Bug#781646: openssh-client: should chdir("/") with ControlPersist

[Johannes Berg <johannes@sipsolutions.net>]

Package: openssh-client
Version: 1:6.7p1-3
Severity: wishlist
Tags: upstream

When ControlPersist is used, it can sometimes cause an unmount failure if
the original ssh process (the one that persists) has a CWD to a directory
within one you're trying to unmount. Since the CWD for this process seems
(to me) completely irrelevant, it'd be good to just chdir("/") before
persisting so that such issues don't occur.

-- System Information:
Debian Release: 8.0
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'unstable'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 3.16.0-4-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages openssh-client depends on:
ii  adduser           3.113+nmu3
ii  dpkg              1.17.24
ii  libc6             2.19-15
ii  libedit2          3.1-20140620-2
ii  libgssapi-krb5-2  1.12.1+dfsg-19
ii  libselinux1       2.3-2
ii  libssl1.0.0       1.0.1k-3
ii  passwd            1:4.2-3
ii  zlib1g            1:1.2.8.dfsg-2+b1

Versions of packages openssh-client recommends:
ii  xauth  1:1.0.9-1

Versions of packages openssh-client suggests:
pn  keychain      <none>
pn  libpam-ssh    <none>
pn  monkeysphere  <none>
pn  ssh-askpass   <none>

-- Configuration Files:
/etc/ssh/ssh_config changed [not included]

-- no debconf information