linux-kernel - Re: [PATCH v3 4/4] Input: Don't send fake button presses to wake system

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <nxticocp26r5mmpkttritw76h5igw7bdpus6zaf5krkso2h5xy@wna6m2quekfi>
Date: Thu, 26 Jun 2025 11:07:40 -0700
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: Mario Limonciello <superm1@...nel.org>
Cc: Hans de Goede <hansg@...nel.org>, Mika Westerberg <westeri@...nel.org>, 
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>, Linus Walleij <linus.walleij@...aro.org>, 
	Bartosz Golaszewski <brgl@...ev.pl>, "open list:GPIO ACPI SUPPORT" <linux-gpio@...r.kernel.org>, 
	"open list:GPIO ACPI SUPPORT" <linux-acpi@...r.kernel.org>, open list <linux-kernel@...r.kernel.org>, 
	"open list:INPUT (KEYBOARD, MOUSE, JOYSTICK, TOUCHSCREEN)..." <linux-input@...r.kernel.org>, Mario Limonciello <mario.limonciello@....com>
Subject: Re: [PATCH v3 4/4] Input: Don't send fake button presses to wake
 system

On Thu, Jun 26, 2025 at 12:53:02PM -0500, Mario Limonciello wrote:
> 
> 
> On 6/26/25 12:44 PM, Dmitry Torokhov wrote:
> > Hi Mario,
> > 
> > On Thu, Jun 26, 2025 at 06:33:08AM -0500, Mario Limonciello wrote:
> > > 
> > > 
> > > On 6/26/25 3:35 AM, Hans de Goede wrote:
> > > > Hi Mario,
> > > > 
> > > > On 25-Jun-25 23:58, Mario Limonciello wrote:
> > > > > From: Mario Limonciello <mario.limonciello@....com>
> > > > > 
> > > > > Sending an input event to wake a system does wake it, but userspace picks
> > > > > up the keypress and processes it.  This isn't the intended behavior as it
> > > > > causes a suspended system to wake up and then potentially turn off if
> > > > > userspace is configured to turn off on power button presses.
> > > > > 
> > > > > Instead send a PM wakeup event for the PM core to handle waking the system.
> > > > > 
> > > > > Cc: Hans de Goede <hansg@...nel.org>
> > > > > Fixes: 0f107573da417 ("Input: gpio_keys - handle the missing key press event in resume phase")
> > > > > Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> > > > > ---
> > > > >    drivers/input/keyboard/gpio_keys.c | 7 +------
> > > > >    1 file changed, 1 insertion(+), 6 deletions(-)
> > > > > 
> > > > > diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c
> > > > > index 773aa5294d269..4c6876b099c43 100644
> > > > > --- a/drivers/input/keyboard/gpio_keys.c
> > > > > +++ b/drivers/input/keyboard/gpio_keys.c
> > > > > @@ -420,12 +420,7 @@ static irqreturn_t gpio_keys_gpio_isr(int irq, void *dev_id)
> > > > >    		pm_stay_awake(bdata->input->dev.parent);
> > > > >    		if (bdata->suspended  &&
> > > > >    		    (button->type == 0 || button->type == EV_KEY)) {
> > > > > -			/*
> > > > > -			 * Simulate wakeup key press in case the key has
> > > > > -			 * already released by the time we got interrupt
> > > > > -			 * handler to run.
> > > > > -			 */
> > > > > -			input_report_key(bdata->input, button->code, 1);
> > > > > +			pm_wakeup_event(bdata->input->dev.parent, 0);
> > 
> > There is already pm_stay_awake() above.
> 
> But that doesn't help with the fact that userspace gets KEY_POWER from this
> and reacts to it.
> 
> > 
> > > > >    		}
> > > > >    	}
> > > > 
> > > > Hmm, we have the same problem on many Bay Trail / Cherry Trail
> > > > windows 8 / win10 tablets, so  this has been discussed before and e.g.
> > > > Android userspace actually needs the button-press (evdev) event to not
> > > > immediately go back to sleep, so a similar patch has been nacked in
> > > > the past.
> > > > 
> > > > At least for GNOME this has been fixed in userspace by ignoring
> > > > power-button events the first few seconds after a resume from suspend.
> > > > 
> > > 
> > > The default behavior for logind is:
> > > 
> > > HandlePowerKey=poweroff
> > > 
> > > Can you share more about what version of GNOME has a workaround?
> > > This was actually GNOME (on Ubuntu 24.04) that I found this issue.
> > > 
> > > Nonetheless if this is dependent on an Android userspace problem could we
> > > perhaps conditionalize it on CONFIG_ANDROID_BINDER_DEVICES?
> > 
> > No it is not only Android, other userspace may want to distinguish
> > between normal and "dark" resume based on keyboard or other user
> > activity.
> > 
> > Thanks.
> > 
> In this specific case does the key passed up to satisfy this userspace
> requirement and keep it awake need to specifically be a fabricated
> KEY_POWER?
> 
> Or could we find a key that doesn't require some userspace to ignore
> KEY_POWER?
> 
> Maybe something like KEY_RESERVED, KEY_FN, or KEY_POWER2?

The code makes no distinction between KEY_POWER and KEY_A or KEY_B, etc.
It simply passes event to userspace for processing.

You need to fix your userspace. Even with your tweak it is possible for
userspace to get a normal key event "too early" and turn off the screen
again, so you still need to handle this situation.

Thanks.

-- 
Dmitry