--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/components/openssh/patches/023-gsskex.patch Mon Jan 25 10:57:40 2016 -0800
@@ -0,0 +1,1256 @@
+#
+# GSS-API key exchange support
+#
+# Based on https://github.com/SimonWilkinson/gss-openssh/commit/ffae842
+# Updated to apply to OpenSSH 6.5.
+# Default value for GSSAPIKeyExchange changed to yes to match SunSSH behavior.
+# New files kexgssc.c and kexgsss.c moved to ../sources/ and made cstyle clean.
+#
+# Upstream rejected GSS-API key exchange several times before.
+#
+diff -pur old/Makefile.in new/Makefile.in
+--- old/Makefile.in 2015-12-10 14:51:47.781146370 -0800
++++ new/Makefile.in 2015-12-10 14:48:21.907121340 -0800
+@@ -85,6 +85,7 @@ LIBSSH_OBJS=${LIBOPENSSH_OBJS} \
+ atomicio.o key.o dispatch.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 \
+ msg.o progressmeter.o dns.o entropy.o gss-genr.o umac.o umac128.o \
++ kexgssc.o \
+ ssh-pkcs11.o smult_curve25519_ref.o \
+ poly1305.o chacha.o cipher-chachapoly.o \
+ ssh-ed25519.o digest-openssl.o digest-libc.o hmac.o \
+@@ -105,7 +106,7 @@ SSHDOBJS=sshd.o auth-rhosts.o auth-passw
+ auth-skey.o auth-bsdauth.o auth2-hostbased.o auth2-kbdint.o \
+ auth2-none.o auth2-passwd.o auth2-pubkey.o \
+ monitor_mm.o monitor.o monitor_wrap.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 -pur old/auth2-gss.c new/auth2-gss.c
+--- old/auth2-gss.c
++++ new/auth2-gss.c
+@@ -1,7 +1,7 @@
+ /* $OpenBSD: auth2-gss.c,v 1.22 2015/01/19 20:07:45 markus 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
+@@ -53,6 +53,39 @@ static int input_gssapi_mic(int type, u_
+ static int input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
+ static int 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));
++
++ 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)
+@@ -290,6 +323,12 @@ input_gssapi_mic(int type, u_int32_t ple
+ return 0;
+ }
+
++Authmethod method_gsskeyex = {
++ "gssapi-keyex",
++ userauth_gsskeyex,
++ &options.gss_authentication
++};
++
+ Authmethod method_gssapi = {
+ "gssapi-with-mic",
+ userauth_gssapi,
+diff -pur old/auth2.c new/auth2.c
+--- old/auth2.c
++++ new/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 -pur old/configure new/configure
+--- old/configure
++++ new/configure
+@@ -10944,8 +10944,10 @@ fi
+
+ fi
+
+- $as_echo "#define USE_GSS_STORE_CRED 1" >>confdefs.h
+- $as_echo "#define GSSAPI_STORECREDS_NEEDS_RUID 1" >>confdefs.h
++cat >>confdefs.h <<\_ACEOF
++#define USE_GSS_STORE_CRED 1
++#define GSSAPI_STORECREDS_NEEDS_RUID 1
++_ACEOF
+
+ TEST_SHELL=$SHELL # let configure find us a capable shell
+ ;;
+diff -pur old/gss-genr.c new/gss-genr.c
+--- old/gss-genr.c
++++ new/gss-genr.c
+@@ -1,7 +1,7 @@
+ /* $OpenBSD: gss-genr.c,v 1.23 2015/01/20 23:14:00 deraadt 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
+@@ -41,12 +41,167 @@
+ #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) {
++ 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));
++}
++
++char *
++ssh_gssapi_kex_mechs(gss_OID_set gss_supported, ssh_gssapi_check_fn *check,
