xref: /freebsd/tests/sys/vfs/lookup_cap_dotdot.c (revision e6bfd18d21b225af6a0ed67ceeaf1293b7b9eba5)
1 /*-
2  * Copyright (c) 2016 Ed Maste <emaste@FreeBSD.org>
3  * Copyright (c) 2016 Conrad Meyer <cem@FreeBSD.org>
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 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/param.h>
31 #include <sys/capsicum.h>
32 #include <sys/sysctl.h>
33 #include <sys/stat.h>
34 
35 #include <atf-c.h>
36 #include <errno.h>
37 #include <stdlib.h>
38 #include <string.h>
39 
40 #include "freebsd_test_suite/macros.h"
41 
42 static int dirfd = -1;
43 static char *abspath;
44 
45 static void
46 touchat(int _dirfd, const char *name)
47 {
48 	int fd;
49 
50 	ATF_REQUIRE((fd = openat(_dirfd, name, O_CREAT | O_TRUNC | O_WRONLY,
51 	    0777)) >= 0);
52 	ATF_REQUIRE(close(fd) == 0);
53 }
54 
55 static void
56 prepare_dotdot_tests(void)
57 {
58 	char cwd[MAXPATHLEN];
59 
60 	ATF_REQUIRE(getcwd(cwd, sizeof(cwd)) != NULL);
61 	asprintf(&abspath, "%s/testdir/d1/f1", cwd);
62 
63 	ATF_REQUIRE(mkdir("testdir", 0777) == 0);
64 	ATF_REQUIRE((dirfd = open("testdir", O_RDONLY)) >= 0);
65 
66 	ATF_REQUIRE(mkdirat(dirfd, "d1", 0777) == 0);
67 	ATF_REQUIRE(mkdirat(dirfd, "d1/d2", 0777) == 0);
68 	ATF_REQUIRE(mkdirat(dirfd, "d1/d2/d3", 0777) == 0);
69 	touchat(dirfd, "d1/f1");
70 	touchat(dirfd, "d1/d2/f2");
71 	touchat(dirfd, "d1/d2/d3/f3");
72 	ATF_REQUIRE(symlinkat("d1/d2/d3", dirfd, "l3") == 0);
73 	ATF_REQUIRE(symlinkat("../testdir/d1", dirfd, "lup") == 0);
74 	ATF_REQUIRE(symlinkat("../..", dirfd, "d1/d2/d3/ld1") == 0);
75 	ATF_REQUIRE(symlinkat("../../f1", dirfd, "d1/d2/d3/lf1") == 0);
76 }
77 
78 static void
79 check_capsicum(void)
80 {
81 	ATF_REQUIRE_FEATURE("security_capabilities");
82 	ATF_REQUIRE_FEATURE("security_capability_mode");
83 	ATF_REQUIRE_SYSCTL_BOOL("kern.trap_enotcap", false);
84 }
85 
86 /*
87  * Positive tests
88  */
89 ATF_TC(openat__basic_positive);
90 ATF_TC_HEAD(openat__basic_positive, tc)
91 {
92 	atf_tc_set_md_var(tc, "descr", "Basic positive openat testcases");
93 }
94 
95 ATF_TC_BODY(openat__basic_positive, tc)
96 {
97 	prepare_dotdot_tests();
98 
99 	ATF_REQUIRE(openat(dirfd, "d1/d2/d3/f3", O_RDONLY) >= 0);
100 	ATF_REQUIRE(openat(dirfd, "d1/d2/d3/../../f1", O_RDONLY) >= 0);
101 	ATF_REQUIRE(openat(dirfd, "l3/f3", O_RDONLY) >= 0);
102 	ATF_REQUIRE(openat(dirfd, "l3/../../f1", O_RDONLY) >= 0);
103 	ATF_REQUIRE(openat(dirfd, "../testdir/d1/f1", O_RDONLY) >= 0);
104 	ATF_REQUIRE(openat(dirfd, "lup/f1", O_RDONLY) >= 0);
