- djm@cvs.openbsd.org 2010/05/07 11:30:30

     [auth-options.c auth-options.h auth.c auth.h auth2-pubkey.c]
     [key.c servconf.c servconf.h sshd.8 sshd_config.5]
     add some optional indirection to matching of principal names listed
     in certificates. Currently, a certificate must include the a user's name
     to be accepted for authentication. This change adds the ability to
     specify a list of certificate principal names that are acceptable.

     When authenticating using a CA trusted through ~/.ssh/authorized_keys,
     this adds a new principals="name1[,name2,...]" key option.

     For CAs listed through sshd_config's TrustedCAKeys option, a new config
     option "AuthorizedPrincipalsFile" specifies a per-user file containing
     the list of acceptable names.

     If either option is absent, the current behaviour of requiring the
     username to appear in principals continues to apply.

     These options are useful for role accounts, disjoint account namespaces
     and "user@realm"-style naming policies in certificates.

     feedback and ok markus@

1 files changed, 39 insertions, 2 deletions

diff --git a/sshd_config.5 b/sshd_config.5
index 2f541028..a5260d35 100644
--- a/sshd_config.5
+++ b/sshd_config.5
@@ -34,8 +34,8 @@
 .\" (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 1.120 2010/03/04 23:17:25 djm Exp $
-.Dd $Mdocdate: March 4 2010 $
+.\" $OpenBSD: sshd_config.5,v 1.121 2010/05/07 11:30:30 djm Exp $
+.Dd $Mdocdate: May 7 2010 $
 .Dt SSHD_CONFIG 5
 .Os
 .Sh NAME
@@ -167,6 +167,43 @@ is taken to be an absolute path or one relative to the user's home
 directory.
 The default is
 .Dq .ssh/authorized_keys .
+.It Cm AuthorizedPrincipalsFile
+Specifies a file that lists principal names that are accepted for
+certificate authentication.
+When using certificates signed by a key listed in
+.Cm TrustedUserCAKeys ,
+this file lists names, one of which must appear in the certificate for it
+to be accepted for authentication.
+Names are listed one per line; empty lines and comments starting with
+.Ql #
+are ignored.
+.Pp
+.Cm AuthorizedPrincipalsFile
+may contain tokens of the form %T which are substituted during connection
+setup.
+The following tokens are defined: %% is replaced by a literal '%',
+%h is replaced by the home directory of the user being authenticated, and
+%u is replaced by the username of that user.
+After expansion,
+.Cm AuthorizedPrincipalsFile
+is taken to be an absolute path or one relative to the user's home
+directory.
+.Pp
+The default is not to use a principals file - in this case, the username
+of the user must appear in a certificate's principals list for it to be
+accepted.
+Note that
+.Cm AuthorizedPrincipalsFile
+is only used when authentication proceeds using a CA listed in
+.Cm TrustedUserCAKeys
+and is not consulted for certification authorities trusted via
+.Pa ~/.ssh/authorized_keys ,
+though the
+.Cm principals=
+key option offers a similar facility (see
+.Xr sshd 8
+for details).
+.Pp
 .It Cm Banner
 The contents of the specified file are sent to the remote user before
 authentication is allowed.