++ const char *data) {
++ 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]), data)) {
++
++ 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)
+@@ -231,6 +386,9 @@ ssh_gssapi_import_name(Gssctxt *ctx, con
+ 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);
+@@ -238,6 +396,19 @@ ssh_gssapi_sign(Gssctxt *ctx, gss_buffer
+ 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)
+@@ -256,6 +427,10 @@ ssh_gssapi_check_mechanism(Gssctxt **ctx
+ 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 &&
+@@ -274,7 +449,7 @@ ssh_gssapi_check_mechanism(Gssctxt **ctx
+ GSS_C_NO_BUFFER);
+ }
+
+- if (GSS_ERROR(major))
++ if (GSS_ERROR(major) || intctx != NULL)
+ ssh_gssapi_delete_ctx(ctx);
+
+ return (!GSS_ERROR(major));
+diff -pur old/gss-serv.c new/gss-serv.c
+--- old/gss-serv.c
++++ new/gss-serv.c
+@@ -1,7 +1,7 @@
+ /* $OpenBSD: gss-serv.c,v 1.29 2015/05/22 03:50:02 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
+@@ -47,6 +47,7 @@
+ #include "servconf.h"
+
+ #include "ssh-gss.h"
++#include "monitor_wrap.h"
+
+ extern ServerOptions options;
+
+@@ -142,6 +143,28 @@ ssh_gssapi_server_ctx(Gssctxt **ctx, gss
+ }
+
+ /* 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));
++}
++
++/* Unprivileged */
++int
++ssh_gssapi_server_check_mech(Gssctxt **dum, gss_OID oid, const char *data) {
++ 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)
+ {
+@@ -151,7 +174,9 @@ ssh_gssapi_supported_oids(gss_OID_set *o
+ 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,
+@@ -427,14 +452,4 @@ ssh_gssapi_userok(char *user)
+ return (0);
+ }
+
+-/* Privileged */
+-OM_uint32
+-ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
+-{
+- ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
+- gssbuf, gssmic, NULL);
+-
+- return (ctx->major);
+-}
+-
+ #endif
+diff -pur old/kex.c new/kex.c
+--- old/kex.c
++++ new/kex.c
+@@ -55,6 +55,10 @@
+ #include "sshbuf.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
+@@ -95,6 +99,11 @@ static const struct kexalg kexalgs[] = {
+ #if defined(HAVE_EVP_SHA256) || !defined(WITH_OPENSSL)
+ { KEX_CURVE25519_SHA256, KEX_C25519_SHA256, 0, SSH_DIGEST_SHA256 },
+ #endif /* HAVE_EVP_SHA256 || !WITH_OPENSSL */
++#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},
+ };
+
+@@ -126,7 +135,7 @@ kex_alg_by_name(const char *name)
+ const struct kexalg *k;
+
+ for (k = kexalgs; k->name != NULL; k++) {
+- if (strcmp(k->name, name) == 0)
++ if (strncmp(k->name, name, strlen(k->name)) == 0)
+ return k;
+ }
+ return NULL;
+diff -pur old/kex.h new/kex.h
+--- old/kex.h
++++ new/kex.h
+@@ -93,6 +93,9 @@ enum kex_exchange {
+ KEX_DH_GEX_SHA256,
+ KEX_ECDH_SHA2,
+ KEX_C25519_SHA256,
++ KEX_GSS_GRP1_SHA1,
++ KEX_GSS_GRP14_SHA1,
++ KEX_GSS_GEX_SHA1,
+ KEX_MAX
+ };
+
+@@ -139,6 +142,10 @@ struct kex {
+ u_int flags;
+ int hash_alg;
+ int ec_nid;
++#ifdef GSSAPI
++ int gss_deleg_creds;
++ char *gss_host;
++#endif
+ char *client_version_string;
+ char *server_version_string;
+ char *failed_choice;
+@@ -186,6 +193,10 @@ int kexecdh_client(struct ssh *);
