diff options
author | Colin Watson <cjwatson@debian.org> | 2014-02-09 16:10:18 +0000 |
---|---|---|
committer | Colin Watson <cjwatson@debian.org> | 2018-10-20 22:54:09 +0100 |
commit | a433d9baa031d7136a8cf3e3807ebff83a3a8634 (patch) | |
tree | 3fecc984dfc9a222bcc8a5353bca9640c1d48c55 | |
parent | da34947128351bee9d2530574432190548f5be58 (diff) |
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: 2017-10-04
Patch-Name: debian-config.patch
-rw-r--r-- | readconf.c | 2 | ||||
-rw-r--r-- | ssh.1 | 21 | ||||
-rw-r--r-- | ssh_config | 6 | ||||
-rw-r--r-- | ssh_config.5 | 19 | ||||
-rw-r--r-- | sshd_config | 16 | ||||
-rw-r--r-- | sshd_config.5 | 22 |
6 files changed, 77 insertions, 9 deletions
diff --git a/readconf.c b/readconf.c index 6b01f20d2..661b8bf40 100644 --- a/readconf.c +++ b/readconf.c | |||
@@ -2000,7 +2000,7 @@ fill_default_options(Options * options) | |||
2000 | if (options->forward_x11 == -1) | 2000 | if (options->forward_x11 == -1) |
2001 | options->forward_x11 = 0; | 2001 | options->forward_x11 = 0; |
2002 | if (options->forward_x11_trusted == -1) | 2002 | if (options->forward_x11_trusted == -1) |
2003 | options->forward_x11_trusted = 0; | 2003 | options->forward_x11_trusted = 1; |
2004 | if (options->forward_x11_timeout == -1) | 2004 | if (options->forward_x11_timeout == -1) |
2005 | options->forward_x11_timeout = 1200; | 2005 | options->forward_x11_timeout = 1200; |
2006 | /* | 2006 | /* |
@@ -782,6 +782,16 @@ directive in | |||
782 | .Xr ssh_config 5 | 782 | .Xr ssh_config 5 |
783 | for more information. | 783 | for more information. |
784 | .Pp | 784 | .Pp |
785 | (Debian-specific: X11 forwarding is not subjected to X11 SECURITY extension | ||
786 | restrictions by default, because too many programs currently crash in this | ||
787 | mode. | ||
788 | Set the | ||
789 | .Cm ForwardX11Trusted | ||
790 | option to | ||
791 | .Dq no | ||
792 | to restore the upstream behaviour. | ||
793 | This may change in future depending on client-side improvements.) | ||
794 | .Pp | ||
785 | .It Fl x | 795 | .It Fl x |
786 | Disables X11 forwarding. | 796 | Disables X11 forwarding. |
787 | .Pp | 797 | .Pp |
@@ -790,6 +800,17 @@ Enables trusted X11 forwarding. | |||
790 | Trusted X11 forwardings are not subjected to the X11 SECURITY extension | 800 | Trusted X11 forwardings are not subjected to the X11 SECURITY extension |
791 | controls. | 801 | controls. |
792 | .Pp | 802 | .Pp |
803 | (Debian-specific: This option does nothing in the default configuration: it | ||
804 | is equivalent to | ||
805 | .Dq Cm ForwardX11Trusted No yes , | ||
806 | which is the default as described above. | ||
807 | Set the | ||
808 | .Cm ForwardX11Trusted | ||
809 | option to | ||
810 | .Dq no | ||
811 | to restore the upstream behaviour. | ||
812 | This may change in future depending on client-side improvements.) | ||
813 | .Pp | ||
793 | .It Fl y | 814 | .It Fl y |
794 | Send log information using the | 815 | Send log information using the |
795 | .Xr syslog 3 | 816 | .Xr syslog 3 |
diff --git a/ssh_config b/ssh_config index bcb9f153d..1b676fb2c 100644 --- a/ssh_config +++ b/ssh_config | |||
@@ -17,9 +17,10 @@ | |||
17 | # list of available options, their meanings and defaults, please see the | 17 | # list of available options, their meanings and defaults, please see the |
