[PATCH bpf-next v2 21/28] selftests/bpf: add tests for bpf_hid_hw_request

Benjamin Tissoires
2022-03-04T17:35:32Z

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>

---

changes in v2:
- split the series by bpf/libbpf/hid/selftests and samples
---
tools/testing/selftests/bpf/prog_tests/hid.c | 71 +++++++++++++++++++-
tools/testing/selftests/bpf/progs/hid.c | 57 ++++++++++++++++
2 files changed, 127 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/hid.c b/tools/testing/selftests/bpf/prog_tests/hid.c
index cc01601c1168..a2bab6a799a1 100644
--- a/tools/testing/selftests/bpf/prog_tests/hid.c
+++ b/tools/testing/selftests/bpf/prog_tests/hid.c
@@ -67,6 +67,8 @@ static unsigned char rdesc[] = {
0xc0, /* END_COLLECTION */
};

+static u8 feature_data[] = { 1, 2 };
+
static pthread_mutex_t uhid_started_mtx = PTHREAD_MUTEX_INITIALIZER;
static pthread_cond_t uhid_started = PTHREAD_COND_INITIALIZER;

@@ -126,7 +128,7 @@ static void destroy(int fd)

static int event(int fd)
{
- struct uhid_event ev;
+ struct uhid_event ev, answer;
ssize_t ret;

memset(&ev, 0, sizeof(ev));
@@ -143,6 +145,8 @@ static int event(int fd)
return -EFAULT;
}

+ memset(&answer, 0, sizeof(answer));
+
switch (ev.type) {
case UHID_START:
pthread_mutex_lock(&uhid_started_mtx);
@@ -167,6 +171,15 @@ static int event(int fd)
break;
case UHID_GET_REPORT:
fprintf(stderr, "UHID_GET_REPORT from uhid-dev\n");
+
+ 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(fd, &answer);
+
break;
case UHID_SET_REPORT:
fprintf(stderr, "UHID_SET_REPORT from uhid-dev\n");
@@ -516,6 +529,59 @@ static int test_hid_user_call(struct hid *hid_skel, int uhid_fd, int sysfs_fd)
return ret;
}

+/*
+ * 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.
+ */
+static int test_hid_user_raw_request_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_raw_request program */
+ hid_skel->links.hid_user_raw_request =
+ bpf_program__attach_hid(hid_skel->progs.hid_user_raw_request, sysfs_fd);
+ if (!ASSERT_OK_PTR(hid_skel->links.hid_user_raw_request,
+ "attach_hid(hid_user_raw_request)"))
+ return PTR_ERR(hid_skel->links.hid_user_raw_request);
+
+ buf[0] = 2; /* HID_FEATURE_REPORT */
+ buf[1] = 1; /* HID_REQ_GET_REPORT */
+ buf[2] = 1; /* report ID */
+
+ prog_fd = bpf_program__fd(hid_skel->progs.hid_user_raw_request);
+
+ 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, 2, "bpf_prog_test_run_xattr_retval"))
+ goto cleanup;
+
+ if (!ASSERT_EQ(buf[3], 2, "hid_user_raw_request_check_in"))
+ 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,
@@ -626,6 +692,9 @@ void serial_test_hid_bpf(void)
err = test_hid_user_call(hid_skel, uhid_fd, sysfs_fd);
ASSERT_OK(err, "hid_user");

+ err = test_hid_user_raw_request_call(hid_skel, uhid_fd, sysfs_fd);
+ ASSERT_OK(err, "hid_user_raw_request");
+
err = test_rdesc_fixup(hid_skel, uhid_fd, sysfs_fd);
ASSERT_OK(err, "hid_rdesc_fixup");

diff --git a/tools/testing/selftests/bpf/progs/hid.c b/tools/testing/selftests/bpf/progs/hid.c
index fabfaf0f2526..ea011ff9e752 100644
--- a/tools/testing/selftests/bpf/progs/hid.c
+++ b/tools/testing/selftests/bpf/progs/hid.c
@@ -9,6 +9,11 @@ char _license[] SEC("license") = "GPL";
__u64 callback_check = 52;
__u64 callback2_check = 52;

+struct {
+ __uint(type, BPF_MAP_TYPE_RINGBUF);
+ __uint(max_entries, 4096 * 64);
+} ringbuf SEC(".maps");
+
SEC("hid/device_event")
int hid_first_event(struct hid_bpf_ctx *ctx)
{
@@ -121,3 +126,55 @@ int hid_user(struct hid_bpf_ctx *ctx)

return 0;
}
+
+SEC("hid/user_event")
+int hid_user_raw_request(struct hid_bpf_ctx *ctx)
+{
+ const unsigned int buflen = 256;
+ const unsigned int _buflen = buflen * sizeof(__u8);
+ __u8 *buf;
+ int ret;
+ __u32 size;
+ __u8 rtype, reqtype;
+
+ buf = bpf_ringbuf_reserve(&ringbuf, _buflen, 0);
+ if (!buf)
+ return -12; /* -ENOMEM */
+
+ __builtin_memcpy(buf, ctx->data, _buflen);
+
+ /*
+ * build up a custom API for our needs:
+ * offset 0, size 1: report type
+ * offset 1, size 1: request type
+ * offset 2+: data
+ */
+ rtype = buf[0];
+ reqtype = buf[1];
+ size = ctx->size - 2;
+
+ if (size < _buflen - 2) {
+ ret = bpf_hid_raw_request(ctx,
+ &buf[2],
+ size,
+ rtype,
+ reqtype);
+ if (ret < 0)
+ goto discard;
+ } else {
+ ret = -7; /* -E2BIG */
+ goto discard;
+ }
+
+ __builtin_memcpy(&ctx->data[2], &buf[2], _buflen - 2);
+
+ ctx->size = ret + 2;
+ ctx->u.user.retval = ret;
+
+ ret = 0;
+
+ discard:
+ bpf_ringbuf_discard(buf, 0);
+
+ return ret;
+}
--
2.35.1