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Message-Id: <20240626-hid_hw_req_bpf-v2-6-cfd60fb6c79f@kernel.org>
Date: Wed, 26 Jun 2024 15:46:27 +0200
From: Benjamin Tissoires <bentiss@...nel.org>
To: Jiri Kosina <jikos@...nel.org>, Alexei Starovoitov <ast@...nel.org>,
Shuah Khan <shuah@...nel.org>, Jonathan Corbet <corbet@....net>
Cc: linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
bpf@...r.kernel.org, linux-kselftest@...r.kernel.org,
linux-doc@...r.kernel.org, Benjamin Tissoires <bentiss@...nel.org>
Subject: [PATCH HID v2 06/13] selftests/hid: add tests for
hid_hw_raw_request HID-BPF hooks
We add 3 new tests:
- first, we make sure we can prevent the raw_request to happen
- second, we make sure that we can detect that a given hidraw client
was actually doing the request, and for that client only, call ourself
hid_bpf_hw_request(), returning a custom value
- last, we ensure that we can not loop between hooks for
hid_hw_raw_request() and manual calls to hid_bpf_hw_request() from that
hook
Signed-off-by: Benjamin Tissoires <bentiss@...nel.org>
---
no changes in v2
---
tools/testing/selftests/hid/hid_bpf.c | 109 ++++++++++++++++++++++++++++++++
tools/testing/selftests/hid/progs/hid.c | 79 +++++++++++++++++++++++
2 files changed, 188 insertions(+)
diff --git a/tools/testing/selftests/hid/hid_bpf.c b/tools/testing/selftests/hid/hid_bpf.c
index 45e173db35bd..f97d56337d8a 100644
--- a/tools/testing/selftests/hid/hid_bpf.c
+++ b/tools/testing/selftests/hid/hid_bpf.c
@@ -470,6 +470,11 @@ static void detach_bpf(FIXTURE_DATA(hid_bpf) * self)
close(self->hidraw_fd);
self->hidraw_fd = 0;
+ if (!self->skel)
+ return;
+
+ hid__detach(self->skel);
+
for (i = 0; i < ARRAY_SIZE(self->hid_links); i++) {
if (self->hid_links[i])
bpf_link__destroy(self->hid_links[i]);
@@ -575,6 +580,8 @@ static void load_programs(const struct test_program programs[],
programs[i].name + 4);
}
+ hid__attach(self->skel);
+
self->hidraw_fd = open_hidraw(self->dev_id);
ASSERT_GE(self->hidraw_fd, 0) TH_LOG("open_hidraw");
}
@@ -919,6 +926,108 @@ TEST_F(hid_bpf, test_hid_user_raw_request_call)
ASSERT_EQ(args.data[1], 2);
}
+/*
+ * Call hid_hw_raw_request against the given uhid device,
+ * check that the program is called and prevents the
+ * call to uhid.
+ */
+TEST_F(hid_bpf, test_hid_filter_raw_request_call)
+{
+ const struct test_program progs[] = {
+ { .name = "hid_test_filter_raw_request" },
+ };
+ __u8 buf[10] = {0};
+ int err;
+
+ LOAD_PROGRAMS(progs);
+
+ /* first check that we did not attach to device_event */
+
+ /* inject one event */
+ buf[0] = 1;
+ buf[1] = 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], 42);
+ ASSERT_EQ(buf[2], 0) TH_LOG("leftovers_from_previous_test");
+
+ /* now check that our program is preventing hid_hw_raw_request() */
+
+ /* emit hid_hw_raw_request from hidraw */
+ /* Get Feature */
+ memset(buf, 0, sizeof(buf));
+ buf[0] = 0x1; /* Report Number */
+ err = ioctl(self->hidraw_fd, HIDIOCGFEATURE(sizeof(buf)), buf);
+ ASSERT_LT(err, 0) TH_LOG("unexpected success while reading HIDIOCGFEATURE: %d", err);
+ ASSERT_EQ(errno, 20) TH_LOG("unexpected error code while reading HIDIOCGFEATURE: %d",
+ errno);
+
+ /* remove our bpf program and check that we can now emit commands */
+
+ /* detach the program */
+ detach_bpf(self);
+
+ self->hidraw_fd = open_hidraw(self->dev_id);
+ ASSERT_GE(self->hidraw_fd, 0) TH_LOG("open_hidraw");
+
+ err = ioctl(self->hidraw_fd, HIDIOCGFEATURE(sizeof(buf)), buf);
+ ASSERT_GE(err, 0) TH_LOG("error while reading HIDIOCGFEATURE: %d", err);
+}
+
+/*
+ * Call hid_hw_raw_request against the given uhid device,
+ * check that the program is called and can issue the call
+ * to uhid and transform the answer.