105 	ATF_REQUIRE(openat(dirfd, "l3/ld1", O_RDONLY) >= 0);
106 	ATF_REQUIRE(openat(dirfd, "l3/lf1", O_RDONLY) >= 0);
107 	ATF_REQUIRE(open(abspath, O_RDONLY) >= 0);
108 	ATF_REQUIRE(openat(dirfd, abspath, O_RDONLY) >= 0);
109 }
110 
111 ATF_TC(lookup_cap_dotdot__basic);
112 ATF_TC_HEAD(lookup_cap_dotdot__basic, tc)
113 {
114 	atf_tc_set_md_var(tc, "descr",
115 	    "Validate cap-mode (testdir)/d1/.. lookup");
116 }
117 
118 ATF_TC_BODY(lookup_cap_dotdot__basic, tc)
119 {
120 	cap_rights_t rights;
121 
122 	check_capsicum();
123 	prepare_dotdot_tests();
124 
125 	cap_rights_init(&rights, CAP_LOOKUP, CAP_READ);
126 	ATF_REQUIRE(cap_rights_limit(dirfd, &rights) >= 0);
127 
128 	ATF_REQUIRE(cap_enter() >= 0);
129 
130 	ATF_REQUIRE_MSG(openat(dirfd, "d1/..", O_RDONLY) >= 0, "%s",
131 	    strerror(errno));
132 }
133 
134 ATF_TC(lookup_cap_dotdot__advanced);
135 ATF_TC_HEAD(lookup_cap_dotdot__advanced, tc)
136 {
137 	atf_tc_set_md_var(tc, "descr",
138 	    "Validate cap-mode (testdir)/d1/.. lookup");
139 }
140 
141 ATF_TC_BODY(lookup_cap_dotdot__advanced, tc)
142 {
143 	cap_rights_t rights;
144 
145 	check_capsicum();
146 	prepare_dotdot_tests();
147 
148 	cap_rights_init(&rights, CAP_LOOKUP, CAP_READ);
149 	ATF_REQUIRE(cap_rights_limit(dirfd, &rights) >= 0);
150 
151 	ATF_REQUIRE(cap_enter() >= 0);
152 
153 	ATF_REQUIRE(openat(dirfd, "d1/d2/d3/../../f1", O_RDONLY) >= 0);
154 	ATF_REQUIRE(openat(dirfd, "l3/../../f1", O_RDONLY) >= 0);
155 	ATF_REQUIRE(openat(dirfd, "l3/ld1", O_RDONLY) >= 0);
156 	ATF_REQUIRE(openat(dirfd, "l3/lf1", O_RDONLY) >= 0);
157 }
158 
159 /*
160  * Negative tests
161  */
162 ATF_TC(openat__basic_negative);
163 ATF_TC_HEAD(openat__basic_negative, tc)
164 {
165 	atf_tc_set_md_var(tc, "descr", "Basic negative openat testcases");
166 }
167 
168 ATF_TC_BODY(openat__basic_negative, tc)
169 {
170 	prepare_dotdot_tests();
171 
172 	ATF_REQUIRE_ERRNO(ENOENT,
173 	    openat(dirfd, "does-not-exist", O_RDONLY) < 0);
174 	ATF_REQUIRE_ERRNO(ENOENT,
175 	    openat(dirfd, "l3/does-not-exist", O_RDONLY) < 0);
176 }
177 
178 ATF_TC(capmode__negative);
179 ATF_TC_HEAD(capmode__negative, tc)
180 {
181 	atf_tc_set_md_var(tc, "descr", "Negative Capability mode testcases");
182 }
183 
184 ATF_TC_BODY(capmode__negative, tc)
185 {
186 	int subdirfd;
187 
188 	check_capsicum();
189 	prepare_dotdot_tests();
190 
191 	ATF_REQUIRE(cap_enter() == 0);
192 
193 	/* open() not permitted in capability mode */
194 	ATF_REQUIRE_ERRNO(ECAPMODE, open("testdir", O_RDONLY) < 0);
