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selftests/hid: add an infinite loop test for hid_bpf_try_input_report

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We don't want this call to allow an infinite loop in HID-BPF, so let's
have some tests.

Link: https://patch.msgid.link/20240626-hid_hw_req_bpf-v2-13-cfd60fb6c79f@kernel.org
Acked-by: Jiri Kosina <jkosina@suse.com>
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
This commit is contained in:
Benjamin Tissoires 2024-06-26 15:46:34 +02:00
parent 62f2e1a096
commit d3e15189bf
2 changed files with 78 additions and 0 deletions
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41
tools/testing/selftests/hid/hid_bpf.c
View File

@ -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,

37
tools/testing/selftests/hid/progs/hid.c
View File

@ -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,
};