LSM: SafeSetID: add GID testing to selftest (a1732d68) · Commits · jan.koester / Linux

tools/testing/selftests/safesetid/safesetid-test.c

+131 −0

Original line number	Diff line number	Diff line
		@@ -3,6 +3,7 @@
		#include <stdio.h>
		#include <errno.h>
		#include <pwd.h>
		#include <grp.h>
		#include <string.h>
		#include <syscall.h>
		#include <sys/capability.h>
		@@ -120,6 +121,7 @@ static void ensure_user_exists(uid_t uid)
		snprintf(name_str, 10, "user %d", uid);
		p.pw_name=name_str;
		p.pw_uid=uid;
		p.pw_gid=uid;
		p.pw_gecos="Test account";
		p.pw_dir="/dev/null";
		p.pw_shell="/bin/false";
		@@ -131,6 +133,33 @@ static void ensure_user_exists(uid_t uid)
		}
		}

		static void ensure_group_exists(gid_t gid)
		{
		struct group g;

		FILE *fd;
		char name_str[10];

		if (getgrgid(gid) == NULL) {
		memset(&g,0x00,sizeof(g));
		fd=fopen("/etc/group","a");
		if (fd == NULL)
		die("couldn't open group file\n");
		if (fseek(fd, 0, SEEK_END))
		die("couldn't fseek group file\n");
		snprintf(name_str, 10, "group %d", gid);
		g.gr_name=name_str;
		g.gr_gid=gid;
		g.gr_passwd=NULL;
		g.gr_mem=NULL;
		int value = putgrent(&g,fd);
		if (value != 0)
		die("putgrent failed\n");
		if (fclose(fd))
		die("fclose failed\n");
		}
		}

		static void ensure_securityfs_mounted(void)
		{
		int fd = open(add_uid_whitelist_policy_file, O_WRONLY);
		@@ -175,6 +204,31 @@ static void write_uid_policies()
		}
		}

		static void write_gid_policies()
		{
		static char *policy_str = UGID_POLICY_STRING;
		ssize_t written;
		int fd;

		fd = open(add_gid_whitelist_policy_file, O_WRONLY);
		if (fd < 0)
		die("can't open add_gid_whitelist_policy file\n");
		written = write(fd, policy_str, strlen(policy_str));
		if (written != strlen(policy_str)) {
		if (written >= 0) {
		die("short write to %s\n", add_gid_whitelist_policy_file);
		} else {
		die("write to %s failed: %s\n",
		add_gid_whitelist_policy_file, strerror(errno));
		}
		}
		if (close(fd) != 0) {
		die("close of %s failed: %s\n",
		add_gid_whitelist_policy_file, strerror(errno));
		}
		}


		static bool test_userns(bool expect_success)
		{
		uid_t uid;
		@@ -265,6 +319,63 @@ static void test_setuid(uid_t child_uid, bool expect_success)
		die("should not reach here\n");
		}

		static void test_setgid(gid_t child_gid, bool expect_success)
		{
		pid_t cpid, w;
		int wstatus;

		cpid = fork();
		if (cpid == -1) {
		die("fork\n");
		}

		if (cpid == 0) { /* Code executed by child */
		if (setgid(child_gid) < 0)
		exit(EXIT_FAILURE);
		if (getgid() == child_gid)
		exit(EXIT_SUCCESS);
		else
		exit(EXIT_FAILURE);
		} else { /* Code executed by parent */
		do {
		w = waitpid(cpid, &wstatus, WUNTRACED \| WCONTINUED);
		if (w == -1) {
		die("waitpid\n");
		}

		if (WIFEXITED(wstatus)) {
		if (WEXITSTATUS(wstatus) == EXIT_SUCCESS) {
		if (expect_success) {
		return;
		} else {
		die("unexpected success\n");
		}
		} else {
		if (expect_success) {
		die("unexpected failure\n");
		} else {
		return;
		}
		}
		} else if (WIFSIGNALED(wstatus)) {
		if (WTERMSIG(wstatus) == 9) {
		if (expect_success)
		die("killed unexpectedly\n");
		else
		return;
		} else {
		die("unexpected signal: %d\n", wstatus);
		}
		} else {
		die("unexpected status: %d\n", wstatus);
		}
		} while (!WIFEXITED(wstatus) && !WIFSIGNALED(wstatus));
		}

		die("should not reach here\n");
		}


		static void ensure_users_exist(void)
		{
		ensure_user_exists(ROOT_UGID);
		@@ -274,6 +385,15 @@ static void ensure_users_exist(void)
		ensure_user_exists(NO_POLICY_UGID);
		}

		static void ensure_groups_exist(void)
		{
		ensure_group_exists(ROOT_UGID);
		ensure_group_exists(RESTRICTED_PARENT_UGID);
		ensure_group_exists(ALLOWED_CHILD1_UGID);
		ensure_group_exists(ALLOWED_CHILD2_UGID);
		ensure_group_exists(NO_POLICY_UGID);
		}

		static void drop_caps(bool setid_retained)
		{
		cap_value_t cap_values[] = {CAP_SETUID, CAP_SETGID};
		@@ -290,9 +410,11 @@ static void drop_caps(bool setid_retained)

		int main(int argc, char **argv)
		{
		ensure_groups_exist();
		ensure_users_exist();
		ensure_securityfs_mounted();
		write_uid_policies();
		write_gid_policies();

		if (prctl(PR_SET_KEEPCAPS, 1L))
		die("Error with set keepcaps\n");
		@@ -325,6 +447,12 @@ int main(int argc, char **argv)
		test_setuid(ALLOWED_CHILD2_UGID, true);
		test_setuid(NO_POLICY_UGID, false);

		test_setgid(ROOT_UGID, false);
		test_setgid(ALLOWED_CHILD1_UGID, true);
		test_setgid(ALLOWED_CHILD2_UGID, true);
		test_setgid(NO_POLICY_UGID, false);


		if (!test_userns(false)) {
		die("test_userns worked when it should fail\n");
		}
		@@ -334,6 +462,9 @@ int main(int argc, char **argv)
		test_setuid(2, false);
		test_setuid(3, false);
		test_setuid(4, false);
		test_setgid(2, false);
		test_setgid(3, false);
		test_setgid(4, false);

		// NOTE: this test doesn't clean up users that were created in
		// /etc/passwd or flush policies that were added to the LSM.