openssh/openssh-6.6p1-gsskex.patch

diff --git a/Makefile.in b/Makefile.in
index bbc3034..c9891e0 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -87,6 +87,7 @@ LIBSSH_OBJS=${LIBOPENSSH_OBJS} \
 	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 umac128.o \
 	ssh-pkcs11.o krl.o smult_curve25519_ref.o \
 	kexc25519.o kexc25519c.o poly1305.o chacha.o cipher-chachapoly.o \
@@ -106,7 +107,7 @@ SSHDOBJS=sshd.o auth-rhosts.o auth-passwd.o auth-rsa.o auth-rh-rsa.o \
 	auth2-none.o auth2-passwd.o auth2-pubkey.o \
 	monitor_mm.o monitor.o monitor_wrap.o kexdhs.o kexgexs.o kexecdhs.o \
 	kexc25519s.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 \
diff --git a/auth2-gss.c b/auth2-gss.c
index 4803e7e..222e3e0 100644
--- a/auth2-gss.c
+++ b/auth2-gss.c
@@ -31,6 +31,7 @@
 #include <sys/types.h>
 
 #include <stdarg.h>
+#include <string.h>
 
 #include "xmalloc.h"
 #include "key.h"
@@ -53,6 +53,40 @@ static void input_gssapi_mic(int type, u_int32_t plen, void *ctxt);
 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);
+	free(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)
@@ -236,7 +270,8 @@ input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
 
 	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);
@@ -278,7 +313,8 @@ input_gssapi_mic(int type, u_int32_t plen, void *ctxt)
 	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");
 
@@ -295,6 +331,12 @@ input_gssapi_mic(int type, u_int32_t plen, void *ctxt)
 	userauth_finish(authctxt, authenticated, "gssapi-with-mic", NULL);
 }
 
+Authmethod method_gsskeyex = {
+	"gssapi-keyex",
+	userauth_gsskeyex,
+	&options.gss_authentication
+};
+
 Authmethod method_gssapi = {
 	"gssapi-with-mic",
 	userauth_gssapi,
diff --git a/auth2.c b/auth2.c
index d6fbc93..124d02b 100644
--- a/auth2.c
+++ b/auth2.c
@@ -70,6 +70,7 @@ extern Authmethod method_passwd;
 extern Authmethod method_kbdint;
 extern Authmethod method_hostbased;
 #ifdef GSSAPI
+extern Authmethod method_gsskeyex;
 extern Authmethod method_gssapi;
 #endif
 
@@ -77,6 +78,7 @@ Authmethod *authmethods[] = {
 	&method_none,
 	&method_pubkey,
 #ifdef GSSAPI
+	&method_gsskeyex,
 	&method_gssapi,
 #endif
 	&method_passwd,
diff --git a/clientloop.c b/clientloop.c
index 397c965..20ce0b5 100644
--- 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;
 
@@ -1596,6 +1600,15 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
 		/* 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;
diff --git a/configure.ac b/configure.ac
index 8dedb95..2c4adac 100644
--- a/configure.ac
+++ b/configure.ac
@@ -584,6 +584,30 @@ main() { if (NSVersionOfRunTimeLibrary("System") >= (60 << 16))
 	    [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])
diff --git a/gss-genr.c b/gss-genr.c
index b39281b..a3a2289 100644
--- a/gss-genr.c
+++ b/gss-genr.c
@@ -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++)
+			free(gss_enc2oid[i].encoded);
+		free(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) {
+		free(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 @@ ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
 	}
 
 	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 @@ ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
 }
 
 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 @@ ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
 	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 @@ ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service,
 }
 
 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_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
 	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 +483,66 @@ ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
 			    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;
+	
+	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 */
diff --git a/gss-serv-krb5.c b/gss-serv-krb5.c
index 795992d..413b845 100644
--- a/gss-serv-krb5.c
+++ b/gss-serv-krb5.c
@@ -121,7 +121,7 @@ ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
 	krb5_error_code problem;
 	krb5_principal princ;
 	OM_uint32 maj_status, min_status;
-	int len;
+	const char *new_ccname, *new_cctype;
 	const char *errmsg;
 
 	if (client->creds == NULL) {
@@ -181,11 +181,26 @@ ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
 		return;
 	}
 
