Ubuntu MATE

Lock Screen can be bypassed by plugging in external monitor on HDMI

Bug #1769278 reported by Jonathan Polak
256
This bug affects 1 person
Affects Status Importance Assigned to Milestone
Ubuntu MATE
New
Undecided
Unassigned

Bug Description

Ubuntu 18.04 - Mate
Machine: Lenovo T460s

Observed Behavior: computer has lid closed and in sleep. Opening the screen results in password protected lockscreen. However, plugging in external monitor on HDMI bypasses the lockscreen and goes straight to the user's desktop. Laptop is set to turn off built in screen upon connection to external screen on HDMI rather than "mirror" or "extend". The "lock screen now" widget in the panel stops working after I bypass the login screen in this manner.

Expected Behavior: it should not be possible to bypass lock-screen without entering password no matter what display is used

Revision history for this message
Etienne Papegnies (etienne-papegnies) wrote :

Hello
Thank you for your report.
We have had another report of something like that happening to another user on a Lenovo T450s.
Can you please provide some additional information to help us decide what to do about this issue?

We would like the output of the commands:

1. xrandr # when external monitor is connected

2. inxi -G # same thing

3. apt-cache policy mate-screensaver

4. gsettings list-recursively | grep -i screensaver

Can you also please investigate your log files for any messages related to mate-screensaver crashing?

Thanks.

Revision history for this message
Jonathan Polak (jpolak) wrote : Re: [Bug 1769278] Re: Lock Screen can be bypassed by plugging in external monitor on HDMI

I will look into this and get back to you.

On Fri, May 4, 2018 at 9:50 PM Etienne Papegnies <
<email address hidden>> wrote:

> Hello
> Thank you for your report.
> We have had another report of something like that happening to another
> user on a Lenovo T450s.
> Can you please provide some additional information to help us decide what
> to do about this issue?
>
> We would like the output of the commands:
>
> 1. xrandr # when external monitor is connected
>
> 2. inxi -G # same thing
>
> 3. apt-cache policy mate-screensaver
>
> 4. gsettings list-recursively | grep -i screensaver
>
> Can you also please investigate your log files for any messages related
> to mate-screensaver crashing?
>
> Thanks.
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1769278
>
> Title:
> Lock Screen can be bypassed by plugging in external monitor on HDMI
>
> Status in ubuntu-mate:
> New
>
> Bug description:
> Ubuntu 18.04 - Mate
> Machine: Lenovo T460s
>
> Observed Behavior: computer has lid closed and in sleep. Opening the
> screen results in password protected lockscreen. However, plugging in
> external monitor on HDMI bypasses the lockscreen and goes straight to
> the user's desktop. Laptop is set to turn off built in screen upon
> connection to external screen on HDMI rather than "mirror" or
> "extend". The "lock screen now" widget in the panel stops working
> after I bypass the login screen in this manner.
>
> Expected Behavior: it should not be possible to bypass lock-screen
> without entering password no matter what display is used
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/ubuntu-mate/+bug/1769278/+subscriptions
>

Revision history for this message
Jonathan Polak (jpolak) wrote :

Hello - please see attached.

On Fri, May 4, 2018 at 9:50 PM Etienne Papegnies <
<email address hidden>> wrote:

> Hello
> Thank you for your report.
> We have had another report of something like that happening to another
> user on a Lenovo T450s.
> Can you please provide some additional information to help us decide what
> to do about this issue?
>
> We would like the output of the commands:
>
> 1. xrandr # when external monitor is connected
>
> 2. inxi -G # same thing
>
> 3. apt-cache policy mate-screensaver
>
> 4. gsettings list-recursively | grep -i screensaver
>
> Can you also please investigate your log files for any messages related
> to mate-screensaver crashing?
>
> Thanks.
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1769278
>
> Title:
> Lock Screen can be bypassed by plugging in external monitor on HDMI
>
> Status in ubuntu-mate:
> New
>
> Bug description:
> Ubuntu 18.04 - Mate
> Machine: Lenovo T460s
>
> Observed Behavior: computer has lid closed and in sleep. Opening the
> screen results in password protected lockscreen. However, plugging in
> external monitor on HDMI bypasses the lockscreen and goes straight to
> the user's desktop. Laptop is set to turn off built in screen upon
> connection to external screen on HDMI rather than "mirror" or
> "extend". The "lock screen now" widget in the panel stops working
> after I bypass the login screen in this manner.
>
> Expected Behavior: it should not be possible to bypass lock-screen
> without entering password no matter what display is used
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/ubuntu-mate/+bug/1769278/+subscriptions
>

