selftests/seccomp: Accept any valid fd in user_notification_addfd

This test expects fds to have specific values, which works fine
when the test is run standalone. However, the kselftest runner
consumes a couple of extra fds for redirection when running
tests, so the test fails when run via kselftest.

Change the test to pass on any valid fd number.
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/testing/selftests/seccomp/seccomp_bpf.c

@@ -4019,18 +4019,14 @@ TEST(user_notification_addfd)
 
 	/* Verify we can set an arbitrary remote fd */
 	fd = ioctl(listener, SECCOMP_IOCTL_NOTIF_ADDFD, &addfd);
-	/*
-	 * The child has fds 0(stdin), 1(stdout), 2(stderr), 3(memfd),
-	 * 4(listener), so the newly allocated fd should be 5.
-	 */
-	EXPECT_EQ(fd, 5);
+	EXPECT_GE(fd, 0);
 	EXPECT_EQ(filecmp(getpid(), pid, memfd, fd), 0);
 
 	/* Verify we can set an arbitrary remote fd with large size */
 	memset(&big, 0x0, sizeof(big));
 	big.addfd = addfd;
 	fd = ioctl(listener, SECCOMP_IOCTL_NOTIF_ADDFD_BIG, &big);
-	EXPECT_EQ(fd, 6);
+	EXPECT_GE(fd, 0);
 
 	/* Verify we can set a specific remote fd */
 	addfd.newfd = 42;