Description: GSSAPI key exchange support
 This patch has been rejected upstream: "None of the OpenSSH developers are
 in favour of adding this, and this situation has not changed for several
 years.  This is not a slight on Simon's patch, which is of fine quality,
 but just that a) we don't trust GSSAPI implementations that much and b) we
 don't like adding new KEX since they are pre-auth attack surface.  This one
 is particularly scary, since it requires hooks out to typically root-owned
 system resources."
 .
 However, quite a lot of people rely on this in Debian, and it's better to
 have it merged into the main openssh package rather than having separate
 -krb5 packages (as we used to have).  It seems to have a generally good
 security history.
Author: Simon Wilkinson <simon@sxw.org.uk>
Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1242
Last-Updated: 2010-02-27

Index: b/ChangeLog.gssapi
===================================================================
--- /dev/null
+++ b/ChangeLog.gssapi
@@ -0,0 +1,113 @@
+20110101
+  - Finally update for OpenSSH 5.6p1
+  - Add GSSAPIServerIdentity option from Jim Basney
+ 
+20100308
+  - [ Makefile.in, key.c, key.h ]
+    Updates for OpenSSH 5.4p1
+  - [ servconf.c ]
+    Include GSSAPI options in the sshd -T configuration dump, and flag
+    some older configuration options as being unsupported. Thanks to Colin 
+    Watson.
+  -
+
+20100124
+  - [ sshconnect2.c ]
+    Adapt to deal with additional element in Authmethod structure. Thanks to
+    Colin Watson
+
+20090615
+  - [ gss-genr.c gss-serv.c kexgssc.c kexgsss.c monitor.c sshconnect2.c
+      sshd.c ]
+    Fix issues identified by Greg Hudson following a code review
+	Check return value of gss_indicate_mechs
+	Protect GSSAPI calls in monitor, so they can only be used if enabled
+	Check return values of bignum functions in key exchange
+	Use BN_clear_free to clear other side's DH value
+	Make ssh_gssapi_id_kex more robust
+	Only configure kex table pointers if GSSAPI is enabled
+	Don't leak mechanism list, or gss mechanism list
+	Cast data.length before printing
+	If serverkey isn't provided, use an empty string, rather than NULL
+
+20090201
+  - [ gss-genr.c gss-serv.c kex.h kexgssc.c readconf.c readconf.h ssh-gss.h
+      ssh_config.5 sshconnet2.c ]
+    Add support for the GSSAPIClientIdentity option, which allows the user
+    to specify which GSSAPI identity to use to contact a given server
+
+20080404
+  - [ gss-serv.c ]
+    Add code to actually implement GSSAPIStrictAcceptCheck, which had somehow
+    been omitted from a previous version of this patch. Reported by Borislav
+    Stoichkov
+
+20070317
+  - [ gss-serv-krb5.c ]
+    Remove C99ism, where new_ccname was being declared in the middle of a 
+    function
+
+20061220
+  - [ servconf.c ]
+    Make default for GSSAPIStrictAcceptorCheck be Yes, to match previous, and 
+    documented, behaviour. Reported by Dan Watson.
+
+20060910
+  - [ gss-genr.c kexgssc.c kexgsss.c kex.h monitor.c sshconnect2.c sshd.c
+      ssh-gss.h ]
+    add support for gss-group14-sha1 key exchange mechanisms
+  - [ gss-serv.c servconf.c servconf.h sshd_config sshd_config.5 ]
+    Add GSSAPIStrictAcceptorCheck option to allow the disabling of
+    acceptor principal checking on multi-homed machines.
+    <Bugzilla #928>
+  - [ sshd_config ssh_config ]
+    Add settings for GSSAPIKeyExchange and GSSAPITrustDNS to the sample
+    configuration files
+  - [ kexgss.c kegsss.c sshconnect2.c sshd.c ]
+    Code cleanup. Replace strlen/xmalloc/snprintf sequences with xasprintf()
+    Limit length of error messages displayed by client
+
+20060909
+  - [ gss-genr.c gss-serv.c ]
+    move ssh_gssapi_acquire_cred() and ssh_gssapi_server_ctx to be server
+    only, where they belong 
+    <Bugzilla #1225>
+
+20060829
+  - [ gss-serv-krb5.c ]
+    Fix CCAPI credentials cache name when creating KRB5CCNAME environment 
+    variable
+
+20060828
+  - [ gss-genr.c ]
+    Avoid Heimdal context freeing problem
+    <Fixed upstream 20060829>
+
+20060818
+  - [ gss-genr.c ssh-gss.h sshconnect2.c ]
+    Make sure that SPENGO is disabled 
+    <Bugzilla #1218 - Fixed upstream 20060818>
+
+20060421
+  - [ gssgenr.c, sshconnect2.c ]
+    a few type changes (signed versus unsigned, int versus size_t) to
+    fix compiler errors/warnings 
+    (from jbasney AT ncsa.uiuc.edu)
+  - [ kexgssc.c, sshconnect2.c ]
+    fix uninitialized variable warnings
+    (from jbasney AT ncsa.uiuc.edu)
+  - [ gssgenr.c ]
+    pass oid to gss_display_status (helpful when using GSSAPI mechglue)
+    (from jbasney AT ncsa.uiuc.edu)
+    <Bugzilla #1220 >
+  - [ gss-serv-krb5.c ]
+    #ifdef HAVE_GSSAPI_KRB5 should be #ifdef HAVE_GSSAPI_KRB5_H
+    (from jbasney AT ncsa.uiuc.edu)
+    <Fixed upstream 20060304>
+  - [ readconf.c, readconf.h, ssh_config.5, sshconnect2.c 
+    add client-side GssapiKeyExchange option
+    (from jbasney AT ncsa.uiuc.edu)
+  - [ sshconnect2.c ]
+    add support for GssapiTrustDns option for gssapi-with-mic
+    (from jbasney AT ncsa.uiuc.edu)
+    <gssapi-with-mic support is Bugzilla #1008>
Index: b/Makefile.in
===================================================================
--- a/Makefile.in
+++ b/Makefile.in
@@ -70,6 +70,7 @@
 	atomicio.o key.o dispatch.o kex.o mac.o uidswap.o uuencode.o misc.o \
 	monitor_fdpass.o rijndael.o ssh-dss.o ssh-ecdsa.o ssh-rsa.o dh.o \
 	kexdh.o kexgex.o kexdhc.o kexgexc.o bufec.o kexecdh.o kexecdhc.o \
+	kexgssc.o \
 	msg.o progressmeter.o dns.o entropy.o gss-genr.o umac.o jpake.o \
 	schnorr.o ssh-pkcs11.o
 
@@ -86,7 +87,7 @@
 	auth2-none.o auth2-passwd.o auth2-pubkey.o auth2-jpake.o \
 	monitor_mm.o monitor.o monitor_wrap.o kexdhs.o kexgexs.o kexecdhs.o \
 	auth-krb5.o \
-	auth2-gss.o gss-serv.o gss-serv-krb5.o \
+	auth2-gss.o gss-serv.o gss-serv-krb5.o kexgsss.o\
 	loginrec.o auth-pam.o auth-shadow.o auth-sia.o md5crypt.o \
 	sftp-server.o sftp-common.o \
 	roaming_common.o roaming_serv.o \
Index: b/auth-krb5.c
===================================================================
--- a/auth-krb5.c
+++ b/auth-krb5.c
@@ -170,8 +170,13 @@
 
 	len = strlen(authctxt->krb5_ticket_file) + 6;
 	authctxt->krb5_ccname = xmalloc(len);
+#ifdef USE_CCAPI
+	snprintf(authctxt->krb5_ccname, len, "API:%s",
+	    authctxt->krb5_ticket_file);
+#else
 	snprintf(authctxt->krb5_ccname, len, "FILE:%s",
 	    authctxt->krb5_ticket_file);
+#endif
 
 #ifdef USE_PAM
 	if (options.use_pam)
@@ -226,15 +231,22 @@
 #ifndef HEIMDAL
 krb5_error_code
 ssh_krb5_cc_gen(krb5_context ctx, krb5_ccache *ccache) {
-	int tmpfd, ret;
+	int ret;
 	char ccname[40];
 	mode_t old_umask;
+#ifdef USE_CCAPI
+	char cctemplate[] = "API:krb5cc_%d";
+#else
+	char cctemplate[] = "FILE:/tmp/krb5cc_%d_XXXXXXXXXX";
+	int tmpfd;
+#endif
 
 	ret = snprintf(ccname, sizeof(ccname),
-	    "FILE:/tmp/krb5cc_%d_XXXXXXXXXX", geteuid());
+	    cctemplate, geteuid());
 	if (ret < 0 || (size_t)ret >= sizeof(ccname))
 		return ENOMEM;
 
+#ifndef USE_CCAPI
 	old_umask = umask(0177);
 	tmpfd = mkstemp(ccname + strlen("FILE:"));
 	umask(old_umask);
@@ -249,6 +261,7 @@
 		return errno;
 	}
 	close(tmpfd);
+#endif
 
 	return (krb5_cc_resolve(ctx, ccname, ccache));
 }
Index: b/auth2-gss.c
===================================================================
--- a/auth2-gss.c
+++ b/auth2-gss.c
@@ -1,7 +1,7 @@
 /* $OpenBSD: auth2-gss.c,v 1.17 2011/03/10 02:52:57 djm Exp $ */
 
 /*
- * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
+ * Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -52,6 +52,40 @@
 static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
 static void input_gssapi_errtok(int, u_int32_t, void *);
 
+/* 
+ * The 'gssapi_keyex' userauth mechanism.
+ */
+static int
+userauth_gsskeyex(Authctxt *authctxt)
+{
+	int authenticated = 0;
+	Buffer b;
+	gss_buffer_desc mic, gssbuf;
+	u_int len;
+
+	mic.value = packet_get_string(&len);
+	mic.length = len;
+
+	packet_check_eom();
+
+	ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
+	    "gssapi-keyex");
+
+	gssbuf.value = buffer_ptr(&b);
+	gssbuf.length = buffer_len(&b);
+
+	/* gss_kex_context is NULL with privsep, so we can't check it here */
+	if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gss_kex_context, 
+	    &gssbuf, &mic))))
+		authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user,
+		    authctxt->pw));
+	
+	buffer_free(&b);
+	xfree(mic.value);
+
+	return (authenticated);
+}
+
 /*
  * We only support those mechanisms that we know about (ie ones that we know
  * how to check local user kuserok and the like)
@@ -244,7 +278,8 @@
 
 	packet_check_eom();
 
-	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
+	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user,
+	    authctxt->pw));
 
 	authctxt->postponed = 0;
 	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
@@ -279,7 +314,8 @@
 	gssbuf.length = buffer_len(&b);
 
 	if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
-		authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
+		authenticated = 
+		    PRIVSEP(ssh_gssapi_userok(authctxt->user, authctxt->pw));
 	else
 		logit("GSSAPI MIC check failed");
 
@@ -294,6 +330,12 @@
 	userauth_finish(authctxt, authenticated, "gssapi-with-mic");
 }
 
+Authmethod method_gsskeyex = {
+	"gssapi-keyex",
+	userauth_gsskeyex,
+	&options.gss_authentication
+};
+
 Authmethod method_gssapi = {
 	"gssapi-with-mic",
 	userauth_gssapi,
Index: b/auth2.c
===================================================================
--- a/auth2.c
+++ b/auth2.c
@@ -69,6 +69,7 @@
 extern Authmethod method_kbdint;
 extern Authmethod method_hostbased;
 #ifdef GSSAPI
+extern Authmethod method_gsskeyex;
 extern Authmethod method_gssapi;
 #endif
 #ifdef JPAKE
@@ -79,6 +80,7 @@
 	&method_none,
 	&method_pubkey,
 #ifdef GSSAPI
+	&method_gsskeyex,
 	&method_gssapi,
 #endif
 #ifdef JPAKE
Index: b/clientloop.c
===================================================================
--- a/clientloop.c
+++ b/clientloop.c
@@ -111,6 +111,10 @@
 #include "msg.h"
 #include "roaming.h"
 
+#ifdef GSSAPI
+#include "ssh-gss.h"
+#endif
+
 /* import options */
 extern Options options;
 
@@ -1540,6 +1544,15 @@
 		/* Do channel operations unless rekeying in progress. */
 		if (!rekeying) {
 			channel_after_select(readset, writeset);
+
+#ifdef GSSAPI
+			if (options.gss_renewal_rekey &&
+			    ssh_gssapi_credentials_updated(GSS_C_NO_CONTEXT)) {
+				debug("credentials updated - forcing rekey");
+				need_rekeying = 1;
+			}
+#endif
+
 			if (need_rekeying || packet_need_rekeying()) {
 				debug("need rekeying");
 				xxx_kex->done = 0;
Index: b/config.h.in
===================================================================
--- a/config.h.in
+++ b/config.h.in
@@ -1465,6 +1465,9 @@
 /* Use btmp to log bad logins */
 #undef USE_BTMP
 
+/* platform uses an in-memory credentials cache */
+#undef USE_CCAPI
+
 /* Use libedit for sftp */
 #undef USE_LIBEDIT
 
@@ -1480,6 +1483,9 @@
 /* Use PIPES instead of a socketpair() */
 #undef USE_PIPES
 
+/* platform has the Security Authorization Session API */
+#undef USE_SECURITY_SESSION_API
+
 /* Define if you have Solaris process contracts */
 #undef USE_SOLARIS_PROCESS_CONTRACTS
 
Index: b/configure
===================================================================
--- a/configure
+++ b/configure
@@ -6608,6 +6608,63 @@
 