-	client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache));
+	new_cctype = krb5_cc_get_type(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
+	if (new_ccname[0] == ':')
+		new_ccname++;
+	xasprintf(&client->store.envval, "%s:%s", new_cctype, new_ccname);
+	if (strcmp(new_cctype, "DIR") == 0) {
+		char *p;
+		p = strrchr(client->store.envval, '/');
+		if (p)
+			*p = '\0';
+	}
+	if ((strcmp(new_cctype, "FILE") == 0) || (strcmp(new_cctype, "DIR") == 0))
+		client->store.filename = xstrdup(new_ccname);
+#endif
 
 #ifdef USE_PAM
 	if (options.use_pam)
@@ -194,9 +209,76 @@ ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
 
 	krb5_cc_close(krb_context, ccache);
 
+	client->store.data = krb_context;
+
 	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",
@@ -204,7 +286,8 @@ ssh_gssapi_mech gssapi_kerberos_mech = {
 	NULL,
 	&ssh_gssapi_krb5_userok,
 	NULL,
-	&ssh_gssapi_krb5_storecreds
+	&ssh_gssapi_krb5_storecreds,
+	&ssh_gssapi_krb5_updatecreds
 };
 
 #endif /* KRB5 */
diff --git a/gss-serv.c b/gss-serv.c
index 5c59924..2289e8e 100644
--- a/gss-serv.c
+++ b/gss-serv.c
@@ -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, 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;
@@ -100,25 +105,32 @@ ssh_gssapi_acquire_cred(Gssctxt *ctx)
 	char lname[NI_MAXHOST];
 	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, sizeof(lname))) {
-		gss_release_oid_set(&status, &oidset);
-		return (-1);
-	}
+		if (gethostname(lname, sizeof(lname))) {
+			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);
-	}
-
-	if ((ctx->major = gss_acquire_cred(&ctx->minor,
-	    ctx->name, 0, oidset, GSS_C_ACCEPT, &ctx->creds, NULL, NULL)))
-		ssh_gssapi_error(ctx);
+	} else {
+		ctx->name = GSS_C_NO_NAME;
+		ctx->creds = GSS_C_NO_CREDENTIAL;
+		return GSS_S_COMPLETE;
+ 	}
 
-	gss_release_oid_set(&status, &oidset);
-	return (ctx->major);
 }
 
 /* Privileged */
@@ -133,6 +145,29 @@ ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid)
 }
 
 /* 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)
 {
@@ -142,7 +177,9 @@ ssh_gssapi_supported_oids(gss_OID_set *oidset)
 	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,
@@ -268,8 +305,48 @@ OM_uint32
 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);
+
+		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_buffer_desc ename;
+		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;
 
@@ -284,6 +361,13 @@ ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
 	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);
@@ -301,6 +385,8 @@ ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
 		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;
@@ -311,11 +397,20 @@ ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
 void
 ssh_gssapi_cleanup_creds(void)
 {
-	if (gssapi_client.store.filename != NULL) {
-		/* Unlink probably isn't sufficient */
-		debug("removing gssapi cred file\"%s\"",
-		    gssapi_client.store.filename);
-		unlink(gssapi_client.store.filename);
+	krb5_ccache ccache = NULL;
+	krb5_error_code problem;
+
+	if (gssapi_client.store.data != NULL) {
+		if ((problem = krb5_cc_resolve(gssapi_client.store.data, gssapi_client.store.envval, &ccache))) {
+			debug("%s: krb5_cc_resolve(): %.100s", __func__,
+				krb5_get_err_text(gssapi_client.store.data, problem));
+		} else if ((problem = krb5_cc_destroy(gssapi_client.store.data, ccache))) {
+			debug("%s: krb5_cc_resolve(): %.100s", __func__,
+				krb5_get_err_text(gssapi_client.store.data, problem));
+		} else {
+			krb5_free_context(gssapi_client.store.data);
+			gssapi_client.store.data = NULL;
+		}
 	}
 }
 