Revision history for this message
Jonathan Polak (jpolak) wrote :

couldn't find any crashes of mate-screensaver in .xsession-errors or in
syslog. I can find in journalctl when the screensaver is unlocked.
a side effect is that when app-menu mate crashes after the screen is
unlocked in this way

On Mon, May 7, 2018 at 1:16 PM Jonathan Polak <email address hidden> wrote:

> Hello - please see attached.
>
> On Fri, May 4, 2018 at 9:50 PM Etienne Papegnies <
> <email address hidden>> wrote:
>
>> Hello
>> Thank you for your report.
>> We have had another report of something like that happening to another
>> user on a Lenovo T450s.
>> Can you please provide some additional information to help us decide what
>> to do about this issue?
>>
>> We would like the output of the commands:
>>
>> 1. xrandr # when external monitor is connected
>>
>> 2. inxi -G # same thing
>>
>> 3. apt-cache policy mate-screensaver
>>
>> 4. gsettings list-recursively | grep -i screensaver
>>
>> Can you also please investigate your log files for any messages related
>> to mate-screensaver crashing?
>>
>> Thanks.
>>
>> --
>> You received this bug notification because you are subscribed to the bug
>> report.
>> https://bugs.launchpad.net/bugs/1769278
>>
>> Title:
>> Lock Screen can be bypassed by plugging in external monitor on HDMI
>>
>> Status in ubuntu-mate:
>> New
>>
>> Bug description:
>> Ubuntu 18.04 - Mate
>> Machine: Lenovo T460s
>>
>> Observed Behavior: computer has lid closed and in sleep. Opening the
>> screen results in password protected lockscreen. However, plugging in
>> external monitor on HDMI bypasses the lockscreen and goes straight to
>> the user's desktop. Laptop is set to turn off built in screen upon
>> connection to external screen on HDMI rather than "mirror" or
>> "extend". The "lock screen now" widget in the panel stops working
>> after I bypass the login screen in this manner.
>>
>> Expected Behavior: it should not be possible to bypass lock-screen
>> without entering password no matter what display is used
>>
>> To manage notifications about this bug go to:
>> https://bugs.launchpad.net/ubuntu-mate/+bug/1769278/+subscriptions
>>
>

Revision history for this message
Jonathan Polak (jpolak) wrote :

Once the lock-screen is bypassed once using the method I described, the
laptop screen is left unprotected (meaning that restarting the computer
from sleep no longer presents a lockscreen on the laptop screen) --
interestingly, it does present a lockscreen on the external screen!

On Mon, May 7, 2018 at 1:45 PM Jonathan Polak <email address hidden> wrote:

> couldn't find any crashes of mate-screensaver in .xsession-errors or in
> syslog. I can find in journalctl when the screensaver is unlocked.
> a side effect is that when app-menu mate crashes after the screen is
> unlocked in this way
>
> On Mon, May 7, 2018 at 1:16 PM Jonathan Polak <email address hidden> wrote:
>
>> Hello - please see attached.
>>
>> On Fri, May 4, 2018 at 9:50 PM Etienne Papegnies <
>> <email address hidden>> wrote:
>>
>>> Hello
>>> Thank you for your report.
>>> We have had another report of something like that happening to another
>>> user on a Lenovo T450s.
>>> Can you please provide some additional information to help us decide
>>> what to do about this issue?
>>>
>>> We would like the output of the commands:
>>>
>>> 1. xrandr # when external monitor is connected
>>>
>>> 2. inxi -G # same thing
>>>
>>> 3. apt-cache policy mate-screensaver
>>>
>>> 4. gsettings list-recursively | grep -i screensaver
>>>
>>> Can you also please investigate your log files for any messages related
>>> to mate-screensaver crashing?
>>>
>>> Thanks.
>>>
>>> --
>>> You received this bug notification because you are subscribed to the bug
>>> report.
>>> https://bugs.launchpad.net/bugs/1769278
>>>
>>> Title:
>>> Lock Screen can be bypassed by plugging in external monitor on HDMI
>>>
>>> Status in ubuntu-mate:
>>> New
>>>
>>> Bug description:
>>> Ubuntu 18.04 - Mate
>>> Machine: Lenovo T460s
>>>
>>> Observed Behavior: computer has lid closed and in sleep. Opening the
>>> screen results in password protected lockscreen. However, plugging in
>>> external monitor on HDMI bypasses the lockscreen and goes straight to
>>> the user's desktop. Laptop is set to turn off built in screen upon
>>> connection to external screen on HDMI rather than "mirror" or
>>> "extend". The "lock screen now" widget in the panel stops working
>>> after I bypass the login screen in this manner.
>>>
>>> Expected Behavior: it should not be possible to bypass lock-screen
>>> without entering password no matter what display is used
>>>
>>> To manage notifications about this bug go to:
>>> https://bugs.launchpad.net/ubuntu-mate/+bug/1769278/+subscriptions
>>>
>>

