[PATCH hid v11 08/14] selftests/hid: add tests for bpf_hid_hw_request

From: Benjamin Tissoires
Date: Tue Oct 25 2022 - 05:36:15 EST


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@xxxxxxxxxx>

---

changes in v11:
- use the new facility from selftests/hid

no changes in v10

no changes in v9

no changes in v8

no changes in v7

changes in v6:
- fixed copy/paste in prog_tests when calling ASSERT_OK
- removed the need for memcpy now that kfuncs can access ctx

changes in v5:
- use the new hid_bpf_allocate_context() API
- remove the need for ctx_in for syscall TEST_RUN

changes in v3:
- use the new hid_get_data API
- directly use HID_FEATURE_REPORT and HID_REQ_GET_REPORT from uapi

changes in v2:
- split the series by bpf/libbpf/hid/selftests and samples
---
tools/testing/selftests/hid/hid_bpf.c | 56 ++++++++++++++++++++++++-
tools/testing/selftests/hid/progs/hid.c | 43 +++++++++++++++++++
2 files changed, 98 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/hid/hid_bpf.c b/tools/testing/selftests/hid/hid_bpf.c
index a6daaadccfb5..7cd976b469b7 100644
--- a/tools/testing/selftests/hid/hid_bpf.c
+++ b/tools/testing/selftests/hid/hid_bpf.c
@@ -83,12 +83,23 @@ 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)

@@ -156,7 +167,7 @@ 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));
@@ -197,6 +208,15 @@ 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");
@@ -687,6 +707,40 @@ 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)
{
diff --git a/tools/testing/selftests/hid/progs/hid.c b/tools/testing/selftests/hid/progs/hid.c
index ee7529c47ad8..fde76f63927b 100644
--- a/tools/testing/selftests/hid/progs/hid.c
+++ b/tools/testing/selftests/hid/progs/hid.c
@@ -10,6 +10,13 @@ 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;

struct attach_prog_args {
int prog_fd;
@@ -56,3 +63,39 @@ 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;
+}
--
2.36.1