upstream commit

Turn off DSA by default; add HostKeyAlgorithms to the
 server and PubkeyAcceptedKeyTypes to the client side, so it still can be
 tested or turned back on; feedback and ok djm@

Upstream-ID: 8450a9e6d83f80c9bfed864ff061dfc9323cec21

1 files changed, 51 insertions, 9 deletions

diff --git a/sshd_config.5 b/sshd_config.5
index edd4cc9b9..b49e91910 100644
--- a/sshd_config.5
+++ b/sshd_config.5
@@ -33,8 +33,8 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.\" $OpenBSD: sshd_config.5,v 1.205 2015/07/03 03:49:45 djm Exp $
-.Dd $Mdocdate: July 3 2015 $
+.\" $OpenBSD: sshd_config.5,v 1.206 2015/07/10 06:21:53 markus Exp $
+.Dd $Mdocdate: July 10 2015 $
 .Dt SSHD_CONFIG 5
 .Os
 .Sh NAME
@@ -640,9 +640,17 @@ The default is
 .It Cm HostbasedAcceptedKeyTypes
 Specifies the key types that will be accepted for hostbased authentication
 as a comma-separated pattern list.
-The default
-.Dq *
-will allow all key types.
+The default for this option is:
+.Bd -literal -offset 3n
+ecdsa-sha2-nistp256-cert-v01@openssh.com,
+ecdsa-sha2-nistp384-cert-v01@openssh.com,
+ecdsa-sha2-nistp521-cert-v01@openssh.com,
+ssh-ed25519-cert-v01@openssh.com,
+ssh-rsa-cert-v01@openssh.com,
+ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,
+ssh-ed25519,ssh-rsa
+.Ed
+.Pp
 The
 .Fl Q
 option of
@@ -694,9 +702,15 @@ for protocol version 1, and
 and
 .Pa /etc/ssh/ssh_host_rsa_key
 for protocol version 2.
+.Pp
 Note that
 .Xr sshd 8
-will refuse to use a file if it is group/world-accessible.
+will refuse to use a file if it is group/world-accessible
+and that the
+.Cm HostKeyAlgorithms
+option restricts which of the keys are actually used by
+.Xr sshd 8 .
+.Pp
 It is possible to have multiple host key files.
 .Dq rsa1
 keys are used for version 1 and
@@ -718,6 +732,26 @@ If
 is specified, the location of the socket will be read from the
 .Ev SSH_AUTH_SOCK
 environment variable.
+.It Cm HostKeyAlgorithms
+Specifies the protocol version 2 host key algorithms
+that the server offers.
+The default for this option is:
+.Bd -literal -offset 3n
+ecdsa-sha2-nistp256-cert-v01@openssh.com,
+ecdsa-sha2-nistp384-cert-v01@openssh.com,
+ecdsa-sha2-nistp521-cert-v01@openssh.com,
+ssh-ed25519-cert-v01@openssh.com,
+ssh-rsa-cert-v01@openssh.com,
+ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,
+ssh-ed25519,ssh-rsa
+.Ed
+.Pp
+The list of available key types may also be obtained using the
+.Fl Q
+option of
+.Xr ssh 1
+with an argument of
+.Dq key .
 .It Cm IgnoreRhosts
 Specifies that
 .Pa .rhosts
@@ -1279,9 +1313,17 @@ is identical to
 .It Cm PubkeyAcceptedKeyTypes
 Specifies the key types that will be accepted for public key authentication
 as a comma-separated pattern list.
-The default
-.Dq *
-will allow all key types.
+The default for this option is:
+.Bd -literal -offset 3n
+ecdsa-sha2-nistp256-cert-v01@openssh.com,
+ecdsa-sha2-nistp384-cert-v01@openssh.com,
+ecdsa-sha2-nistp521-cert-v01@openssh.com,
+ssh-ed25519-cert-v01@openssh.com,
+ssh-rsa-cert-v01@openssh.com,
+ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,
+ssh-ed25519,ssh-rsa
+.Ed
+.Pp
 The
 .Fl Q
 option of