 $as_echo "#define SSH_TUN_PREPEND_AF 1" >>confdefs.h
 
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if we have the Security Authorization Session API" >&5
+$as_echo_n "checking if we have the Security Authorization Session API... " >&6; }
+	cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <Security/AuthSession.h>
+int
+main ()
+{
+SessionCreate(0, 0);
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  ac_cv_use_security_session_api="yes"
+
+$as_echo "#define USE_SECURITY_SESSION_API 1" >>confdefs.h
+
+		 LIBS="$LIBS -framework Security"
+		 { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+else
+  ac_cv_use_security_session_api="no"
+		 { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if we have an in-memory credentials cache" >&5
+$as_echo_n "checking if we have an in-memory credentials cache... " >&6; }
+	cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <Kerberos/Kerberos.h>
+int
+main ()
+{
+cc_context_t c;
+		 (void) cc_initialize (&c, 0, NULL, NULL);
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+$as_echo "#define USE_CCAPI 1" >>confdefs.h
+
+		 LIBS="$LIBS -framework Security"
+		 { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+		 if test "x$ac_cv_use_security_session_api" = "xno"; then
+			as_fn_error $? "*** Need a security framework to use the credentials cache API ***" "$LINENO" 5
+		fi
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
 	ac_fn_c_check_decl "$LINENO" "AU_IPv4" "ac_cv_have_decl_AU_IPv4" "$ac_includes_default"
 if test "x$ac_cv_have_decl_AU_IPv4" = xyes; then :
Index: b/configure.ac
===================================================================
--- a/configure.ac
+++ b/configure.ac
@@ -545,6 +545,30 @@
 	    [Use tunnel device compatibility to OpenBSD])
 	AC_DEFINE([SSH_TUN_PREPEND_AF], [1],
 	    [Prepend the address family to IP tunnel traffic])
+	AC_MSG_CHECKING([if we have the Security Authorization Session API])
+	AC_TRY_COMPILE([#include <Security/AuthSession.h>],
+		[SessionCreate(0, 0);],
+		[ac_cv_use_security_session_api="yes"
+		 AC_DEFINE([USE_SECURITY_SESSION_API], [1], 
+			[platform has the Security Authorization Session API])
+		 LIBS="$LIBS -framework Security"
+		 AC_MSG_RESULT([yes])],
+		[ac_cv_use_security_session_api="no"
+		 AC_MSG_RESULT([no])])
+	AC_MSG_CHECKING([if we have an in-memory credentials cache])
+	AC_TRY_COMPILE(
+		[#include <Kerberos/Kerberos.h>],
+		[cc_context_t c;
+		 (void) cc_initialize (&c, 0, NULL, NULL);],
+		[AC_DEFINE([USE_CCAPI], [1], 
+			[platform uses an in-memory credentials cache])
+		 LIBS="$LIBS -framework Security"
+		 AC_MSG_RESULT([yes])
+		 if test "x$ac_cv_use_security_session_api" = "xno"; then
+			AC_MSG_ERROR([*** Need a security framework to use the credentials cache API ***])
+		fi],
+		[AC_MSG_RESULT([no])]
+	)
 	m4_pattern_allow([AU_IPv])
 	AC_CHECK_DECL([AU_IPv4], [], 
 	    AC_DEFINE([AU_IPv4], [0], [System only supports IPv4 audit records])
Index: b/gss-genr.c
===================================================================
--- a/gss-genr.c
+++ b/gss-genr.c
@@ -1,7 +1,7 @@
 /* $OpenBSD: gss-genr.c,v 1.20 2009/06/22 05:39:28 dtucker Exp $ */
 
 /*
- * Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved.
+ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -39,12 +39,167 @@
 #include "buffer.h"
 #include "log.h"
 #include "ssh2.h"
+#include "cipher.h"
+#include "key.h"
+#include "kex.h"
+#include <openssl/evp.h>
 
 #include "ssh-gss.h"
 
 extern u_char *session_id2;
 extern u_int session_id2_len;
 
+typedef struct {
+	char *encoded;
+	gss_OID oid;
+} ssh_gss_kex_mapping;
+
+/*
+ * XXX - It would be nice to find a more elegant way of handling the
+ * XXX   passing of the key exchange context to the userauth routines
+ */
+
+Gssctxt *gss_kex_context = NULL;
+
+static ssh_gss_kex_mapping *gss_enc2oid = NULL;
+
+int 
+ssh_gssapi_oid_table_ok() {
+	return (gss_enc2oid != NULL);
+}
+
+/*
+ * Return a list of the gss-group1-sha1 mechanisms supported by this program
+ *
+ * We test mechanisms to ensure that we can use them, to avoid starting
+ * a key exchange with a bad mechanism
+ */
+
+char *
+ssh_gssapi_client_mechanisms(const char *host, const char *client) {
+	gss_OID_set gss_supported;
+	OM_uint32 min_status;
+
+	if (GSS_ERROR(gss_indicate_mechs(&min_status, &gss_supported)))
+		return NULL;
+
+	return(ssh_gssapi_kex_mechs(gss_supported, ssh_gssapi_check_mechanism,
+	    host, client));
+}
+
+char *
+ssh_gssapi_kex_mechs(gss_OID_set gss_supported, ssh_gssapi_check_fn *check,
+    const char *host, const char *client) {
+	Buffer buf;
+	size_t i;
+	int oidpos, enclen;
+	char *mechs, *encoded;
+	u_char digest[EVP_MAX_MD_SIZE];
+	char deroid[2];
+	const EVP_MD *evp_md = EVP_md5();
+	EVP_MD_CTX md;
+
+	if (gss_enc2oid != NULL) {
+		for (i = 0; gss_enc2oid[i].encoded != NULL; i++)
+			xfree(gss_enc2oid[i].encoded);
+		xfree(gss_enc2oid);
+	}
+
+	gss_enc2oid = xmalloc(sizeof(ssh_gss_kex_mapping) *
+	    (gss_supported->count + 1));
+
+	buffer_init(&buf);
+
+	oidpos = 0;
+	for (i = 0; i < gss_supported->count; i++) {
+		if (gss_supported->elements[i].length < 128 &&
+		    (*check)(NULL, &(gss_supported->elements[i]), host, client)) {
+
+			deroid[0] = SSH_GSS_OIDTYPE;
+			deroid[1] = gss_supported->elements[i].length;
+
+			EVP_DigestInit(&md, evp_md);
+			EVP_DigestUpdate(&md, deroid, 2);
+			EVP_DigestUpdate(&md,
+			    gss_supported->elements[i].elements,
+			    gss_supported->elements[i].length);
+			EVP_DigestFinal(&md, digest, NULL);
+
+			encoded = xmalloc(EVP_MD_size(evp_md) * 2);
+			enclen = __b64_ntop(digest, EVP_MD_size(evp_md),
+			    encoded, EVP_MD_size(evp_md) * 2);
+
+			if (oidpos != 0)
+				buffer_put_char(&buf, ',');
+
+			buffer_append(&buf, KEX_GSS_GEX_SHA1_ID,
+			    sizeof(KEX_GSS_GEX_SHA1_ID) - 1);
+			buffer_append(&buf, encoded, enclen);
+			buffer_put_char(&buf, ',');
+			buffer_append(&buf, KEX_GSS_GRP1_SHA1_ID, 
+			    sizeof(KEX_GSS_GRP1_SHA1_ID) - 1);
+			buffer_append(&buf, encoded, enclen);
+			buffer_put_char(&buf, ',');
+			buffer_append(&buf, KEX_GSS_GRP14_SHA1_ID,
+			    sizeof(KEX_GSS_GRP14_SHA1_ID) - 1);
+			buffer_append(&buf, encoded, enclen);
+
+			gss_enc2oid[oidpos].oid = &(gss_supported->elements[i]);
+			gss_enc2oid[oidpos].encoded = encoded;
+			oidpos++;
+		}
+	}
+	gss_enc2oid[oidpos].oid = NULL;
+	gss_enc2oid[oidpos].encoded = NULL;
+
+	buffer_put_char(&buf, '\0');
+
+	mechs = xmalloc(buffer_len(&buf));
+	buffer_get(&buf, mechs, buffer_len(&buf));
+	buffer_free(&buf);
+
+	if (strlen(mechs) == 0) {
+		xfree(mechs);
+		mechs = NULL;
+	}
+	
+	return (mechs);
+}
+
+gss_OID
+ssh_gssapi_id_kex(Gssctxt *ctx, char *name, int kex_type) {
+	int i = 0;
+	
+	switch (kex_type) {
+	case KEX_GSS_GRP1_SHA1:
+		if (strlen(name) < sizeof(KEX_GSS_GRP1_SHA1_ID))
+			return GSS_C_NO_OID;
+		name += sizeof(KEX_GSS_GRP1_SHA1_ID) - 1;
+		break;
+	case KEX_GSS_GRP14_SHA1:
+		if (strlen(name) < sizeof(KEX_GSS_GRP14_SHA1_ID))
+			return GSS_C_NO_OID;
+		name += sizeof(KEX_GSS_GRP14_SHA1_ID) - 1;
+		break;
+	case KEX_GSS_GEX_SHA1:
+		if (strlen(name) < sizeof(KEX_GSS_GEX_SHA1_ID))
+			return GSS_C_NO_OID;
+		name += sizeof(KEX_GSS_GEX_SHA1_ID) - 1;
+		break;
+	default:
+		return GSS_C_NO_OID;
+	}
+
+	while (gss_enc2oid[i].encoded != NULL &&
+	    strcmp(name, gss_enc2oid[i].encoded) != 0)
+		i++;
+
+	if (gss_enc2oid[i].oid != NULL && ctx != NULL)
+		ssh_gssapi_set_oid(ctx, gss_enc2oid[i].oid);
+
+	return gss_enc2oid[i].oid;
+}
+
 /* Check that the OID in a data stream matches that in the context */
 int
 ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
@@ -197,7 +352,7 @@
 	}
 
 	ctx->major = gss_init_sec_context(&ctx->minor,
-	    GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
+	    ctx->client_creds, &ctx->context, ctx->name, ctx->oid,
 	    GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
 	    0, NULL, recv_tok, NULL, send_tok, flags, NULL);
 
@@ -227,8 +382,42 @@
 }
 
 OM_uint32
+ssh_gssapi_client_identity(Gssctxt *ctx, const char *name)
+{
+	gss_buffer_desc gssbuf;
+	gss_name_t gssname;
+	OM_uint32 status;
+	gss_OID_set oidset;
+
+	gssbuf.value = (void *) name;
+	gssbuf.length = strlen(gssbuf.value);
+
+	gss_create_empty_oid_set(&status, &oidset);
+	gss_add_oid_set_member(&status, ctx->oid, &oidset);
+
+	ctx->major = gss_import_name(&ctx->minor, &gssbuf,
+	    GSS_C_NT_USER_NAME, &gssname);
+
+	if (!ctx->major)
+		ctx->major = gss_acquire_cred(&ctx->minor, 
+		    gssname, 0, oidset, GSS_C_INITIATE, 
+		    &ctx->client_creds, NULL, NULL);
+
+	gss_release_name(&status, &gssname);
+	gss_release_oid_set(&status, &oidset);
+
+	if (ctx->major)
+		ssh_gssapi_error(ctx);
+
+	return(ctx->major);
+}
+
+OM_uint32
 ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
 {
+	if (ctx == NULL) 
+		return -1;
+
 	if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
 	    GSS_C_QOP_DEFAULT, buffer, hash)))
 		ssh_gssapi_error(ctx);
@@ -236,6 +425,19 @@
 	return (ctx->major);
 }
 
+/* Priviledged when used by server */
+OM_uint32
+ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
+{
+	if (ctx == NULL)
+		return -1;
+
+	ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
+	    gssbuf, gssmic, NULL);
+
+	return (ctx->major);
+}
+
 void
 ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service,
     const char *context)
@@ -249,11 +451,16 @@
 }
 
 int
-ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
+ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host, 
+    const char *client)
 {
 	gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
 	OM_uint32 major, minor;
 	gss_OID_desc spnego_oid = {6, (void *)"\x2B\x06\x01\x05\x05\x02"};
+	Gssctxt *intctx = NULL;
+
+	if (ctx == NULL)
+		ctx = &intctx;
 
 	/* RFC 4462 says we MUST NOT do SPNEGO */
 	if (oid->length == spnego_oid.length && 
@@ -263,6 +470,10 @@
 	ssh_gssapi_build_ctx(ctx);
 	ssh_gssapi_set_oid(*ctx, oid);
 	major = ssh_gssapi_import_name(*ctx, host);
+
+	if (!GSS_ERROR(major) && client)
+		major = ssh_gssapi_client_identity(*ctx, client);
+
 	if (!GSS_ERROR(major)) {
 		major = ssh_gssapi_init_ctx(*ctx, 0, GSS_C_NO_BUFFER, &token, 
 		    NULL);
@@ -272,10 +483,67 @@
 			    GSS_C_NO_BUFFER);
 	}
 