@@ -348,7 +443,7 @@ ssh_gssapi_do_child(char ***envp, u_int *envsizep)
 
 /* Privileged */
 int
-ssh_gssapi_userok(char *user)
+ssh_gssapi_userok(char *user, struct passwd *pw)
 {
 	OM_uint32 lmin;
 
@@ -358,9 +453,11 @@ ssh_gssapi_userok(char *user)
 		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);
@@ -374,14 +471,90 @@ ssh_gssapi_userok(char *user)
 	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
diff --git a/kex.c b/kex.c
index a173e70..4563920 100644
--- a/kex.c
+++ b/kex.c
@@ -53,6 +53,10 @@
 #include "roaming.h"
 #include "digest.h"
 
+#ifdef GSSAPI
+#include "ssh-gss.h"
+#endif
+
 #if OPENSSL_VERSION_NUMBER >= 0x00907000L
 # if defined(HAVE_EVP_SHA256)
 # define evp_ssh_sha256 EVP_sha256
@@ -94,6 +98,11 @@ static const struct kexalg kexalgs[] = {
 #ifdef HAVE_EVP_SHA256
 	{ KEX_CURVE25519_SHA256, KEX_C25519_SHA256, 0, SSH_DIGEST_SHA256 },
 #endif /* HAVE_EVP_SHA256 */
+#ifdef GSSAPI
+	{ KEX_GSS_GEX_SHA1_ID, KEX_GSS_GEX_SHA1, 0, SSH_DIGEST_SHA1 },
+	{ KEX_GSS_GRP1_SHA1_ID, KEX_GSS_GRP1_SHA1, 0, SSH_DIGEST_SHA1 },
+	{ KEX_GSS_GRP14_SHA1_ID, KEX_GSS_GRP14_SHA1, 0, SSH_DIGEST_SHA1 },
+#endif
 	{ NULL, -1, -1, -1},
 };
 
@@ -123,6 +132,12 @@ kex_alg_by_name(const char *name)
 	for (k = kexalgs; k->name != NULL; k++) {
 		if (strcmp(k->name, name) == 0)
 			return k;
+#ifdef GSSAPI
+		if (strncmp(name, "gss-", 4) == 0) {
+			if (strncmp(k->name, name, strlen(k->name)) == 0)
+				return k;
+		}
+#endif
 	}
 	return NULL;
 }
diff --git a/kex.h b/kex.h
index 4c40ec8..1c76c08 100644
--- a/kex.h
+++ b/kex.h
@@ -76,6 +76,11 @@ enum kex_exchange {
 	KEX_DH_GEX_SHA256,
 	KEX_ECDH_SHA2,
 	KEX_C25519_SHA256,
+#ifdef GSSAPI
+	KEX_GSS_GRP1_SHA1,
+	KEX_GSS_GRP14_SHA1,
+	KEX_GSS_GEX_SHA1,
+#endif
 	KEX_MAX
 };
 