Revision history for this message
Jonathan Polak (jpolak) wrote :
  • xrandr.txt Edit (2.4 KiB, text/plain; charset="US-ASCII"; name="xrandr.txt")
  • mateSC.txt Edit (209 bytes, text/plain; charset="US-ASCII"; name="mateSC.txt")
  • inxi.txt Edit (529 bytes, text/plain; charset="x-binaryenc"; name="inxi.txt")
  • gsettings.txt Edit (2.1 KiB, text/plain; charset="US-ASCII"; name="gsettings.txt")
  • .xsession-errors Edit (18.1 KiB, application/octet-stream; name=".xsession-errors")
  • syslog.txt Edit (44.5 KiB, text/plain; charset="US-ASCII"; name="syslog.txt")

attached again the logs you asked for.

I also attached syslog and .xsession-errors. The display errors occurred
at ~0930 local time (gmt -7).

On Mon, May 7, 2018 at 8:39 PM Jonathan Polak <email address hidden> wrote:

> Once the lock-screen is bypassed once using the method I described, the
> laptop screen is left unprotected (meaning that restarting the computer
> from sleep no longer presents a lockscreen on the laptop screen) --
> interestingly, it does present a lockscreen on the external screen!
>
> On Mon, May 7, 2018 at 1:45 PM Jonathan Polak <email address hidden> wrote:
>
>> couldn't find any crashes of mate-screensaver in .xsession-errors or in
>> syslog. I can find in journalctl when the screensaver is unlocked.
>> a side effect is that when app-menu mate crashes after the screen is
>> unlocked in this way
>>
>> On Mon, May 7, 2018 at 1:16 PM Jonathan Polak <email address hidden> wrote:
>>
>>> Hello - please see attached.
>>>
>>> On Fri, May 4, 2018 at 9:50 PM Etienne Papegnies <
>>> <email address hidden>> wrote:
>>>
>>>> Hello
>>>> Thank you for your report.
>>>> We have had another report of something like that happening to another
>>>> user on a Lenovo T450s.
>>>> Can you please provide some additional information to help us decide
>>>> what to do about this issue?
>>>>
>>>> We would like the output of the commands:
>>>>
>>>> 1. xrandr # when external monitor is connected
>>>>
>>>> 2. inxi -G # same thing
>>>>
>>>> 3. apt-cache policy mate-screensaver
>>>>
>>>> 4. gsettings list-recursively | grep -i screensaver
>>>>
>>>> Can you also please investigate your log files for any messages related
>>>> to mate-screensaver crashing?
>>>>
>>>> Thanks.
>>>>
>>>> --
>>>> You received this bug notification because you are subscribed to the bug
>>>> report.
>>>> https://bugs.launchpad.net/bugs/1769278
>>>>
>>>> Title:
>>>> Lock Screen can be bypassed by plugging in external monitor on HDMI
>>>>
>>>> Status in ubuntu-mate:
>>>> New
>>>>
>>>> Bug description:
>>>> Ubuntu 18.04 - Mate
>>>> Machine: Lenovo T460s
>>>>
>>>> Observed Behavior: computer has lid closed and in sleep. Opening the
>>>> screen results in password protected lockscreen. However, plugging in
>>>> external monitor on HDMI bypasses the lockscreen and goes straight to
>>>> the user's desktop. Laptop is set to turn off built in screen upon
>>>> connection to external screen on HDMI rather than "mirror" or
>>>> "extend". The "lock screen now" widget in the panel stops working
>>>> after I bypass the login screen in this manner.
>>>>
>>>> Expected Behavior: it should not be possible to bypass lock-screen
>>>> without entering password no matter what display is used
>>>>
>>>> To manage notifications about this bug go to:
>>>> https://bugs.launchpad.net/ubuntu-mate/+bug/1769278/+subscriptions
>>>>
>>>

