diff options
| -rw-r--r-- | drivers/hid/hid-core.c | 58 | ||||
| -rw-r--r-- | include/linux/hid.h | 4 |
2 files changed, 62 insertions, 0 deletions
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index ab59fdf06230..e937a5847bf0 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -821,6 +821,64 @@ static int search(__s32 *array, __s32 value, unsigned n) return -1; } +static const char * const hid_report_names[] = { + "HID_INPUT_REPORT", + "HID_OUTPUT_REPORT", + "HID_FEATURE_REPORT", +}; +/** + * hid_validate_values - validate existing device report's value indexes + * + * @device: hid device + * @type: which report type to examine + * @id: which report ID to examine (0 for first) + * @field_index: which report field to examine + * @report_counts: expected number of values + * + * Validate the number of values in a given field of a given report, after + * parsing. + */ +struct hid_report *hid_validate_values(struct hid_device *hid, + unsigned int type, unsigned int id, + unsigned int field_index, + unsigned int report_counts) +{ + struct hid_report *report; + + if (type > HID_FEATURE_REPORT) { + hid_err(hid, "invalid HID report type %u\n", type); + return NULL; + } + + if (id >= HID_MAX_IDS) { + hid_err(hid, "invalid HID report id %u\n", id); + return NULL; + } + + /* + * Explicitly not using hid_get_report() here since it depends on + * ->numbered being checked, which may not always be the case when + * drivers go to access report values. + */ + report = hid->report_enum[type].report_id_hash[id]; + if (!report) { + hid_err(hid, "missing %s %u\n", hid_report_names[type], id); + return NULL; + } + if (report->maxfield <= field_index) { + hid_err(hid, "not enough fields in %s %u\n", + hid_report_names[type], id); + return NULL; + } + if (report->field[field_index]->report_count < report_counts) { + hid_err(hid, "not enough values in %s %u field %u\n", + hid_report_names[type], id, field_index); + return NULL; + } + return report; +} +EXPORT_SYMBOL_GPL(hid_validate_values); + /** * hid_match_report - check if driver's raw_event should be called * diff --git a/include/linux/hid.h b/include/linux/hid.h index 8c933a86cba9..3572ecd29ccc 100644 --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -737,6 +737,10 @@ void hid_output_report(struct hid_report *report, __u8 *data); struct hid_device *hid_allocate_device(void); struct hid_report *hid_register_report(struct hid_device *device, unsigned type, unsigned id); int hid_parse_report(struct hid_device *hid, __u8 *start, unsigned size); +struct hid_report *hid_validate_values(struct hid_device *hid, + unsigned int type, unsigned int id, + unsigned int field_index, + unsigned int report_counts); int hid_check_keys_pressed(struct hid_device *hid); int hid_connect(struct hid_device *hid, unsigned int connect_mask); void hid_disconnect(struct hid_device *hid); |