[screen-devel] [bug #48870] Screen attach unexpectedly

[Amadeusz Sławiński]

Update of bug #48870 (project screen):

  Status:None => Invalid
 Open/Closed:Open => Closed 

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Follow-up Comment #1:

It works correctly in 4.4.0.

Also as far as I know it's debian specific behaviour introduced by their
patch
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=799929

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Re: [screen-devel] Screen caused buffer owerflow?

[Amadeusz Sławiński]

Hi,

On Wed, 31 Aug 2016 04:46:55 -0400 (EDT)
Josef Ridky  wrote:

> | What is strange and confusing in that bug report is that the
> original | reporter says he got the error message "terminal name too
> long. (max. | 20 char)". But at least Screen 4.4.0 has MAXTERMLEN set
> to 32 in os.h. | (So unless Fedora patches that value as we do in
> Debian for backwards | compatibility, it's not Screen 4.4.0 issuing
> that error message.)
> 
> in the latest version of screen in Fedora (screen-4.4.0) is this
> change applied, but unfortunately, in the error message is still
> presented wrong number of characters of terminal name (but in this
> case the error message isn't shown anymore). 

Yes, error message needs to be fixed as it hardcodes number, I will do
that.

> | So for me it's likely that the issue is in an older version of
> screen. | The original reporter also wrote something about a pending
> upgrade. So | I assume that the version number in the report is moot.
> 
> I have asked him to upgrade/reinstall screen package to the newest
> version, but he has still the same issue even with actual screen
> version. That's strange.

Overall, I'm also not sure what may cause this problem, code seems
fairly simple and I can't reproduce it here.

Some ideas to try are to make sure he has right screen (md5sum it and
check 'screen --version'). Also same can be done with libraries screen
is linked with.
Another thing I would check is screen.xterm-256color file itself

Also does it work with other terminfo entries?
Does "screen -c /dev/null" work fine?

Amadeusz

Re: [screen-devel] Screen caused buffer owerflow?

[Josef Ridky]

Hi Axel,

thank you very much for your reply,
 
| What is strange and confusing in that bug report is that the original
| reporter says he got the error message "terminal name too long. (max.
| 20 char)". But at least Screen 4.4.0 has MAXTERMLEN set to 32 in os.h.
| (So unless Fedora patches that value as we do in Debian for backwards
| compatibility, it's not Screen 4.4.0 issuing that error message.)

in the latest version of screen in Fedora (screen-4.4.0) is this change 
applied, 
but unfortunately, in the error message is still presented wrong number of 
characters 
of terminal name (but in this case the error message isn't shown anymore).
 
| So for me it's likely that the issue is in an older version of screen.
| The original reporter also wrote something about a pending upgrade. So
| I assume that the version number in the report is moot.

I have asked him to upgrade/reinstall screen package to the newest version, 
but he has still the same issue even with actual screen version. That's strange.

Regards

Josef

Re: [screen-devel] Screen caused buffer owerflow?

[Axel Beckert]

Hi Josef,

On Wed, Aug 31, 2016 at 03:47:56AM -0400, Josef Ridky wrote:
> I have been requested to solve following problem with screen, but I am 
> confuse, because, I am not able to reproduce it anyhow.
> For more information see https://bugzilla.redhat.com/show_bug.cgi?id=1350549.
> 
> Can anyone help me, how to solve this? Where can be the issue?

Works fine for me with 4.4.0-4 on Debian Unstable, too.

What is strange and confusing in that bug report is that the original
reporter says he got the error message "terminal name too long. (max.
20 char)". But at least Screen 4.4.0 has MAXTERMLEN set to 32 in os.h.
(So unless Fedora patches that value as we do in Debian for backwards
compatibility, it's not Screen 4.4.0 issuing that error message.)

So for me it's likely that the issue is in an older version of screen.
The original reporter also wrote something about a pending upgrade. So
I assume that the version number in the report is moot.

About the crash, my only idea is that this might be related to using
new client with old server process or similar as they might use
different values for some of these constants. But I'm not sure at all
if that can cause such a crash as I mostly experienced hanging (but
still living) clients or some features (e.g. window resizing) not
working when client and server have different versions.

Kind regards, Axel
-- 
 ,''`.  |  Axel Beckert , http://people.debian.org/~abe/
: :' :  |  Debian Developer, ftp.ch.debian.org Admin
`. `'   |  4096R: 2517 B724 C5F6 CA99 5329  6E61 2FF9 CD59 6126 16B5
  `-|  1024D: F067 EA27 26B9 C3FC 1486  202E C09E 1D89 9593 0EDE

[screen-devel] Screen caused buffer owerflow?

[Josef Ridky]

Hi folks,

I have been requested to solve following problem with screen, but I am confuse, 
because, I am not able to reproduce it anyhow.
For more information see https://bugzilla.redhat.com/show_bug.cgi?id=1350549.

Can anyone help me, how to solve this? Where can be the issue?

Thanks

Regards

Josef Ridky
Associate Software Engineer
Core Services Team
Red Hat Czech, s.r.o.