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Fix mouse-key spamming empty reports (#21663)

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Problem:

`mousekey_task` spams empty hid reports with when a mouse key is
pressed, causing resource exhaustion in the USB mouse endpoint.

Cause:

The check whether or not to send a new mouse report would always
evaluate to true if a mouse key is pressed:

1. `mouse_report` has non-zero fields and `tmpmr` is a copy of this
   fields.
2. `mouse_report` is set to zero, `tmpmr` has now non-zero fields.
3. `has_mouse_report_changed` compares the two and evaluates to true
4. a mouse report is sent.

Fix:

The check condition of `has_mouse_report_changed` will evaluate any
empty record as unchanged, as mouse report data is relative and doesn't
need to return to zero. An empty report will still be send by
`register_mouse` on release of all mouse buttons.
This commit is contained in:
Stefan Kerkmann 2023-08-02 13:47:25 +02:00 committed by GitHub
parent 7fbc4153e8
commit b2d068d1aa
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GPG key ID: 4AEE18F83AFDEB23
1 changed files with 10 additions and 2 deletions
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12
tmk_core/protocol/report.c
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@ -281,13 +281,21 @@ void clear_keys_from_report(report_keyboard_t* keyboard_report) {
#ifdef MOUSE_ENABLE
/**
* @brief Compares 2 mouse reports for difference and returns result
* @brief Compares 2 mouse reports for difference and returns result. Empty
* reports always evaluate as unchanged.
*
* @param[in] new_report report_mouse_t
* @param[in] old_report report_mouse_t
* @return bool result
*/
__attribute__((weak)) bool has_mouse_report_changed(report_mouse_t* new_report, report_mouse_t* old_report) {
return memcmp(new_report, old_report, sizeof(report_mouse_t));
// memcmp doesn't work here because of the `report_id` field when using
// shared mouse endpoint
bool changed = ((new_report->buttons != old_report->buttons) ||
# ifdef MOUSE_EXTENDED_REPORT
(new_report->boot_x != 0 && new_report->boot_x != old_report->boot_x) || (new_report->boot_y != 0 && new_report->boot_y != old_report->boot_y) ||
# endif
(new_report->x != 0 && new_report->x != old_report->x) || (new_report->y != 0 && new_report->y != old_report->y) || (new_report->h != 0 && new_report->h != old_report->h) || (new_report->v != 0 && new_report->v != old_report->v));
return changed;
}
#endif