@@ -135,6 +140,12 @@ struct Kex {
 	int	flags;
 	int	hash_alg;
 	int	ec_nid;
+#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 *);
@@ -166,6 +177,10 @@ void	 kexecdh_client(Kex *);
 void	 kexecdh_server(Kex *);
 void	 kexc25519_client(Kex *);
 void	 kexc25519_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,
diff --git a/kexgssc.c b/kexgssc.c
new file mode 100644
index 0000000..e90b567
--- /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)
+			free(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 ((int)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);
+	free(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->hash_alg,
+		    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");
+
+	free(msg_tok.value);
+
+	DH_free(dh);
+	if (serverhostkey)
+		free(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_bn(kex, hash, hashlen, shared_secret);
+	BN_clear_free(shared_secret);
+	kex_finish(kex);
+}
+
+#endif /* GSSAPI */
diff --git a/kexgsss.c b/kexgsss.c
new file mode 100644
index 0000000..b880998
--- /dev/null
+++ b/kexgsss.c
@@ -0,0 +1,290 @@
+/*
+ * 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 "misc.h"      /* servconf.h needs misc.h for struct ForwardOptions */
+#include "servconf.h"
+#include "ssh-gss.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()))
+			free(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));
+
+		free(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 ((int)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);
+	free(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->hash_alg,
+		    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_bn(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 */
diff --git a/monitor.c b/monitor.c
index d3f87e1..7ebc76e 100644
--- a/monitor.c
+++ b/monitor.c
@@ -181,6 +181,8 @@ int mm_answer_gss_setup_ctx(int, Buffer *);
 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
@@ -261,11 +263,18 @@ struct mon_table mon_dispatch_proto20[] = {
     {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
     {0, 0, NULL}
 };
 
 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
 #ifdef WITH_OPENSSL
     {MONITOR_REQ_MODULI, 0, mm_answer_moduli},
 #endif
@@ -380,6 +389,10 @@ monitor_child_preauth(Authctxt *_authctxt, struct monitor *pmonitor)
 		/* 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;
 
@@ -488,6 +501,10 @@ monitor_child_postauth(struct monitor *pmonitor)
 		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);
@@ -1893,6 +1910,13 @@ mm_get_kex(Buffer *m)
 	kex->kex[KEX_ECDH_SHA2] = kexecdh_server;
 #endif
 	kex->kex[KEX_C25519_SHA256] = kexc25519_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);
@@ -2100,6 +2124,9 @@ mm_answer_gss_setup_ctx(int sock, Buffer *m)
 	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;
 
@@ -2127,6 +2154,9 @@ mm_answer_gss_accept_ctx(int sock, Buffer *m)
 	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);
@@ -2144,6 +2174,7 @@ mm_answer_gss_accept_ctx(int sock, Buffer *m)
 		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);
 }
@@ -2155,6 +2186,9 @@ mm_answer_gss_checkmic(int sock, Buffer *m)
 	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);
@@ -2181,7 +2215,11 @@ mm_answer_gss_userok(int sock, Buffer *m)
 {
 	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);
@@ -2194,5 +2232,73 @@ mm_answer_gss_userok(int sock, Buffer *m)
 	/* 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);
+
+	free(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);
+
+	free(store.filename);
+	free(store.envvar);
+	free(store.envval);
+
+	buffer_clear(m);
+	buffer_put_int(m, ok);
+
+	mm_request_send(socket, MONITOR_ANS_GSSUPCREDS, m);
+
+	return(0);
+}
+
 #endif /* GSSAPI */
 
diff --git a/monitor.h b/monitor.h
index 20e2b4a..ff79fbb 100644
--- a/monitor.h
+++ b/monitor.h
@@ -60,6 +60,8 @@ enum monitor_reqtype {
 #ifdef WITH_SELINUX
 	MONITOR_REQ_AUTHROLE = 80,
 #endif
+	MONITOR_REQ_GSSSIGN = 82, MONITOR_ANS_GSSSIGN = 83,
+	MONITOR_REQ_GSSUPCREDS = 84, MONITOR_ANS_GSSUPCREDS = 85,
 
 	MONITOR_REQ_PAM_START = 100,
 	MONITOR_REQ_PAM_ACCOUNT = 102, MONITOR_ANS_PAM_ACCOUNT = 103,
diff --git a/monitor_wrap.c b/monitor_wrap.c
index 82f114c..7e991e6 100644
--- a/monitor_wrap.c
+++ b/monitor_wrap.c
@@ -1300,7 +1300,7 @@ mm_ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
 }
 
 int
-mm_ssh_gssapi_userok(char *user)
+mm_ssh_gssapi_userok(char *user, struct passwd *pw)
 {
 	Buffer m;
 	int authenticated = 0;
@@ -1317,5 +1317,50 @@ mm_ssh_gssapi_userok(char *user)
 	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 */
 
