1 /* SPDX-License-Identifier: LGPL-2.1+ */
3 #include <netinet/in.h>
5 #include <sys/capability.h>
7 #include <sys/socket.h>
11 #include "alloc-util.h"
12 #include "capability-util.h"
16 #include "missing_prctl.h"
17 #include "parse-util.h"
21 static uid_t test_uid
= -1;
22 static gid_t test_gid
= -1;
24 #if HAS_FEATURE_ADDRESS_SANITIZER
25 /* Keep CAP_SYS_PTRACE when running under Address Sanitizer */
26 static const uint64_t test_flags
= UINT64_C(1) << CAP_SYS_PTRACE
;
28 /* We keep CAP_DAC_OVERRIDE to avoid errors with gcov when doing test coverage */
29 static const uint64_t test_flags
= UINT64_C(1) << CAP_DAC_OVERRIDE
;
32 /* verify cap_last_cap() against /proc/sys/kernel/cap_last_cap */
33 static void test_last_cap_file(void) {
34 _cleanup_free_
char *content
= NULL
;
35 unsigned long val
= 0;
38 r
= read_one_line_file("/proc/sys/kernel/cap_last_cap", &content
);
41 r
= safe_atolu(content
, &val
);
44 assert_se(val
== cap_last_cap());
47 /* verify cap_last_cap() against syscall probing */
48 static void test_last_cap_probe(void) {
49 unsigned long p
= (unsigned long)CAP_LAST_CAP
;
51 if (prctl(PR_CAPBSET_READ
, p
) < 0) {
52 for (p
--; p
> 0; p
--)
53 if (prctl(PR_CAPBSET_READ
, p
) >= 0)
57 if (prctl(PR_CAPBSET_READ
, p
+1) < 0)
62 assert_se(p
== cap_last_cap());
65 static void fork_test(void (*test_func
)(void)) {
76 assert_se(waitpid(pid
, &status
, 0) > 0);
77 assert_se(WIFEXITED(status
) && WEXITSTATUS(status
) == 0);
81 static void show_capabilities(void) {
85 caps
= cap_get_proc();
88 text
= cap_to_text(caps
, NULL
);
91 log_info("Capabilities:%s", text
);
96 static int setup_tests(bool *run_ambient
) {
97 struct passwd
*nobody
;
100 nobody
= getpwnam(NOBODY_USER_NAME
);
102 return log_error_errno(SYNTHETIC_ERRNO(ENOENT
), "Could not find nobody user: %m");
104 test_uid
= nobody
->pw_uid
;
105 test_gid
= nobody
->pw_gid
;
107 *run_ambient
= false;
109 r
= prctl(PR_CAP_AMBIENT
, PR_CAP_AMBIENT_CLEAR_ALL
, 0, 0, 0);
111 /* There's support for PR_CAP_AMBIENT if the prctl() call
112 * succeeded or error code was something else than EINVAL. The
113 * EINVAL check should be good enough to rule out false
116 if (r
>= 0 || errno
!= EINVAL
)
122 static void test_drop_privileges_keep_net_raw(void) {
125 sock
= socket(AF_INET
, SOCK_RAW
, IPPROTO_UDP
);
126 assert_se(sock
>= 0);
129 assert_se(drop_privileges(test_uid
, test_gid
, test_flags
| (1ULL << CAP_NET_RAW
)) >= 0);
130 assert_se(getuid() == test_uid
);
131 assert_se(getgid() == test_gid
);
134 sock
= socket(AF_INET
, SOCK_RAW
, IPPROTO_UDP
);
135 assert_se(sock
>= 0);
139 static void test_drop_privileges_dontkeep_net_raw(void) {
142 sock
= socket(AF_INET
, SOCK_RAW
, IPPROTO_UDP
);
143 assert_se(sock
>= 0);
146 assert_se(drop_privileges(test_uid
, test_gid
, test_flags
) >= 0);
147 assert_se(getuid() == test_uid
);
148 assert_se(getgid() == test_gid
);
151 sock
= socket(AF_INET
, SOCK_RAW
, IPPROTO_UDP
);
155 static void test_drop_privileges_fail(void) {
156 assert_se(drop_privileges(test_uid
, test_gid
, test_flags
) >= 0);
157 assert_se(getuid() == test_uid
);
158 assert_se(getgid() == test_gid
);
160 assert_se(drop_privileges(test_uid
, test_gid
, test_flags
) < 0);
161 assert_se(drop_privileges(0, 0, test_flags
) < 0);
164 static void test_drop_privileges(void) {
165 fork_test(test_drop_privileges_keep_net_raw
);
166 fork_test(test_drop_privileges_dontkeep_net_raw
);
167 fork_test(test_drop_privileges_fail
);
170 static void test_have_effective_cap(void) {
171 assert_se(have_effective_cap(CAP_KILL
));
172 assert_se(have_effective_cap(CAP_CHOWN
));
174 assert_se(drop_privileges(test_uid
, test_gid
, test_flags
| (1ULL << CAP_KILL
)) >= 0);
175 assert_se(getuid() == test_uid
);
176 assert_se(getgid() == test_gid
);
178 assert_se(have_effective_cap(CAP_KILL
));
179 assert_se(!have_effective_cap(CAP_CHOWN
));
182 static void test_update_inherited_set(void) {
187 caps
= cap_get_proc();
190 set
= (UINT64_C(1) << CAP_CHOWN
);
192 assert_se(!capability_update_inherited_set(caps
, set
));
193 assert_se(!cap_get_flag(caps
, CAP_CHOWN
, CAP_INHERITABLE
, &fv
));
194 assert(fv
== CAP_SET
);
199 static void test_set_ambient_caps(void) {
204 assert_se(prctl(PR_CAP_AMBIENT
, PR_CAP_AMBIENT_IS_SET
, CAP_CHOWN
, 0, 0) == 0);
206 set
= (UINT64_C(1) << CAP_CHOWN
);
208 assert_se(!capability_ambient_set_apply(set
, true));
210 caps
= cap_get_proc();
211 assert_se(!cap_get_flag(caps
, CAP_CHOWN
, CAP_INHERITABLE
, &fv
));
212 assert(fv
== CAP_SET
);
215 assert_se(prctl(PR_CAP_AMBIENT
, PR_CAP_AMBIENT_IS_SET
, CAP_CHOWN
, 0, 0) == 1);
218 static void test_ensure_cap_64bit(void) {
219 _cleanup_free_
char *content
= NULL
;
223 r
= read_one_line_file("/proc/sys/kernel/cap_last_cap", &content
);
224 if (r
== -ENOENT
) /* kernel pre 3.2 */
228 assert_se(safe_atolu(content
, &p
) >= 0);
230 /* If caps don't fit into 64bit anymore, we have a problem, fail the test. */
233 /* Also check for the header definition */
234 assert_se(CAP_LAST_CAP
<= 63);
237 int main(int argc
, char *argv
[]) {
240 test_setup_logging(LOG_INFO
);
242 test_ensure_cap_64bit();
244 test_last_cap_file();
245 test_last_cap_probe();
247 log_info("have ambient caps: %s", yes_no(ambient_capabilities_supported()));
250 return log_tests_skipped("not running as root");
252 if (setup_tests(&run_ambient
) < 0)
253 return log_tests_skipped("setup failed");
257 test_drop_privileges();
258 test_update_inherited_set();
260 fork_test(test_have_effective_cap
);
263 fork_test(test_set_ambient_caps
);