tests: add test-capability

Makefile.am

@@ -1245,7 +1245,8 @@ tests += \
 	test-architecture \
 	test-socket-util \
 	test-fdset \
-	test-conf-files
+	test-conf-files \
+	test-capability
 
 EXTRA_DIST += \
 	test/sched_idle_bad.service \
@@ -1349,6 +1350,13 @@ test_utf8_SOURCES = \
 test_utf8_LDADD = \
 	libsystemd-shared.la
 
+test_capability_SOURCES = \
+	src/test/test-capability.c
+
+test_capability_LDADD = \
+	libsystemd-shared.la \
+	libsystemd-capability.la
+
 test_fdset_SOURCES = \
 	src/test/test-fdset.c
 

src/test/test-capability.c

@@ -0,0 +1,161 @@
+/***
+  This file is part of systemd
+
+  Copyright 2014 Ronny Chevalier
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/capability.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <pwd.h>
+#include <unistd.h>
+
+#include "capability.h"
+#include "util.h"
+#include "macro.h"
+
+static uid_t test_uid = -1;
+static gid_t test_gid = -1;
+// We keep CAP_DAC_OVERRIDE to avoid errors with gcov when doing test coverage
+static uint64_t test_flags = 1ULL << CAP_DAC_OVERRIDE;
+
+static void fork_test(void (*test_func)(void)) {
+        pid_t pid = 0;
+
+        pid = fork();
+        assert_se(pid >= 0);
+        if (pid == 0) {
+                test_func();
+                exit(0);
+        } else if (pid > 0) {
+                int status;
+
+                assert_se(waitpid(pid, &status, 0) > 0);
+                assert_se(WIFEXITED(status) && WEXITSTATUS(status) == 0);
+        }
+}
+
+static void show_capabilities(void) {
+        cap_t caps;
+        char *text;
+
+        caps = cap_get_proc();
+        assert_se(caps);
+
+        text = cap_to_text(caps, NULL);
+        assert_se(text);
+
+        log_info("Capabilities:%s", text);
+        cap_free(caps);
+        cap_free(text);
+}
+
+static int setup_tests(void) {
+        struct passwd *nobody;
+
+        nobody = getpwnam("nobody");
+        if (!nobody) {
+                log_error("Could not find nobody user: %m");
+                return -EXIT_TEST_SKIP;
+        }
+        test_uid = nobody->pw_uid;
+        test_gid = nobody->pw_gid;
+
+        return 0;
+}
+
+static void test_drop_privileges_keep_net_raw(void) {
+        int sock;
+
+        sock = socket(AF_INET, SOCK_RAW, IPPROTO_UDP);
+        assert_se(sock >= 0);
+        safe_close(sock);
+
+        assert_se(drop_privileges(test_uid, test_gid, test_flags | (1ULL << CAP_NET_RAW)) >= 0);
+        assert_se(getuid() == test_uid);
+        assert_se(getgid() == test_gid);
+        show_capabilities();
+
+        sock = socket(AF_INET, SOCK_RAW, IPPROTO_UDP);
+        assert_se(sock >= 0);
+        safe_close(sock);
+}
+
+static void test_drop_privileges_dontkeep_net_raw(void) {
+        int sock;
+
+        sock = socket(AF_INET, SOCK_RAW, IPPROTO_UDP);
+        assert_se(sock >= 0);
+        safe_close(sock);
+
+        assert_se(drop_privileges(test_uid, test_gid, test_flags) >= 0);
+        assert_se(getuid() == test_uid);
+        assert_se(getgid() == test_gid);
+        show_capabilities();
+
+        sock = socket(AF_INET, SOCK_RAW, IPPROTO_UDP);
+        assert_se(sock < 0);
+}
+
+static void test_drop_privileges_fail(void) {
+        assert_se(drop_privileges(test_uid, test_gid, test_flags) >= 0);
+        assert_se(getuid() == test_uid);
+        assert_se(getgid() == test_gid);
+
+        assert_se(drop_privileges(test_uid, test_gid, test_flags) < 0);
+        assert_se(drop_privileges(0, 0, test_flags) < 0);
+}
+
+static void test_drop_privileges(void) {
+        fork_test(test_drop_privileges_keep_net_raw);
+        fork_test(test_drop_privileges_dontkeep_net_raw);
+        fork_test(test_drop_privileges_fail);
+}
+
+static void test_have_effective_cap(void) {
+        assert_se(have_effective_cap(CAP_KILL));
+        assert_se(have_effective_cap(CAP_CHOWN));
+
+        assert_se(drop_privileges(test_uid, test_gid, test_flags | (1ULL << CAP_KILL)) >= 0);
+        assert_se(getuid() == test_uid);
+        assert_se(getgid() == test_gid);
+
+        assert_se(have_effective_cap(CAP_KILL));
+        assert_se(!have_effective_cap(CAP_CHOWN));
+}
+
+int main(int argc, char *argv[]) {
+        int r;
+
+        log_parse_environment();
+        log_open();
+
+        if (getuid() != 0)
+                return EXIT_TEST_SKIP;
+
+        r = setup_tests();
+        if (r < 0)
+                return -r;
+
+        show_capabilities();
+
+        test_drop_privileges();
+        fork_test(test_have_effective_cap);
+
+        return 0;
+}