-	if (GSS_ERROR(major)) 
+	if (GSS_ERROR(major) || intctx != NULL) 
 		ssh_gssapi_delete_ctx(ctx);
 
 	return (!GSS_ERROR(major));
 }
 
+int
+ssh_gssapi_credentials_updated(Gssctxt *ctxt) {
+	static gss_name_t saved_name = GSS_C_NO_NAME;
+	static OM_uint32 saved_lifetime = 0;
+	static gss_OID saved_mech = GSS_C_NO_OID;
+	static gss_name_t name;
+	static OM_uint32 last_call = 0;
+	OM_uint32 lifetime, now, major, minor;
+	int equal;
+	gss_cred_usage_t usage = GSS_C_INITIATE;
+	
+	now = time(NULL);
+
+	if (ctxt) {
+		debug("Rekey has happened - updating saved versions");
+
+		if (saved_name != GSS_C_NO_NAME)
+			gss_release_name(&minor, &saved_name);
+
+		major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
+		    &saved_name, &saved_lifetime, NULL, NULL);
+
+		if (!GSS_ERROR(major)) {
+			saved_mech = ctxt->oid;
+		        saved_lifetime+= now;
+		} else {
+			/* Handle the error */
+		}
+		return 0;
+	}
+
+	if (now - last_call < 10)
+		return 0;
+
+	last_call = now;
+
+	if (saved_mech == GSS_C_NO_OID)
+		return 0;
+	
+	major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL, 
+	    &name, &lifetime, NULL, NULL);
+	if (major == GSS_S_CREDENTIALS_EXPIRED)
+		return 0;
+	else if (GSS_ERROR(major))
+		return 0;
+
+	major = gss_compare_name(&minor, saved_name, name, &equal);
+	gss_release_name(&minor, &name);
+	if (GSS_ERROR(major))
+		return 0;
+
+	if (equal && (saved_lifetime < lifetime + now - 10))
+		return 1;
+
+	return 0;
+}
+
 #endif /* GSSAPI */
Index: b/gss-serv-krb5.c
===================================================================
--- a/gss-serv-krb5.c
+++ b/gss-serv-krb5.c
@@ -1,7 +1,7 @@
 /* $OpenBSD: gss-serv-krb5.c,v 1.7 2006/08/03 03:34:42 deraadt Exp $ */
 
 /*
- * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
+ * Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -120,6 +120,7 @@
 	krb5_principal princ;
 	OM_uint32 maj_status, min_status;
 	int len;
+	const char *new_ccname;
 
 	if (client->creds == NULL) {
 		debug("No credentials stored");
@@ -168,11 +169,16 @@
 		return;
 	}
 
-	client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache));
+	new_ccname = krb5_cc_get_name(krb_context, ccache);
+
 	client->store.envvar = "KRB5CCNAME";
-	len = strlen(client->store.filename) + 6;
-	client->store.envval = xmalloc(len);
-	snprintf(client->store.envval, len, "FILE:%s", client->store.filename);
+#ifdef USE_CCAPI
+	xasprintf(&client->store.envval, "API:%s", new_ccname);
+	client->store.filename = NULL;
+#else
+	xasprintf(&client->store.envval, "FILE:%s", new_ccname);
+	client->store.filename = xstrdup(new_ccname);
+#endif
 
 #ifdef USE_PAM
 	if (options.use_pam)
@@ -184,6 +190,71 @@
 	return;
 }
 
+int
+ssh_gssapi_krb5_updatecreds(ssh_gssapi_ccache *store, 
+    ssh_gssapi_client *client)
+{
+	krb5_ccache ccache = NULL;
+	krb5_principal principal = NULL;
+	char *name = NULL;
+	krb5_error_code problem;
+	OM_uint32 maj_status, min_status;
+
+   	if ((problem = krb5_cc_resolve(krb_context, store->envval, &ccache))) {
+                logit("krb5_cc_resolve(): %.100s",
+                    krb5_get_err_text(krb_context, problem));
+                return 0;
+       	}
+	
+	/* Find out who the principal in this cache is */
+	if ((problem = krb5_cc_get_principal(krb_context, ccache, 
+	    &principal))) {
+		logit("krb5_cc_get_principal(): %.100s",
+		    krb5_get_err_text(krb_context, problem));
+		krb5_cc_close(krb_context, ccache);
+		return 0;
+	}
+
+	if ((problem = krb5_unparse_name(krb_context, principal, &name))) {
+		logit("krb5_unparse_name(): %.100s",
+		    krb5_get_err_text(krb_context, problem));
+		krb5_free_principal(krb_context, principal);
+		krb5_cc_close(krb_context, ccache);
+		return 0;
+	}
+
+
+	if (strcmp(name,client->exportedname.value)!=0) {
+		debug("Name in local credentials cache differs. Not storing");
+		krb5_free_principal(krb_context, principal);
+		krb5_cc_close(krb_context, ccache);
+		krb5_free_unparsed_name(krb_context, name);
+		return 0;
+	}
+	krb5_free_unparsed_name(krb_context, name);
+
+	/* Name matches, so lets get on with it! */
+
+	if ((problem = krb5_cc_initialize(krb_context, ccache, principal))) {
+		logit("krb5_cc_initialize(): %.100s",
+		    krb5_get_err_text(krb_context, problem));
+		krb5_free_principal(krb_context, principal);
+		krb5_cc_close(krb_context, ccache);
+		return 0;
+	}
+
+	krb5_free_principal(krb_context, principal);
+
+	if ((maj_status = gss_krb5_copy_ccache(&min_status, client->creds,
+	    ccache))) {
+		logit("gss_krb5_copy_ccache() failed. Sorry!");
+		krb5_cc_close(krb_context, ccache);
+		return 0;
+	}
+
+	return 1;
+}
+
 ssh_gssapi_mech gssapi_kerberos_mech = {
 	"toWM5Slw5Ew8Mqkay+al2g==",
 	"Kerberos",
@@ -191,7 +262,8 @@
 	NULL,
 	&ssh_gssapi_krb5_userok,
 	NULL,
-	&ssh_gssapi_krb5_storecreds
+	&ssh_gssapi_krb5_storecreds,
+	&ssh_gssapi_krb5_updatecreds
 };
 
 #endif /* KRB5 */
Index: b/gss-serv.c
===================================================================
--- a/gss-serv.c
+++ b/gss-serv.c
@@ -1,7 +1,7 @@
 /* $OpenBSD: gss-serv.c,v 1.23 2011/08/01 19:18:15 markus Exp $ */
 
 /*
- * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
+ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -45,15 +45,20 @@
 #include "channels.h"
 #include "session.h"
 #include "misc.h"
+#include "servconf.h"
+#include "uidswap.h"
 
 #include "ssh-gss.h"
+#include "monitor_wrap.h"
+
+extern ServerOptions options;
 
 static ssh_gssapi_client gssapi_client =
     { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER,
-    GSS_C_NO_CREDENTIAL, NULL, {NULL, NULL, NULL}};
+    GSS_C_NO_CREDENTIAL, GSS_C_NO_NAME,  NULL, {NULL, NULL, NULL}, 0, 0};
 
 ssh_gssapi_mech gssapi_null_mech =
-    { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL};
+    { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL, NULL};
 
 #ifdef KRB5
 extern ssh_gssapi_mech gssapi_kerberos_mech;
@@ -81,25 +86,32 @@
 	char lname[MAXHOSTNAMELEN];
 	gss_OID_set oidset;
 
-	gss_create_empty_oid_set(&status, &oidset);
-	gss_add_oid_set_member(&status, ctx->oid, &oidset);
+	if (options.gss_strict_acceptor) {
+		gss_create_empty_oid_set(&status, &oidset);
+		gss_add_oid_set_member(&status, ctx->oid, &oidset);
+
+		if (gethostname(lname, MAXHOSTNAMELEN)) {
+			gss_release_oid_set(&status, &oidset);
+			return (-1);
+		}
 
-	if (gethostname(lname, MAXHOSTNAMELEN)) {
-		gss_release_oid_set(&status, &oidset);
-		return (-1);
-	}
+		if (GSS_ERROR(ssh_gssapi_import_name(ctx, lname))) {
+			gss_release_oid_set(&status, &oidset);
+			return (ctx->major);
+		}
+
+		if ((ctx->major = gss_acquire_cred(&ctx->minor,
+		    ctx->name, 0, oidset, GSS_C_ACCEPT, &ctx->creds, 
+		    NULL, NULL)))
+			ssh_gssapi_error(ctx);
 
-	if (GSS_ERROR(ssh_gssapi_import_name(ctx, lname))) {
 		gss_release_oid_set(&status, &oidset);
 		return (ctx->major);
+	} else {
+		ctx->name = GSS_C_NO_NAME;
+		ctx->creds = GSS_C_NO_CREDENTIAL;
 	}
-
-	if ((ctx->major = gss_acquire_cred(&ctx->minor,
-	    ctx->name, 0, oidset, GSS_C_ACCEPT, &ctx->creds, NULL, NULL)))
-		ssh_gssapi_error(ctx);
-
-	gss_release_oid_set(&status, &oidset);
-	return (ctx->major);
+	return GSS_S_COMPLETE;
 }
 
 /* Privileged */
@@ -114,6 +126,29 @@
 }
 
 /* Unprivileged */
+char *
+ssh_gssapi_server_mechanisms() {
+	gss_OID_set	supported;
+
+	ssh_gssapi_supported_oids(&supported);
+	return (ssh_gssapi_kex_mechs(supported, &ssh_gssapi_server_check_mech,
+	    NULL, NULL));
+}
+
+/* Unprivileged */
+int
+ssh_gssapi_server_check_mech(Gssctxt **dum, gss_OID oid, const char *data,
+    const char *dummy) {
+	Gssctxt *ctx = NULL;
+	int res;
+ 
+	res = !GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctx, oid)));
+	ssh_gssapi_delete_ctx(&ctx);
+
+	return (res);
+}
+
+/* Unprivileged */
 void
 ssh_gssapi_supported_oids(gss_OID_set *oidset)
 {
@@ -123,7 +158,9 @@
 	gss_OID_set supported;
 
 	gss_create_empty_oid_set(&min_status, oidset);
-	gss_indicate_mechs(&min_status, &supported);
+
+	if (GSS_ERROR(gss_indicate_mechs(&min_status, &supported)))
+		return;
 
 	while (supported_mechs[i]->name != NULL) {
 		if (GSS_ERROR(gss_test_oid_set_member(&min_status,
@@ -249,8 +286,48 @@
 ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
 {
 	int i = 0;
+	int equal = 0;
+	gss_name_t new_name = GSS_C_NO_NAME;
+	gss_buffer_desc ename = GSS_C_EMPTY_BUFFER;
+
+	if (options.gss_store_rekey && client->used && ctx->client_creds) {
+		if (client->mech->oid.length != ctx->oid->length ||
+		    (memcmp(client->mech->oid.elements,
+		     ctx->oid->elements, ctx->oid->length) !=0)) {
+			debug("Rekeyed credentials have different mechanism");
+			return GSS_S_COMPLETE;
+		}
+
+		if ((ctx->major = gss_inquire_cred_by_mech(&ctx->minor, 
+		    ctx->client_creds, ctx->oid, &new_name, 
+		    NULL, NULL, NULL))) {
+			ssh_gssapi_error(ctx);
+			return (ctx->major);
+		}
+
+		ctx->major = gss_compare_name(&ctx->minor, client->name, 
+		    new_name, &equal);
 
-	gss_buffer_desc ename;
+		if (GSS_ERROR(ctx->major)) {
+			ssh_gssapi_error(ctx);
+			return (ctx->major);
+		}
+ 
+		if (!equal) {
+			debug("Rekeyed credentials have different name");
+			return GSS_S_COMPLETE;
+		}
+
+		debug("Marking rekeyed credentials for export");
+
+		gss_release_name(&ctx->minor, &client->name);
+		gss_release_cred(&ctx->minor, &client->creds);
+		client->name = new_name;
+		client->creds = ctx->client_creds;
+        	ctx->client_creds = GSS_C_NO_CREDENTIAL;
+		client->updated = 1;
+		return GSS_S_COMPLETE;
+	}
 
 	client->mech = NULL;
 
@@ -265,6 +342,13 @@
 	if (client->mech == NULL)
 		return GSS_S_FAILURE;
 
+	if (ctx->client_creds &&
+	    (ctx->major = gss_inquire_cred_by_mech(&ctx->minor,
+	     ctx->client_creds, ctx->oid, &client->name, NULL, NULL, NULL))) {
+		ssh_gssapi_error(ctx);
+		return (ctx->major);
+	}
+
 	if ((ctx->major = gss_display_name(&ctx->minor, ctx->client,
 	    &client->displayname, NULL))) {
 		ssh_gssapi_error(ctx);
@@ -282,6 +366,8 @@
 		return (ctx->major);
 	}
 
+	gss_release_buffer(&ctx->minor, &ename);
+
 	/* We can't copy this structure, so we just move the pointer to it */
 	client->creds = ctx->client_creds;
 	ctx->client_creds = GSS_C_NO_CREDENTIAL;
@@ -329,7 +415,7 @@
 
 /* Privileged */
 int
-ssh_gssapi_userok(char *user)
+ssh_gssapi_userok(char *user, struct passwd *pw)
 {
 	OM_uint32 lmin;
 
@@ -339,9 +425,11 @@
 		return 0;
 	}
 	if (gssapi_client.mech && gssapi_client.mech->userok)
-		if ((*gssapi_client.mech->userok)(&gssapi_client, user))
+		if ((*gssapi_client.mech->userok)(&gssapi_client, user)) {
+			gssapi_client.used = 1;
+			gssapi_client.store.owner = pw;
 			return 1;
-		else {
+		} else {
 			/* Destroy delegated credentials if userok fails */
 			gss_release_buffer(&lmin, &gssapi_client.displayname);
 			gss_release_buffer(&lmin, &gssapi_client.exportedname);
@@ -354,14 +442,90 @@
 	return (0);
 }
 
-/* Privileged */
-OM_uint32
-ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
+/* These bits are only used for rekeying. The unpriviledged child is running 
+ * as the user, the monitor is root.
+ *
+ * In the child, we want to :
+ *    *) Ask the monitor to store our credentials into the store we specify
+ *    *) If it succeeds, maybe do a PAM update
+ */
+
+/* Stuff for PAM */
+
+#ifdef USE_PAM
+static int ssh_gssapi_simple_conv(int n, const struct pam_message **msg, 
+    struct pam_response **resp, void *data)
 {
-	ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
-	    gssbuf, gssmic, NULL);
+	return (PAM_CONV_ERR);
+}
+#endif
 