18 | # ssh_config(5) man page. | 18 | # ssh_config(5) man page. |
19 | 19 | ||
20 | # Host * | 20 | Host * |
21 | # ForwardAgent no | 21 | # ForwardAgent no |
22 | # ForwardX11 no | 22 | # ForwardX11 no |
23 | # ForwardX11Trusted yes | ||
23 | # PasswordAuthentication yes | 24 | # PasswordAuthentication yes |
24 | # HostbasedAuthentication no | 25 | # HostbasedAuthentication no |
25 | # GSSAPIAuthentication no | 26 | # GSSAPIAuthentication no |
@@ -46,3 +47,6 @@ | |||
46 | # VisualHostKey no | 47 | # VisualHostKey no |
47 | # ProxyCommand ssh -q -W %h:%p gateway.example.com | 48 | # ProxyCommand ssh -q -W %h:%p gateway.example.com |
48 | # RekeyLimit 1G 1h | 49 | # RekeyLimit 1G 1h |
50 | SendEnv LANG LC_* | ||
51 | HashKnownHosts yes | ||
52 | GSSAPIAuthentication yes | ||
diff --git a/ssh_config.5 b/ssh_config.5 index a91355726..1a8e24bd1 100644 --- a/ssh_config.5 +++ b/ssh_config.5 | |||
@@ -71,6 +71,22 @@ Since the first obtained value for each parameter is used, more | |||
71 | host-specific declarations should be given near the beginning of the | 71 | host-specific declarations should be given near the beginning of the |
72 | file, and general defaults at the end. | 72 | file, and general defaults at the end. |
73 | .Pp | 73 | .Pp |
74 | Note that the Debian | ||
75 | .Ic openssh-client | ||
76 | package sets several options as standard in | ||
77 | .Pa /etc/ssh/ssh_config | ||
78 | which are not the default in | ||
79 | .Xr ssh 1 : | ||
80 | .Pp | ||
81 | .Bl -bullet -offset indent -compact | ||
82 | .It | ||
83 | .Cm SendEnv No LANG LC_* | ||
84 | .It | ||
85 | .Cm HashKnownHosts No yes | ||
86 | .It | ||
87 | .Cm GSSAPIAuthentication No yes | ||
88 | .El | ||
89 | .Pp | ||
74 | The file contains keyword-argument pairs, one per line. | 90 | The file contains keyword-argument pairs, one per line. |
75 | Lines starting with | 91 | Lines starting with |
76 | .Ql # | 92 | .Ql # |
@@ -699,11 +715,12 @@ elapsed. | |||
699 | .It Cm ForwardX11Trusted | 715 | .It Cm ForwardX11Trusted |
700 | If this option is set to | 716 | If this option is set to |
701 | .Cm yes , | 717 | .Cm yes , |
718 | (the Debian-specific default), | ||
702 | remote X11 clients will have full access to the original X11 display. | 719 | remote X11 clients will have full access to the original X11 display. |
703 | .Pp | 720 | .Pp |
704 | If this option is set to | 721 | If this option is set to |
705 | .Cm no | 722 | .Cm no |
706 | (the default), | 723 | (the upstream default), |
707 | remote X11 clients will be considered untrusted and prevented | 724 | remote X11 clients will be considered untrusted and prevented |
708 | from stealing or tampering with data belonging to trusted X11 | 725 | from stealing or tampering with data belonging to trusted X11 |
709 | clients. | 726 | clients. |
diff --git a/sshd_config b/sshd_config index 2c48105f8..ed8272f6d 100644 --- a/sshd_config +++ b/sshd_config | |||
@@ -57,8 +57,9 @@ AuthorizedKeysFile .ssh/authorized_keys | |||
57 | #PasswordAuthentication yes | 57 | #PasswordAuthentication yes |
58 | #PermitEmptyPasswords no | 58 | #PermitEmptyPasswords no |
59 | 59 | ||
60 | # Change to no to disable s/key passwords | 60 | # Change to yes to enable challenge-response passwords (beware issues with |
61 | #ChallengeResponseAuthentication yes | 61 | # some PAM modules and threads) |
