Various Debian-specific configuration changes

ssh: Enable ForwardX11Trusted, returning to earlier semantics which cause
fewer problems with existing setups (http://bugs.debian.org/237021).

ssh: Set 'SendEnv LANG LC_*' by default (http://bugs.debian.org/264024).

ssh: Enable HashKnownHosts by default to try to limit the spread of ssh
worms.

ssh: Enable GSSAPIAuthentication and disable GSSAPIDelegateCredentials by
default.

Document all of this, along with several sshd defaults set in
debian/openssh-server.postinst.

Author: Russ Allbery <rra@debian.org>
Forwarded: not-needed
Last-Update: 2015-12-07

Patch-Name: debian-config.patch

1 files changed, 25 insertions, 0 deletions

diff --git a/sshd_config.5 b/sshd_config.5
index 4d255e5ce..2387b51b8 100644
--- a/sshd_config.5
+++ b/sshd_config.5
@@ -57,6 +57,31 @@ Arguments may optionally be enclosed in double quotes
 .Pq \&"
 in order to represent arguments containing spaces.
 .Pp
+Note that the Debian
+.Ic openssh-server
+package sets several options as standard in
+.Pa /etc/ssh/sshd_config
+which are not the default in
+.Xr sshd 8 .
+The exact list depends on whether the package was installed fresh or
+upgraded from various possible previous versions, but includes at least the
+following:
+.Pp
+.Bl -bullet -offset indent -compact
+.It
+.Cm ChallengeResponseAuthentication No no
+.It
+.Cm X11Forwarding No yes
+.It
+.Cm PrintMotd No no
+.It
+.Cm AcceptEnv No LANG LC_*
+.It
+.Cm Subsystem No sftp /usr/lib/openssh/sftp-server
+.It
+.Cm UsePAM No yes
+.El
+.Pp
 The possible
 keywords and their meanings are as follows (note that
 keywords are case-insensitive and arguments are case-sensitive):