X-Git-Url: http://andersk.mit.edu/gitweb/gssapi-openssh.git/blobdiff_plain/91d9cdd3ca06d1809bc05a285dafdea2954850b2..b5afdff53b51d529e596da3b4c2aa5ee14cc8b08:/openssh/sshconnect2.c

diff --git a/openssh/sshconnect2.c b/openssh/sshconnect2.c
index a762eec..4744e37 100644
--- a/openssh/sshconnect2.c
+++ b/openssh/sshconnect2.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshconnect2.c,v 1.170 2008/11/04 08:22:13 djm Exp $ */
+/* $OpenBSD: sshconnect2.c,v 1.171 2009/03/05 07:18:19 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  * Copyright (c) 2008 Damien Miller.  All rights reserved.
@@ -68,6 +68,7 @@
 #include "msg.h"
 #include "pathnames.h"
 #include "uidswap.h"
+#include "schnorr.h"
 #include "jpake.h"
 
 #ifdef GSSAPI
@@ -78,6 +79,22 @@
 extern char *client_version_string;
 extern char *server_version_string;
 extern Options options;
+extern Kex *xxx_kex;
+
+/* tty_flag is set in ssh.c. use this in ssh_userauth2 */
+/* if it is set then prevent the switch to the null cipher */
+
+extern int tty_flag;
+
+/* tty_flag is set in ssh.c. use this in ssh_userauth2 */
+/* if it is set then prevent the switch to the null cipher */
+
+extern int tty_flag;
+
+/* tty_flag is set in ssh.c. use this in ssh_userauth2 */
+/* if it is set then prevent the switch to the null cipher */
+
+extern int tty_flag;
 
 /*
  * SSH2 key exchange
@@ -104,9 +121,34 @@ ssh_kex2(char *host, struct sockaddr *hostaddr)
 {
 	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;
@@ -134,6 +176,17 @@ ssh_kex2(char *host, struct sockaddr *hostaddr)
 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
 		    options.hostkeyalgorithms;
 
+#ifdef GSSAPI
+	/* If we've got GSSAPI algorithms, then we also support the
+	 * 'null' hostkey, as a last resort */
+	if (options.gss_keyex && gss) {
+		orig = myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS];
+		xasprintf(&myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS], 
+		    "%s,null", orig);
+		xfree(gss);
+	}
+#endif
+
 	if (options.rekey_limit)
 		packet_set_rekey_limit((u_int32_t)options.rekey_limit);
 
@@ -143,10 +196,26 @@ ssh_kex2(char *host, struct sockaddr *hostaddr)
 	kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
 	kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
 	kex->kex[KEX_DH_GEX_SHA256] = kexgex_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;
+		kex->gss_host = gss_host;
+	}
+#endif
+
 	xxx_kex = kex;
 
 	dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
@@ -229,12 +298,16 @@ int	userauth_jpake(Authctxt *);
 void	userauth_jpake_cleanup(Authctxt *);
 
 #ifdef GSSAPI
+int	userauth_external(Authctxt *authctxt);
 int	userauth_gssapi(Authctxt *authctxt);
+int	userauth_gssapi_with_mic(Authctxt *authctxt);
+int	userauth_gssapi_without_mic(Authctxt *authctxt);
 void	input_gssapi_response(int type, u_int32_t, void *);
 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 *);
@@ -250,11 +323,26 @@ static char *authmethods_get(void);
 
 Authmethod authmethods[] = {
 #ifdef GSSAPI
+	{"gssapi-keyex",
+		userauth_gsskeyex,
+		NULL,
+		&options.gss_authentication,
+		NULL},
+	{"external-keyx",
+		userauth_external,
+		NULL,
+		&options.gss_authentication,
+		NULL},
 	{"gssapi-with-mic",
 		userauth_gssapi,
 		NULL,
 		&options.gss_authentication,
 		NULL},
+	{"gssapi",
+		userauth_gssapi,
+		NULL,
+		&options.gss_authentication,
+		NULL},
 #endif
 	{"hostbased",
 		userauth_hostbased,
@@ -350,6 +438,28 @@ ssh_userauth2(const char *local_user, const char *server_user, char *host,
 	pubkey_cleanup(&authctxt);
 	dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
 
