Segfault with guacamole 0.9.14

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Segfault with guacamole 0.9.14

Nicolas Lécureuil
Hi,

i rebuilded guacd 0.9.14 ( using my own build debs )

# dpkg -l | grep guac
ii  guacamole                               0.9.14-4                                    all          HTML5 web application for accessing remote desktops
ii  guacamole-auth-mysql                    0.9.14-1                                    all          Guacamole Mysql Identification
ii  guacd                                   0.9.14-1                                    amd64        HTML5 web application for accessing remote desktops (proxy daemon)
ii  guacd-dbgsym                            0.9.14-1                                    amd64        Debug symbols for guacd
ii  libguac-client-rdp0:amd64               0.9.14-1                                    amd64        HTML5 web application for accessing remote desktops (RDP support)
ii  libguac-client-rdp0-dbgsym:amd64        0.9.14-1                                    amd64        Debug symbols for libguac-client-rdp0
ii  libguac-client-ssh0:amd64               0.9.14-1                                    amd64        HTML5 web application for accessing remote desktops (SSH support)
ii  libguac-client-ssh0-dbgsym:amd64        0.9.14-1                                    amd64        Debug symbols for libguac-client-ssh0
ii  libguac-client-vnc0:amd64               0.9.14-1                                    amd64        HTML5 web application for accessing remote desktops (VNC support)
ii  libguac-client-vnc0-dbgsym:amd64        0.9.14-1                                    amd64        Debug symbols for libguac-client-vnc0
ii  libguac-dev:amd64                       0.9.14-1                                    amd64        Guacamole proxy daemon (core library headers)
ii  libguac11:amd64                         0.9.14-1                                    amd64        HTML5 web application for accessing remote desktops (library)
ii  libguac11-dbgsym:amd64                  0.9.14-1                                    amd64        Debug symbols for libguac11


Each time i use the vnc plugin i can see a segfault in the logs.

Jun 27 14:48:28 pulsemaster kernel: [712278.556955] guacd[25572]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9ead477d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:49:35 pulsemaster kernel: [712345.817333] guacd[25612]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9eadc78d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:50:41 pulsemaster kernel: [712412.051393] guacd[25655]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9eacc76d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:51:47 pulsemaster kernel: [712477.883688] guacd[25700]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9ead477d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:52:54 pulsemaster kernel: [712544.755122] guacd[25746]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9eadc78d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:54:03 pulsemaster kernel: [712613.432083] guacd[25794]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9eacc76d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:55:08 pulsemaster kernel: [712678.871467] guacd[25836]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9ead477d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:55:29 pulsemaster kernel: [712699.432836] guacd[25883]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9eadc78d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:57:39 pulsemaster kernel: [712829.633618] guacd[26029]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9eacc76d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:58:35 pulsemaster kernel: [712885.994620] guacd[26072]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9ead477d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:59:20 pulsemaster kernel: [712931.152907] guacd[26119]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9eadc78d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]

I use a debian stretch.
The vnc server is installed on a windows 10 ( TightVNC )

i am sure i use the new guacd and plugins ( as shown in the dpkg command ).

Btw the rdp plugin works 100% of the time What can i do to help debugging ? Regards, Nicolas Lécureuil.

 

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Re: Segfault with guacamole 0.9.14

vnick


On Wed, Jun 27, 2018 at 10:01 AM Nicolas Lécureuil <[hidden email]> wrote:
Hi,

i rebuilded guacd 0.9.14 ( using my own build debs )