195 
196 	/* AT_FDCWD not permitted in capability mode */
197 	ATF_REQUIRE_ERRNO(ECAPMODE, openat(AT_FDCWD, "d1/f1", O_RDONLY) < 0);
198 
199 	/* Relative path above dirfd not capable */
200 	ATF_REQUIRE_ERRNO(ENOTCAPABLE, openat(dirfd, "..", O_RDONLY) < 0);
201 	ATF_REQUIRE((subdirfd = openat(dirfd, "l3", O_RDONLY)) >= 0);
202 	ATF_REQUIRE_ERRNO(ENOTCAPABLE,
203 	    openat(subdirfd, "../../f1", O_RDONLY) < 0);
204 
205 	/* Absolute paths not capable */
206 	ATF_REQUIRE_ERRNO(ENOTCAPABLE, openat(dirfd, abspath, O_RDONLY) < 0);
207 
208 	/* Symlink above dirfd */
209 	ATF_REQUIRE_ERRNO(ENOTCAPABLE, openat(dirfd, "lup/f1", O_RDONLY) < 0);
210 }
211 
212 ATF_TC(lookup_cap_dotdot__negative);
213 ATF_TC_HEAD(lookup_cap_dotdot__negative, tc)
214 {
215 	atf_tc_set_md_var(tc, "descr",
216 	    "Validate cap-mode (testdir)/.. lookup fails");
217 }
218 
219 ATF_TC_BODY(lookup_cap_dotdot__negative, tc)
220 {
221 	cap_rights_t rights;
222 
223 	check_capsicum();
224 	prepare_dotdot_tests();
225 
226 	cap_rights_init(&rights, CAP_LOOKUP, CAP_READ);
227 	ATF_REQUIRE(cap_rights_limit(dirfd, &rights) >= 0);
228 
229 	ATF_REQUIRE(cap_enter() >= 0);
230 
231 	ATF_REQUIRE_ERRNO(ENOTCAPABLE, openat(dirfd, "..", O_RDONLY) < 0);
232 	ATF_REQUIRE_ERRNO(ENOTCAPABLE, openat(dirfd, "d1/../..", O_RDONLY) < 0);
233 	ATF_REQUIRE_ERRNO(ENOTCAPABLE, openat(dirfd, "../testdir/d1/f1", O_RDONLY) < 0);
234 }
235 
236 ATF_TC(lookup_cap_dotdot__root);
237 ATF_TC_HEAD(lookup_cap_dotdot__root, tc)
238 {
239 	atf_tc_set_md_var(tc, "descr", "Validate cap-mode /.. lookup fails");
240 }
241 
242 ATF_TC_BODY(lookup_cap_dotdot__root, tc)
243 {
244 	int dfd, dfd2;
245 
246 	check_capsicum();
247 
248 	dfd = open("/", O_DIRECTORY);
249 	ATF_REQUIRE(dfd >= 0);
250 
251 	dfd2 = openat(dfd, "..", O_DIRECTORY);
252 	ATF_REQUIRE(dfd2 >= 0);
253 	ATF_REQUIRE(close(dfd2) == 0);
254 
255 	ATF_REQUIRE(cap_enter() >= 0);
256 
257 	dfd2 = openat(dfd, "..", O_DIRECTORY);
258 	ATF_REQUIRE_ERRNO(ENOTCAPABLE, openat(dfd, "..", O_DIRECTORY));
259 }
260 
261 ATF_TP_ADD_TCS(tp)
262 {
263 
264 	ATF_TP_ADD_TC(tp, openat__basic_positive);
265 	ATF_TP_ADD_TC(tp, openat__basic_negative);
266 
267 	ATF_TP_ADD_TC(tp, capmode__negative);
268 
269 	ATF_TP_ADD_TC(tp, lookup_cap_dotdot__basic);
270 	ATF_TP_ADD_TC(tp, lookup_cap_dotdot__advanced);
271 	ATF_TP_ADD_TC(tp, lookup_cap_dotdot__negative);
272 	ATF_TP_ADD_TC(tp, lookup_cap_dotdot__root);
273 
274 	return (atf_no_error());
275 }
276