-	return (ctx->major);
+void
+ssh_gssapi_rekey_creds() {
+	int ok;
+	int ret;
+#ifdef USE_PAM
+	pam_handle_t *pamh = NULL;
+	struct pam_conv pamconv = {ssh_gssapi_simple_conv, NULL};
+	char *envstr;
+#endif
+
+	if (gssapi_client.store.filename == NULL && 
+	    gssapi_client.store.envval == NULL &&
+	    gssapi_client.store.envvar == NULL)
+		return;
+ 
+	ok = PRIVSEP(ssh_gssapi_update_creds(&gssapi_client.store));
+
+	if (!ok)
+		return;
+
+	debug("Rekeyed credentials stored successfully");
+
+	/* Actually managing to play with the ssh pam stack from here will
+	 * be next to impossible. In any case, we may want different options
+	 * for rekeying. So, use our own :)
+	 */
+#ifdef USE_PAM	
+	if (!use_privsep) {
+		debug("Not even going to try and do PAM with privsep disabled");
+		return;
+	}
+
+	ret = pam_start("sshd-rekey", gssapi_client.store.owner->pw_name,
+ 	    &pamconv, &pamh);
+	if (ret)
+		return;
+
+	xasprintf(&envstr, "%s=%s", gssapi_client.store.envvar, 
+	    gssapi_client.store.envval);
+
+	ret = pam_putenv(pamh, envstr);
+	if (!ret)
+		pam_setcred(pamh, PAM_REINITIALIZE_CRED);
+	pam_end(pamh, PAM_SUCCESS);
+#endif
+}
+
+int 
+ssh_gssapi_update_creds(ssh_gssapi_ccache *store) {
+	int ok = 0;
+
+	/* Check we've got credentials to store */
+	if (!gssapi_client.updated)
+		return 0;
+
+	gssapi_client.updated = 0;
+
+	temporarily_use_uid(gssapi_client.store.owner);
+	if (gssapi_client.mech && gssapi_client.mech->updatecreds)
+		ok = (*gssapi_client.mech->updatecreds)(store, &gssapi_client);
+	else
+		debug("No update function for this mechanism");
+
+	restore_uid();
+
+	return ok;
 }
 
 #endif
Index: b/kex.c
===================================================================
--- a/kex.c
+++ b/kex.c
@@ -50,6 +50,10 @@
 #include "monitor.h"
 #include "roaming.h"
 
+#ifdef GSSAPI
+#include "ssh-gss.h"
+#endif
+
 #if OPENSSL_VERSION_NUMBER >= 0x00907000L
 # if defined(HAVE_EVP_SHA256)
 # define evp_ssh_sha256 EVP_sha256
@@ -358,6 +362,20 @@
  		k->kex_type = KEX_ECDH_SHA2;
 		k->evp_md = kex_ecdh_name_to_evpmd(k->name);
 #endif
+#ifdef GSSAPI
+	} else if (strncmp(k->name, KEX_GSS_GEX_SHA1_ID,
+	    sizeof(KEX_GSS_GEX_SHA1_ID) - 1) == 0) {
+		k->kex_type = KEX_GSS_GEX_SHA1;
+		k->evp_md = EVP_sha1();
+	} else if (strncmp(k->name, KEX_GSS_GRP1_SHA1_ID,
+	    sizeof(KEX_GSS_GRP1_SHA1_ID) - 1) == 0) {
+		k->kex_type = KEX_GSS_GRP1_SHA1;
+		k->evp_md = EVP_sha1();
+	} else if (strncmp(k->name, KEX_GSS_GRP14_SHA1_ID,
+	    sizeof(KEX_GSS_GRP14_SHA1_ID) - 1) == 0) {
+		k->kex_type = KEX_GSS_GRP14_SHA1;
+		k->evp_md = EVP_sha1();
+#endif
 	} else
 		fatal("bad kex alg %s", k->name);
 }
Index: b/kex.h
===================================================================
--- a/kex.h
+++ b/kex.h
@@ -73,6 +73,9 @@
 	KEX_DH_GEX_SHA1,
 	KEX_DH_GEX_SHA256,
 	KEX_ECDH_SHA2,
+	KEX_GSS_GRP1_SHA1,
+	KEX_GSS_GRP14_SHA1,
+	KEX_GSS_GEX_SHA1,
 	KEX_MAX
 };
 
@@ -129,6 +132,12 @@
 	sig_atomic_t done;
 	int	flags;
 	const EVP_MD *evp_md;
+#ifdef GSSAPI
+	int	gss_deleg_creds;
+	int	gss_trust_dns;
+	char    *gss_host;
+	char	*gss_client;
+#endif
 	char	*client_version_string;
 	char	*server_version_string;
 	int	(*verify_host_key)(Key *);
@@ -156,6 +165,11 @@
 void	 kexecdh_client(Kex *);
 void	 kexecdh_server(Kex *);
 