# dpkg -l | grep guac
ii  guacamole                               0.9.14-4                                    all          HTML5 web application for accessing remote desktops
ii  guacamole-auth-mysql                    0.9.14-1                                    all          Guacamole Mysql Identification
ii  guacd                                   0.9.14-1                                    amd64        HTML5 web application for accessing remote desktops (proxy daemon)
ii  guacd-dbgsym                            0.9.14-1                                    amd64        Debug symbols for guacd
ii  libguac-client-rdp0:amd64               0.9.14-1                                    amd64        HTML5 web application for accessing remote desktops (RDP support)
ii  libguac-client-rdp0-dbgsym:amd64        0.9.14-1                                    amd64        Debug symbols for libguac-client-rdp0
ii  libguac-client-ssh0:amd64               0.9.14-1                                    amd64        HTML5 web application for accessing remote desktops (SSH support)
ii  libguac-client-ssh0-dbgsym:amd64        0.9.14-1                                    amd64        Debug symbols for libguac-client-ssh0
ii  libguac-client-vnc0:amd64               0.9.14-1                                    amd64        HTML5 web application for accessing remote desktops (VNC support)
ii  libguac-client-vnc0-dbgsym:amd64        0.9.14-1                                    amd64        Debug symbols for libguac-client-vnc0
ii  libguac-dev:amd64                       0.9.14-1                                    amd64        Guacamole proxy daemon (core library headers)
ii  libguac11:amd64                         0.9.14-1                                    amd64        HTML5 web application for accessing remote desktops (library)
ii  libguac11-dbgsym:amd64                  0.9.14-1                                    amd64        Debug symbols for libguac11

What version of the libvncserver/libvncclient are you building against? 


Each time i use the vnc plugin i can see a segfault in the logs.

Jun 27 14:48:28 pulsemaster kernel: [712278.556955] guacd[25572]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9ead477d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:49:35 pulsemaster kernel: [712345.817333] guacd[25612]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9eadc78d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:50:41 pulsemaster kernel: [712412.051393] guacd[25655]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9eacc76d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:51:47 pulsemaster kernel: [712477.883688] guacd[25700]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9ead477d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:52:54 pulsemaster kernel: [712544.755122] guacd[25746]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9eadc78d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:54:03 pulsemaster kernel: [712613.432083] guacd[25794]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9eacc76d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:55:08 pulsemaster kernel: [712678.871467] guacd[25836]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9ead477d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:55:29 pulsemaster kernel: [712699.432836] guacd[25883]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9eadc78d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:57:39 pulsemaster kernel: [712829.633618] guacd[26029]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9eacc76d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:58:35 pulsemaster kernel: [712885.994620] guacd[26072]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9ead477d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:59:20 pulsemaster kernel: [712931.152907] guacd[26119]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9eadc78d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]

I use a debian stretch.
The vnc server is installed on a windows 10 ( TightVNC )
Any special configuration for VNC?  Are you trying to use encryption?  Anything else different about your VNC server configuration?  Have you tried against other VNC servers on other target?

-Nick 
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Re: Segfault with guacamole 0.9.14

Nicolas Lécureuil
Le 27 juin 2018 à 16:11, Nick Couchman <[hidden email]> a écrit :



On Wed, Jun 27, 2018 at 10:01 AM Nicolas Lécureuil <[hidden email]> wrote:
Hi,

i rebuilded guacd 0.9.14 ( using my own build debs )

# dpkg -l | grep guac
ii  guacamole                               0.9.14-4                                    all          HTML5 web application for accessing remote desktops
ii  guacamole-auth-mysql                    0.9.14-1                                    all          Guacamole Mysql Identification
ii  guacd                                   0.9.14-1                                    amd64        HTML5 web application for accessing remote desktops (proxy daemon)
ii  guacd-dbgsym                            0.9.14-1                                    amd64        Debug symbols for guacd
ii  libguac-client-rdp0:amd64               0.9.14-1                                    amd64        HTML5 web application for accessing remote desktops (RDP support)
ii  libguac-client-rdp0-dbgsym:amd64        0.9.14-1                                    amd64        Debug symbols for libguac-client-rdp0
ii  libguac-client-ssh0:amd64               0.9.14-1                                    amd64        HTML5 web application for accessing remote desktops (SSH support)
ii  libguac-client-ssh0-dbgsym:amd64        0.9.14-1                                    amd64        Debug symbols for libguac-client-ssh0
ii  libguac-client-vnc0:amd64               0.9.14-1                                    amd64        HTML5 web application for accessing remote desktops (VNC support)
ii  libguac-client-vnc0-dbgsym:amd64        0.9.14-1                                    amd64        Debug symbols for libguac-client-vnc0
ii  libguac-dev:amd64                       0.9.14-1                                    amd64        Guacamole proxy daemon (core library headers)
ii  libguac11:amd64                         0.9.14-1                                    amd64        HTML5 web application for accessing remote desktops (library)
ii  libguac11-dbgsym:amd64                  0.9.14-1                                    amd64        Debug symbols for libguac11

What version of the libvncserver/libvncclient are you building against? 