diff --git a/monitor_wrap.h b/monitor_wrap.h
index 9d5e5ba..93929e0 100644
--- a/monitor_wrap.h
+++ b/monitor_wrap.h
@@ -61,8 +61,10 @@ BIGNUM *mm_auth_rsa_generate_challenge(Key *);
 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
diff --git a/readconf.c b/readconf.c
index 3f5c58b..1c07766 100644
--- a/readconf.c
+++ b/readconf.c
@@ -143,6 +143,8 @@ typedef enum {
 	oClearAllForwardings, oNoHostAuthenticationForLocalhost,
 	oEnableSSHKeysign, oRekeyLimit, oVerifyHostKeyDNS, oConnectTimeout,
 	oAddressFamily, oGssAuthentication, oGssDelegateCreds,
+	oGssTrustDns, oGssKeyEx, oGssClientIdentity, oGssRenewalRekey,
+	oGssServerIdentity, 
 	oServerAliveInterval, oServerAliveCountMax, oIdentitiesOnly,
 	oSendEnv, oControlPath, oControlMaster, oControlPersist,
 	oHashKnownHosts,
@@ -187,10 +189,19 @@ static struct {
 	{ "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 },
@@ -868,10 +879,30 @@ parse_time:
 		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;
@@ -1553,7 +1584,12 @@ initialize_options(Options * options)
 	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;
@@ -1677,8 +1713,14 @@ fill_default_options(Options * options)
 		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)
diff --git a/readconf.h b/readconf.h
index a028306..1dbe509 100644
--- a/readconf.h
+++ b/readconf.h
@@ -45,7 +45,12 @@ typedef struct {
 	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. */
diff --git a/regress/cert-hostkey.sh b/regress/cert-hostkey.sh
index 1d9e0ed..1277409 100644
--- a/regress/cert-hostkey.sh
+++ b/regress/cert-hostkey.sh
@@ -17,7 +17,7 @@ ${SSHKEYGEN} -q -N '' -t rsa  -f $OBJ/host_ca_key ||\
 	cat $OBJ/host_ca_key.pub
 ) > $OBJ/known_hosts-cert
 
-PLAIN_TYPES=`$SSH -Q key-plain | sed 's/^ssh-dss/ssh-dsa/g;s/^ssh-//'`
+PLAIN_TYPES=`$SSH -Q key-plain | grep -v null | sed 's/^ssh-dss/ssh-dsa/g;s/^ssh-//'`
 
 type_has_legacy() {
 	case $1 in
diff --git a/regress/cert-userkey.sh b/regress/cert-userkey.sh
index b093a91..4c8da00 100644
--- a/regress/cert-userkey.sh
+++ b/regress/cert-userkey.sh
@@ -6,7 +6,7 @@ tid="certified user keys"
 rm -f $OBJ/authorized_keys_$USER $OBJ/user_ca_key* $OBJ/cert_user_key*
 cp $OBJ/sshd_proxy $OBJ/sshd_proxy_bak
 
-PLAIN_TYPES=`$SSH -Q key-plain | sed 's/^ssh-dss/ssh-dsa/;s/^ssh-//'`
+PLAIN_TYPES=`$SSH -Q key-plain | grep -v null | sed 's/^ssh-dss/ssh-dsa/;s/^ssh-//'`
 
 type_has_legacy() {
 	case $1 in
diff --git a/regress/kextype.sh b/regress/kextype.sh
index 6f952f4..bcb609b 100644
--- a/regress/kextype.sh
+++ b/regress/kextype.sh
@@ -14,6 +14,9 @@ echo "KexAlgorithms=$KEXOPT" >> $OBJ/sshd_proxy
 