+#ifdef GSSAPI
+void	kexgss_client(Kex *);
+void	kexgss_server(Kex *);
+#endif
+
 void
 kex_dh_hash(char *, char *, char *, int, char *, int, u_char *, int,
     BIGNUM *, BIGNUM *, BIGNUM *, u_char **, u_int *);
Index: b/kexgssc.c
===================================================================
--- /dev/null
+++ b/kexgssc.c
@@ -0,0 +1,334 @@
+/*
+ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+
+#ifdef GSSAPI
+
+#include "includes.h"
+
+#include <openssl/crypto.h>
+#include <openssl/bn.h>
+
+#include <string.h>
+
+#include "xmalloc.h"
+#include "buffer.h"
+#include "ssh2.h"
+#include "key.h"
+#include "cipher.h"
+#include "kex.h"
+#include "log.h"
+#include "packet.h"
+#include "dh.h"
+
+#include "ssh-gss.h"
+
+void
+kexgss_client(Kex *kex) {
+	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
+	gss_buffer_desc recv_tok, gssbuf, msg_tok, *token_ptr;
+	Gssctxt *ctxt;
+	OM_uint32 maj_status, min_status, ret_flags;
+	u_int klen, kout, slen = 0, hashlen, strlen;
+	DH *dh; 
+	BIGNUM *dh_server_pub = NULL;
+	BIGNUM *shared_secret = NULL;
+	BIGNUM *p = NULL;
+	BIGNUM *g = NULL;	
+	u_char *kbuf, *hash;
+	u_char *serverhostkey = NULL;
+	u_char *empty = "";
+	char *msg;
+	char *lang;
+	int type = 0;
+	int first = 1;
+	int nbits = 0, min = DH_GRP_MIN, max = DH_GRP_MAX;
+
+	/* Initialise our GSSAPI world */	
+	ssh_gssapi_build_ctx(&ctxt);
+	if (ssh_gssapi_id_kex(ctxt, kex->name, kex->kex_type) 
+	    == GSS_C_NO_OID)
+		fatal("Couldn't identify host exchange");
+
+	if (ssh_gssapi_import_name(ctxt, kex->gss_host))
+		fatal("Couldn't import hostname");
+
+	if (kex->gss_client && 
+	    ssh_gssapi_client_identity(ctxt, kex->gss_client))
+		fatal("Couldn't acquire client credentials");
+
+	switch (kex->kex_type) {
+	case KEX_GSS_GRP1_SHA1:
+		dh = dh_new_group1();
+		break;
+	case KEX_GSS_GRP14_SHA1:
+		dh = dh_new_group14();
+		break;
+	case KEX_GSS_GEX_SHA1:
+		debug("Doing group exchange\n");
+		nbits = dh_estimate(kex->we_need * 8);
+		packet_start(SSH2_MSG_KEXGSS_GROUPREQ);
+		packet_put_int(min);
+		packet_put_int(nbits);
+		packet_put_int(max);
+
+		packet_send();
+
+		packet_read_expect(SSH2_MSG_KEXGSS_GROUP);
+
+		if ((p = BN_new()) == NULL)
+			fatal("BN_new() failed");
+		packet_get_bignum2(p);
+		if ((g = BN_new()) == NULL)
+			fatal("BN_new() failed");
+		packet_get_bignum2(g);
+		packet_check_eom();
+
+		if (BN_num_bits(p) < min || BN_num_bits(p) > max)
+			fatal("GSSGRP_GEX group out of range: %d !< %d !< %d",
+			    min, BN_num_bits(p), max);
+
+		dh = dh_new_group(g, p);
+		break;
+	default:
+		fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type);
+	}
+	
+	/* Step 1 - e is dh->pub_key */
+	dh_gen_key(dh, kex->we_need * 8);
+
+	/* This is f, we initialise it now to make life easier */
+	dh_server_pub = BN_new();
+	if (dh_server_pub == NULL)
+		fatal("dh_server_pub == NULL");
+
+	token_ptr = GSS_C_NO_BUFFER;
+			 
+	do {
+		debug("Calling gss_init_sec_context");
+		
+		maj_status = ssh_gssapi_init_ctx(ctxt,
+		    kex->gss_deleg_creds, token_ptr, &send_tok,
+		    &ret_flags);
+
+		if (GSS_ERROR(maj_status)) {
+			if (send_tok.length != 0) {
+				packet_start(SSH2_MSG_KEXGSS_CONTINUE);
+				packet_put_string(send_tok.value,
+				    send_tok.length);
+			}
+			fatal("gss_init_context failed");
+		}
+
+		/* If we've got an old receive buffer get rid of it */
+		if (token_ptr != GSS_C_NO_BUFFER)
+			xfree(recv_tok.value);
+
+		if (maj_status == GSS_S_COMPLETE) {
+			/* If mutual state flag is not true, kex fails */
+			if (!(ret_flags & GSS_C_MUTUAL_FLAG))
+				fatal("Mutual authentication failed");
+
+			/* If integ avail flag is not true kex fails */
+			if (!(ret_flags & GSS_C_INTEG_FLAG))
+				fatal("Integrity check failed");
+		}
+
+		/* 
+		 * If we have data to send, then the last message that we
+		 * received cannot have been a 'complete'. 
+		 */
+		if (send_tok.length != 0) {
+			if (first) {
+				packet_start(SSH2_MSG_KEXGSS_INIT);
+				packet_put_string(send_tok.value,
+				    send_tok.length);
+				packet_put_bignum2(dh->pub_key);
+				first = 0;
+			} else {
+				packet_start(SSH2_MSG_KEXGSS_CONTINUE);
+				packet_put_string(send_tok.value,
+				    send_tok.length);
+			}
+			packet_send();
+			gss_release_buffer(&min_status, &send_tok);
+
+			/* If we've sent them data, they should reply */
+			do {	
+				type = packet_read();
+				if (type == SSH2_MSG_KEXGSS_HOSTKEY) {
+					debug("Received KEXGSS_HOSTKEY");
+					if (serverhostkey)
+						fatal("Server host key received more than once");
+					serverhostkey = 
+					    packet_get_string(&slen);
+				}
+			} while (type == SSH2_MSG_KEXGSS_HOSTKEY);
+
+			switch (type) {
+			case SSH2_MSG_KEXGSS_CONTINUE:
+				debug("Received GSSAPI_CONTINUE");
+				if (maj_status == GSS_S_COMPLETE) 
+					fatal("GSSAPI Continue received from server when complete");
+				recv_tok.value = packet_get_string(&strlen);
+				recv_tok.length = strlen; 
+				break;
+			case SSH2_MSG_KEXGSS_COMPLETE:
+				debug("Received GSSAPI_COMPLETE");
+				packet_get_bignum2(dh_server_pub);
+				msg_tok.value =  packet_get_string(&strlen);
+				msg_tok.length = strlen; 
+
+				/* Is there a token included? */
+				if (packet_get_char()) {
+					recv_tok.value=
+					    packet_get_string(&strlen);
+					recv_tok.length = strlen;
+					/* If we're already complete - protocol error */
+					if (maj_status == GSS_S_COMPLETE)
+						packet_disconnect("Protocol error: received token when complete");
+					} else {
+						/* No token included */
+						if (maj_status != GSS_S_COMPLETE)
+							packet_disconnect("Protocol error: did not receive final token");
+				}
+				break;
+			case SSH2_MSG_KEXGSS_ERROR:
+				debug("Received Error");
+				maj_status = packet_get_int();
+				min_status = packet_get_int();
+				msg = packet_get_string(NULL);
+				lang = packet_get_string(NULL);
+				fatal("GSSAPI Error: \n%.400s",msg);
+			default:
+				packet_disconnect("Protocol error: didn't expect packet type %d",
+		    		type);
+			}
+			token_ptr = &recv_tok;
+		} else {
+			/* No data, and not complete */
+			if (maj_status != GSS_S_COMPLETE)
+				fatal("Not complete, and no token output");
+		}
+	} while (maj_status & GSS_S_CONTINUE_NEEDED);
+
+	/* 
+	 * We _must_ have received a COMPLETE message in reply from the 
+	 * server, which will have set dh_server_pub and msg_tok 
+	 */
+
+	if (type != SSH2_MSG_KEXGSS_COMPLETE)
+		fatal("Didn't receive a SSH2_MSG_KEXGSS_COMPLETE when I expected it");
+
+	/* Check f in range [1, p-1] */
+	if (!dh_pub_is_valid(dh, dh_server_pub))
+		packet_disconnect("bad server public DH value");
+
+	/* compute K=f^x mod p */
+	klen = DH_size(dh);
+	kbuf = xmalloc(klen);
+	kout = DH_compute_key(kbuf, dh_server_pub, dh);
+	if (kout < 0)
+		fatal("DH_compute_key: failed");
+
+	shared_secret = BN_new();
+	if (shared_secret == NULL)
+		fatal("kexgss_client: BN_new failed");
+
+	if (BN_bin2bn(kbuf, kout, shared_secret) == NULL)
+		fatal("kexdh_client: BN_bin2bn failed");
+
+	memset(kbuf, 0, klen);
+	xfree(kbuf);
+
+	switch (kex->kex_type) {
+	case KEX_GSS_GRP1_SHA1:
+	case KEX_GSS_GRP14_SHA1:
+		kex_dh_hash( kex->client_version_string, 
+		    kex->server_version_string,
+		    buffer_ptr(&kex->my), buffer_len(&kex->my),
+		    buffer_ptr(&kex->peer), buffer_len(&kex->peer),
+		    (serverhostkey ? serverhostkey : empty), slen,
+		    dh->pub_key,	/* e */
+		    dh_server_pub,	/* f */
+		    shared_secret,	/* K */
+		    &hash, &hashlen
+		);
+		break;
+	case KEX_GSS_GEX_SHA1:
+		kexgex_hash(
+		    kex->evp_md,
+		    kex->client_version_string,
+		    kex->server_version_string,
+		    buffer_ptr(&kex->my), buffer_len(&kex->my),
+		    buffer_ptr(&kex->peer), buffer_len(&kex->peer),
+		    (serverhostkey ? serverhostkey : empty), slen,
+ 		    min, nbits, max,
+		    dh->p, dh->g,
+		    dh->pub_key,
+		    dh_server_pub,
+		    shared_secret,
+		    &hash, &hashlen
+		);
+		break;
+	default:
+		fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type);
+	}
+
+	gssbuf.value = hash;
+	gssbuf.length = hashlen;
+
+	/* Verify that the hash matches the MIC we just got. */
+	if (GSS_ERROR(ssh_gssapi_checkmic(ctxt, &gssbuf, &msg_tok)))
+		packet_disconnect("Hash's MIC didn't verify");
+
+	xfree(msg_tok.value);
+
+	DH_free(dh);
+	if (serverhostkey)
+		xfree(serverhostkey);
+	BN_clear_free(dh_server_pub);
+
+	/* save session id */
+	if (kex->session_id == NULL) {
+		kex->session_id_len = hashlen;
+		kex->session_id = xmalloc(kex->session_id_len);
+		memcpy(kex->session_id, hash, kex->session_id_len);
+	}
+
+	if (kex->gss_deleg_creds)
+		ssh_gssapi_credentials_updated(ctxt);
+
+	if (gss_kex_context == NULL)
+		gss_kex_context = ctxt;
+	else
+		ssh_gssapi_delete_ctx(&ctxt);
+
+	kex_derive_keys(kex, hash, hashlen, shared_secret);
+	BN_clear_free(shared_secret);
+	kex_finish(kex);
+}
+
+#endif /* GSSAPI */
Index: b/kexgsss.c
===================================================================
--- /dev/null
+++ b/kexgsss.c
@@ -0,0 +1,288 @@
+/*
+ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+
+#ifdef GSSAPI
+
+#include <string.h>
+
+#include <openssl/crypto.h>
+#include <openssl/bn.h>
+
+#include "xmalloc.h"
+#include "buffer.h"
+#include "ssh2.h"
+#include "key.h"
+#include "cipher.h"
+#include "kex.h"
+#include "log.h"
+#include "packet.h"
+#include "dh.h"
+#include "ssh-gss.h"
+#include "monitor_wrap.h"
+#include "servconf.h"
+
+extern ServerOptions options;
+
+void
+kexgss_server(Kex *kex)
+{
+	OM_uint32 maj_status, min_status;
+	
+	/* 
+	 * Some GSSAPI implementations use the input value of ret_flags (an
+ 	 * output variable) as a means of triggering mechanism specific 
+ 	 * features. Initializing it to zero avoids inadvertently 
+ 	 * activating this non-standard behaviour.
+	 */
+
+	OM_uint32 ret_flags = 0;
+	gss_buffer_desc gssbuf, recv_tok, msg_tok;
+	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
+	Gssctxt *ctxt = NULL;
+	u_int slen, klen, kout, hashlen;
+	u_char *kbuf, *hash;
+	DH *dh;
+	int min = -1, max = -1, nbits = -1;
+	BIGNUM *shared_secret = NULL;
+	BIGNUM *dh_client_pub = NULL;
+	int type = 0;
+	gss_OID oid;
+	char *mechs;
+
+	/* Initialise GSSAPI */
+
+	/* If we're rekeying, privsep means that some of the private structures
+	 * in the GSSAPI code are no longer available. This kludges them back
+	 * into life
+	 */
+	if (!ssh_gssapi_oid_table_ok()) 
+		if ((mechs = ssh_gssapi_server_mechanisms()))
+			xfree(mechs);
+
+	debug2("%s: Identifying %s", __func__, kex->name);
+	oid = ssh_gssapi_id_kex(NULL, kex->name, kex->kex_type);
+	if (oid == GSS_C_NO_OID)
+	   fatal("Unknown gssapi mechanism");
+
+	debug2("%s: Acquiring credentials", __func__);
+
+	if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, oid))))
+		fatal("Unable to acquire credentials for the server");
+
+	switch (kex->kex_type) {
+	case KEX_GSS_GRP1_SHA1:
+		dh = dh_new_group1();
+		break;
+	case KEX_GSS_GRP14_SHA1:
+		dh = dh_new_group14();
+		break;
+	case KEX_GSS_GEX_SHA1:
+		debug("Doing group exchange");
+		packet_read_expect(SSH2_MSG_KEXGSS_GROUPREQ);
+		min = packet_get_int();
+		nbits = packet_get_int();
+		max = packet_get_int();
+		min = MAX(DH_GRP_MIN, min);
+		max = MIN(DH_GRP_MAX, max);
+		packet_check_eom();
+		if (max < min || nbits < min || max < nbits)
+			fatal("GSS_GEX, bad parameters: %d !< %d !< %d",
+			    min, nbits, max);
+		dh = PRIVSEP(choose_dh(min, nbits, max));
+		if (dh == NULL)
+			packet_disconnect("Protocol error: no matching group found");
+
+		packet_start(SSH2_MSG_KEXGSS_GROUP);
+		packet_put_bignum2(dh->p);
+		packet_put_bignum2(dh->g);
+		packet_send();
+
+		packet_write_wait();
+		break;
+	default:
+		fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type);
+	}
+
+	dh_gen_key(dh, kex->we_need * 8);
+
+	do {
+		debug("Wait SSH2_MSG_GSSAPI_INIT");
+		type = packet_read();
+		switch(type) {
+		case SSH2_MSG_KEXGSS_INIT:
+			if (dh_client_pub != NULL) 
+				fatal("Received KEXGSS_INIT after initialising");
+			recv_tok.value = packet_get_string(&slen);
+			recv_tok.length = slen; 
+
+			if ((dh_client_pub = BN_new()) == NULL)
+				fatal("dh_client_pub == NULL");
+
+			packet_get_bignum2(dh_client_pub);
+
+			/* Send SSH_MSG_KEXGSS_HOSTKEY here, if we want */
+			break;
+		case SSH2_MSG_KEXGSS_CONTINUE:
+			recv_tok.value = packet_get_string(&slen);
+			recv_tok.length = slen; 
+			break;
+		default:
+			packet_disconnect(
+			    "Protocol error: didn't expect packet type %d",
+			    type);
+		}
+
+		maj_status = PRIVSEP(ssh_gssapi_accept_ctx(ctxt, &recv_tok, 
+		    &send_tok, &ret_flags));
+
+		xfree(recv_tok.value);
+
+		if (maj_status != GSS_S_COMPLETE && send_tok.length == 0)
+			fatal("Zero length token output when incomplete");
+
+		if (dh_client_pub == NULL)
+			fatal("No client public key");
+		
+		if (maj_status & GSS_S_CONTINUE_NEEDED) {
+			debug("Sending GSSAPI_CONTINUE");
+			packet_start(SSH2_MSG_KEXGSS_CONTINUE);
+			packet_put_string(send_tok.value, send_tok.length);
+			packet_send();
+			gss_release_buffer(&min_status, &send_tok);
+		}
+	} while (maj_status & GSS_S_CONTINUE_NEEDED);
+
+	if (GSS_ERROR(maj_status)) {
+		if (send_tok.length > 0) {
+			packet_start(SSH2_MSG_KEXGSS_CONTINUE);
+			packet_put_string(send_tok.value, send_tok.length);
+			packet_send();
+		}
+		fatal("accept_ctx died");
+	}
+
+	if (!(ret_flags & GSS_C_MUTUAL_FLAG))
+		fatal("Mutual Authentication flag wasn't set");
+
+	if (!(ret_flags & GSS_C_INTEG_FLAG))
+		fatal("Integrity flag wasn't set");
+	
+	if (!dh_pub_is_valid(dh, dh_client_pub))
+		packet_disconnect("bad client public DH value");
+
+	klen = DH_size(dh);
+	kbuf = xmalloc(klen); 
+	kout = DH_compute_key(kbuf, dh_client_pub, dh);
+	if (kout < 0)
+		fatal("DH_compute_key: failed");
+
+	shared_secret = BN_new();
+	if (shared_secret == NULL)
+		fatal("kexgss_server: BN_new failed");
+
+	if (BN_bin2bn(kbuf, kout, shared_secret) == NULL)
+		fatal("kexgss_server: BN_bin2bn failed");
+
+	memset(kbuf, 0, klen);
+	xfree(kbuf);
+
+	switch (kex->kex_type) {
+	case KEX_GSS_GRP1_SHA1:
+	case KEX_GSS_GRP14_SHA1:
+		kex_dh_hash(
+		    kex->client_version_string, kex->server_version_string,
+		    buffer_ptr(&kex->peer), buffer_len(&kex->peer),
+		    buffer_ptr(&kex->my), buffer_len(&kex->my),
+		    NULL, 0, /* Change this if we start sending host keys */
+		    dh_client_pub, dh->pub_key, shared_secret,
+		    &hash, &hashlen
+		);
+		break;
+	case KEX_GSS_GEX_SHA1:
+		kexgex_hash(
+		    kex->evp_md,
+		    kex->client_version_string, kex->server_version_string,
+		    buffer_ptr(&kex->peer), buffer_len(&kex->peer),
+		    buffer_ptr(&kex->my), buffer_len(&kex->my),
+		    NULL, 0,
+		    min, nbits, max,
+		    dh->p, dh->g,
+		    dh_client_pub,
+		    dh->pub_key,
+		    shared_secret,
+		    &hash, &hashlen
+		);
+		break;
+	default:
+		fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type);
+	}
+
+	BN_clear_free(dh_client_pub);
+
+	if (kex->session_id == NULL) {
+		kex->session_id_len = hashlen;
+		kex->session_id = xmalloc(kex->session_id_len);
+		memcpy(kex->session_id, hash, kex->session_id_len);
+	}
+
+	gssbuf.value = hash;
+	gssbuf.length = hashlen;
+
+	if (GSS_ERROR(PRIVSEP(ssh_gssapi_sign(ctxt,&gssbuf,&msg_tok))))
+		fatal("Couldn't get MIC");
+
+	packet_start(SSH2_MSG_KEXGSS_COMPLETE);
+	packet_put_bignum2(dh->pub_key);
+	packet_put_string(msg_tok.value,msg_tok.length);
+
+	if (send_tok.length != 0) {
+		packet_put_char(1); /* true */
+		packet_put_string(send_tok.value, send_tok.length);
+	} else {
+		packet_put_char(0); /* false */
+	}
+	packet_send();
+
+	gss_release_buffer(&min_status, &send_tok);
+	gss_release_buffer(&min_status, &msg_tok);
+
+	if (gss_kex_context == NULL)
+		gss_kex_context = ctxt;
+	else 
+		ssh_gssapi_delete_ctx(&ctxt);
+
+	DH_free(dh);
+
+	kex_derive_keys(kex, hash, hashlen, shared_secret);
+	BN_clear_free(shared_secret);
+	kex_finish(kex);
+
+	/* If this was a rekey, then save out any delegated credentials we
+	 * just exchanged.  */
+	if (options.gss_store_rekey)
+		ssh_gssapi_rekey_creds();
+}
+#endif /* GSSAPI */
Index: b/key.c
===================================================================
--- a/key.c
+++ b/key.c
@@ -971,6 +971,8 @@
 		}
 		break;
 #endif /* OPENSSL_HAS_ECC */
+	case KEY_NULL:
+		return "null";
 	}
 	return "ssh-unknown";
 }
@@ -1276,6 +1278,8 @@
 	    strcmp(name, "ecdsa-sha2-nistp521-cert-v01@openssh.com") == 0) {
 		return KEY_ECDSA_CERT;
 #endif
+	} else if (strcmp(name, "null") == 0) {
+		return KEY_NULL;
 	}
 
 	debug2("key_type_from_name: unknown key type '%s'", name);
Index: b/key.h
===================================================================
--- a/key.h
+++ b/key.h
@@ -44,6 +44,7 @@
 	KEY_ECDSA_CERT,
 	KEY_RSA_CERT_V00,
 	KEY_DSA_CERT_V00,
+	KEY_NULL,
 	KEY_UNSPEC
 };
 enum fp_type {
Index: b/monitor.c
===================================================================
--- a/monitor.c
+++ b/monitor.c
@@ -180,6 +180,8 @@
 int mm_answer_gss_accept_ctx(int, Buffer *);
 int mm_answer_gss_userok(int, Buffer *);
 int mm_answer_gss_checkmic(int, Buffer *);
+int mm_answer_gss_sign(int, Buffer *);
+int mm_answer_gss_updatecreds(int, Buffer *);
 #endif
 
