From 502882e081247d51a61032c4ec9eb8535c7b24ec Mon Sep 17 00:00:00 2001 From: hselasky Date: Tue, 14 Jan 2014 08:43:38 +0000 Subject: [PATCH] Don't output any modifier keys before we see a valid non-modifier key press. This prevents so-called "ghost keyboards" keeping modifier keys pressed while not actually seen as a real keyboard. MFC after: 2 weeks --- sys/dev/usb/input/ukbd.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/sys/dev/usb/input/ukbd.c b/sys/dev/usb/input/ukbd.c index dd4b32956944..6bc1468edf26 100644 --- a/sys/dev/usb/input/ukbd.c +++ b/sys/dev/usb/input/ukbd.c @@ -197,6 +197,7 @@ struct ukbd_softc { #define UKBD_FLAG_NUMLOCK 0x00080000 #define UKBD_FLAG_CAPSLOCK 0x00100000 #define UKBD_FLAG_SCROLLLOCK 0x00200000 +#define UKBD_FLAG_VALID_KEYS 0x00400000 int sc_mode; /* input mode (K_XLATE,K_RAW,K_CODE) */ int sc_state; /* shift/lock key state */ @@ -512,6 +513,41 @@ ukbd_interrupt(struct ukbd_softc *sc) n_mod = sc->sc_ndata.modifiers; o_mod = sc->sc_odata.modifiers; + + /* + * Don't output any modifier keys before we see a valid + * non-modifier key press. This prevents so-called "ghost + * keyboards" keeping modifier keys pressed while not actually + * seen as a real keyboard. + */ + if (sc->sc_flags & UKBD_FLAG_VALID_KEYS) + goto kfound; + + for (i = 0; i != UKBD_NKEYCODE; i++) { + key = sc->sc_ndata.keycode[i]; + switch (key) { + case 0xe0: + case 0xe4: + case 0xe1: + case 0xe5: + case 0xe2: + case 0xe6: + case 0xe3: + case 0xe7: + case 0x00: + case KEY_ERROR: + break; + default: + sc->sc_flags |= UKBD_FLAG_VALID_KEYS; + goto kfound; + } + } + DPRINTF("Keeping modifiers buffered\n"); + + /* keep modifiers in buffer */ + sc->sc_ndata.modifiers = n_mod = 0; + +kfound: if (n_mod != o_mod) { for (i = 0; i < UKBD_NMOD; i++) { if ((n_mod & ukbd_mods[i].mask) !=