Each time i use the vnc plugin i can see a segfault in the logs.

Jun 27 14:48:28 pulsemaster kernel: [712278.556955] guacd[25572]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9ead477d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:49:35 pulsemaster kernel: [712345.817333] guacd[25612]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9eadc78d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:50:41 pulsemaster kernel: [712412.051393] guacd[25655]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9eacc76d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:51:47 pulsemaster kernel: [712477.883688] guacd[25700]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9ead477d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:52:54 pulsemaster kernel: [712544.755122] guacd[25746]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9eadc78d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:54:03 pulsemaster kernel: [712613.432083] guacd[25794]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9eacc76d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:55:08 pulsemaster kernel: [712678.871467] guacd[25836]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9ead477d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:55:29 pulsemaster kernel: [712699.432836] guacd[25883]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9eadc78d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:57:39 pulsemaster kernel: [712829.633618] guacd[26029]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9eacc76d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:58:35 pulsemaster kernel: [712885.994620] guacd[26072]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9ead477d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]
Jun 27 14:59:20 pulsemaster kernel: [712931.152907] guacd[26119]: segfault at 10 ip 00007f9eaea6f692 sp 00007f9eadc78d10 error 4 in libguac-client-vnc.so.0.0.0[7f9eaea67000+13000]

I use a debian stretch.
The vnc server is installed on a windows 10 ( TightVNC )
Any special configuration for VNC?  Are you trying to use encryption?  Anything else different about your VNC server configuration?  Have you tried against other VNC servers on other target?

-Nick 


What version of the libvncserver/libvncclient are you building against?

# dpkg -l | grep vncclient
ii libvncclient1:amd64 0.9.11+dfsg-1+deb9u1 amd64 API to write one's own VNC server - client library

Any special configuration for VNC? 


for the client, this is nothing special


Are you trying to use encryption? 

No encryption


Anything else different about your VNC server configuration? 

no password, trought reverse ssh with ssh-key without passphrase


Have you tried against other VNC servers on other target?

No, only tightvnc as this is the plugin we use on our software


in the logs i can see:

Jun 27 16:10:31 pulsemaster guacd[24552]: Creating new client for protocol "vnc"
Jun 27 16:10:31 pulsemaster guacd[24552]: Connection ID is "$2b73afc9-4268-4f26-8942-5ddf0024536c"
Jun 27 16:10:31 pulsemaster guacd[29002]: Cursor rendering: local
Jun 27 16:10:31 pulsemaster guacd[29002]: User "@ae1d47fe-24e6-4557-ad07-2178e528524f" joined connection "$2b73afc9-4268-4f26-8942-5ddf0024536c" (1 users now present)
Jun 27 16:10:31 pulsemaster guacd[29002]: Listening for connections on port 65408
Jun 27 16:10:31 pulsemaster guacd[29002]: -listennofork: Listening on port 65408
Jun 27 16:10:31 pulsemaster guacd[29002]: -listennofork: Command line errors are not reported until a connection comes in.
Jun 27 16:10:34 pulsemaster guacd[28941]: User is not responding.
Jun 27 16:10:34 pulsemaster guacd[24552]: Connection "$12c5328c-c127-453d-bc9c-f631bf8e90f8" removed.
Jun 27 16:10:34 pulsemaster kernel: [717204.421339] guacd[28944]: segfault at 10 ip 00007f9ead26c692 sp 00007f9eaec7ad10 error 4 in libguac-client-vnc.so.0.0.0[7f9ead264000+13000]

 Cordialement,

Nicolas Lécureuil

Web: http://www.siveo.net

 

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Re: Segfault with guacamole 0.9.14

vnick
What version of the libvncserver/libvncclient are you building against? 