 #ifdef SSH_AUDIT_EVENTS
@@ -251,6 +253,7 @@
     {MONITOR_REQ_GSSSTEP, MON_ISAUTH, mm_answer_gss_accept_ctx},
     {MONITOR_REQ_GSSUSEROK, MON_AUTH, mm_answer_gss_userok},
     {MONITOR_REQ_GSSCHECKMIC, MON_ISAUTH, mm_answer_gss_checkmic},
+    {MONITOR_REQ_GSSSIGN, MON_ONCE, mm_answer_gss_sign},
 #endif
 #ifdef JPAKE
     {MONITOR_REQ_JPAKE_GET_PWDATA, MON_ONCE, mm_answer_jpake_get_pwdata},
@@ -263,6 +266,12 @@
 };
 
 struct mon_table mon_dispatch_postauth20[] = {
+#ifdef GSSAPI
+    {MONITOR_REQ_GSSSETUP, 0, mm_answer_gss_setup_ctx},
+    {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx},
+    {MONITOR_REQ_GSSSIGN, 0, mm_answer_gss_sign},
+    {MONITOR_REQ_GSSUPCREDS, 0, mm_answer_gss_updatecreds},
+#endif
     {MONITOR_REQ_MODULI, 0, mm_answer_moduli},
     {MONITOR_REQ_SIGN, 0, mm_answer_sign},
     {MONITOR_REQ_PTY, 0, mm_answer_pty},
@@ -371,6 +380,10 @@
 		/* Permit requests for moduli and signatures */
 		monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
 		monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
+#ifdef GSSAPI
+		/* and for the GSSAPI key exchange */
+		monitor_permit(mon_dispatch, MONITOR_REQ_GSSSETUP, 1);
+#endif
 	} else {
 		mon_dispatch = mon_dispatch_proto15;
 
@@ -468,6 +481,10 @@
 		monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
 		monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
 		monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
+#ifdef GSSAPI
+		/* and for the GSSAPI key exchange */
+		monitor_permit(mon_dispatch, MONITOR_REQ_GSSSETUP, 1);
+#endif		
 	} else {
 		mon_dispatch = mon_dispatch_postauth15;
 		monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
@@ -1803,6 +1820,13 @@
 	kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
 	kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
 	kex->kex[KEX_ECDH_SHA2] = kexecdh_server;
+#ifdef GSSAPI
+	if (options.gss_keyex) {
+		kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_server;
+		kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_server;
+		kex->kex[KEX_GSS_GEX_SHA1] = kexgss_server;
+	}
+#endif
 	kex->server = 1;
 	kex->hostkey_type = buffer_get_int(m);
 	kex->kex_type = buffer_get_int(m);
@@ -2009,6 +2033,9 @@
 	OM_uint32 major;
 	u_int len;
 
+	if (!options.gss_authentication && !options.gss_keyex)
+		fatal("In GSSAPI monitor when GSSAPI is disabled");
+
 	goid.elements = buffer_get_string(m, &len);
 	goid.length = len;
 
@@ -2036,6 +2063,9 @@
 	OM_uint32 flags = 0; /* GSI needs this */
 	u_int len;
 
+	if (!options.gss_authentication && !options.gss_keyex)
+		fatal("In GSSAPI monitor when GSSAPI is disabled");
+
 	in.value = buffer_get_string(m, &len);
 	in.length = len;
 	major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags);
@@ -2053,6 +2083,7 @@
 		monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0);
 		monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
 		monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1);
+		monitor_permit(mon_dispatch, MONITOR_REQ_GSSSIGN, 1);
 	}
 	return (0);
 }
@@ -2064,6 +2095,9 @@
 	OM_uint32 ret;
 	u_int len;
 
+	if (!options.gss_authentication && !options.gss_keyex)
+		fatal("In GSSAPI monitor when GSSAPI is disabled");
+
 	gssbuf.value = buffer_get_string(m, &len);
 	gssbuf.length = len;
 	mic.value = buffer_get_string(m, &len);
@@ -2090,7 +2124,11 @@
 {
 	int authenticated;
 
-	authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user);
+	if (!options.gss_authentication && !options.gss_keyex)
+		fatal("In GSSAPI monitor when GSSAPI is disabled");
+
+	authenticated = authctxt->valid && 
+	    ssh_gssapi_userok(authctxt->user, authctxt->pw);
 
 	buffer_clear(m);
 	buffer_put_int(m, authenticated);
@@ -2103,6 +2141,74 @@
 	/* Monitor loop will terminate if authenticated */
 	return (authenticated);
 }
+
+int 
+mm_answer_gss_sign(int socket, Buffer *m)
+{
+	gss_buffer_desc data;
+	gss_buffer_desc hash = GSS_C_EMPTY_BUFFER;
+	OM_uint32 major, minor;
+	u_int len;
+
+	if (!options.gss_authentication && !options.gss_keyex)
+		fatal("In GSSAPI monitor when GSSAPI is disabled");
+
+	data.value = buffer_get_string(m, &len);
+	data.length = len;
+	if (data.length != 20) 
+		fatal("%s: data length incorrect: %d", __func__, 
+		    (int) data.length);
+
+	/* Save the session ID on the first time around */
+	if (session_id2_len == 0) {
+		session_id2_len = data.length;
+		session_id2 = xmalloc(session_id2_len);
+		memcpy(session_id2, data.value, session_id2_len);
+	}
+	major = ssh_gssapi_sign(gsscontext, &data, &hash);
+
+	xfree(data.value);
+
+	buffer_clear(m);
+	buffer_put_int(m, major);
+	buffer_put_string(m, hash.value, hash.length);
+
+	mm_request_send(socket, MONITOR_ANS_GSSSIGN, m);
+
+	gss_release_buffer(&minor, &hash);
+
+	/* Turn on getpwnam permissions */
+	monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
+	
+	/* And credential updating, for when rekeying */
+	monitor_permit(mon_dispatch, MONITOR_REQ_GSSUPCREDS, 1);
+
+	return (0);
+}
+
+int
+mm_answer_gss_updatecreds(int socket, Buffer *m) {
+	ssh_gssapi_ccache store;
+	int ok;
+
+	store.filename = buffer_get_string(m, NULL);
+	store.envvar   = buffer_get_string(m, NULL);
+	store.envval   = buffer_get_string(m, NULL);
+
+	ok = ssh_gssapi_update_creds(&store);
+
+	xfree(store.filename);
+	xfree(store.envvar);
+	xfree(store.envval);
+
+	buffer_clear(m);
+	buffer_put_int(m, ok);
+
+	mm_request_send(socket, MONITOR_ANS_GSSUPCREDS, m);
+
+	return(0);
+}
+
 #endif /* GSSAPI */
 
 #ifdef JPAKE
Index: b/monitor.h
===================================================================
--- a/monitor.h
+++ b/monitor.h
@@ -53,6 +53,8 @@
 	MONITOR_REQ_GSSSTEP, MONITOR_ANS_GSSSTEP,
 	MONITOR_REQ_GSSUSEROK, MONITOR_ANS_GSSUSEROK,
 	MONITOR_REQ_GSSCHECKMIC, MONITOR_ANS_GSSCHECKMIC,
+	MONITOR_REQ_GSSSIGN, MONITOR_ANS_GSSSIGN,
+	MONITOR_REQ_GSSUPCREDS, MONITOR_ANS_GSSUPCREDS,
 	MONITOR_REQ_PAM_START,
 	MONITOR_REQ_PAM_ACCOUNT, MONITOR_ANS_PAM_ACCOUNT,
 	MONITOR_REQ_PAM_INIT_CTX, MONITOR_ANS_PAM_INIT_CTX,
Index: b/monitor_wrap.c
===================================================================
--- a/monitor_wrap.c
+++ b/monitor_wrap.c
@@ -1270,7 +1270,7 @@
 }
 
 int
-mm_ssh_gssapi_userok(char *user)
+mm_ssh_gssapi_userok(char *user, struct passwd *pw)
 {
 	Buffer m;
 	int authenticated = 0;
@@ -1287,6 +1287,51 @@
 	debug3("%s: user %sauthenticated",__func__, authenticated ? "" : "not ");
 	return (authenticated);
 }
+
+OM_uint32
+mm_ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_desc *data, gss_buffer_desc *hash)
+{
+	Buffer m;
+	OM_uint32 major;
+	u_int len;
+
+	buffer_init(&m);
+	buffer_put_string(&m, data->value, data->length);
+
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSSIGN, &m);
+	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSSIGN, &m);
+
+	major = buffer_get_int(&m);
+	hash->value = buffer_get_string(&m, &len);
+	hash->length = len;
+
+	buffer_free(&m);
+
+	return(major);
+}
+
+int
+mm_ssh_gssapi_update_creds(ssh_gssapi_ccache *store)
+{
+	Buffer m;
+	int ok;
+
+	buffer_init(&m);
+
+	buffer_put_cstring(&m, store->filename ? store->filename : "");
+	buffer_put_cstring(&m, store->envvar ? store->envvar : "");
+	buffer_put_cstring(&m, store->envval ? store->envval : "");
+	
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSUPCREDS, &m);
+	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSUPCREDS, &m);
+
+	ok = buffer_get_int(&m);
+
+	buffer_free(&m);
+	
+	return (ok);
+}
+
 #endif /* GSSAPI */
 
 #ifdef JPAKE
Index: b/monitor_wrap.h
===================================================================
--- a/monitor_wrap.h
+++ b/monitor_wrap.h
@@ -58,8 +58,10 @@
 OM_uint32 mm_ssh_gssapi_server_ctx(Gssctxt **, gss_OID);
 OM_uint32 mm_ssh_gssapi_accept_ctx(Gssctxt *,
    gss_buffer_desc *, gss_buffer_desc *, OM_uint32 *);
-int mm_ssh_gssapi_userok(char *user);
+int mm_ssh_gssapi_userok(char *user, struct passwd *);
 OM_uint32 mm_ssh_gssapi_checkmic(Gssctxt *, gss_buffer_t, gss_buffer_t);
+OM_uint32 mm_ssh_gssapi_sign(Gssctxt *, gss_buffer_t, gss_buffer_t);
+int mm_ssh_gssapi_update_creds(ssh_gssapi_ccache *);
 #endif
 
 #ifdef USE_PAM
Index: b/readconf.c
===================================================================
--- a/readconf.c
+++ b/readconf.c
@@ -129,6 +129,8 @@
 	oClearAllForwardings, oNoHostAuthenticationForLocalhost,
 	oEnableSSHKeysign, oRekeyLimit, oVerifyHostKeyDNS, oConnectTimeout,
 	oAddressFamily, oGssAuthentication, oGssDelegateCreds,
+	oGssTrustDns, oGssKeyEx, oGssClientIdentity, oGssRenewalRekey,
+	oGssServerIdentity, 
 	oServerAliveInterval, oServerAliveCountMax, oIdentitiesOnly,
 	oSendEnv, oControlPath, oControlMaster, oControlPersist,
 	oHashKnownHosts,
@@ -169,10 +171,19 @@
 	{ "afstokenpassing", oUnsupported },
 #if defined(GSSAPI)
 	{ "gssapiauthentication", oGssAuthentication },
+	{ "gssapikeyexchange", oGssKeyEx },
 	{ "gssapidelegatecredentials", oGssDelegateCreds },
+	{ "gssapitrustdns", oGssTrustDns },
+	{ "gssapiclientidentity", oGssClientIdentity },
+	{ "gssapiserveridentity", oGssServerIdentity },
+	{ "gssapirenewalforcesrekey", oGssRenewalRekey },
 #else
 	{ "gssapiauthentication", oUnsupported },
+	{ "gssapikeyexchange", oUnsupported },
 	{ "gssapidelegatecredentials", oUnsupported },
+	{ "gssapitrustdns", oUnsupported },
+	{ "gssapiclientidentity", oUnsupported },
+	{ "gssapirenewalforcesrekey", oUnsupported },
 #endif
 	{ "fallbacktorsh", oDeprecated },
 	{ "usersh", oDeprecated },
@@ -483,10 +494,30 @@
 		intptr = &options->gss_authentication;
 		goto parse_flag;
 
+	case oGssKeyEx:
+		intptr = &options->gss_keyex;
+		goto parse_flag;
+
 	case oGssDelegateCreds:
 		intptr = &options->gss_deleg_creds;
 		goto parse_flag;
 
