From cd404114ded78fc51d5d9cbd458d55c9b2f67daa Mon Sep 17 00:00:00 2001
From: Simon Wilkinson <simon@sxw.org.uk>
Date: Sun, 9 Feb 2014 16:09:48 +0000
Subject: GSSAPI key exchange support

This patch has been rejected upstream: "None of the OpenSSH developers are
in favour of adding this, and this situation has not changed for several
years.  This is not a slight on Simon's patch, which is of fine quality, but
just that a) we don't trust GSSAPI implementations that much and b) we don't
like adding new KEX since they are pre-auth attack surface.  This one is
particularly scary, since it requires hooks out to typically root-owned
system resources."

However, quite a lot of people rely on this in Debian, and it's better to
have it merged into the main openssh package rather than having separate
-krb5 packages (as we used to have).  It seems to have a generally good
security history.

Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1242
Last-Updated: 2014-02-10

Patch-Name: gssapi.patch
---
 servconf.c | 38 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 37 insertions(+), 1 deletion(-)

(limited to 'servconf.c')

diff --git a/servconf.c b/servconf.c
index 9bcd05bf2..29209e452 100644
--- a/servconf.c
+++ b/servconf.c
@@ -108,7 +108,10 @@ 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;
@@ -245,8 +248,14 @@ 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)
@@ -343,7 +352,9 @@ typedef enum {
 	sBanner, sUseDNS, sHostbasedAuthentication,
 	sHostbasedUsesNameFromPacketOnly, sClientAliveInterval,
 	sClientAliveCountMax, sAuthorizedKeysFile,
-	sGssAuthentication, sGssCleanupCreds, sAcceptEnv, sPermitTunnel,
+	sGssAuthentication, sGssCleanupCreds, sGssStrictAcceptor,
+	sGssKeyEx, sGssStoreRekey,
+	sAcceptEnv, sPermitTunnel,
 	sMatch, sPermitOpen, sForceCommand, sChrootDirectory,
 	sUsePrivilegeSeparation, sAllowAgentForwarding,
 	sZeroKnowledgePasswordAuthentication, sHostCertificate,
@@ -410,10 +421,20 @@ 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 },
@@ -1094,10 +1115,22 @@ 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;
@@ -2008,7 +2041,10 @@ dump_config(ServerOptions *o)
 #endif
 #ifdef GSSAPI
 	dump_cfg_fmtint(sGssAuthentication, o->gss_authentication);
+	dump_cfg_fmtint(sGssKeyEx, o->gss_keyex);
 	dump_cfg_fmtint(sGssCleanupCreds, o->gss_cleanup_creds);
+	dump_cfg_fmtint(sGssStrictAcceptor, o->gss_strict_acceptor);
+	dump_cfg_fmtint(sGssStoreRekey, o->gss_store_rekey);
 #endif
 #ifdef JPAKE
 	dump_cfg_fmtint(sZeroKnowledgePasswordAuthentication,
-- 
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