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From:   Sargun Dhillon <sargun@sargun.me>
To:     LKML <linux-kernel@vger.kernel.org>
Cc:     Christian Brauner <christian.brauner@ubuntu.com>,
        Aleksa Sarai <cyphar@cyphar.com>,
        Tycho Andersen <tycho@tycho.ws>,
        Sargun Dhillon <sargun@sargun.me>,
        Kees Cook <keescook@chromium.org>
Subject: [PATCH] selftests/seccomp: Test kernel catches garbage on SECCOMP_IOCTL_NOTIF_RECV
Date:   Mon, 30 Dec 2019 12:38:11 -0800
Message-Id: <20191230203811.4996-1-sargun@sargun.me>
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Sender: linux-kernel-owner@vger.kernel.org
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This adds to the user_notification_basic to set a field of seccomp_notif
to an invalid value to ensure that the kernel returns EINVAL if any of the
seccomp_notif fields are set to invalid values.

Signed-off-by: Sargun Dhillon <sargun@sargun.me>
Suggested-by: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Kees Cook <keescook@chromium.org>
---
 tools/testing/selftests/seccomp/seccomp_bpf.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index f53f14971bff..393578a78dbc 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -3158,6 +3158,13 @@ TEST(user_notification_basic)
 	EXPECT_GT(poll(&pollfd, 1, -1), 0);
 	EXPECT_EQ(pollfd.revents, POLLIN);
 
+	/* Test that we can't pass garbage to the kernel. */
+	memset(&req, 0, sizeof(req));
+	req.pid = -1;
+	EXPECT_EQ(-1, ioctl(listener, SECCOMP_IOCTL_NOTIF_RECV, &req));
+	EXPECT_EQ(EINVAL, errno);
+
+	req.pid = 0;
 	EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_RECV, &req), 0);
 
 	pollfd.fd = listener;
-- 
2.20.1