+	case oGssTrustDns:
+		intptr = &options->gss_trust_dns;
+		goto parse_flag;
+
+	case oGssClientIdentity:
+		charptr = &options->gss_client_identity;
+		goto parse_string;
+
+	case oGssServerIdentity:
+		charptr = &options->gss_server_identity;
+		goto parse_string;
+
+	case oGssRenewalRekey:
+		intptr = &options->gss_renewal_rekey;
+		goto parse_flag;
+
 	case oBatchMode:
 		intptr = &options->batch_mode;
 		goto parse_flag;
@@ -1139,7 +1170,12 @@
 	options->pubkey_authentication = -1;
 	options->challenge_response_authentication = -1;
 	options->gss_authentication = -1;
+	options->gss_keyex = -1;
 	options->gss_deleg_creds = -1;
+	options->gss_trust_dns = -1;
+	options->gss_renewal_rekey = -1;
+	options->gss_client_identity = NULL;
+	options->gss_server_identity = NULL;
 	options->password_authentication = -1;
 	options->kbd_interactive_authentication = -1;
 	options->kbd_interactive_devices = NULL;
@@ -1239,8 +1275,14 @@
 		options->challenge_response_authentication = 1;
 	if (options->gss_authentication == -1)
 		options->gss_authentication = 0;
+	if (options->gss_keyex == -1)
+		options->gss_keyex = 0;
 	if (options->gss_deleg_creds == -1)
 		options->gss_deleg_creds = 0;
+	if (options->gss_trust_dns == -1)
+		options->gss_trust_dns = 0;
+	if (options->gss_renewal_rekey == -1)
+		options->gss_renewal_rekey = 0;
 	if (options->password_authentication == -1)
 		options->password_authentication = 1;
 	if (options->kbd_interactive_authentication == -1)
Index: b/readconf.h
===================================================================
--- a/readconf.h
+++ b/readconf.h
@@ -48,7 +48,12 @@
 	int     challenge_response_authentication;
 					/* Try S/Key or TIS, authentication. */
 	int     gss_authentication;	/* Try GSS authentication */
+	int     gss_keyex;		/* Try GSS key exchange */
 	int     gss_deleg_creds;	/* Delegate GSS credentials */
+	int	gss_trust_dns;		/* Trust DNS for GSS canonicalization */
+	int	gss_renewal_rekey;	/* Credential renewal forces rekey */
+	char    *gss_client_identity;   /* Principal to initiate GSSAPI with */
+	char    *gss_server_identity;   /* GSSAPI target principal */
 	int     password_authentication;	/* Try password
 						 * authentication. */
 	int     kbd_interactive_authentication; /* Try keyboard-interactive auth. */
Index: b/servconf.c
===================================================================
--- a/servconf.c
+++ b/servconf.c
@@ -97,7 +97,10 @@
 	options->kerberos_ticket_cleanup = -1;
 	options->kerberos_get_afs_token = -1;
 	options->gss_authentication=-1;
+	options->gss_keyex = -1;
 	options->gss_cleanup_creds = -1;
+	options->gss_strict_acceptor = -1;
+	options->gss_store_rekey = -1;
 	options->password_authentication = -1;
 	options->kbd_interactive_authentication = -1;
 	options->challenge_response_authentication = -1;
@@ -225,8 +228,14 @@
 		options->kerberos_get_afs_token = 0;
 	if (options->gss_authentication == -1)
 		options->gss_authentication = 0;
+	if (options->gss_keyex == -1)
+		options->gss_keyex = 0;
 	if (options->gss_cleanup_creds == -1)
 		options->gss_cleanup_creds = 1;
+	if (options->gss_strict_acceptor == -1)
+		options->gss_strict_acceptor = 1;
+	if (options->gss_store_rekey == -1)
+		options->gss_store_rekey = 0;
 	if (options->password_authentication == -1)
 		options->password_authentication = 1;
 	if (options->kbd_interactive_authentication == -1)
@@ -318,7 +327,9 @@
 	sBanner, sUseDNS, sHostbasedAuthentication,
 	sHostbasedUsesNameFromPacketOnly, sClientAliveInterval,
 	sClientAliveCountMax, sAuthorizedKeysFile,
-	sGssAuthentication, sGssCleanupCreds, sAcceptEnv, sPermitTunnel,
+	sGssAuthentication, sGssCleanupCreds, sGssStrictAcceptor,
+	sGssKeyEx, sGssStoreRekey,
+	sAcceptEnv, sPermitTunnel,
 	sMatch, sPermitOpen, sForceCommand, sChrootDirectory,
 	sUsePrivilegeSeparation, sAllowAgentForwarding,
 	sZeroKnowledgePasswordAuthentication, sHostCertificate,
@@ -382,10 +393,20 @@
 #ifdef GSSAPI
 	{ "gssapiauthentication", sGssAuthentication, SSHCFG_ALL },
 	{ "gssapicleanupcredentials", sGssCleanupCreds, SSHCFG_GLOBAL },
+	{ "gssapicleanupcreds", sGssCleanupCreds, SSHCFG_GLOBAL },
+	{ "gssapistrictacceptorcheck", sGssStrictAcceptor, SSHCFG_GLOBAL },
+	{ "gssapikeyexchange", sGssKeyEx, SSHCFG_GLOBAL },
+	{ "gssapistorecredentialsonrekey", sGssStoreRekey, SSHCFG_GLOBAL },
 #else
 	{ "gssapiauthentication", sUnsupported, SSHCFG_ALL },
 	{ "gssapicleanupcredentials", sUnsupported, SSHCFG_GLOBAL },
+	{ "gssapicleanupcreds", sUnsupported, SSHCFG_GLOBAL },
+	{ "gssapistrictacceptorcheck", sUnsupported, SSHCFG_GLOBAL },
+	{ "gssapikeyexchange", sUnsupported, SSHCFG_GLOBAL },
+	{ "gssapistorecredentialsonrekey", sUnsupported, SSHCFG_GLOBAL },
 #endif
+	{ "gssusesessionccache", sUnsupported, SSHCFG_GLOBAL },
+	{ "gssapiusesessioncredcache", sUnsupported, SSHCFG_GLOBAL },
 	{ "passwordauthentication", sPasswordAuthentication, SSHCFG_ALL },
 	{ "kbdinteractiveauthentication", sKbdInteractiveAuthentication, SSHCFG_ALL },
 	{ "challengeresponseauthentication", sChallengeResponseAuthentication, SSHCFG_GLOBAL },
@@ -962,10 +983,22 @@
 		intptr = &options->gss_authentication;
 		goto parse_flag;
 
+	case sGssKeyEx:
+		intptr = &options->gss_keyex;
+		goto parse_flag;
+
 	case sGssCleanupCreds:
 		intptr = &options->gss_cleanup_creds;
 		goto parse_flag;
 
+	case sGssStrictAcceptor:
+		intptr = &options->gss_strict_acceptor;
+		goto parse_flag;
+
+	case sGssStoreRekey:
+		intptr = &options->gss_store_rekey;
+		goto parse_flag;
+
 	case sPasswordAuthentication:
 		intptr = &options->password_authentication;
 		goto parse_flag;
@@ -1720,7 +1753,10 @@
 #endif
 #ifdef GSSAPI
 	dump_cfg_fmtint(sGssAuthentication, o->gss_authentication);
+	dump_cfg_fmtint(sGssKeyEx, o->gss_keyex);
 	dump_cfg_fmtint(sGssCleanupCreds, o->gss_cleanup_creds);
+	dump_cfg_fmtint(sGssStrictAcceptor, o->gss_strict_acceptor);
+	dump_cfg_fmtint(sGssStoreRekey, o->gss_store_rekey);
 #endif
 #ifdef JPAKE
 	dump_cfg_fmtint(sZeroKnowledgePasswordAuthentication,
Index: b/servconf.h
===================================================================
--- a/servconf.h
+++ b/servconf.h
@@ -103,7 +103,10 @@
 	int     kerberos_get_afs_token;		/* If true, try to get AFS token if
 						 * authenticated with Kerberos. */
 	int     gss_authentication;	/* If true, permit GSSAPI authentication */
+	int     gss_keyex;		/* If true, permit GSSAPI key exchange */
 	int     gss_cleanup_creds;	/* If true, destroy cred cache on logout */
+	int 	gss_strict_acceptor;	/* If true, restrict the GSSAPI acceptor name */
+	int 	gss_store_rekey;
 	int     password_authentication;	/* If true, permit password
 						 * authentication. */
 	int     kbd_interactive_authentication;	/* If true, permit */
Index: b/ssh-gss.h
===================================================================
--- a/ssh-gss.h
+++ b/ssh-gss.h
@@ -1,6 +1,6 @@
 /* $OpenBSD: ssh-gss.h,v 1.10 2007/06/12 08:20:00 djm Exp $ */
 /*
- * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
+ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -60,10 +60,22 @@
 
 #define SSH_GSS_OIDTYPE 0x06
 
+#define SSH2_MSG_KEXGSS_INIT                            30
+#define SSH2_MSG_KEXGSS_CONTINUE                        31
+#define SSH2_MSG_KEXGSS_COMPLETE                        32
+#define SSH2_MSG_KEXGSS_HOSTKEY                         33
+#define SSH2_MSG_KEXGSS_ERROR                           34
+#define SSH2_MSG_KEXGSS_GROUPREQ			40
+#define SSH2_MSG_KEXGSS_GROUP				41
+#define KEX_GSS_GRP1_SHA1_ID				"gss-group1-sha1-"
+#define KEX_GSS_GRP14_SHA1_ID				"gss-group14-sha1-"
+#define KEX_GSS_GEX_SHA1_ID				"gss-gex-sha1-"
+
 typedef struct {
 	char *filename;
 	char *envvar;
 	char *envval;
+	struct passwd *owner;
 	void *data;
 } ssh_gssapi_ccache;
 
@@ -71,8 +83,11 @@
 	gss_buffer_desc displayname;
 	gss_buffer_desc exportedname;
 	gss_cred_id_t creds;
+	gss_name_t name;
 	struct ssh_gssapi_mech_struct *mech;
 	ssh_gssapi_ccache store;
+	int used;
+	int updated;
 } ssh_gssapi_client;
 
 typedef struct ssh_gssapi_mech_struct {
@@ -83,6 +98,7 @@
 	int (*userok) (ssh_gssapi_client *, char *);
 	int (*localname) (ssh_gssapi_client *, char **);
 	void (*storecreds) (ssh_gssapi_client *);
+	int (*updatecreds) (ssh_gssapi_ccache *, ssh_gssapi_client *);
 } ssh_gssapi_mech;
 
 typedef struct {
@@ -93,10 +109,11 @@
 	gss_OID		oid; /* client */
 	gss_cred_id_t	creds; /* server */
 	gss_name_t	client; /* server */
-	gss_cred_id_t	client_creds; /* server */
+	gss_cred_id_t	client_creds; /* both */
 } Gssctxt;
 
 extern ssh_gssapi_mech *supported_mechs[];
+extern Gssctxt *gss_kex_context;
 
 int  ssh_gssapi_check_oid(Gssctxt *, void *, size_t);
 void ssh_gssapi_set_oid_data(Gssctxt *, void *, size_t);
@@ -116,16 +133,30 @@
 void ssh_gssapi_delete_ctx(Gssctxt **);
 OM_uint32 ssh_gssapi_sign(Gssctxt *, gss_buffer_t, gss_buffer_t);
 void ssh_gssapi_buildmic(Buffer *, const char *, const char *, const char *);
-int ssh_gssapi_check_mechanism(Gssctxt **, gss_OID, const char *);
+int ssh_gssapi_check_mechanism(Gssctxt **, gss_OID, const char *, const char *);
+OM_uint32 ssh_gssapi_client_identity(Gssctxt *, const char *);
+int ssh_gssapi_credentials_updated(Gssctxt *);
 
 /* In the server */
+typedef int ssh_gssapi_check_fn(Gssctxt **, gss_OID, const char *, 
+    const char *);
+char *ssh_gssapi_client_mechanisms(const char *, const char *);
+char *ssh_gssapi_kex_mechs(gss_OID_set, ssh_gssapi_check_fn *, const char *,
+    const char *);
+gss_OID ssh_gssapi_id_kex(Gssctxt *, char *, int);
+int ssh_gssapi_server_check_mech(Gssctxt **,gss_OID, const char *, 
+    const char *);
 OM_uint32 ssh_gssapi_server_ctx(Gssctxt **, gss_OID);
-int ssh_gssapi_userok(char *name);
+int ssh_gssapi_userok(char *name, struct passwd *);
 OM_uint32 ssh_gssapi_checkmic(Gssctxt *, gss_buffer_t, gss_buffer_t);
 void ssh_gssapi_do_child(char ***, u_int *);
 void ssh_gssapi_cleanup_creds(void);
 void ssh_gssapi_storecreds(void);
 
+char *ssh_gssapi_server_mechanisms(void);
+int ssh_gssapi_oid_table_ok();
+
+int ssh_gssapi_update_creds(ssh_gssapi_ccache *store);
 #endif /* GSSAPI */
 
 #endif /* _SSH_GSS_H */
Index: b/ssh_config
===================================================================
--- a/ssh_config
+++ b/ssh_config
@@ -26,6 +26,8 @@
 #   HostbasedAuthentication no
 #   GSSAPIAuthentication no
 #   GSSAPIDelegateCredentials no
+#   GSSAPIKeyExchange no
+#   GSSAPITrustDNS no
 #   BatchMode no
 #   CheckHostIP yes
 #   AddressFamily any
Index: b/ssh_config.5
===================================================================
--- a/ssh_config.5
+++ b/ssh_config.5
@@ -527,11 +527,43 @@
 The default is
 .Dq no .
 Note that this option applies to protocol version 2 only.
+.It Cm GSSAPIKeyExchange
+Specifies whether key exchange based on GSSAPI may be used. When using
+GSSAPI key exchange the server need not have a host key.
+The default is
+.Dq no .
+Note that this option applies to protocol version 2 only.
+.It Cm GSSAPIClientIdentity
+If set, specifies the GSSAPI client identity that ssh should use when 
+connecting to the server. The default is unset, which means that the default 
+identity will be used.
+.It Cm GSSAPIServerIdentity
+If set, specifies the GSSAPI server identity that ssh should expect when 
+connecting to the server. The default is unset, which means that the
+expected GSSAPI server identity will be determined from the target
+hostname.
 .It Cm GSSAPIDelegateCredentials
 Forward (delegate) credentials to the server.
 The default is
 .Dq no .
-Note that this option applies to protocol version 2 only.
+Note that this option applies to protocol version 2 connections using GSSAPI.
+.It Cm GSSAPIRenewalForcesRekey
+If set to 
+.Dq yes
+then renewal of the client's GSSAPI credentials will force the rekeying of the
+ssh connection. With a compatible server, this can delegate the renewed 
+credentials to a session on the server.
+The default is
+.Dq no .
+.It Cm GSSAPITrustDns
+Set to 
+.Dq yes to indicate that the DNS is trusted to securely canonicalize
+the name of the host being connected to. If 
+.Dq no, the hostname entered on the
+command line will be passed untouched to the GSSAPI library.
+The default is
+.Dq no .
+This option only applies to protocol version 2 connections using GSSAPI.
 .It Cm HashKnownHosts
 Indicates that
 .Xr ssh 1
Index: b/sshconnect2.c
===================================================================
--- a/sshconnect2.c
+++ b/sshconnect2.c
@@ -160,9 +160,34 @@
 {
 	Kex *kex;
 