+	/* if the user wants to use the none cipher do it */
+	/* post authentication and only if the right conditions are met */
+	/* both of the NONE commands must be true and there must be no */
+	/* tty allocated */
+	if ((options.none_switch == 1) && (options.none_enabled == 1)) 
+	{
+		if (!tty_flag) /* no null on tty sessions */
+		{
+			debug("Requesting none rekeying...");
+			myproposal[PROPOSAL_ENC_ALGS_STOC] = "none";
+			myproposal[PROPOSAL_ENC_ALGS_CTOS] = "none";
+			kex_prop2buf(&xxx_kex->my,myproposal);
+			packet_request_rekeying();
+			fprintf(stderr, "WARNING: ENABLED NONE CIPHER\n");
+		}
+		else
+		{
+			/* requested NONE cipher when in a tty */
+			debug("Cannot switch to NONE cipher with tty allocated");
+			fprintf(stderr, "NONE cipher switch disabled when a TTY is allocated\n");
+		}
+	}
 	debug("Authentication succeeded (%s).", authctxt.method->name);
 }
 
@@ -541,19 +651,34 @@ userauth_gssapi(Authctxt *authctxt)
 	static u_int mech = 0;
 	OM_uint32 min;
 	int ok = 0;
+	char *gss_host = NULL;
+
+	if (!options.gss_authentication) {
+		verbose("GSSAPI authentication disabled.");
+		return 0;
+	}
+
+	if (options.gss_trust_dns)
+		gss_host = (char *)get_canonical_hostname(1);
+	else
+		gss_host = (char *)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++;
@@ -617,7 +742,8 @@ process_gssapi_token(void *ctxt, gss_buffer_t recv_tok)
 
 	if (status == GSS_S_COMPLETE) {
 		/* send either complete or MIC, depending on mechanism */
-		if (!(flags & GSS_C_INTEG_FLAG)) {
+		if (strcmp(authctxt->method->name,"gssapi")==0 ||
+		    (!(flags & GSS_C_INTEG_FLAG))) {
 			packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
 			packet_send();
 		} else {
@@ -650,8 +776,8 @@ 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");
@@ -761,6 +887,106 @@ input_gssapi_error(int type, u_int32_t plen, void *ctxt)
 	xfree(msg);
 	xfree(lang);
 }
+
+#ifdef GSI
+extern
+const gss_OID_desc * const              gss_mech_globus_gssapi_openssl;
+#define is_gsi_oid(oid) \
+  (oid->length == gss_mech_globus_gssapi_openssl->length && \
+   (memcmp(oid->elements, gss_mech_globus_gssapi_openssl->elements, \
+	   oid->length) == 0))
+#endif
+
+int
+userauth_external(Authctxt *authctxt)
+{
+    static int attempt = 0;
+        
+    if (attempt++ >= 1)
+        return 0;
+                                
+	/* The client MUST NOT try this method if initial key exchange
+	   was not performed using a GSSAPI-based key exchange
+	   method. */
+	if (gss_kex_context == NULL) {
+		debug2("gsskex not performed, skipping external-keyx");
+		return 0;
+	}
+
+    debug2("userauth_external");
+    packet_start(SSH2_MSG_USERAUTH_REQUEST);
+#ifdef GSI
+    if (options.implicit && is_gsi_oid(gss_kex_context->oid)) {
+        packet_put_cstring("");
+	} else {
+#endif
+    packet_put_cstring(authctxt->server_user);
+#ifdef GSI
+	}
+#endif
+    packet_put_cstring(authctxt->service);
+    packet_put_cstring(authctxt->method->name);
+    packet_send();
+    packet_write_wait();
+    return 1;
+}                                                                                                
+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);
+	}
+
+#ifdef GSI
+    if (options.implicit && is_gsi_oid(gss_kex_context->oid)) {
+        ssh_gssapi_buildmic(&b, "", authctxt->service, "gssapi-keyex");
+	} else {
+#endif
+        ssh_gssapi_buildmic(&b, authctxt->server_user, authctxt->service,
+                            "gssapi-keyex");
+#ifdef GSI
+	}
+#endif
+
+	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);
+#ifdef GSI
+    if (options.implicit && is_gsi_oid(gss_kex_context->oid)) {
+        packet_put_cstring("");
+	} else {
+#endif
+	packet_put_cstring(authctxt->server_user);
+#ifdef GSI
+	}
+#endif
+	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