Bug#410599: openssh-server: scp dies with "fatal: buffer_append_space: alloc 10506240 not supported" when using control sockets and compression

[Kris Shannon <kris@shannon.id.au>]

Package: openssh-server
Version: 1:4.3p2-8
Severity: normal

I connect to most of our servers from my laptop with "ssh -4MANf servername"
in the morning, and then use the open control connection for the rest of
the day.

If I try to scp using this control connection (specifically the
debian-testing-i386-netinst.iso) it dies pretty quickly with
"fatal: buffer_append_space: alloc 10506240 not supported" in
/var/log/auth.log

I can redo the scp without using -M or without compression
and everything is fine either way.

My default settings in .ssh/config:
Host *
AddressFamily inet
ForwardAgent no
Compression yes
CompressionLevel 5
Cipher blowfish
Ciphers arcfour
MACs hmac-sha1-96
ForwardX11Trusted no
ForwardX11 no
VerifyHostKeyDNS yes
SendEnv COLORTERM LESS VTYSH_PAGER EMAIL DEBFULLNAME
ControlMaster auto
ControlPath ~/.ssh/%r@%h,%p.opensshctl


-- System Information:
Debian Release: 4.0
  APT prefers testing
  APT policy: (800, 'testing'), (750, 'unstable'), (700, 'experimental')
Architecture: i386 (i686)
Shell:  /bin/sh linked to /bin/bash
Kernel: Linux 2.6.18-2-vserver-k7
Locale: LANG=C, LC_CTYPE=C (charmap=ANSI_X3.4-1968)

Versions of packages openssh-server depends on:
ii  adduser  3.102                           Add and remove users and groups
ii  debconf  1.5.11                          Debian configuration management sy
ii  dpkg     1.13.25                         package maintenance system for Deb
ii  libc6    2.3.6.ds1-10                    GNU C Library: Shared libraries
ii  libcomer 1.39+1.40-WIP-2006.11.14+dfsg-1 common error description library
ii  libkrb53 1.4.4-6                         MIT Kerberos runtime libraries
ii  libpam-m 0.79-4                          Pluggable Authentication Modules f
ii  libpam-r 0.79-4                          Runtime support for the PAM librar
ii  libpam0g 0.79-4                          Pluggable Authentication Modules l
ii  libselin 1.32-3                          SELinux shared libraries
ii  libssl0. 0.9.8c-4                        SSL shared libraries
ii  libwrap0 7.6.dbs-12                      Wietse Venema's TCP wrappers libra
ii  openssh- 1:4.3p2-8                       Secure shell client, an rlogin/rsh
ii  zlib1g   1:1.2.3-13                      compression library - runtime

openssh-server recommends no packages.

-- debconf information:
  ssh/new_config: true
* ssh/use_old_init_script: true
  ssh/encrypted_host_key_but_no_keygen:
  ssh/disable_cr_auth: false

-- 
Kris Shannon <kris@shannon.id.au>