+ */
+TEST_F(hid_bpf, test_hid_change_raw_request_call)
+{
+ const struct test_program progs[] = {
+ { .name = "hid_test_hidraw_raw_request" },
+ };
+ __u8 buf[10] = {0};
+ int err;
+
+ LOAD_PROGRAMS(progs);
+
+ /* emit hid_hw_raw_request from hidraw */
+ /* Get Feature */
+ memset(buf, 0, sizeof(buf));
+ buf[0] = 0x1; /* Report Number */
+ err = ioctl(self->hidraw_fd, HIDIOCGFEATURE(sizeof(buf)), buf);
+ ASSERT_EQ(err, 3) TH_LOG("unexpected returned size while reading HIDIOCGFEATURE: %d", err);
+
+ ASSERT_EQ(buf[0], 2);
+ ASSERT_EQ(buf[1], 3);
+ ASSERT_EQ(buf[2], 4);
+}
+
+/*
+ * Call hid_hw_raw_request against the given uhid device,
+ * check that the program is not making infinite loops.
+ */
+TEST_F(hid_bpf, test_hid_infinite_loop_raw_request_call)
+{
+ const struct test_program progs[] = {
+ { .name = "hid_test_infinite_loop_raw_request" },
+ };
+ __u8 buf[10] = {0};
+ int err;
+
+ LOAD_PROGRAMS(progs);
+
+ /* emit hid_hw_raw_request from hidraw */
+ /* Get Feature */
+ memset(buf, 0, sizeof(buf));
+ buf[0] = 0x1; /* Report Number */
+ err = ioctl(self->hidraw_fd, HIDIOCGFEATURE(sizeof(buf)), buf);
+ ASSERT_EQ(err, 3) TH_LOG("unexpected returned size while reading HIDIOCGFEATURE: %d", err);
+}
+
/*
* 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 2e7e5a736dc6..0ad452fcca58 100644
--- a/tools/testing/selftests/hid/progs/hid.c
+++ b/tools/testing/selftests/hid/progs/hid.c
@@ -306,3 +306,82 @@ SEC(".struct_ops.link")
struct hid_bpf_ops test_insert3 = {
.hid_device_event = (void *)hid_test_insert3,
};
+
+SEC("?struct_ops/hid_hw_request")
+int BPF_PROG(hid_test_filter_raw_request, struct hid_bpf_ctx *hctx, unsigned char reportnum,
+ enum hid_report_type rtype, enum hid_class_request reqtype, __u64 source)
+{
+ return -20;
+}
+
+SEC(".struct_ops.link")
+struct hid_bpf_ops test_filter_raw_request = {
+ .hid_hw_request = (void *)hid_test_filter_raw_request,
+};
+
+static struct file *current_file;
+
+SEC("fentry/hidraw_open")
+int BPF_PROG(hidraw_open, struct inode *inode, struct file *file)
+{
+ current_file = file;
+ return 0;
+}
+
+SEC("?struct_ops.s/hid_hw_request")
+int BPF_PROG(hid_test_hidraw_raw_request, struct hid_bpf_ctx *hctx, unsigned char reportnum,
+ enum hid_report_type rtype, enum hid_class_request reqtype, __u64 source)
+{
+ __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 3 /* size */);
+ int ret;
+
+ if (!data)
+ return 0; /* EPERM check */
+
+ /* check if the incoming request comes from our hidraw operation */
+ if (source == (__u64)current_file) {
+ data[0] = reportnum;
+
+ ret = hid_bpf_hw_request(hctx, data, 2, rtype, reqtype);
+ if (ret != 2)
+ return -1;
+ data[0] = reportnum + 1;
+ data[1] = reportnum + 2;
+ data[2] = reportnum + 3;
+ return 3;
+ }
+
+ return 0;
+}
+
+SEC(".struct_ops.link")
+struct hid_bpf_ops test_hidraw_raw_request = {
+ .hid_hw_request = (void *)hid_test_hidraw_raw_request,
+};
+
+SEC("?struct_ops.s/hid_hw_request")
+int BPF_PROG(hid_test_infinite_loop_raw_request, struct hid_bpf_ctx *hctx, unsigned char reportnum,
+ enum hid_report_type rtype, enum hid_class_request reqtype, __u64 source)
+{
+ __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 3 /* size */);
+ int ret;
+
+ if (!data)
+ return 0; /* EPERM check */
+
+ /* always forward the request as-is to the device, hid-bpf should prevent
+ * infinite loops.
+ */
+ data[0] = reportnum;
+
+ ret = hid_bpf_hw_request(hctx, data, 2, rtype, reqtype);
+ if (ret == 2)
+ return 3;
+
+ return 0;
+}
+
+SEC(".struct_ops.link")
+struct hid_bpf_ops test_infinite_loop_raw_request = {
+ .hid_hw_request = (void *)hid_test_infinite_loop_raw_request,
+};
--
2.44.0
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