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634b43e1 CB |
1 | /* liblxcapi |
2 | * | |
3 | * Copyright © 2021 Christian Brauner <christian.brauner@ubuntu.com>. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License version 2, as | |
7 | * published by the Free Software Foundation. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License along | |
15 | * with this program; if not, write to the Free Software Foundation, Inc., | |
16 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
17 | */ | |
18 | ||
19 | #include "config.h" | |
20 | ||
21 | #include <errno.h> | |
22 | #include <fcntl.h> | |
23 | #include <inttypes.h> | |
24 | #include <signal.h> | |
25 | #include <stdio.h> | |
26 | #include <stdlib.h> | |
27 | #include <string.h> | |
28 | #include <unistd.h> | |
29 | #include <sys/stat.h> | |
30 | #include <sys/types.h> | |
31 | #include <sys/wait.h> | |
32 | ||
33 | #include "lxccontainer.h" | |
34 | #include "attach_options.h" | |
35 | ||
36 | #include "caps.h" | |
37 | #include "lxctest.h" | |
38 | #include "utils.h" | |
39 | ||
40 | #if HAVE_LIBCAP | |
8a0de7e7 CB |
41 | __u32 *cap_bset_bits = NULL; |
42 | __u32 last_cap = 0; | |
43 | ||
634b43e1 CB |
44 | static int capabilities_allow(void *payload) |
45 | { | |
7418b27f | 46 | for (__u32 cap = 0; cap <= last_cap; cap++) { |
634b43e1 CB |
47 | bool bret; |
48 | ||
8a0de7e7 CB |
49 | if (!is_set(cap, cap_bset_bits)) |
50 | continue; | |
51 | ||
634b43e1 CB |
52 | if (cap == CAP_MKNOD) |
53 | bret = cap_get_bound(cap) == CAP_SET; | |
54 | else | |
55 | bret = cap_get_bound(cap) != CAP_SET; | |
56 | if (!bret) { | |
57 | lxc_error("Capability %d unexpectedly raised or lowered\n", cap); | |
58 | return EXIT_FAILURE; | |
59 | } | |
60 | } | |
61 | ||
62 | return EXIT_SUCCESS; | |
63 | } | |
64 | ||
09f2a3ef CB |
65 | static int capabilities_deny(void *payload) |
66 | { | |
09f2a3ef CB |
67 | for (__u32 cap = 0; cap <= last_cap; cap++) { |
68 | bool bret; | |
69 | ||
8a0de7e7 CB |
70 | if (!is_set(cap, cap_bset_bits)) |
71 | continue; | |
72 | ||
09f2a3ef CB |
73 | if (cap == CAP_MKNOD) |
74 | bret = cap_get_bound(cap) != CAP_SET; | |
75 | else | |
76 | bret = cap_get_bound(cap) == CAP_SET; | |
77 | if (!bret) { | |
78 | lxc_error("Capability %d unexpectedly raised or lowered\n", cap); | |
79 | return EXIT_FAILURE; | |
80 | } | |
81 | } | |
82 | ||
83 | return EXIT_SUCCESS; | |
84 | } | |
85 | ||
86 | static int run(int (*test)(void *), bool allow) | |
634b43e1 | 87 | { |
b8eb6ca7 | 88 | int fd_log = -EBADF, fret = -1; |
634b43e1 CB |
89 | lxc_attach_options_t attach_options = LXC_ATTACH_OPTIONS_DEFAULT; |
90 | int ret; | |
91 | pid_t pid; | |
92 | struct lxc_container *c; | |
93 | struct lxc_log log; | |
09f2a3ef | 94 | char template[sizeof(P_tmpdir"/capabilities_XXXXXX")]; |
634b43e1 | 95 | |
09f2a3ef | 96 | (void)strlcpy(template, P_tmpdir"/capabilities_XXXXXX", sizeof(template)); |
634b43e1 CB |
97 | |
98 | fd_log = lxc_make_tmpfile(template, false); | |
99 | if (fd_log < 0) { | |
09f2a3ef CB |
100 | lxc_error("%s", "Failed to create temporary log file for container \"capabilities\""); |
101 | return fret; | |
634b43e1 CB |
102 | } |
103 | ||
09f2a3ef | 104 | log.name = "capabilities"; |
634b43e1 CB |
105 | log.file = template; |
106 | log.level = "TRACE"; | |
107 | log.prefix = "capabilities"; | |
108 | log.quiet = false; | |
109 | log.lxcpath = NULL; | |
110 | ||
111 | if (lxc_log_init(&log)) | |
09f2a3ef | 112 | return fret; |
634b43e1 | 113 | |
09f2a3ef | 114 | c = lxc_container_new("capabilities", NULL); |
634b43e1 | 115 | if (!c) { |
09f2a3ef CB |
116 | lxc_error("%s\n", "Failed to create container \"capabilities\""); |
117 | return fret; | |
634b43e1 CB |
118 | } |
119 | ||
120 | if (c->is_defined(c)) { | |
09f2a3ef | 121 | lxc_error("%s\n", "Container \"capabilities\" is defined"); |
634b43e1 CB |
122 | goto on_error_put; |
123 | } | |
124 | ||
125 | if (!c->createl(c, "busybox", NULL, NULL, 0, NULL)) { | |
09f2a3ef | 126 | lxc_error("%s\n", "Failed to create busybox container \"capabilities\""); |
634b43e1 CB |
127 | goto on_error_put; |
128 | } | |
129 | ||
130 | if (!c->is_defined(c)) { | |
09f2a3ef | 131 | lxc_error("%s\n", "Container \"capabilities\" is not defined"); |
