right) == 0);
143 		i = right_to_index(right);
144 		assert(i >= 0);
145 		assert(i < n);
146 		assert(CAPIDXBIT(rights->cr_rights[i]) == CAPIDXBIT(right));
147 		rights->cr_rights[i] |= right;
148 		assert(CAPIDXBIT(rights->cr_rights[i]) == CAPIDXBIT(right));
149 	}
150 }
151 
152 static void
cap_rights_vclear(cap_rights_t * rights,va_list ap)153 cap_rights_vclear(cap_rights_t *rights, va_list ap)
154 {
155 	uint64_t right;
156 	int i, n __unused;
157 
158 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
159 
160 	n = CAPARSIZE(rights);
161 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
162 
163 	for (;;) {
164 		right = (uint64_t)va_arg(ap, unsigned long long);
165 		if (right == 0)
166 			break;
167 		assert(CAPRVER(right) == 0);
168 		i = right_to_index(right);
169 		assert(i >= 0);
170 		assert(i < n);
171 		assert(CAPIDXBIT(rights->cr_rights[i]) == CAPIDXBIT(right));
172 		rights->cr_rights[i] &= ~(right & 0x01FFFFFFFFFFFFFFULL);
173 		assert(CAPIDXBIT(rights->cr_rights[i]) == CAPIDXBIT(right));
174 	}
175 }
176 
177 static bool
cap_rights_is_vset(const cap_rights_t * rights,va_list ap)178 cap_rights_is_vset(const cap_rights_t *rights, va_list ap)
179 {
180 	uint64_t right;
181 	int i, n __unused;
182 
183 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
184 
185 	n = CAPARSIZE(rights);
186 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
187 
188 	for (;;) {
189 		right = (uint64_t)va_arg(ap, unsigned long long);
190 		if (right == 0)
191 			break;
192 		assert(CAPRVER(right) == 0);
193 		i = right_to_index(right);
194 		assert(i >= 0);
195 		assert(i < n);
196 		assert(CAPIDXBIT(rights->cr_rights[i]) == CAPIDXBIT(right));
197 		if ((rights->cr_rights[i] & right) != right)
198 			return (false);
199 	}
200 
201 	return (true);
202 }
203 
204 cap_rights_t *
__cap_rights_init(int version,cap_rights_t * rights,...)205 __cap_rights_init(int version, cap_rights_t *rights, ...)
206 {
207 	unsigned int n __unused;
208 	va_list ap;
209 
210 	assert(version == CAP_RIGHTS_VERSION_00);
211 
212 	n = version + 2;
213 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
214 	CAP_NONE(rights);
215 	va_start(ap, rights);
216 	cap_rights_vset(rights, ap);
217 	va_end(ap);
218 
219 	return (rights);
220 }
221 
222 cap_rights_t *
__cap_rights_set(cap_rights_t * rights,...)223 __cap_rights_set(cap_rights_t *rights, ...)
224 {
225 	va_list ap;
226 
227 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
228 
229 	va_start(ap, rights);
230 	cap_rights_vset(rights, ap);
231 	va_end(ap);
232 
233 	return (rights);
234 }
235 
236 cap_rights_t *
__cap_rights_clear(cap_rights_t * rights,...)237 __cap_rights_clear(cap_rights_t *rights, ...)
238 {
239 	va_list ap;
240 
241 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
242 
243 	va_start(ap, rights);
244 	cap_rights_vclear(rights, ap);
245 	va_end(ap);
246 
247 	return (rights);
