We don't want this call to allow an infinite loop in HID-BPF, so let's
have some tests.
Signed-off-by: Benjamin Tissoires <bentiss@xxxxxxxxxx>
---
tools/testing/selftests/hid/hid_bpf.c | 41 +++++++++++++++++++++++++++++++++
tools/testing/selftests/hid/progs/hid.c | 37 +++++++++++++++++++++++++++++
2 files changed, 78 insertions(+)
diff --git a/tools/testing/selftests/hid/hid_bpf.c b/tools/testing/selftests/hid/hid_bpf.c
index 36bbad8e0f9f..dc0408a831d0 100644
--- a/tools/testing/selftests/hid/hid_bpf.c
+++ b/tools/testing/selftests/hid/hid_bpf.c
@@ -1204,6 +1204,47 @@ TEST_F(hid_bpf, test_multiply_events)
ASSERT_EQ(buf[1], 52);
}
+/*
+ * Call hid_bpf_input_report against the given uhid device,
+ * check that the program is not making infinite loops.
+ */
+TEST_F(hid_bpf, test_hid_infinite_loop_input_report_call)
+{
+ const struct test_program progs[] = {
+ { .name = "hid_test_infinite_loop_input_report" },
+ };
+ __u8 buf[10] = {0};
+ int err;
+
+ LOAD_PROGRAMS(progs);
+
+ /* emit hid_hw_output_report from hidraw */
+ buf[0] = 1; /* report ID */
+ buf[1] = 2;
+ buf[2] = 42;
+
+ uhid_send_event(_metadata, self->uhid_fd, buf, 6);
+
+ /* read the data from hidraw */
+ memset(buf, 0, sizeof(buf));
+ err = read(self->hidraw_fd, buf, sizeof(buf));
+ ASSERT_EQ(err, 6) TH_LOG("read_hidraw");
+ ASSERT_EQ(buf[0], 1);
+ ASSERT_EQ(buf[1], 3);
+
+ /* read the data from hidraw: hid_bpf_try_input_report should work exactly one time */
+ memset(buf, 0, sizeof(buf));
+ err = read(self->hidraw_fd, buf, sizeof(buf));
+ ASSERT_EQ(err, 6) TH_LOG("read_hidraw");
+ ASSERT_EQ(buf[0], 1);
+ ASSERT_EQ(buf[1], 4);
+
+ /* read the data from hidraw: there should be none */
+ memset(buf, 0, sizeof(buf));
+ err = read(self->hidraw_fd, buf, sizeof(buf));
+ ASSERT_EQ(err, -1) TH_LOG("read_hidraw");
+}
+
/*
* Attach hid_insert{0,1,2} to the given uhid device,
* retrieve and open the matching hidraw node,
diff --git a/tools/testing/selftests/hid/progs/hid.c b/tools/testing/selftests/hid/progs/hid.c
index 46feeb91d1d5..ee9bbbcf751b 100644
--- a/tools/testing/selftests/hid/progs/hid.c
+++ b/tools/testing/selftests/hid/progs/hid.c
@@ -561,3 +561,40 @@ SEC(".struct_ops.link")
struct hid_bpf_ops test_multiply_events = {
.hid_device_event = (void *)hid_test_multiply_events,
};
+
+SEC("?struct_ops/hid_device_event")
+int BPF_PROG(hid_test_infinite_loop_input_report, struct hid_bpf_ctx *hctx,
+ enum hid_report_type report_type, __u64 source)
+{
+ __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 6 /* size */);
+ __u8 buf[6];
+
+ if (!data)
+ return 0; /* EPERM check */
+
+ /*
+ * we have to use an intermediate buffer as hid_bpf_input_report
+ * will memset data to \0
+ */
+ __builtin_memcpy(buf, data, sizeof(buf));
+
+ /* always forward the request as-is to the device, hid-bpf should prevent
+ * infinite loops.
+ * the return value is ignored so the event is passing to userspace.
+ */
+
+ hid_bpf_try_input_report(hctx, report_type, buf, sizeof(buf));
+
+ /* each time we process the event, we increment by one data[1]:
+ * after each successful call to hid_bpf_try_input_report, buf
+ * has been memcopied into data by the kernel.
+ */
+ data[1] += 1;
+
+ return 0;
+}
+
+SEC(".struct_ops.link")
+struct hid_bpf_ops test_infinite_loop_input_report = {
+ .hid_device_event = (void *)hid_test_infinite_loop_input_report,
+};
--
2.44.0