634b43e1 CB |
132 | goto on_error_destroy; |
133 | } | |
134 | ||
135 | if (!c->clear_config_item(c, "lxc.cap.drop")) { | |
136 | lxc_error("%s\n", "Failed to clear config item \"lxc.cap.drop\""); | |
137 | goto on_error_destroy; | |
138 | } | |
139 | ||
140 | if (!c->clear_config_item(c, "lxc.cap.keep")) { | |
141 | lxc_error("%s\n", "Failed to clear config item \"lxc.cap.drop\""); | |
142 | goto on_error_destroy; | |
143 | } | |
144 | ||
09f2a3ef CB |
145 | if (allow) { |
146 | if (!c->set_config_item(c, "lxc.cap.keep", "mknod")) { | |
147 | lxc_error("%s\n", "Failed to set config item \"lxc.cap.keep=mknod\""); | |
148 | goto on_error_destroy; | |
149 | } | |
150 | } else { | |
151 | if (!c->set_config_item(c, "lxc.cap.drop", "mknod")) { | |
152 | lxc_error("%s\n", "Failed to set config item \"lxc.cap.drop=mknod\""); | |
153 | goto on_error_destroy; | |
154 | } | |
634b43e1 CB |
155 | } |
156 | ||
157 | if (!c->want_daemonize(c, true)) { | |
09f2a3ef | 158 | lxc_error("%s\n", "Failed to mark container \"capabilities\" daemonized"); |
634b43e1 CB |
159 | goto on_error_destroy; |
160 | } | |
161 | ||
162 | if (!c->startl(c, 0, NULL)) { | |
09f2a3ef | 163 | lxc_error("%s\n", "Failed to start container \"capabilities\" daemonized"); |
634b43e1 CB |
164 | goto on_error_destroy; |
165 | } | |
166 | ||
09f2a3ef | 167 | ret = c->attach(c, test, NULL, &attach_options, &pid); |
634b43e1 | 168 | if (ret < 0) { |
09f2a3ef | 169 | lxc_error("%s\n", "Failed to run function in container \"capabilities\""); |
634b43e1 CB |
170 | goto on_error_stop; |
171 | } | |
172 | ||
173 | ret = wait_for_pid(pid); | |
174 | if (ret) { | |
09f2a3ef | 175 | lxc_error("%s\n", "Function \"capabilities\" failed"); |
634b43e1 CB |
176 | goto on_error_stop; |
177 | } | |
178 | ||
179 | fret = 0; | |
180 | ||
181 | on_error_stop: | |
182 | if (c->is_running(c) && !c->stop(c)) | |
09f2a3ef | 183 | lxc_error("%s\n", "Failed to stop container \"capabilities\""); |
634b43e1 CB |
184 | |
185 | on_error_destroy: | |
186 | if (!c->destroy(c)) | |
09f2a3ef | 187 | lxc_error("%s\n", "Failed to destroy container \"capabilities\""); |
634b43e1 CB |
188 | |
189 | on_error_put: | |
190 | lxc_container_put(c); | |
191 | ||
192 | if (fret == EXIT_SUCCESS) { | |
09f2a3ef | 193 | lxc_debug("All capability %s tests passed\n", allow ? "allow" : "deny"); |
634b43e1 CB |
194 | } else { |
195 | int fd; | |
196 | ||
197 | fd = open(template, O_RDONLY); | |
198 | if (fd >= 0) { | |
199 | char buf[4096]; | |
200 | ssize_t buflen; | |
201 | while ((buflen = read(fd, buf, 1024)) > 0) { | |
202 | buflen = write(STDERR_FILENO, buf, buflen); | |
203 | if (buflen <= 0) | |
204 | break; | |
205 | } | |
206 | close(fd); | |
207 | } | |
208 | } | |
209 | (void)unlink(template); | |
210 | ||
09f2a3ef CB |
211 | return fret; |
212 | } | |
213 | ||
8a0de7e7 CB |
214 | static void __attribute__((constructor)) capabilities_init(void) |
215 | { | |
216 | int ret; | |
217 | __u32 nr_u32; | |
218 | ||
219 | ret = lxc_caps_last_cap(&last_cap); | |
220 | if (ret || last_cap > 200) | |
221 | _exit(EXIT_FAILURE); | |
222 | ||
223 | nr_u32 = BITS_TO_LONGS(last_cap); | |
224 | cap_bset_bits = zalloc(nr_u32 * sizeof(__u32)); | |
225 | if (!cap_bset_bits) | |
226 | _exit(EXIT_FAILURE); | |
227 | ||
228 | for (__u32 cap_bit = 0; cap_bit <= last_cap; cap_bit++) { | |
229 | if (prctl(PR_CAPBSET_READ, prctl_arg(cap_bit)) == 0) | |
230 | continue; | |
231 | ||
232 | set_bit(cap_bit, cap_bset_bits); | |
233 | } | |
234 | } | |
235 | ||
236 | static void __attribute__((destructor)) capabilities_exit(void) | |
237 | { | |
238 | free(cap_bset_bits); | |
239 | } | |
240 | ||
09f2a3ef CB |
241 | int main(int argc, char *argv[]) |
242 | { | |
243 | if (run(capabilities_allow, true)) | |
244 | exit(EXIT_FAILURE); | |
245 | ||
246 | if (run(capabilities_deny, false)) | |
247 | exit(EXIT_FAILURE); | |
248 | ||
249 | exit(EXIT_SUCCESS); | |
634b43e1 CB |
250 | } |
251 | ||
252 | #else /* !HAVE_LIBCAP */ | |
253 | ||
254 | int main(int argc, char *argv[]) | |
255 | { | |
256 | lxc_debug("%s\n", "Capabilities not supported. Skipping."); | |
257 | exit(EXIT_SUCCESS); | |
258 | } | |
259 | #endif |