1/*-
2 * Copyright (c) 2016 Mariusz Zaborski <oshogbo@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#ifndef _CAPSICUM_HELPERS_H_
28#define	_CAPSICUM_HELPERS_H_
29
30#include <sys/param.h>
31#include <sys/capsicum.h>
32#include <sys/ioctl.h>
33
34#include <errno.h>
35#include <nl_types.h>
36#include <termios.h>
37#include <time.h>
38#include <unistd.h>
39
40#include <libcasper.h>
41
42#define	CAPH_IGNORE_EBADF	0x0001
43#define	CAPH_READ		0x0002
44#define	CAPH_WRITE		0x0004
45#define	CAPH_LOOKUP		0x0008
46
47__BEGIN_DECLS
48
49static const unsigned long caph_stream_cmds[] =
50    {
51#ifdef TIOCGETA
52	TIOCGETA,
53#endif
54#ifdef TIOCGWINSZ
55	TIOCGWINSZ,
56#endif
57#ifdef FIODTYPE
58	FIODTYPE,
59#endif
60    };
61static const uint32_t caph_stream_fcntls = CAP_FCNTL_GETFL;
62
63static __inline void
64caph_stream_rights(cap_rights_t *rights, int flags)
65{
66
67	cap_rights_init(rights, CAP_EVENT, CAP_FCNTL, CAP_FSTAT,
68	    CAP_IOCTL, CAP_SEEK);
69
70	if ((flags & CAPH_READ) != 0)
71		cap_rights_set(rights, CAP_READ);
72	if ((flags & CAPH_WRITE) != 0)
73		cap_rights_set(rights, CAP_WRITE);
74	if ((flags & CAPH_LOOKUP) != 0)
75		cap_rights_set(rights, CAP_LOOKUP);
76}
77
78static __inline int
79caph_limit_stream(int fd, int flags)
80{
81	cap_rights_t rights;
82
83	caph_stream_rights(&rights, flags);
84	if (cap_rights_limit(fd, &rights) < 0 && errno != ENOSYS) {
85		if (errno == EBADF && (flags & CAPH_IGNORE_EBADF) != 0)
86			return (0);
87		return (-1);
88	}
89
90	if (cap_ioctls_limit(fd, caph_stream_cmds,
91	    nitems(caph_stream_cmds)) < 0 && errno != ENOSYS)
92		return (-1);
93
94	if (cap_fcntls_limit(fd, caph_stream_fcntls) < 0 && errno != ENOSYS)
95		return (-1);
96
97	return (0);
98}
99
100static __inline int
101caph_limit_stdin(void)
102{
103
104	return (caph_limit_stream(STDIN_FILENO, CAPH_READ));
105}
106
107static __inline int
108caph_limit_stderr(void)
109{
110
111	return (caph_limit_stream(STDERR_FILENO, CAPH_WRITE));
112}
113
114static __inline int
115caph_limit_stdout(void)
116{
117
118	return (caph_limit_stream(STDOUT_FILENO, CAPH_WRITE));
119}
120
121static __inline int
122caph_limit_stdio(void)
123{
124	const int iebadf = CAPH_IGNORE_EBADF;
125
126	if (caph_limit_stream(STDIN_FILENO, CAPH_READ | iebadf) == -1 ||
127	    caph_limit_stream(STDOUT_FILENO, CAPH_WRITE | iebadf) == -1 ||
128	    caph_limit_stream(STDERR_FILENO, CAPH_WRITE | iebadf) == -1)
129		return (-1);
130	return (0);
131}
132
133static __inline void
134caph_cache_tzdata(void)
135{
136	time_t delta;
137
138	tzset();
139
140	/*
141	 * The tzset() function does not cache all time zones.
142	 * Some functions, such as gmtime(), require a GMT time zone.
143	 * The only way to cache them is to call the function directly.
144	 */
145	delta = 0;
146	(void)gmtime(&delta);
147}
148
149static __inline void
150caph_cache_catpages(void)
151{
152
153	(void)catopen("libc", NL_CAT_LOCALE);
154}
155
156static __inline int
157caph_enter(void)
158{
159
160	if (cap_enter() < 0 && errno != ENOSYS)
161		return (-1);
162
163	return (0);
164}
165
166static __inline int
167caph_rights_limit(int fd, const cap_rights_t *rights)
168{
169
170	if (cap_rights_limit(fd, rights) < 0 && errno != ENOSYS)
171		return (-1);
172
173	return (0);
174}
175
176static __inline int
177caph_ioctls_limit(int fd, const unsigned long *cmds, size_t ncmds)
178{
179
180	if (cap_ioctls_limit(fd, cmds, ncmds) < 0 && errno != ENOSYS)
181		return (-1);
182
183	return (0);
184}
185
186static __inline int
187caph_fcntls_limit(int fd, uint32_t fcntlrights)
188{
189
190	if (cap_fcntls_limit(fd, fcntlrights) < 0 && errno != ENOSYS)
191		return (-1);
192
193	return (0);
194}
195
196static __inline int
197caph_enter_casper(void)
198{
199
200	return (CASPER_SUPPORT == 0 ? 0 : caph_enter());
201}
202
203__END_DECLS
204
205#endif /* _CAPSICUM_HELPERS_H_ */
206