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From:   Benjamin Tissoires <benjamin.tissoires@redhat.com>
To:     Greg KH <gregkh@linuxfoundation.org>,
        Jiri Kosina <jikos@kernel.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>, Shuah Khan <shuah@kernel.org>,
        Dave Marchevsky <davemarchevsky@fb.com>,
        Joe Stringer <joe@cilium.io>, Jonathan Corbet <corbet@lwn.net>
Cc:     Tero Kristo <tero.kristo@linux.intel.com>,
        linux-kernel@vger.kernel.org, linux-input@vger.kernel.org,
        netdev@vger.kernel.org, bpf@vger.kernel.org,
        linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org,
        Benjamin Tissoires <benjamin.tissoires@redhat.com>
Subject: [PATCH bpf-next v3 10/17] selftests/bpf: add test for user call of HID bpf programs
Date:   Fri, 18 Mar 2022 17:15:21 +0100
Message-Id: <20220318161528.1531164-11-benjamin.tissoires@redhat.com>
In-Reply-To: <20220318161528.1531164-1-benjamin.tissoires@redhat.com>
References: <20220318161528.1531164-1-benjamin.tissoires@redhat.com>
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Add a simple test to see if we can trigger a bpf program of type
"hid/user_event".

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

---

changes in v3:
- use the new hid_get_data API

changes in v2:
- split the series by bpf/libbpf/hid/selftests and samples
---
 tools/testing/selftests/bpf/prog_tests/hid.c | 56 ++++++++++++++++++++
 tools/testing/selftests/bpf/progs/hid.c      | 15 ++++++
 2 files changed, 71 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/hid.c b/tools/testing/selftests/bpf/prog_tests/hid.c
index b8d4dcf20b05..edc3af71e9ed 100644
--- a/tools/testing/selftests/bpf/prog_tests/hid.c
+++ b/tools/testing/selftests/bpf/prog_tests/hid.c
@@ -478,6 +478,59 @@ static int test_hid_attach_flags(struct hid *hid_skel, int uhid_fd, int sysfs_fd
 	return ret;
 }
 
+/*
+ * Attach hid_user to the given uhid device,
+ * call the bpf program from userspace
+ * check that the program is called and does the expected.
+ */
+static int test_hid_user_call(struct hid *hid_skel, int uhid_fd, int sysfs_fd)
+{
+	int err, prog_fd;
+	u8 buf[10] = {0};
+	int ret = -1;
+
+	LIBBPF_OPTS(bpf_test_run_opts, run_attrs,
+		    .repeat = 1,
+		    .ctx_in = &sysfs_fd,
+		    .ctx_size_in = sizeof(sysfs_fd),
+		    .data_in = buf,
+		    .data_size_in = sizeof(buf),
+		    .data_out = buf,
+		    .data_size_out = sizeof(buf),
+	);
+
+	/* attach hid_user program */
+	hid_skel->links.hid_user = bpf_program__attach_hid(hid_skel->progs.hid_user, sysfs_fd, 0);
+	if (!ASSERT_OK_PTR(hid_skel->links.hid_user,
+			   "attach_hid(hid_user)"))
+		return PTR_ERR(hid_skel->links.hid_user);
+
+	buf[0] = 39;
+
+	prog_fd = bpf_program__fd(hid_skel->progs.hid_user);
+
+	err = bpf_prog_test_run_opts(prog_fd, &run_attrs);
+	if (!ASSERT_EQ(err, 0, "bpf_prog_test_run_xattr"))
+		goto cleanup;
+
+	if (!ASSERT_EQ(run_attrs.retval, 72, "bpf_prog_test_run_opts"))
+		goto cleanup;
+
+	if (!ASSERT_EQ(buf[1], 42, "hid_user_check_in"))
+		goto cleanup;
+
+	if (!ASSERT_EQ(buf[2], 4, "hid_user_check_static_out"))
+		goto cleanup;
+
+	ret = 0;
+
+cleanup:
+
+	hid__detach(hid_skel);
+
+	return ret;
+}
+
 /*
  * Attach hid_rdesc_fixup to the given uhid device,
  * retrieve and open the matching hidraw node,
@@ -585,6 +638,9 @@ void serial_test_hid_bpf(void)
 	err = test_hid_attach_flags(hid_skel, uhid_fd, sysfs_fd);
 	ASSERT_OK(err, "hid_user_raw_request");
 
+	err = test_hid_user_call(hid_skel, uhid_fd, sysfs_fd);
+	ASSERT_OK(err, "hid_user");
+
 	/*
 	 * this test should be run last because we disconnect/reconnect
 	 * the device, meaning that it changes the overall uhid device
diff --git a/tools/testing/selftests/bpf/progs/hid.c b/tools/testing/selftests/bpf/progs/hid.c
index 390c1bb8d850..fbdbe9d1b605 100644
--- a/tools/testing/selftests/bpf/progs/hid.c
+++ b/tools/testing/selftests/bpf/progs/hid.c
@@ -128,3 +128,18 @@ int hid_test_insert3(struct hid_bpf_ctx *ctx)
 
 	return 0;
 }
+
+SEC("hid/user_event")
+int hid_user(struct hid_bpf_ctx *ctx)
+{
+	__u8 *data = bpf_hid_get_data(ctx, 0 /* offset */, 3 /* size */);
+
+	if (!data)
+		return 0; /* EPERM check */
+
+	data[1] = data[0] + 3;
+	data[2] = 4;
+	ctx->retval = 72;
+
+	return 0;
+}
-- 
2.35.1