[scponly] segfault when trying to connect

[Tim Donnelly]

Kaleb,

Using the debug2.patch file I again was unable to login to the server,
however this time I did not get the segfault, just a straight connection
closed on the client machine.  I haven't been rebuilding the chroot jail
after each recompile/install, is that something I need to do?

The /var/log/messages output is below, and traces are at
http://www.coalliance.org/public.

Jul 31 10:01:02 tester sshd[605]: Accepted keyboard-interactive/pam for
scponly from 208.178.237.10 port 54051 ssh2
Jul 31 10:01:02 tester sshd[639]: subsystem request for sftp
Jul 31 10:01:02 tester scponly[640]: chrooted binary in place, will chroot()
Jul 31 10:01:02 tester scponly[640]: 3 arguments in total.
Jul 31 10:01:02 tester scponly[640]:    arg 0 is scponlyc
Jul 31 10:01:02 tester scponly[640]:    arg 1 is -c
Jul 31 10:01:02 tester scponly[640]:    arg 2 is /usr/lib64/ssh/sftp-server
Jul 31 10:01:02 tester scponly[640]: opened log at LOG_AUTHPRIV, opts
0x00000029
Jul 31 10:01:02 tester scponly[640]: determined USER is "scponly" from
environment
Jul 31 10:01:02 tester scponly[640]: retrieved home directory of
"/home/scponly" for user "scponly"
Jul 31 10:01:02 tester scponly[640]: Looking at root_dir: /home/scponly
Jul 31 10:01:02 tester scponly[640]: Looking at root_dir: /scponly
Jul 31 10:01:02 tester scponly[640]: chrooting to dir: "/home/scponly"
Jul 31 10:01:02 tester scponly[640]: chdiring to dir: "/"
Jul 31 16:01:02 tester scponly[640]: setting uid to 1007
Jul 31 16:01:02 tester scponly[640]: processing request:
"/usr/lib64/ssh/sftp-server"
Jul 31 16:01:02 tester scponly[640]: checking restrictive
filenames(username: scponly(1007), IP/port: 208.178.237.10 54051 22)
Jul 31 16:01:02 tester scponly[640]: building arg vector (username:
scponly(1007), IP/port: 208.178.237.10 54051 22)
Jul 31 16:01:02 tester scponly[640]: substituting known paths (username:
scponly(1007), IP/port: 208.178.237.10 54051 22)

-----Original Message-----
From: Kaleb Pederson [mailto:kibab at icehouse.net] 
Sent: Wednesday, July 25, 2007 10:33 PM
To: scponly at lists.ccs.neu.edu
Cc: Tim Donnelly
Subject: Re: [scponly] segfault when trying to connect

Thanks for trying Tim.

I have attached a patch that will hopefully help us figure out about where
it's failing...

Feel free to add in other debug code similar to what I have attached that
might help us figure out where it's segfaulting.

Thanks.

--Kaleb

On Tuesday 24 July 2007, Tim Donnelly wrote:
> Kaleb,
>
> I installed the snapshot version from your post to the list dated Jul 
> 18 and got the same results.  Below I have pasted the 
> /var/log/messages output and the trace output is available at the same 
> location (www.coalliance.org/public).
>
> Jul 23 15:23:36 tester sshd[18661]: Accepted keyboard-interactive/pam 
> for scponly from 208.178.237.110 port 38253 ssh2 Jul 23 15:23:36 
> tester sshd[18664]: subsystem request for sftp Jul 23 15:23:36 tester 
> scponly[18665]: chrooted binary in place, will
> chroot()
> Jul 23 15:23:36 tester scponly[18665]: 3 arguments in total.
> Jul 23 15:23:36 tester scponly[18665]:  arg 0 is scponlyc Jul 23 
> 15:23:36 tester scponly[18665]:  arg 1 is -c Jul 23 15:23:36 tester 
> scponly[18665]:  arg 2 is /usr/lib64/ssh/sftp-server Jul 23 15:23:36 
> tester scponly[18665]: opened log at LOG_AUTHPRIV, opts
> 0x00000029
> Jul 23 15:23:36 tester scponly[18665]: determined USER is "scponly" 
> from environment Jul 23 15:23:36 tester scponly[18665]: retrieved home 
> directory of "/home/scponly" for user "scponly"
> Jul 23 15:23:36 tester scponly[18665]: Looking at root_dir: 
> /home/scponly Jul 23 15:23:36 tester scponly[18665]: Looking at 
> root_dir: /scponly Jul 23 15:23:36 tester scponly[18665]: chrooting to
dir: "/home/scponly"
> Jul 23 15:23:36 tester scponly[18665]: chdiring to dir: "/"
> Jul 23 21:23:36 tester scponly[18665]: setting uid to 1007 Jul 23 
> 21:23:36 tester scponly[18665]: processing request:
> "/usr/lib64/ssh/sftp-server"
> Jul 23 15:23:36 tester kernel: scponlyc[18665]: segfault at
> 0000000000402c89 rip 00002b8aa095d972 rsp 00007fff0a2a1df0 e rror 7
>
> Any ideas?
>
> -----Original Message-----
> From: Kaleb Pederson [mailto:kibab at icehouse.net]
> Sent: Friday, July 20, 2007 4:58 PM
> To: scponly at lists.ccs.neu.edu
> Cc: Tim Donnelly
> Subject: Re: [scponly] segfault when trying to connect
>
> Thanks for the details Tim.
>
> Can you try the latest CVS or the version I linked to a couple of days
ago?
>
> I'm not aware of any prcoblems in that area, but I would like to know 
> that this is fixed or fix the problem before our next release.
>
> Thanks.
>
> --Kaleb
>
>
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