Re: [PATCH v2 3/3] selftests/seccomp: Test SECCOMP_IOCTL_NOTIF_ADDFD

On Fri, May 29, 2020 at 06:46:07PM +0000, Sargun Dhillon wrote:

On Fri, May 29, 2020 at 12:41:51AM -0700, Kees Cook wrote:

quoted

On Thu, May 28, 2020 at 04:08:58AM -0700, Sargun Dhillon wrote:

quoted

+	EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_SEND, &resp), 0);
+
+	nextid = req.id + 1;
+
+	/* Wait for getppid to be called for the second time */
+	sleep(1);

I always rebel at finding "sleep" in tests. ;) Is this needed? IIUC,
userspace will immediately see EINPROGRESS after the NOTIF_SEND
finishes, yes?

Otherwise, yes, this looks good.

-- 
Kees Cook

I'm open to better suggestions, but there's a race where if getppid
is not called before the second SECCOMP_IOCTL_NOTIF_ADDFD is called,
you will just get an ENOENT, since the notification ID is not found.

Ah, I see. The goal is to test the -EINPROGRESS here.

If you use write() instead of getppid(), and write to a socket, will
that work? The parent can block for the read, and once some thing has
been read it can test for -EINPROGRESS.

The user_notification_signal test does something similar.

Tycho