Bug#314347: openssh-client: "Bad owner or permissions on $HOME/.ssh/config" check too aggressive

[Branden Robinson <branden@debian.org>]

Package: openssh-client
Version: 1:4.1p1-3
Severity: important

Setting severity to important because this unexpectedly busted Subversion,
though I don't honestly believe it's a *critical* bug.

I just upgraded from sid as of about the time sarge released, and got a blitz
of new packages, including the new openssh-client package.

Here's a session transcript:

1148 {0} branden@sisyphus:~/packages/xorg-x11/svn/trunk/debian$ svn up
Bad owner or permissions on /home/branden/.ssh/config
svn: Connection closed unexpectedly
1149 {1} branden@sisyphus:~/packages/xorg-x11/svn/trunk/debian$ l -l $HOME/.ssh/config
-rw-rw-r--  1 branden branden 125 Jun 26  2004 /home/branden/.ssh/config
1150 {0} branden@sisyphus:~/packages/xorg-x11/svn/trunk/debian$ chmod 644 /home/branden/.ssh/config
1151 {0} branden@sisyphus:~/packages/xorg-x11/svn/trunk/debian$ svn up
At revision 220.

I think that check is excessively paranoid.  I can think of a few
possibilities for resolving this bug:

1) Have the ssh client check to see if usergroups are configured in
   adduser.  Perhaps not a great solution because 1) it's complicated, and
   2) this doesn't tell you anything about whether a particular user's
   account was created with this property or not.

2) Simply tolerate group-writable files if the group name in question is
   identical to the user name.

3) Alternatively or additionally to 2), ensure that the user is the only
   member of the group owning the group-writable file.

4) Step this fatal error down to a warning.  (I'd find it annoying,
   though.)

5) As part of the many migrations done to the new openssh world order, walk
   /home and chmod g-w on all .ssh/config files.  Some people might
   consider this intrusive, though, and it doesn't prevent the creation of
   new accounts with this problem.

6) Tell everybody in my position "tough cookie" and add a NEWS item
   advising people that the default umask with usergroups enabled in
   adduser is just bad news for .ssh/config.

In any case:

7) It would be nice if the ssh client would identify itself before spewing
that message; e.g.:

ssh: bad owner or permissions on /home/branden/.ssh/config

-- System Information:
Debian Release: testing/unstable
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: powerpc (ppc)
Shell:  /bin/sh linked to /bin/bash
Kernel: Linux 2.6.9-powerpc-smp
Locale: LANG=C, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)

Versions of packages openssh-client depends on:
ii  adduser               3.63               Add and remove users and groups
ii  debconf [debconf-2.0] 1.4.51             Debian configuration management sy
ii  dpkg                  1.13.9             Package maintenance system for Deb
ii  libc6                 2.3.2.ds1-22       GNU C Library: Shared libraries an
ii  libedit2              2.9.cvs.20050518-2 BSD editline and history libraries
ii  libncurses5           5.4-6              Shared libraries for terminal hand
ii  libssl0.9.7           0.9.7g-1           SSL shared libraries
ii  zlib1g                1:1.2.2-4          compression library - runtime

-- no debconf information