+ int kexecdh_server(struct ssh *);
+ int kexc25519_client(struct ssh *);
+ int kexc25519_server(struct ssh *);
++#ifdef GSSAPI
++int kexgss_client(struct ssh *);
++int kexgss_server(struct ssh *);
++#endif
+
+ int kex_dh_hash(const char *, const char *,
+ const u_char *, size_t, const u_char *, size_t, const u_char *, size_t,
+diff -pur old/monitor.c new/monitor.c
+--- old/monitor.c
++++ new/monitor.c
+@@ -160,6 +160,7 @@ 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 *);
+ #endif
+
+ #ifdef SSH_AUDIT_EVENTS
+@@ -244,11 +245,17 @@ 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},
++#endif
+ #ifdef WITH_OPENSSL
+ {MONITOR_REQ_MODULI, 0, mm_answer_moduli},
+ #endif
+@@ -363,6 +370,10 @@ monitor_child_preauth(Authctxt *_authctx
+ /* 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;
+
+@@ -502,6 +513,10 @@ monitor_child_postauth(struct monitor *p
+ 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);
+@@ -1927,6 +1942,13 @@ monitor_apply_keystate(struct monitor *p
+ # endif
+ #endif /* WITH_OPENSSL */
+ 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->load_host_public_key=&get_hostkey_public_by_type;
+ kex->load_host_private_key=&get_hostkey_private_by_type;
+ kex->host_key_index=&get_hostkey_index;
+@@ -2026,6 +2048,9 @@ mm_answer_gss_setup_ctx(int sock, Buffer
+ 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;
+
+@@ -2053,6 +2078,9 @@ mm_answer_gss_accept_ctx(int sock, Buffe
+ 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);
+@@ -2070,6 +2098,7 @@ mm_answer_gss_accept_ctx(int sock, Buffe
+ 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);
+ }
+@@ -2081,6 +2110,9 @@ mm_answer_gss_checkmic(int sock, Buffer
+ 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);
+@@ -2107,6 +2139,9 @@ mm_answer_gss_userok(int sock, Buffer *m
+ {
+ int authenticated;
+
++ if (!options.gss_authentication && !options.gss_keyex)
++ fatal("In GSSAPI monitor when GSSAPI is disabled");
++
+ authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user);
+
+ buffer_clear(m);
+@@ -2120,5 +2155,47 @@ 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);
++
++ return (0);
++}
++
+ #endif /* GSSAPI */
+
+diff -pur old/monitor.h new/monitor.h
+--- old/monitor.h
++++ new/monitor.h
+@@ -68,6 +68,9 @@ enum monitor_reqtype {
+ #ifdef PAM_ENHANCEMENT
+ MONITOR_REQ_AUTHMETHOD = 114,
+ #endif
++#ifdef GSSAPI
++ MONITOR_REQ_GSSSIGN = 130, MONITOR_ANS_GSSSIGN = 131,
++#endif
+ };
+
+ struct mm_master;
+diff -pur old/monitor_wrap.c new/monitor_wrap.c
+--- old/monitor_wrap.c
++++ new/monitor_wrap.c
+@@ -1103,5 +1103,28 @@ 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);
++}
++
+ #endif /* GSSAPI */
+
+diff -pur old/monitor_wrap.h new/monitor_wrap.h
+--- old/monitor_wrap.h
++++ new/monitor_wrap.h
+@@ -60,6 +60,7 @@ OM_uint32 mm_ssh_gssapi_accept_ctx(Gssct
+ gss_buffer_desc *, gss_buffer_desc *, OM_uint32 *);
+ int mm_ssh_gssapi_userok(char *user);
+ 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);
+ #endif
+
+ #ifdef USE_PAM
