tests: test ambient capabilities.

The ambient capability tests are only run if the kernel has support for
ambient capabilities.

1 files changed, 66 insertions, 2 deletions

diff --git a/src/test/test-capability.c b/src/test/test-capability.c
index fc8d3ffe0d..629bb63c81 100644
--- a/src/test/test-capability.c
+++ b/src/test/test-capability.c
@@ -20,6 +20,7 @@
 #include <netinet/in.h>
 #include <pwd.h>
 #include <sys/capability.h>
+#include <sys/prctl.h>
 #include <sys/socket.h>
 #include <sys/wait.h>
 #include <unistd.h>
@@ -66,8 +67,9 @@ static void show_capabilities(void) {
         cap_free(text);
 }
 
-static int setup_tests(void) {
+static int setup_tests(bool *run_ambient) {
         struct passwd *nobody;
+        int r;
 
         nobody = getpwnam("nobody");
         if (!nobody) {
@@ -77,6 +79,18 @@ static int setup_tests(void) {
         test_uid = nobody->pw_uid;
         test_gid = nobody->pw_gid;
 
+        *run_ambient = false;
+
+        r = prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_CLEAR_ALL, 0, 0, 0);
+
+        /* There's support for PR_CAP_AMBIENT if the prctl() call
+         * succeeded or error code was something else than EINVAL. The
+         * EINVAL check should be good enough to rule out false
+         * positives. */
+
+        if (r >= 0 || errno != EINVAL)
+                *run_ambient = true;
+
         return 0;
 }
 
@@ -140,8 +154,53 @@ static void test_have_effective_cap(void) {
         assert_se(!have_effective_cap(CAP_CHOWN));
 }
 
+static void test_update_inherited_set(void) {
+        cap_t caps;
+        uint64_t set = 0;
+        cap_flag_value_t fv;
+
+        caps = cap_get_proc();
+        assert_se(caps);
+        assert_se(!cap_get_flag(caps, CAP_CHOWN, CAP_INHERITABLE, &fv));
+        assert(fv == CAP_CLEAR);
+
+        set = (UINT64_C(1) << CAP_CHOWN);
+
+        assert_se(!capability_update_inherited_set(caps, set));
+        assert_se(!cap_get_flag(caps, CAP_CHOWN, CAP_INHERITABLE, &fv));
+        assert(fv == CAP_SET);
+
+        cap_free(caps);
+}
+
+static void test_set_ambient_caps(void) {
+        cap_t caps;
+        uint64_t set = 0;
+        cap_flag_value_t fv;
+
+        caps = cap_get_proc();
+        assert_se(caps);
+        assert_se(!cap_get_flag(caps, CAP_CHOWN, CAP_INHERITABLE, &fv));
+        assert(fv == CAP_CLEAR);
+        cap_free(caps);
+
+        assert_se(prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_CHOWN, 0, 0) == 0);
+
+        set = (UINT64_C(1) << CAP_CHOWN);
+
+        assert_se(!capability_ambient_set_apply(set, true));
+
+        caps = cap_get_proc();
+        assert_se(!cap_get_flag(caps, CAP_CHOWN, CAP_INHERITABLE, &fv));
+        assert(fv == CAP_SET);
+        cap_free(caps);
+
+        assert_se(prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_CHOWN, 0, 0) == 1);
+}
+
 int main(int argc, char *argv[]) {
         int r;
+        bool run_ambient;
 
         log_parse_environment();
         log_open();
@@ -149,14 +208,19 @@ int main(int argc, char *argv[]) {
         if (getuid() != 0)
                 return EXIT_TEST_SKIP;
 
-        r = setup_tests();
+        r = setup_tests(&run_ambient);
         if (r < 0)
                 return -r;
 
         show_capabilities();
 
         test_drop_privileges();
+        test_update_inherited_set();
+
         fork_test(test_have_effective_cap);
 
+        if (run_ambient)
+                fork_test(test_set_ambient_caps);
+
         return 0;
 }