NetBSD Problem Report #53599

From gson@gson.org  Wed Sep 12 13:00:57 2018
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Message-Id: <20180912130050.8B70E989770@guava.gson.org>
Date: Wed, 12 Sep 2018 16:00:50 +0300 (EEST)
From: gson@gson.org (Andreas Gustafsson)
Reply-To: gson@gson.org (Andreas Gustafsson)
To: gnats-bugs@NetBSD.org
Subject: Can't enter ddb using USB keyboard because console
X-Send-Pr-Version: 3.95

>Number:         53599
>Category:       kern
>Synopsis:       Can't enter ddb using USB keyboard because console
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Sep 12 13:05:00 +0000 2018
>Last-Modified:  Wed Sep 12 20:25:00 +0000 2018
>Originator:     Andreas Gustafsson
>Release:        NetBSD 8.0
>Organization:
>Environment:
System: NetBSD
Architecture: x86_64
Machine: amd64
>Description:

When I plug a USB keyboard into a USB port on a HP DL360 G7 running a
GENERIC kernel from the NetBSD/amd64 8.0 release and hit ctrl-alt-esc,
nothing happens.

Apparently this is because the call to console_debugger() in wskbd.c
is inside "if (sc->sc_isconsole)", and sc_isconsole is false.  The
dmesg says:

  pckbd0 at pckbc1 (kbd slot)
  pckbc1: using irq 1 for kbd slot
  wskbd0 at pckbd0: console keyboard
  [...]
  uhidev0 at uhub0 port 1 configuration 1 interface 0
  uhidev0: HP (0x3f0) Virtual Keyboard (0x7029), rev 1.10/0.02, addr 2, iclass 3/1
  ukbd0 at uhidev0
  wskbd1 at ukbd0 mux 1
  wskbd1: connecting to wsdisplay0
  [...]
  uhidev2 at uhub3 port 1 configuration 1 interface 0
  uhidev2: Hewlett-Packard Company (0x3f0) HP USB Smart Card Keyboard (0x1024), rev 2.00/5.35, addr 2, iclass 3/1
  ukbd1 at uhidev2
  wskbd2 at ukbd1 mux 1
  wskbd2: connecting to wsdisplay0

The machine does not have a PS/2 keyboard connector.  The keyboard I
plugged in and tried to enter ddb from is the one attached as wskbd2.

I realize that there is a tradeoff between security and debuggability
here, but at least there should be a simple and documented way to
configure the system to allow ddb to be entered from any USB keyboard
without having to build a custom kernel.  If there already is one,
please enlighten me...

>How-To-Repeat:

>Fix:

>Audit-Trail:
From: Martin Husemann <martin@duskware.de>
To: gnats-bugs@NetBSD.org
Cc: 
Subject: Re: kern/53599: Can't enter ddb using USB keyboard because console
Date: Wed, 12 Sep 2018 15:08:57 +0200

 Try
 	userconf=disable pcbkc*

 in your /boot.cfg.

 Martin

From: Andreas Gustafsson <gson@gson.org>
To: Martin Husemann <martin@duskware.de>
Cc: gnats-bugs@NetBSD.org
Subject: Re: kern/53599: Can't enter ddb using USB keyboard because console
Date: Wed, 12 Sep 2018 17:41:15 +0300

 Martin Husemann wrote:
 >  Try
 >  	userconf=disable pcbkc*
 >  
 >  in your /boot.cfg.

 I think you mean pckbc*, not pcbkc*.

 But that doesn't work, either: with "userconf=disable pckbc*" in
 boot.cfg, the dmesg shows

   [130] pckbc* disabled

 but pckbc0 attaches anyway:

   pckbc0 at isa0 port 0x60-0x64 
   pckbd0 at pckbc0 (kbd slot) 
   pckbc0: using irq 1 for kbd slot 
   wskbd0 at pckbd0: console keyboard, using wsdisplay0

 If I add the two lines

   userconf=disable pckbc0
   userconf=disable pckbc*

 no pckbc attaches, but I still get the "HP Virtual Keyboard" as
 wskbd0:

   uhidev0 at uhub0 port 1 configuration 1 interface 0
   uhidev0: HP (0x3f0) Virtual Keyboard (0x7029), rev 1.10/0.02, addr 2, iclass 3/1
   ukbd0 at uhidev0
   wskbd0 at ukbd0 mux 1
   wskbd0: connecting to wsdisplay0
   uhidev1 at uhub0 port 1 configuration 1 interface 1
   uhidev1: HP (0x3f0) Virtual Keyboard (0x7029), rev 1.10/0.02, addr 2, iclass 3/1
   ums0 at uhidev1: 3 buttons
   wsmouse0 at ums0 mux 0
   uhidev2 at uhub3 port 1 configuration 1 interface 0
   uhidev2: Hewlett-Packard Company (0x3f0) HP USB Smart Card Keyboard (0x1024), rev 2.00/5.35, addr 2, iclass 3/1
   ukbd1 at uhidev2
   wskbd1 at ukbd1 mux 1
   wskbd1: connecting to wsdisplay0

 Unsurprisingly, ctrl-alt-esc one the one physical keyboards still
 doesn't work.  But what I find most confusing is that now *none* of
 the keyboards is marked as "console keyboard" in the dmesg.
 -- 
 Andreas Gustafsson, gson@gson.org

From: matthew green <mrg@eterna.com.au>
To: gnats-bugs@NetBSD.org
Cc: kern-bug-people@netbsd.org, gnats-admin@netbsd.org,
    netbsd-bugs@netbsd.org, gson@gson.org (Andreas Gustafsson)
Subject: re: kern/53599: Can't enter ddb using USB keyboard because console
Date: Thu, 13 Sep 2018 06:20:02 +1000

 >  Martin Husemann wrote:
 >  >  Try
 >  >  	userconf=disable pcbkc*
 >  >  
 >  >  in your /boot.cfg.
 >  
 >  I think you mean pckbc*, not pcbkc*.
 >  
 >  But that doesn't work, either: with "userconf=disable pckbc*" in
 >  boot.cfg, the dmesg shows
 >  
 >    [130] pckbc* disabled
 >  
 >  but pckbc0 attaches anyway:
 >  
 >    pckbc0 at isa0 port 0x60-0x64 
 >    pckbd0 at pckbc0 (kbd slot) 
 >    pckbc0: using irq 1 for kbd slot 
 >    wskbd0 at pckbd0: console keyboard, using wsdisplay0
 >  
 >  If I add the two lines
 >  
 >    userconf=disable pckbc0
 >    userconf=disable pckbc*
 >  
 >  no pckbc attaches, but I still get the "HP Virtual Keyboard" as
 >  wskbd0:

 yes - the "pckbc*" is a literal match here.  it matches the
 configuration "pckbc*", which itself is able to attach to
 any instance, but it doesn't stop the literal pckbc0 at isa
 that is in GENERIC.  so, this is entirely "as designed".

 the base problem - i wonder if we can have a wsconcstl or
 wsconscfg based method (ioctl) to enable console/ddb.  then
 we can at least have a simple method to enable this while
 not actually affecting security.


 .mrg.

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