 tries="1 2 3 4"
 for k in `${SSH} -Q kex`; do
+	if [ $k = "gss-gex-sha1-" -o $k = "gss-group1-sha1-" -o $k = "gss-group14-sha1-" ]; then
+		continue
+	fi
 	verbose "kex $k"
 	for i in $tries; do
 		${SSH} -F $OBJ/ssh_proxy -o KexAlgorithms=$k x true
diff --git a/regress/rekey.sh b/regress/rekey.sh
index fd452b0..1148197 100644
--- a/regress/rekey.sh
+++ b/regress/rekey.sh
@@ -38,6 +38,9 @@ increase_datafile_size 300
 
 opts=""
 for i in `${SSH} -Q kex`; do
+	if [ $i = "gss-gex-sha1-" -o $i = "gss-group1-sha1-" -o $i = "gss-group14-sha1-" ]; then
+		continue
+	fi
 	opts="$opts KexAlgorithms=$i"
 done
 for i in `${SSH} -Q cipher`; do
@@ -56,6 +59,9 @@ done
 if ${SSH} -Q cipher-auth | grep '^.*$' >/dev/null 2>&1 ; then
   for c in `${SSH} -Q cipher-auth`; do
     for kex in `${SSH} -Q kex`; do
+	if [ $kex = "gss-gex-sha1-" -o $kex = "gss-group1-sha1-" -o $kex = "gss-group14-sha1-" ]; then
+		continue
+	fi
 	verbose "client rekey $c $kex"
 	ssh_data_rekeying "KexAlgorithms=$kex" -oRekeyLimit=256k -oCiphers=$c
     done
diff --git a/servconf.c b/servconf.c
index c8a3f28..179c20d 100644
--- a/servconf.c
+++ b/servconf.c
@@ -110,7 +110,10 @@ initialize_server_options(ServerOptions *options)
 	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;
@@ -253,8 +256,14 @@ fill_default_server_options(ServerOptions *options)
 		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)
@@ -359,7 +368,8 @@ typedef enum {
 	sBanner, sShowPatchLevel, sUseDNS, sHostbasedAuthentication,
 	sHostbasedUsesNameFromPacketOnly, sClientAliveInterval,
 	sClientAliveCountMax, sAuthorizedKeysFile,
-	sGssAuthentication, sGssCleanupCreds, sAcceptEnv, sPermitTunnel,
+	sGssAuthentication, sGssCleanupCreds, sGssStrictAcceptor,
+	sGssKeyEx, sGssStoreRekey, sAcceptEnv, sPermitTunnel,
 	sMatch, sPermitOpen, sForceCommand, sChrootDirectory,
 	sUsePrivilegeSeparation, sAllowAgentForwarding,
 	sHostCertificate,
@@ -428,10 +438,20 @@ static struct {
 #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 },
@@ -1113,10 +1133,22 @@ process_server_config_line(ServerOptions *options, char *line,
 		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;
@@ -2070,6 +2102,9 @@ dump_config(ServerOptions *o)
 #ifdef GSSAPI
 	dump_cfg_fmtint(sGssAuthentication, o->gss_authentication);
 	dump_cfg_fmtint(sGssCleanupCreds, o->gss_cleanup_creds);
+	dump_cfg_fmtint(sGssKeyEx, o->gss_keyex);
+	dump_cfg_fmtint(sGssStrictAcceptor, o->gss_strict_acceptor);
+	dump_cfg_fmtint(sGssStoreRekey, o->gss_store_rekey);
 #endif
 	dump_cfg_fmtint(sPasswordAuthentication, o->password_authentication);
 	dump_cfg_fmtint(sKbdInteractiveAuthentication,
diff --git a/servconf.h b/servconf.h
index 21719e2..397698b 100644
--- a/servconf.h
+++ b/servconf.h
@@ -113,7 +113,10 @@ typedef struct {
 	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 */
diff --git a/ssh-gss.h b/ssh-gss.h
index a99d7f0..0374c88 100644
--- a/ssh-gss.h
+++ b/ssh-gss.h
@@ -1,6 +1,6 @@
 /* $OpenBSD: ssh-gss.h,v 1.11 2014/02/26 20:28:44 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
@@ -61,10 +61,22 @@
 
 #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;
 
