We add 3 new tests: - first, we make sure we can prevent the output_report 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_output_report(), returning a custom value - last, we ensure that we can not loop between hooks for hid_hw_output_report() and manual calls to hid_bpf_hw_output_report() from that same hook
Signed-off-by: Benjamin Tissoires bentiss@kernel.org --- drivers/hid/bpf/hid_bpf_dispatch.c | 5 ++ tools/testing/selftests/hid/hid_bpf.c | 102 ++++++++++++++++++++++++++++++++ tools/testing/selftests/hid/progs/hid.c | 58 ++++++++++++++++++ 3 files changed, 165 insertions(+)
diff --git a/drivers/hid/bpf/hid_bpf_dispatch.c b/drivers/hid/bpf/hid_bpf_dispatch.c index 2a29a0625a3b..709403340fd7 100644 --- a/drivers/hid/bpf/hid_bpf_dispatch.c +++ b/drivers/hid/bpf/hid_bpf_dispatch.c @@ -457,11 +457,16 @@ hid_bpf_hw_request(struct hid_bpf_ctx *ctx, __u8 *buf, size_t buf__sz, __bpf_kfunc int hid_bpf_hw_output_report(struct hid_bpf_ctx *ctx, __u8 *buf, size_t buf__sz) { + struct hid_bpf_ctx_kern *ctx_kern; struct hid_device *hdev; size_t size = buf__sz; u8 *dma_data; int ret;
+ ctx_kern = container_of(ctx, struct hid_bpf_ctx_kern, ctx); + if (ctx_kern->from_bpf) + return -EDEADLOCK; + /* check arguments */ ret = __hid_bpf_hw_check_params(ctx, buf, &size, HID_OUTPUT_REPORT); if (ret) diff --git a/tools/testing/selftests/hid/hid_bpf.c b/tools/testing/selftests/hid/hid_bpf.c index f97d56337d8a..40aedd1d9dc5 100644 --- a/tools/testing/selftests/hid/hid_bpf.c +++ b/tools/testing/selftests/hid/hid_bpf.c @@ -1028,6 +1028,108 @@ TEST_F(hid_bpf, test_hid_infinite_loop_raw_request_call) ASSERT_EQ(err, 3) TH_LOG("unexpected returned size while reading HIDIOCGFEATURE: %d", err); }
+/* + * Call hid_hw_output_report against the given uhid device, + * check that the program is called and prevents the + * call to uhid. + */ +TEST_F(hid_bpf, test_hid_filter_output_report_call) +{ + const struct test_program progs[] = { + { .name = "hid_test_filter_output_report" }, + }; + __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_output_report() */ + + buf[0] = 1; /* report ID */ + buf[1] = 2; + buf[2] = 42; + + err = write(self->hidraw_fd, buf, 3); + ASSERT_LT(err, 0) TH_LOG("unexpected success while sending hid_hw_output_report: %d", err); + ASSERT_EQ(errno, 25) TH_LOG("unexpected error code while sending hid_hw_output_report: %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 = write(self->hidraw_fd, buf, 3); + ASSERT_GE(err, 0) TH_LOG("error while sending hid_hw_output_report: %d", err); +} + +/* + * Call hid_hw_output_report 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_output_report_call) +{ + const struct test_program progs[] = { + { .name = "hid_test_hidraw_output_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; + + err = write(self->hidraw_fd, buf, 10); + ASSERT_EQ(err, 2) TH_LOG("unexpected returned size while sending hid_hw_output_report: %d", + err); +} + +/* + * Call hid_hw_output_report against the given uhid device, + * check that the program is not making infinite loops. + */ +TEST_F(hid_bpf, test_hid_infinite_loop_output_report_call) +{ + const struct test_program progs[] = { + { .name = "hid_test_infinite_loop_output_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; + + err = write(self->hidraw_fd, buf, 8); + ASSERT_EQ(err, 2) TH_LOG("unexpected returned size while sending hid_hw_output_report: %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 0ad452fcca58..1fa288b76cd5 100644 --- a/tools/testing/selftests/hid/progs/hid.c +++ b/tools/testing/selftests/hid/progs/hid.c @@ -385,3 +385,61 @@ SEC(".struct_ops.link") struct hid_bpf_ops test_infinite_loop_raw_request = { .hid_hw_request = (void *)hid_test_infinite_loop_raw_request, }; + +SEC("?struct_ops/hid_hw_output_report") +int BPF_PROG(hid_test_filter_output_report, struct hid_bpf_ctx *hctx, unsigned char reportnum, + enum hid_report_type rtype, enum hid_class_request reqtype, __u64 source) +{ + return -25; +} + +SEC(".struct_ops.link") +struct hid_bpf_ops test_filter_output_report = { + .hid_hw_output_report = (void *)hid_test_filter_output_report, +}; + +SEC("?struct_ops.s/hid_hw_output_report") +int BPF_PROG(hid_test_hidraw_output_report, struct hid_bpf_ctx *hctx, __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) + return hid_bpf_hw_output_report(hctx, data, 2); + + return 0; +} + +SEC(".struct_ops.link") +struct hid_bpf_ops test_hidraw_output_report = { + .hid_hw_output_report = (void *)hid_test_hidraw_output_report, +}; + +SEC("?struct_ops.s/hid_hw_output_report") +int BPF_PROG(hid_test_infinite_loop_output_report, struct hid_bpf_ctx *hctx, __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. + */ + + ret = hid_bpf_hw_output_report(hctx, data, 2); + if (ret == 2) + return 2; + + return 0; +} + +SEC(".struct_ops.link") +struct hid_bpf_ops test_infinite_loop_output_report = { + .hid_hw_output_report = (void *)hid_test_infinite_loop_output_report, +};