selftests: safesetid: Check the return value of setuid/setgid

Check the return value of setuid() and setgid().
This fixes the following warnings and improves test result.

safesetid-test.c: In function ‘main’:
safesetid-test.c:294:2: warning: ignoring return value of ‘setuid’, declared with attribute warn_unused_result [-Wunused-result]
  setuid(NO_POLICY_USER);
  ^~~~~~~~~~~~~~~~~~~~~~
safesetid-test.c:295:2: warning: ignoring return value of ‘setgid’, declared with attribute warn_unused_result [-Wunused-result]
  setgid(NO_POLICY_USER);
  ^~~~~~~~~~~~~~~~~~~~~~
safesetid-test.c:309:2: warning: ignoring return value of ‘setuid’, declared with attribute warn_unused_result [-Wunused-result]
  setuid(RESTRICTED_PARENT);
  ^~~~~~~~~~~~~~~~~~~~~~~~~
safesetid-test.c:310:2: warning: ignoring return value of ‘setgid’, declared with attribute warn_unused_result [-Wunused-result]
  setgid(RESTRICTED_PARENT);
  ^~~~~~~~~~~~~~~~~~~~~~~~~
safesetid-test.c: In function ‘test_setuid’:
safesetid-test.c:216:3: warning: ignoring return value of ‘setuid’, declared with attribute warn_unused_result [-Wunused-result]
   setuid(child_uid);
   ^~~~~~~~~~~~~~~~~

Fixes: c67e8ec03f3f ("LSM: SafeSetID: add selftest")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

diff --git a/tools/testing/selftests/safesetid/safesetid-test.c b/tools/testing/selftests/safesetid/safesetid-test.c
index 8f40c6e..0c4d506 100644 (file)
--- a/tools/testing/selftests/safesetid/safesetid-test.c
+++ b/tools/testing/selftests/safesetid/safesetid-test.c
@@ -213,7 +213,8 @@ static void test_setuid(uid_t child_uid, bool expect_success)
        }
 
        if (cpid == 0) {            /* Code executed by child */
-               setuid(child_uid);
+               if (setuid(child_uid) < 0)
+                       exit(EXIT_FAILURE);
                if (getuid() == child_uid)
                        exit(EXIT_SUCCESS);
                else
@@ -291,8 +292,10 @@ int main(int argc, char **argv)
 
        // First test to make sure we can write userns mappings from a user
        // that doesn't have any restrictions (as long as it has CAP_SETUID);
-       setuid(NO_POLICY_USER);
-       setgid(NO_POLICY_USER);
+       if (setuid(NO_POLICY_USER) < 0)
+               die("Error with set uid(%d)\n", NO_POLICY_USER);
+       if (setgid(NO_POLICY_USER) < 0)
+               die("Error with set gid(%d)\n", NO_POLICY_USER);
 
        // Take away all but setid caps
        drop_caps(true);
@@ -306,8 +309,10 @@ int main(int argc, char **argv)
                die("test_userns failed when it should work\n");
        }
 
-       setuid(RESTRICTED_PARENT);
-       setgid(RESTRICTED_PARENT);
+       if (setuid(RESTRICTED_PARENT) < 0)
+               die("Error with set uid(%d)\n", RESTRICTED_PARENT);
+       if (setgid(RESTRICTED_PARENT) < 0)
+               die("Error with set gid(%d)\n", RESTRICTED_PARENT);
 
        test_setuid(ROOT_USER, false);
        test_setuid(ALLOWED_CHILD1, true);