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 by default.

sshd: Enable PAM, disable ChallengeResponseAuthentication, and disable
PrintMotd.

sshd: Enable X11Forwarding.

sshd: Set 'AcceptEnv LANG LC_*' by default.

sshd: Change sftp subsystem path to /usr/lib/openssh/sftp-server.

Document all of this.

Author: Russ Allbery <rra@debian.org>
Forwarded: not-needed
Last-Update: 2020-02-19

Patch-Name: debian-config.patch

1 files changed, 24 insertions, 0 deletions

diff --git a/ssh.1 b/ssh.1
index b33a8049f..a8967c2f8 100644
--- a/ssh.1
+++ b/ssh.1
@@ -809,6 +809,16 @@ directive in
 .Xr ssh_config 5
 for more information.
 .Pp
+(Debian-specific: X11 forwarding is not subjected to X11 SECURITY extension
+restrictions by default, because too many programs currently crash in this
+mode.
+Set the
+.Cm ForwardX11Trusted
+option to
+.Dq no
+to restore the upstream behaviour.
+This may change in future depending on client-side improvements.)
+.Pp
 .It Fl x
 Disables X11 forwarding.
 .Pp
@@ -817,6 +827,20 @@ Enables trusted X11 forwarding.
 Trusted X11 forwardings are not subjected to the X11 SECURITY extension
 controls.
 .Pp
+(Debian-specific: In the default configuration, this option is equivalent to
+.Fl X ,
+since
+.Cm ForwardX11Trusted
+defaults to
+.Dq yes
+as described above.
+Set the
+.Cm ForwardX11Trusted
+option to
+.Dq no
+to restore the upstream behaviour.
+This may change in future depending on client-side improvements.)
+.Pp
 .It Fl y
 Send log information using the
 .Xr syslog 3