selftests/hid: add tests for bpf_hid_hw_request

Add tests for the newly implemented function.
We test here only the GET_REPORT part because the other calls are pure
HID protocol and won't infer the result of the test of the bpf hook.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

tools/testing/selftests/hid/hid_bpf.c

@@ -82,12 +82,23 @@ static unsigned char rdesc[] = {
 	0xc0,			/* END_COLLECTION */
 };
 
+static __u8 feature_data[] = { 1, 2 };
+
 struct attach_prog_args {
 	int prog_fd;
 	unsigned int hid;
 	int retval;
 };
 
+struct hid_hw_request_syscall_args {
+	__u8 data[10];
+	unsigned int hid;
+	int retval;
+	size_t size;
+	enum hid_report_type type;
+	__u8 request_type;
+};
+
 #define ASSERT_OK(data) ASSERT_FALSE(data)
 #define ASSERT_OK_PTR(ptr) ASSERT_NE(NULL, ptr)
 
@@ -155,7 +166,7 @@ static void uhid_destroy(struct __test_metadata *_metadata, int fd)
 
 static int uhid_event(struct __test_metadata *_metadata, int fd)
 {
-	struct uhid_event ev;
+	struct uhid_event ev, answer;
 	ssize_t ret;
 
 	memset(&ev, 0, sizeof(ev));
@@ -196,6 +207,15 @@ static int uhid_event(struct __test_metadata *_metadata, int fd)
 		break;
 	case UHID_GET_REPORT:
 		UHID_LOG("UHID_GET_REPORT from uhid-dev");
+
+		answer.type = UHID_GET_REPORT_REPLY;
+		answer.u.get_report_reply.id = ev.u.get_report.id;
+		answer.u.get_report_reply.err = ev.u.get_report.rnum == 1 ? 0 : -EIO;
+		answer.u.get_report_reply.size = sizeof(feature_data);
+		memcpy(answer.u.get_report_reply.data, feature_data, sizeof(feature_data));
+
+		uhid_write(_metadata, fd, &answer);
+
 		break;
 	case UHID_SET_REPORT:
 		UHID_LOG("UHID_SET_REPORT from uhid-dev");
@@ -686,6 +706,40 @@ TEST_F(hid_bpf, test_hid_change_report)
 	ASSERT_EQ(buf[2], 0) TH_LOG("leftovers_from_previous_test");
 }
 
+/*
+ * Attach hid_user_raw_request to the given uhid device,
+ * call the bpf program from userspace
+ * check that the program is called and does the expected.
+ */
+TEST_F(hid_bpf, test_hid_user_raw_request_call)
+{
+	struct hid_hw_request_syscall_args args = {
+		.retval = -1,
+		.type = HID_FEATURE_REPORT,
+		.request_type = HID_REQ_GET_REPORT,
+		.size = 10,
+	};
+	DECLARE_LIBBPF_OPTS(bpf_test_run_opts, tattrs,
+			    .ctx_in = &args,
+			    .ctx_size_in = sizeof(args),
+	);
+	int err, prog_fd;
+
+	LOAD_BPF;
+
+	args.hid = self->hid_id;
+	args.data[0] = 1; /* report ID */
+
+	prog_fd = bpf_program__fd(self->skel->progs.hid_user_raw_request);
+
+	err = bpf_prog_test_run_opts(prog_fd, &tattrs);
+	ASSERT_OK(err) TH_LOG("error while calling bpf_prog_test_run_opts");
+
+	ASSERT_EQ(args.retval, 2);
+
+	ASSERT_EQ(args.data[1], 2);
+}
+
 static int libbpf_print_fn(enum libbpf_print_level level,
 			   const char *format, va_list args)
 {

tools/testing/selftests/hid/progs/hid.c

@@ -52,3 +52,39 @@ int attach_prog(struct attach_prog_args *ctx)
 					  0);
 	return 0;
 }
+
+struct hid_hw_request_syscall_args {
+	/* data needs to come at offset 0 so we can use it in calls */
+	__u8 data[10];
+	unsigned int hid;
+	int retval;
+	size_t size;
+	enum hid_report_type type;
+	__u8 request_type;
+};
+
+SEC("syscall")
+int hid_user_raw_request(struct hid_hw_request_syscall_args *args)
+{
+	struct hid_bpf_ctx *ctx;
+	const size_t size = args->size;
+	int i, ret = 0;
+
+	if (size > sizeof(args->data))
+		return -7; /* -E2BIG */
+
+	ctx = hid_bpf_allocate_context(args->hid);
+	if (!ctx)
+		return -1; /* EPERM check */
+
+	ret = hid_bpf_hw_request(ctx,
+				 args->data,
+				 size,
+				 args->type,
+				 args->request_type);
+	args->retval = ret;
+
+	hid_bpf_release_context(ctx);
+
+	return 0;
+}

tools/testing/selftests/hid/progs/hid_bpf_helpers.h

@@ -10,5 +10,12 @@ extern __u8 *hid_bpf_get_data(struct hid_bpf_ctx *ctx,
 			      unsigned int offset,
 			      const size_t __sz) __ksym;
 extern int hid_bpf_attach_prog(unsigned int hid_id, int prog_fd, u32 flags) __ksym;
+extern struct hid_bpf_ctx *hid_bpf_allocate_context(unsigned int hid_id) __ksym;
+extern void hid_bpf_release_context(struct hid_bpf_ctx *ctx) __ksym;
+extern int hid_bpf_hw_request(struct hid_bpf_ctx *ctx,
+			      __u8 *data,
+			      size_t buf__sz,
+			      enum hid_report_type type,
+			      enum hid_class_request reqtype) __ksym;
 
 #endif /* __HID_BPF_HELPERS_H */