selftests/seccomp: Handle EINVAL on unshare(CLONE_NEWPID)

stable inclusion
from stable-v6.6.30
commit 612fbf658803dd19d49bcc66e7bbfdbe9b6981ff
bugzilla: https://gitee.com/openeuler/kernel/issues/I9MPZ8

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=612fbf658803dd19d49bcc66e7bbfdbe9b6981ff

--------------------------------

commit ecaaa55c9fa5e8058445a8b891070b12208cdb6d upstream.

unshare(CLONE_NEWPID) can return EINVAL if the kernel does not have the
CONFIG_PID_NS option enabled.

Add a check on these calls to skip the test if we receive EINVAL.

Signed-off-by: Terry Tritton <terry.tritton@linaro.org>
Link: https://lore.kernel.org/r/20240124141357.1243457-2-terry.tritton@linaro.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>

Author: Terry Tritton

tools/testing/selftests/seccomp/seccomp_bpf.c

@@ -3722,7 +3722,12 @@ TEST(user_notification_sibling_pid_ns)
 	ASSERT_GE(pid, 0);
 
 	if (pid == 0) {
-		ASSERT_EQ(unshare(CLONE_NEWPID), 0);
+		ASSERT_EQ(unshare(CLONE_NEWPID), 0) {
+			if (errno == EPERM)
+				SKIP(return, "CLONE_NEWPID requires CAP_SYS_ADMIN");
+			else if (errno == EINVAL)
+				SKIP(return, "CLONE_NEWPID is invalid (missing CONFIG_PID_NS?)");
+		}
 
 		pid2 = fork();
 		ASSERT_GE(pid2, 0);
@@ -3740,6 +3745,8 @@ TEST(user_notification_sibling_pid_ns)
 	ASSERT_EQ(unshare(CLONE_NEWPID), 0) {
 		if (errno == EPERM)
 			SKIP(return, "CLONE_NEWPID requires CAP_SYS_ADMIN");
+		else if (errno == EINVAL)
+			SKIP(return, "CLONE_NEWPID is invalid (missing CONFIG_PID_NS?)");
 	}
 	ASSERT_EQ(errno, 0);