Martin Wimpress  (flexiondotorg)
information type: Private Security → Public Security
Revision history for this message
M. Kurt (paralaks) wrote :
Download full text (5.2 KiB)

I am running into this issue when I click suspend from the session applet. Laptop goes to sleep but when it wakes login screen is bypassed. This happens when I am using laptop monitor only or external HDMI monitor only. I noticed some ACPI BIOS errors in DMESG but when I was using Unity, waking up from sleep would not bypass login screen. I started noticing this after I swithced to MATE. I am on Ubuntu 20.04.

[309740.201936] ACPI: Waking up from system sleep state S3
[309740.203642] ACPI: EC: interrupt unblocked
[309741.318738] ACPI: EC: event unblocked
[309741.318961] ACPI BIOS Error (bug): Could not resolve symbol [\_SB.PCI0.SAT0.CHN0.DRV1._GTF.DSSP], AE_NOT_FOUND (20200528/psargs-330)
[309741.318969] No Local Variables are initialized for Method [_GTF]
[309741.318971] No Arguments are initialized for method [_GTF]
[309741.318976] ACPI Error: Aborting method \_SB.PCI0.SAT0.CHN0.DRV1._GTF due to previous error (AE_NOT_FOUND) (20200528/psparse-529)
[309741.319067] ACPI BIOS Error (bug): Could not resolve symbol [\_SB.PCI0.SAT1.CHN0.DRV0._GTF.DSSP], AE_NOT_FOUND (20200528/psargs-330)
[309741.319076] No Local Variables are initialized for Method [_GTF]
[309741.319078] No Arguments are initialized for method [_GTF]
[309741.319082] ACPI Error: Aborting method \_SB.PCI0.SAT1.CHN0.DRV0._GTF due to previous error (AE_NOT_FOUND) (20200528/psparse-529)
[309741.319297] ACPI BIOS Error (bug): Could not resolve symbol [\_SB.PCI0.SAT0.CHN1.DRV0._GTF.DSSP], AE_NOT_FOUND (20200528/psargs-330)
[309741.319305] No Local Variables are initialized for Method [_GTF]
[309741.319306] No Arguments are initialized for method [_GTF]
[309741.319309] ACPI Error: Aborting method \_SB.PCI0.SAT0.CHN1.DRV0._GTF due to previous error (AE_NOT_FOUND) (20200528/psparse-529)
[309741.319749] sd 2:0:0:0: [sdb] Starting disk
[309741.319762] sd 1:0:0:0: [sda] Starting disk
[309741.494573] ACPI BIOS Error (bug): Could not resolve symbol [\_SB.PCI0.SAT0.CHN1.DRV0._GTF.DSSP], AE_NOT_FOUND (20200528/psargs-330)
[309741.494580] No Local Variables are initialized for Method [_GTF]
[309741.494581] No Arguments are initialized for method [_GTF]
[309741.494582] ACPI Error: Aborting method \_SB.PCI0.SAT0.CHN1.DRV0._GTF due to previous error (AE_NOT_FOUND) (20200528/psparse-529)
[309741.502611] usb 3-14: reset full-speed USB device number 21 using xhci_hcd
[309741.514618] ACPI BIOS Error (bug): Could not resolve symbol [\_SB.PCI0.SAT0.CHN0.DRV1._GTF.DSSP], AE_NOT_FOUND (20200528/psargs-330)
[309741.514625] No Local Variables are initialized for Method [_GTF]
[309741.514626] No Arguments are initialized for method [_GTF]
[309741.514627] ACPI Error: Aborting method \_SB.PCI0.SAT0.CHN0.DRV1._GTF due to previous error (AE_NOT_FOUND) (20200528/psparse-529)
[309741.570378] usb 1-1.4: reset high-speed USB device number 5 using ehci-pci
[309741.652497] PM: dpm_run_callback(): usb_dev_resume+0x0/0x20 returns -5
[309741.652498] PM: Device 3-14 failed to resume async: error -5
[309741.758400] usb 1-1.5: reset high-speed USB device number 4 using ehci-pci
[309741.790436] ata3: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
[309741.792784] ACPI BIOS Error (bug): Could not resolve symbol [\_SB.PCI0.SAT1...

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