+#ifdef GSSAPI
+	char *orig = NULL, *gss = NULL;
+	char *gss_host = NULL;
+#endif
+
 	xxx_host = host;
 	xxx_hostaddr = hostaddr;
 
+#ifdef GSSAPI
+	if (options.gss_keyex) {
+		/* Add the GSSAPI mechanisms currently supported on this 
+		 * client to the key exchange algorithm proposal */
+		orig = myproposal[PROPOSAL_KEX_ALGS];
+
+		if (options.gss_trust_dns)
+			gss_host = (char *)get_canonical_hostname(1);
+		else
+			gss_host = host;
+
+		gss = ssh_gssapi_client_mechanisms(gss_host, options.gss_client_identity);
+		if (gss) {
+			debug("Offering GSSAPI proposal: %s", gss);
+			xasprintf(&myproposal[PROPOSAL_KEX_ALGS],
+			    "%s,%s", gss, orig);
+		}
+	}
+#endif
+
 	if (options.ciphers == (char *)-1) {
 		logit("No valid ciphers for protocol version 2 given, using defaults.");
 		options.ciphers = NULL;
@@ -197,6 +222,17 @@
 	if (options.kex_algorithms != NULL)
 		myproposal[PROPOSAL_KEX_ALGS] = options.kex_algorithms;
 
+#ifdef GSSAPI
+	/* If we've got GSSAPI algorithms, then we also support the
+	 * 'null' hostkey, as a last resort */
+	if (options.gss_keyex && gss) {
+		orig = myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS];
+		xasprintf(&myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS], 
+		    "%s,null", orig);
+		xfree(gss);
+	}
+#endif
+
 	if (options.rekey_limit)
 		packet_set_rekey_limit((u_int32_t)options.rekey_limit);
 
@@ -207,10 +243,30 @@
 	kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
 	kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
 	kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
+#ifdef GSSAPI
+	if (options.gss_keyex) {
+		kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_client;
+		kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_client;
+		kex->kex[KEX_GSS_GEX_SHA1] = kexgss_client;
+	}
+#endif
 	kex->client_version_string=client_version_string;
 	kex->server_version_string=server_version_string;
 	kex->verify_host_key=&verify_host_key_callback;
 
+#ifdef GSSAPI
+	if (options.gss_keyex) {
+		kex->gss_deleg_creds = options.gss_deleg_creds;
+		kex->gss_trust_dns = options.gss_trust_dns;
+		kex->gss_client = options.gss_client_identity;
+		if (options.gss_server_identity) {
+			kex->gss_host = options.gss_server_identity;
+		} else {
+			kex->gss_host = gss_host;
+        }
+	}
+#endif
+
 	xxx_kex = kex;
 
 	dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
@@ -305,6 +361,7 @@
 void	input_gssapi_hash(int type, u_int32_t, void *);
 void	input_gssapi_error(int, u_int32_t, void *);
 void	input_gssapi_errtok(int, u_int32_t, void *);
+int	userauth_gsskeyex(Authctxt *authctxt);
 #endif
 
 void	userauth(Authctxt *, char *);
@@ -320,6 +377,11 @@
 
 Authmethod authmethods[] = {
 #ifdef GSSAPI
+	{"gssapi-keyex",
+		userauth_gsskeyex,
+		NULL,
+		&options.gss_authentication,
+		NULL},
 	{"gssapi-with-mic",
 		userauth_gssapi,
 		NULL,
@@ -626,19 +688,31 @@
 	static u_int mech = 0;
 	OM_uint32 min;
 	int ok = 0;
+	const char *gss_host;
+
+	if (options.gss_server_identity)
+		gss_host = options.gss_server_identity;
+	else if (options.gss_trust_dns)
+		gss_host = get_canonical_hostname(1);
+	else
+		gss_host = authctxt->host;
 
 	/* Try one GSSAPI method at a time, rather than sending them all at
 	 * once. */
 
 	if (gss_supported == NULL)
-		gss_indicate_mechs(&min, &gss_supported);
+		if (GSS_ERROR(gss_indicate_mechs(&min, &gss_supported))) {
+			gss_supported = NULL;
+			return 0;
+		}
 
 	/* Check to see if the mechanism is usable before we offer it */
 	while (mech < gss_supported->count && !ok) {
 		/* My DER encoding requires length<128 */
 		if (gss_supported->elements[mech].length < 128 &&
 		    ssh_gssapi_check_mechanism(&gssctxt, 
-		    &gss_supported->elements[mech], authctxt->host)) {
+		    &gss_supported->elements[mech], gss_host, 
+                    options.gss_client_identity)) {
 			ok = 1; /* Mechanism works */
 		} else {
 			mech++;
@@ -735,8 +809,8 @@
 {
 	Authctxt *authctxt = ctxt;
 	Gssctxt *gssctxt;
-	int oidlen;
-	char *oidv;
+	u_int oidlen;
+	u_char *oidv;
 
 	if (authctxt == NULL)
 		fatal("input_gssapi_response: no authentication context");
@@ -846,6 +920,48 @@
 	xfree(msg);
 	xfree(lang);
 }
+
+int
+userauth_gsskeyex(Authctxt *authctxt)
+{
+	Buffer b;
+	gss_buffer_desc gssbuf;
+	gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
+	OM_uint32 ms;
+
+	static int attempt = 0;
+	if (attempt++ >= 1)
+		return (0);
+
+	if (gss_kex_context == NULL) {
+		debug("No valid Key exchange context"); 
+		return (0);
+	}
+
+	ssh_gssapi_buildmic(&b, authctxt->server_user, authctxt->service,
+	    "gssapi-keyex");
+
+	gssbuf.value = buffer_ptr(&b);
+	gssbuf.length = buffer_len(&b);
+
+	if (GSS_ERROR(ssh_gssapi_sign(gss_kex_context, &gssbuf, &mic))) {
+		buffer_free(&b);
+		return (0);
+	}
+
+	packet_start(SSH2_MSG_USERAUTH_REQUEST);
+	packet_put_cstring(authctxt->server_user);
+	packet_put_cstring(authctxt->service);
+	packet_put_cstring(authctxt->method->name);
+	packet_put_string(mic.value, mic.length);
+	packet_send();
+
+	buffer_free(&b);
+	gss_release_buffer(&ms, &mic);
+
+	return (1);
+}
+
 #endif /* GSSAPI */
 
 int
Index: b/sshd.c
===================================================================
--- a/sshd.c
+++ b/sshd.c
@@ -121,6 +121,10 @@
 #include "ssh-sandbox.h"
 #include "version.h"
 
+#ifdef USE_SECURITY_SESSION_API
+#include <Security/AuthSession.h>
+#endif
+
 #ifdef LIBWRAP
 #include <tcpd.h>
 #include <syslog.h>
@@ -1616,10 +1620,13 @@
 		logit("Disabling protocol version 1. Could not load host key");
 		options.protocol &= ~SSH_PROTO_1;
 	}
+#ifndef GSSAPI
+	/* The GSSAPI key exchange can run without a host key */
 	if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
 		logit("Disabling protocol version 2. Could not load host key");
 		options.protocol &= ~SSH_PROTO_2;
 	}
+#endif
 	if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
 		logit("sshd: no hostkeys available -- exiting.");
 		exit(1);
@@ -1948,6 +1955,60 @@
 	/* Log the connection. */
 	verbose("Connection from %.500s port %d", remote_ip, remote_port);
 
+#ifdef USE_SECURITY_SESSION_API
+	/*
+	 * Create a new security session for use by the new user login if
+	 * the current session is the root session or we are not launched
+	 * by inetd (eg: debugging mode or server mode).  We do not
+	 * necessarily need to create a session if we are launched from
+	 * inetd because Panther xinetd will create a session for us.
+	 *
+	 * The only case where this logic will fail is if there is an
+	 * inetd running in a non-root session which is not creating
+	 * new sessions for us.  Then all the users will end up in the
+	 * same session (bad).
+	 *
+	 * When the client exits, the session will be destroyed for us
+	 * automatically.
+	 *
+	 * We must create the session before any credentials are stored
+	 * (including AFS pags, which happens a few lines below).
+	 */
+	{
+		OSStatus err = 0;
+		SecuritySessionId sid = 0;
+		SessionAttributeBits sattrs = 0;
+
+		err = SessionGetInfo(callerSecuritySession, &sid, &sattrs);
+		if (err)
+			error("SessionGetInfo() failed with error %.8X",
+			    (unsigned) err);
+		else
+			debug("Current Session ID is %.8X / Session Attributes are %.8X",
+			    (unsigned) sid, (unsigned) sattrs);
+
+		if (inetd_flag && !(sattrs & sessionIsRoot))
+			debug("Running in inetd mode in a non-root session... "
+			    "assuming inetd created the session for us.");
+		else {
+			debug("Creating new security session...");
+			err = SessionCreate(0, sessionHasTTY | sessionIsRemote);
+			if (err)
+				error("SessionCreate() failed with error %.8X",
+				    (unsigned) err);
+
+			err = SessionGetInfo(callerSecuritySession, &sid, 
+			    &sattrs);
+			if (err)
+				error("SessionGetInfo() failed with error %.8X",
+				    (unsigned) err);
+			else
+				debug("New Session ID is %.8X / Session Attributes are %.8X",
+				    (unsigned) sid, (unsigned) sattrs);
+		}
+	}
+#endif
+
 	/*
 	 * We don't want to listen forever unless the other side
 	 * successfully authenticates itself.  So we set up an alarm which is
@@ -2329,6 +2390,48 @@
 
 	myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
 
+#ifdef GSSAPI
+	{
+	char *orig;
+	char *gss = NULL;
+	char *newstr = NULL;
+	orig = myproposal[PROPOSAL_KEX_ALGS];
+
+	/* 
+	 * If we don't have a host key, then there's no point advertising
+	 * the other key exchange algorithms
+	 */
+
+	if (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]) == 0)
+		orig = NULL;
+
+	if (options.gss_keyex)
+		gss = ssh_gssapi_server_mechanisms();
+	else
+		gss = NULL;
+
+	if (gss && orig)
+		xasprintf(&newstr, "%s,%s", gss, orig);
+	else if (gss)
+		newstr = gss;
+	else if (orig)
+		newstr = orig;
+
+	/* 
+	 * If we've got GSSAPI mechanisms, then we've got the 'null' host
+	 * key alg, but we can't tell people about it unless its the only
+  	 * host key algorithm we support
+	 */
+	if (gss && (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS])) == 0)
+		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = "null";
+
+	if (newstr)
+		myproposal[PROPOSAL_KEX_ALGS] = newstr;
+	else
+		fatal("No supported key exchange algorithms");
+	}
+#endif
+
 	/* start key exchange */
 	kex = kex_setup(myproposal);
 	kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
@@ -2336,6 +2439,13 @@
 	kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
 	kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
 	kex->kex[KEX_ECDH_SHA2] = kexecdh_server;
+#ifdef GSSAPI
+	if (options.gss_keyex) {
+		kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_server;
+		kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_server;
+		kex->kex[KEX_GSS_GEX_SHA1] = kexgss_server;
+	}
+#endif
 	kex->server = 1;
 	kex->client_version_string=client_version_string;
 	kex->server_version_string=server_version_string;
Index: b/sshd_config
===================================================================
--- a/sshd_config
+++ b/sshd_config
@@ -75,6 +75,8 @@
 # GSSAPI options
 #GSSAPIAuthentication no
 #GSSAPICleanupCredentials yes
+#GSSAPIStrictAcceptorCheck yes
+#GSSAPIKeyExchange no
 
 # Set this to 'yes' to enable PAM authentication, account processing, 
 # and session processing. If this is enabled, PAM authentication will 
Index: b/sshd_config.5
===================================================================
--- a/sshd_config.5
+++ b/sshd_config.5
@@ -424,12 +424,40 @@
 The default is
 .Dq no .
 Note that this option applies to protocol version 2 only.
+.It Cm GSSAPIKeyExchange
+Specifies whether key exchange based on GSSAPI is allowed. GSSAPI key exchange
+doesn't rely on ssh keys to verify host identity.
+The default is
+.Dq no .
+Note that this option applies to protocol version 2 only.
 .It Cm GSSAPICleanupCredentials
 Specifies whether to automatically destroy the user's credentials cache
 on logout.
 The default is
 .Dq yes .
 Note that this option applies to protocol version 2 only.
+.It Cm GSSAPIStrictAcceptorCheck
+Determines whether to be strict about the identity of the GSSAPI acceptor 
+a client authenticates against. If
+.Dq yes
+then the client must authenticate against the
+.Pa host
+service on the current hostname. If 
+.Dq no
+then the client may authenticate against any service key stored in the 
+machine's default store. This facility is provided to assist with operation 
+on multi homed machines. 
+The default is
+.Dq yes .
+Note that this option applies only to protocol version 2 GSSAPI connections,
+and setting it to 
+.Dq no
+may only work with recent Kerberos GSSAPI libraries.
+.It Cm GSSAPIStoreCredentialsOnRekey
+Controls whether the user's GSSAPI credentials should be updated following a 
+successful connection rekeying. This option can be used to accepted renewed 
+or updated credentials from a compatible client. The default is
+.Dq no .
 .It Cm HostbasedAuthentication
 Specifies whether rhosts or /etc/hosts.equiv authentication together
 with successful public key client host authentication is allowed