62 | ChallengeResponseAuthentication no | ||
62 | 63 | ||
63 | # Kerberos options | 64 | # Kerberos options |
64 | #KerberosAuthentication no | 65 | #KerberosAuthentication no |
@@ -81,16 +82,16 @@ AuthorizedKeysFile .ssh/authorized_keys | |||
81 | # If you just want the PAM account and session checks to run without | 82 | # If you just want the PAM account and session checks to run without |
82 | # PAM authentication, then enable this but set PasswordAuthentication | 83 | # PAM authentication, then enable this but set PasswordAuthentication |
83 | # and ChallengeResponseAuthentication to 'no'. | 84 | # and ChallengeResponseAuthentication to 'no'. |
84 | #UsePAM no | 85 | UsePAM yes |
85 | 86 | ||
86 | #AllowAgentForwarding yes | 87 | #AllowAgentForwarding yes |
87 | #AllowTcpForwarding yes | 88 | #AllowTcpForwarding yes |
88 | #GatewayPorts no | 89 | #GatewayPorts no |
89 | #X11Forwarding no | 90 | X11Forwarding yes |
90 | #X11DisplayOffset 10 | 91 | #X11DisplayOffset 10 |
91 | #X11UseLocalhost yes | 92 | #X11UseLocalhost yes |
92 | #PermitTTY yes | 93 | #PermitTTY yes |
93 | #PrintMotd yes | 94 | PrintMotd no |
94 | #PrintLastLog yes | 95 | #PrintLastLog yes |
95 | #TCPKeepAlive yes | 96 | #TCPKeepAlive yes |
96 | #PermitUserEnvironment no | 97 | #PermitUserEnvironment no |
@@ -107,8 +108,11 @@ AuthorizedKeysFile .ssh/authorized_keys | |||
107 | # no default banner path | 108 | # no default banner path |
108 | #Banner none | 109 | #Banner none |
109 | 110 | ||
111 | # Allow client to pass locale environment variables | ||
112 | AcceptEnv LANG LC_* | ||
113 | |||
110 | # override default of no subsystems | 114 | # override default of no subsystems |
111 | Subsystem sftp /usr/libexec/sftp-server | 115 | Subsystem sftp /usr/lib/openssh/sftp-server |
112 | 116 | ||
113 | # Example of overriding settings on a per-user basis | 117 | # Example of overriding settings on a per-user basis |
114 | #Match User anoncvs | 118 | #Match User anoncvs |
diff --git a/sshd_config.5 b/sshd_config.5 index 23f71fd1d..ba50a30f1 100644 --- a/sshd_config.5 +++ b/sshd_config.5 | |||
@@ -56,6 +56,28 @@ Arguments may optionally be enclosed in double quotes | |||
56 | .Pq \&" | 56 | .Pq \&" |
57 | in order to represent arguments containing spaces. | 57 | in order to represent arguments containing spaces. |
58 | .Pp | 58 | .Pp |
59 | Note that the Debian | ||
60 | .Ic openssh-server | ||
61 | package sets several options as standard in | ||
62 | .Pa /etc/ssh/sshd_config | ||
63 | which are not the default in | ||
64 | .Xr sshd 8 : | ||
65 | .Pp | ||
66 | .Bl -bullet -offset indent -compact | ||
67 | .It | ||
68 | .Cm ChallengeResponseAuthentication No no | ||
69 | .It | ||
70 | .Cm X11Forwarding No yes | ||
71 | .It | ||
72 | .Cm PrintMotd No no | ||
73 | .It | ||
74 | .Cm AcceptEnv No LANG LC_* | ||
75 | .It | ||
76 | .Cm Subsystem No sftp /usr/lib/openssh/sftp-server | ||
77 | .It | ||
78 | .Cm UsePAM No yes | ||
79 | .El | ||
80 | .Pp | ||
59 | The possible | 81 | The possible |
60 | keywords and their meanings are as follows (note that | 82 | keywords and their meanings are as follows (note that |
61 | keywords are case-insensitive and arguments are case-sensitive): | 83 | keywords are case-insensitive and arguments are case-sensitive): |