# dpkg -l | grep vncclient
ii libvncclient1:amd64 0.9.11+dfsg-1+deb9u1 amd64 API to write one's own VNC server - client library


Hmmm....I can't remember if there are any version-specific issues with that version of libvncclient, but I'd expect the segfault message to happen in libvncclient not the Guacamole library, if that were the case.
 

Any special configuration for VNC? 

for the client, this is nothing special

Are you trying to use encryption? 

No encryption

no password, trought reverse ssh with ssh-key without passphrase

Jun 27 16:10:34 pulsemaster kernel: [717204.421339] guacd[28944]: segfault at 10 ip 00007f9ead26c692 sp 00007f9eaec7ad10 error 4 in libguac-client-vnc.so.0.0.0[7f9ead264000+13000]

At this point I'd probably need a core dump or gdb stack trace to track down the issue.

You can see if any of the following issues match the scenario you're running into:

Those issues are related - one deals with VNC password issues, but it looks like the fix takes care of at least a couple of scenarios.  It looks like that's not fixed in the 0.9.14 code but will be in the 1.0.0 code, so you could try building guacd from the git repo, either the master branch or the staging/1.0.0 branch.

-Nick 
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Re: Segfault with guacamole 0.9.14

Mike Jumper-2
In reply to this post by Nicolas Lécureuil
On Wed, Jun 27, 2018 at 7:20 AM, Nicolas Lécureuil
<[hidden email]> wrote:
>
> ...
> Jun 27 16:10:34 pulsemaster guacd[28941]: User is not responding.
> Jun 27 16:10:34 pulsemaster guacd[24552]: Connection "$12c5328c-c127-453d-bc9c-f631bf8e90f8" removed.
> Jun 27 16:10:34 pulsemaster kernel: [717204.421339] guacd[28944]: segfault at 10 ip 00007f9ead26c692 sp 00007f9eaec7ad10 error 4 in libguac-client-vnc.so.0.0.0[7f9ead264000+13000]
> ...
>

This segfault is occurring after the connection has already ended,
while the resources consumed by that connection are being freed (the
"User is not responding" message indicates that the connection has
been closed due to a network timeout). I believe this was recently
fixed:

https://issues.apache.org/jira/browse/GUACAMOLE-424

The segfault in the case of the above issue was due to an erroneous
attempt to free SFTP-related resources when SFTP was not actually
being used for the connection. If you're seeing unexpected
disconnections, the issue causing those disconnections is likely
elsewhere, as this particular bug did not affect connection stability.

- Mike
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Re: Segfault with guacamole 0.9.14

Mike Jumper-2
On Wed, Jun 27, 2018 at 12:47 PM, Mike Jumper <[hidden email]> wrote:

> On Wed, Jun 27, 2018 at 7:20 AM, Nicolas Lécureuil
> <[hidden email]> wrote:
>>
>> ...
>> Jun 27 16:10:34 pulsemaster guacd[28941]: User is not responding.
>> Jun 27 16:10:34 pulsemaster guacd[24552]: Connection "$12c5328c-c127-453d-bc9c-f631bf8e90f8" removed.
>> Jun 27 16:10:34 pulsemaster kernel: [717204.421339] guacd[28944]: segfault at 10 ip 00007f9ead26c692 sp 00007f9eaec7ad10 error 4 in libguac-client-vnc.so.0.0.0[7f9ead264000+13000]
>> ...
>>
>
> This segfault is occurring after the connection has already ended,
> while the resources consumed by that connection are being freed (the
> "User is not responding" message indicates that the connection has
> been closed due to a network timeout). I believe this was recently
> fixed:
>
> https://issues.apache.org/jira/browse/GUACAMOLE-424
>
> The segfault in the case of the above issue was due to an erroneous
> attempt to free SFTP-related resources when SFTP was not actually
> being used for the connection. If you're seeing unexpected
> disconnections, the issue causing those disconnections is likely
> elsewhere, as this particular bug did not affect connection stability.
>

Unless I'm thinking of a different issue, and the above was related to
freeing display resources that were not actually yet allocated.

Either way ... if you're seeing unexpected disconnects, this segfault
is due to something going wrong while handling the disconnect that has
already occurred; it isn't the cause of the disconnect.

- Mike