SSH daemon segmentation fault

SSH daemon segmentation fault

[Martin Klier]

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Hi there,

I'm experiencing a strange, annoying ssh daemon problem, I'm rather 
desperated:

At transmitting huge files (about 2GB) via scp to the ssh server, I earn an 
"Connection reset by peer" in about 90% of the cases, in average between the 
100th and 1800th megabyte of transfer. Long-lasting ssh sessions without huge 
data amounts remain untouched.

Tracking down the issue, I found out that the TCP session is terminated by 
flags RST,ACK, for which RFC793 says "connection not known to the stack".
Due to this, I started verbose logging of the daemon, the end of the log 
created by sshd -ddd follows here:

--------------------cut---------------------
debug2: channel 0: window 61440 sent adjust 69632
<many of them>
debug2: channel 0: window 61440 sent adjust 69632
debug2: channel 0: window 61440 sent adjust 69632
Segmentation fault
--------------------cut---------------------
Nothing further, of course the process is dead now.

The client tells me the following:
--------------------cut---------------------
<usual connection-rising-crap>
debug3: channel 0: close_fds r -1 w -1 e -1
test.zero |========>        75% 1509MB  10.5MB/s   00:46 ETA
Read from remote host svdbslx007: Connection reset by peer
lost connection
--------------------cut---------------------
I see, referencing to the received RST the client could not do anything 
else :)

The SSH server is a SLES9 32bit, I already updated to SP1 and SP2 - no change 
of the behaviour. Actually the sshd version is OpenSSH_3.8p1.

As client I tried several SuSE versions (9.3 Prof at current patch level, 
SLES9 32bit at SP2, SLES9 64bit SP1, etc...) and my Debian Sarge stable 
notebook. Always the same.

Are there any suggestions?

Thanks in advance and best regards,
-- 
Mit freundlichen Grüßen

i.A. Martin Klier
PC-Benutzerunterstützung / Linux-Server
IT Asset Management

A.T.U - Auto-Teile-Unger
Dr.-Kilian-Straße 11
92637 Weiden

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Re: SSH daemon segmentation fault

[Michael Iatrou]

When the date was Wednesday 21 September 2005 10:23, Martin Klier wrote:

> Actually the sshd version is OpenSSH_3.8p1.

Update it to OpenSSH 4.1p1.
If you really need to hunt the bug, try to strace sshd.

-- 
 Michael Iatrou
 Electrical and Computer Engineering Dept.
 University of Patras, Greece

Re: SSH daemon segmentation fault

[Martin Klier]

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Hi Michael,

Am Mittwoch, 21. September 2005 11:33 schrieb Michael Iatrou:
> Update it to OpenSSH 4.1p1.
I think it's not possible, I need the certified base OS for support contracts. 
SuSE does not provide a newer version.

> If you really need to hunt the bug, try to strace sshd.
I will try and keep you updated.

Regards,
-- 
Mit freundlichen Grüßen

i.A. Martin Klier
PC-Benutzerunterstützung / Linux-Server
IT Asset Management

A.T.U - Auto-Teile-Unger
Dr.-Kilian-Straße 11
92637 Weiden

Telefon:  (0961) 306-5663
Telefax:  (0961) 306-9345663

Internet: www.atu.de

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