+diff -pur old/readconf.c new/readconf.c
+--- old/readconf.c
++++ new/readconf.c
+@@ -147,6 +147,7 @@ typedef enum {
+ oClearAllForwardings, oNoHostAuthenticationForLocalhost,
+ oEnableSSHKeysign, oRekeyLimit, oVerifyHostKeyDNS, oConnectTimeout,
+ oAddressFamily, oGssAuthentication, oGssDelegateCreds,
++ oGssKeyEx,
+ oServerAliveInterval, oServerAliveCountMax, oIdentitiesOnly,
+ oSendEnv, oControlPath, oControlMaster, oControlPersist,
+ oHashKnownHosts,
+@@ -198,11 +199,15 @@ static struct {
+ { "gssauthentication", oGssAuthentication }, /* alias */
+ { "gssapidelegatecredentials", oGssDelegateCreds },
+ { "gssdelegatecreds", oGssDelegateCreds }, /* alias */
++ { "gssapikeyexchange", oGssKeyEx },
++ { "gsskeyex", oGssKeyEx }, /* alias */
+ #else
+ { "gssapiauthentication", oUnsupported },
+ { "gssauthentication", oUnsupported },
+ { "gssapidelegatecredentials", oUnsupported },
+ { "gssdelegatecreds", oUnsupported },
++ { "gssapikeyexchange", oUnsupported },
++ { "gsskeyex", oUnsupported },
+ #endif
+ { "fallbacktorsh", oDeprecated },
+ { "usersh", oDeprecated },
+@@ -933,6 +938,10 @@ 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;
+@@ -1647,6 +1656,7 @@ 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->password_authentication = -1;
+ options->kbd_interactive_authentication = -1;
+@@ -1786,6 +1796,12 @@ fill_default_options(Options * options)
+ #else
+ options->gss_authentication = 0;
+ #endif
++ if (options->gss_keyex == -1)
++#ifdef OPTION_DEFAULT_VALUE
++ options->gss_keyex = 1;
++#else
++ options->gss_keyex = 0;
++#endif
+ if (options->gss_deleg_creds == -1)
+ options->gss_deleg_creds = 0;
+ if (options->password_authentication == -1)
+diff -pur old/readconf.h new/readconf.h
+--- old/readconf.h
++++ new/readconf.h
+@@ -45,6 +45,7 @@ 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 password_authentication; /* Try password
+ * authentication. */
+diff -pur old/servconf.c new/servconf.c
+--- old/servconf.c
++++ new/servconf.c
+@@ -117,6 +117,7 @@ initialize_server_options(ServerOptions
+ 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->password_authentication = -1;
+@@ -300,6 +301,12 @@ fill_default_server_options(ServerOption
+ #else
+ options->gss_authentication = 0;
+ #endif
++ if (options->gss_keyex == -1)
++#ifdef OPTION_DEFAULT_VALUE
++ options->gss_keyex = 1;
++#else
++ options->gss_keyex = 0;
++#endif
+ if (options->gss_cleanup_creds == -1)
+ options->gss_cleanup_creds = 1;
+ if (options->gss_strict_acceptor == -1)
+@@ -442,6 +449,7 @@ typedef enum {
+ sHostbasedUsesNameFromPacketOnly, sHostbasedAcceptedKeyTypes,
+ sHostKeyAlgorithms,
+ sClientAliveInterval, sClientAliveCountMax, sAuthorizedKeysFile,
++ sGssKeyEx,
+ sGssAuthentication, sGssCleanupCreds, sGssStrictAcceptor,
+ sAcceptEnv, sPermitTunnel,
+ sMatch, sPermitOpen, sForceCommand, sChrootDirectory,
+@@ -519,6 +527,8 @@ static struct {
+ #ifdef GSSAPI
+ { "gssapiauthentication", sGssAuthentication, SSHCFG_ALL },
+ { "gssauthentication", sGssAuthentication, SSHCFG_ALL }, /* alias */