248 }
249 
250 bool
__cap_rights_is_set(const cap_rights_t * rights,...)251 __cap_rights_is_set(const cap_rights_t *rights, ...)
252 {
253 	va_list ap;
254 	bool ret;
255 
256 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
257 
258 	va_start(ap, rights);
259 	ret = cap_rights_is_vset(rights, ap);
260 	va_end(ap);
261 
262 	return (ret);
263 }
264 
265 bool
cap_rights_is_empty(const cap_rights_t * rights)266 cap_rights_is_empty(const cap_rights_t *rights)
267 {
268 #ifndef _KERNEL
269 	cap_rights_t cap_no_rights;
270 	cap_rights_init(&cap_no_rights);
271 #endif
272 
273 	assert(CAPVER(rights) == CAP_RIGHTS_VERSION_00);
274 	assert(CAPVER(&cap_no_rights) == CAP_RIGHTS_VERSION_00);
275 
276 	for (int i = 0; i < CAPARSIZE(rights); i++) {
277 		if (rights->cr_rights[i] != cap_no_rights.cr_rights[i])
278 			return (false);
279 	}
280 
281 	return (true);
282 }
283 
284 bool
cap_rights_is_valid(const cap_rights_t * rights)285 cap_rights_is_valid(const cap_rights_t *rights)
286 {
287 	cap_rights_t allrights;
288 	int i, j;
289 
290 	if (CAPVER(rights) != CAP_RIGHTS_VERSION_00)
291 		return (false);
292 	if (CAPARSIZE(rights) < CAPARSIZE_MIN ||
293 	    CAPARSIZE(rights) > CAPARSIZE_MAX) {
294 		return (false);
295 	}
296 	CAP_ALL(&allrights);
297 	if (!cap_rights_contains(&allrights, rights))
298 		return (false);
299 	for (i = 0; i < CAPARSIZE(rights); i++) {
300 		j = right_to_index(rights->cr_rights[i]);
301 		if (i != j)
302 			return (false);
303 		if (i > 0) {
304 			if (CAPRVER(rights->cr_rights[i]) != 0)
305 				return (false);
306 		}
307 	}
308 
309 	return (true);
310 }
311 
312 cap_rights_t *
cap_rights_merge(cap_rights_t * dst,const cap_rights_t * src)313 cap_rights_merge(cap_rights_t *dst, const cap_rights_t *src)
314 {
315 	unsigned int i, n;
316 
317 	assert(CAPVER(dst) == CAP_RIGHTS_VERSION_00);
318 	assert(CAPVER(src) == CAP_RIGHTS_VERSION_00);
319 	assert(CAPVER(dst) == CAPVER(src));
320 	assert(cap_rights_is_valid(src));
321 	assert(cap_rights_is_valid(dst));
322 
323 	n = CAPARSIZE(dst);
324 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
325 
326 	for (i = 0; i < n; i++)
327 		dst->cr_rights[i] |= src->cr_rights[i];
328 
329 	assert(cap_rights_is_valid(src));
330 	assert(cap_rights_is_valid(dst));
331 
332 	return (dst);
333 }
334 
335 cap_rights_t *
cap_rights_remove(cap_rights_t * dst,const cap_rights_t * src)336 cap_rights_remove(cap_rights_t *dst, const cap_rights_t *src)
337 {
338 	unsigned int i, n;
339 
340 	assert(CAPVER(dst) == CAP_RIGHTS_VERSION_00);
341 	assert(CAPVER(src) == CAP_RIGHTS_VERSION_00);
342 	assert(CAPVER(dst) == CAPVER(src));
343 	assert(cap_rights_is_valid(src));
344 	assert(cap_rights_is_valid(dst));
345 
346 	n = CAPARSIZE(dst);
347 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
348 
349 	for (i = 0; i < n; i++) {
350 		dst->cr_rights[i] &=
351 		    ~(src->cr_rights[i] & 0x01FFFFFFFFFFFFFFULL);
352 	}
353 
354 	assert(cap_rights_is_valid(src));
355 	assert(cap_rights_is_valid(dst));
356 
357 	return (dst);
358 }
359 
360 #ifndef _KERNEL
361 bool
cap_rights_contains(const cap_rights_t * big,const cap_rights_t * little)362 cap_rights_contains(const cap_rights_t *big, const cap_rights_t *little)
363 {
364 	unsigned int i, n;
365 
366 	assert(CAPVER(big) == CAP_RIGHTS_VERSION_00);
367 	assert(CAPVER(little) == CAP_RIGHTS_VERSION_00);
368 	assert(CAPVER(big) == CAPVER(little));
369 
370 	n = CAPARSIZE(big);
371 	assert(n >= CAPARSIZE_MIN && n <= CAPARSIZE_MAX);
372 
373 	for (i = 0; i < n; i++) {
374 		if ((big->cr_rights[i] & little->cr_rights[i]) !=
375 		    little->cr_rights[i]) {
376 			return (false);
377 		}
378 	}
379 
380 	return (true);
381 }
382 #endif
383