@@ -72,8 +84,11 @@ typedef struct {
 	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 {
@@ -84,6 +99,7 @@ typedef struct ssh_gssapi_mech_struct {
 	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 {
@@ -94,10 +110,11 @@ typedef struct {
 	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);
@@ -119,16 +136,32 @@ void ssh_gssapi_build_ctx(Gssctxt **);
 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);
+
+void ssh_gssapi_rekey_creds(void);
 #endif /* GSSAPI */
 
 #endif /* _SSH_GSS_H */
diff --git a/ssh_config b/ssh_config
index 3f83c40..4a0fb82 100644
--- 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
diff --git a/ssh_config.5 b/ssh_config.5
index f9ede7a..e6649ac 100644
--- a/ssh_config.5
+++ b/ssh_config.5
@@ -701,11 +701,43 @@ Specifies whether user authentication based on GSSAPI is allowed.
 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
diff --git a/sshconnect2.c b/sshconnect2.c
index 4724b66..703f8e4 100644
--- a/sshconnect2.c
+++ b/sshconnect2.c
@@ -159,9 +159,34 @@ ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port)
 	char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
 	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;
@@ -199,6 +224,17 @@ ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port)
 	myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(
 	    myproposal[PROPOSAL_KEX_ALGS]);
 
+#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);
+		free(gss);
+	}
+#endif
+
 	if (options.rekey_limit || options.rekey_interval)
 		packet_set_rekey_limits((u_int32_t)options.rekey_limit,
 		    (time_t)options.rekey_interval);
@@ -213,10 +249,30 @@ ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port)
 	kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
 #endif
 	kex->kex[KEX_C25519_SHA256] = kexc25519_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);
@@ -306,6 +362,7 @@ void	input_gssapi_token(int type, u_int32_t, void *);
 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 *);
@@ -321,6 +378,11 @@ static char *authmethods_get(void);
 
 Authmethod authmethods[] = {
 #ifdef GSSAPI
+	{"gssapi-keyex",
+		userauth_gsskeyex,
+		NULL,
+		&options.gss_authentication,
+		NULL},
 	{"gssapi-with-mic",
 		userauth_gssapi,
 		NULL,
@@ -617,19 +679,31 @@ userauth_gssapi(Authctxt *authctxt)
 	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++;
@@ -726,8 +800,8 @@ input_gssapi_response(int type, u_int32_t plen, void *ctxt)
 {
 	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");
@@ -836,6 +910,48 @@ input_gssapi_error(int type, u_int32_t plen, void *ctxt)
 	free(msg);
 	free(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
diff --git a/sshd.c b/sshd.c
index f7b8aba..2871fe9 100644
--- a/sshd.c
+++ b/sshd.c
@@ -1761,10 +1761,13 @@ main(int ac, char **av)
 		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);
@@ -2501,6 +2504,49 @@ do_ssh2_kex(void)
 	myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal(
 	    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);
 #ifdef WITH_OPENSSL
@@ -2511,6 +2557,13 @@ do_ssh2_kex(void)
 	kex->kex[KEX_ECDH_SHA2] = kexecdh_server;
 #endif
 	kex->kex[KEX_C25519_SHA256] = kexc25519_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;
diff --git a/sshd_config b/sshd_config
index 7061f75..f4796fc 100644
--- a/sshd_config
+++ b/sshd_config
@@ -91,6 +91,8 @@ ChallengeResponseAuthentication no
 # GSSAPI options
 GSSAPIAuthentication yes
 GSSAPICleanupCredentials no
+#GSSAPIStrictAcceptorCheck yes
+#GSSAPIKeyExchange no
 
 # Set this to 'yes' to enable PAM authentication, account processing,
 # and session processing. If this is enabled, PAM authentication will
diff --git a/sshd_config.5 b/sshd_config.5
index cccb310..8ad79d9 100644
--- a/sshd_config.5
+++ b/sshd_config.5
@@ -536,12 +536,40 @@ Specifies whether user authentication based on GSSAPI is allowed.
 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