++ { "gssapikeyexchange", sGssKeyEx, SSHCFG_ALL },
++ { "gsskeyex", sGssKeyEx, SSHCFG_ALL }, /* alias */
+ #ifdef USE_GSS_STORE_CRED
+ { "gssapicleanupcredentials", sUnsupported, SSHCFG_GLOBAL },
+ #else /* USE_GSS_STORE_CRED */
+@@ -528,6 +538,8 @@ static struct {
+ #else
+ { "gssapiauthentication", sUnsupported, SSHCFG_ALL },
+ { "gssauthentication", sUnsupported, SSHCFG_ALL }, /* alias */
++ { "gssapikeyexchange", sUnsupported,, SSHCFG_ALL },
++ { "gsskeyex", sUnsupported,, SSHCFG_ALL },
+ { "gssapicleanupcredentials", sUnsupported, SSHCFG_GLOBAL },
+ { "gssapistrictacceptorcheck", sUnsupported, SSHCFG_GLOBAL },
+ #endif
+@@ -1311,6 +1323,10 @@ process_server_config_line(ServerOptions
+ 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;
+@@ -2357,6 +2373,7 @@ dump_config(ServerOptions *o)
+ #endif
+ #ifdef GSSAPI
+ dump_cfg_fmtint(sGssAuthentication, o->gss_authentication);
++ dump_cfg_fmtint(sGssKeyEx, o->gss_keyex);
+ #ifndef USE_GSS_STORE_CRED
+ dump_cfg_fmtint(sGssCleanupCreds, o->gss_cleanup_creds);
+ #endif /* !USE_GSS_STORE_CRED */
+diff -pur old/servconf.h new/servconf.h
+--- old/servconf.h
++++ new/servconf.h
+@@ -122,6 +122,7 @@ 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 password_authentication; /* If true, permit password
+diff -pur old/ssh-gss.h new/ssh-gss.h
+--- old/ssh-gss.h
++++ new/ssh-gss.h
+@@ -61,6 +61,17 @@
+
+ #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;
+@@ -98,6 +109,7 @@ typedef struct {
+ } 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);
+@@ -122,6 +134,11 @@ void ssh_gssapi_buildmic(Buffer *, const
+ int ssh_gssapi_check_mechanism(Gssctxt **, gss_OID, const char *);
+
+ /* In the server */
++typedef int ssh_gssapi_check_fn(Gssctxt **, gss_OID, const char *);
++char *ssh_gssapi_client_mechanisms(const char *host);
++char *ssh_gssapi_kex_mechs(gss_OID_set, ssh_gssapi_check_fn *, const char *);
++gss_OID ssh_gssapi_id_kex(Gssctxt *, char *, int);
++int ssh_gssapi_server_check_mech(Gssctxt **,gss_OID, const char *);
+ OM_uint32 ssh_gssapi_server_ctx(Gssctxt **, gss_OID);
+ int ssh_gssapi_userok(char *name);
+ OM_uint32 ssh_gssapi_checkmic(Gssctxt *, gss_buffer_t, gss_buffer_t);
+@@ -129,6 +146,8 @@ 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();
+ #endif /* GSSAPI */
+
+ #endif /* _SSH_GSS_H */
+diff -pur old/ssh_config new/ssh_config
+--- old/ssh_config
++++ new/ssh_config
+@@ -26,6 +26,7 @@
+ # HostbasedAuthentication no
+ # GSSAPIAuthentication no
+ # GSSAPIDelegateCredentials no
++# GSSAPIKeyExchange yes
+ # BatchMode no
+ # CheckHostIP yes
+ # AddressFamily any
+diff -pur old/ssh_config.5 new/ssh_config.5
+--- old/ssh_config.5
++++ new/ssh_config.5
+@@ -757,6 +757,12 @@ Specifies whether user authentication ba
+ The default on Solaris is
+ .Dq yes .
+ 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 on Solaris is
++.Dq yes .
++Note that this option applies to protocol version 2 only.
+ .It Cm GSSAPIDelegateCredentials
+ Forward (delegate) credentials to the server.
+ The default is
+diff -pur old/sshconnect2.c new/sshconnect2.c
+--- old/sshconnect2.c
++++ new/sshconnect2.c
+@@ -163,12 +163,37 @@ ssh_kex2(char *host, struct sockaddr *ho
+ char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
+ struct kex *kex;
+ int r;
++#ifdef GSSAPI
++ char *orig = NULL, *gss = NULL;
++ char *gss_host = NULL;
++#endif
++
+
+ xxx_host = host;
+ xxx_hostaddr = hostaddr;
+
++ if (options.kex_algorithms != NULL)
++ myproposal[PROPOSAL_KEX_ALGS] = options.kex_algorithms;
++
++#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];
++
++ gss_host = (char *)get_canonical_hostname(1);
++
++ gss = ssh_gssapi_client_mechanisms(gss_host);
++ if (gss) {
++ debug("Offering GSSAPI proposal: %s", gss);
++ xasprintf(&myproposal[PROPOSAL_KEX_ALGS],
++ "%s,%s", gss, orig);
++ }
++ }
++#endif
++
+ myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(
+- options.kex_algorithms);
++ myproposal[PROPOSAL_KEX_ALGS]);
+ myproposal[PROPOSAL_ENC_ALGS_CTOS] =
+ compat_cipher_proposal(options.ciphers);
+ myproposal[PROPOSAL_ENC_ALGS_STOC] =
+@@ -197,6 +222,17 @@ ssh_kex2(char *host, struct sockaddr *ho
+ order_hostkeyalgs(host, hostaddr, port));
+ }
+
++#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);
+@@ -215,9 +251,22 @@ ssh_kex2(char *host, struct sockaddr *ho
+ # endif
+ #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_host = gss_host;
++ }
++#endif
+
+ dispatch_run(DISPATCH_BLOCK, &kex->done, active_state);
+
+@@ -310,6 +359,7 @@ int input_gssapi_token(int type, u_int32
+ int input_gssapi_hash(int type, u_int32_t, void *);
+ int input_gssapi_error(int, u_int32_t, void *);
+ int input_gssapi_errtok(int, u_int32_t, void *);
++int userauth_gsskeyex(Authctxt *authctxt);
+ #endif
+
+ void userauth(Authctxt *, char *);
+@@ -325,6 +375,11 @@ static char *authmethods_get(void);
+
+ Authmethod authmethods[] = {
+ #ifdef GSSAPI
++ {"gssapi-keyex",
++ userauth_gsskeyex,
++ NULL,
++ &options.gss_authentication,
++ NULL},
+ {"gssapi-with-mic",
+ userauth_gssapi,
+ NULL,
+@@ -649,7 +704,10 @@ userauth_gssapi(Authctxt *authctxt)
+ * 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) {
+@@ -753,8 +811,8 @@ input_gssapi_response(int type, u_int32_
+ {
+ 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");
+@@ -867,6 +925,48 @@ input_gssapi_error(int type, u_int32_t p
+ free(lang);
+ return 0;
+ }
++
++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 -pur old/sshd.c new/sshd.c
+--- old/sshd.c
++++ new/sshd.c
+@@ -1827,10 +1827,13 @@ 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);
+@@ -2588,6 +2591,48 @@ 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 */
+ if ((r = kex_setup(active_state, myproposal)) != 0)
+ fatal("kex_setup: %s", ssh_err(r));
+@@ -2602,6 +2647,13 @@ do_ssh2_kex(void)
+ # endif
+ #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 -pur old/sshd_config new/sshd_config
+--- old/sshd_config
++++ new/sshd_config
+@@ -82,8 +82,9 @@ AuthorizedKeysFile .ssh/authorized_keys
+ #KerberosGetAFSToken no
+
+ # GSSAPI options
+-#GSSAPIAuthentication no
++#GSSAPIAuthentication yes
+ #GSSAPICleanupCredentials yes
++#GSSAPIKeyExchange yes
+
+ # Set this to 'yes' to enable PAM authentication, account processing,
+ # and session processing. If this is enabled, PAM authentication will
+diff -pur old/sshd_config.5 new/sshd_config.5
+--- old/sshd_config.5
++++ new/sshd_config.5
+@@ -621,6 +621,12 @@ Specifies whether user authentication ba
+ The default on Solaris is
+ .Dq yes .
+ 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 on Solaris is
++.Dq yes .
++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.
+diff -pur old/sshkey.c new/sshkey.c
+--- old/sshkey.c
++++ new/sshkey.c
+@@ -112,6 +112,7 @@ static const struct keytype keytypes[] =
+ # endif /* OPENSSL_HAS_NISTP521 */
+ # endif /* OPENSSL_HAS_ECC */
+ #endif /* WITH_OPENSSL */
++ { "null", "null", KEY_NULL, 0, 0 },
+ { NULL, NULL, -1, -1, 0 }
+ };
+
+diff -pur old/sshkey.h new/sshkey.h
+--- old/sshkey.h
++++ new/sshkey.h
+@@ -62,6 +62,7 @@ enum sshkey_types {
+ KEY_DSA_CERT,
+ KEY_ECDSA_CERT,
+ KEY_ED25519_CERT,
++ KEY_NULL,
+ KEY_UNSPEC
+ };
+