This patch is adding support for TLS hello extensions and externally
generated pre-shared key material to OpenSSL 0.9.8. This is
based on the patch from Alexey Kobozev <akobozev@cisco.com>
(sent to openssl-dev mailing list on Tue, 07 Jun 2005 15:40:58 +0300).


diff -uprN openssl-0.9.8.orig/include/openssl/ssl.h openssl-0.9.8/include/openssl/ssl.h
--- openssl-0.9.8.orig/include/openssl/ssl.h	2005-06-10 12:51:16.000000000 -0700
+++ openssl-0.9.8/include/openssl/ssl.h	2005-07-19 20:02:15.000000000 -0700
@@ -340,6 +340,7 @@ extern "C" {
  * 'struct ssl_st *' function parameters used to prototype callbacks
  * in SSL_CTX. */
 typedef struct ssl_st *ssl_crock_st;
+typedef struct tls_extension_st TLS_EXTENSION;
 
 /* used to hold info on the particular ciphers used */
 typedef struct ssl_cipher_st
@@ -361,6 +362,8 @@ DECLARE_STACK_OF(SSL_CIPHER)
 typedef struct ssl_st SSL;
 typedef struct ssl_ctx_st SSL_CTX;
 
+typedef int (*tls_session_secret_cb_fn)(SSL *s, void *secret, int *secret_len, STACK_OF(SSL_CIPHER) *peer_ciphers, SSL_CIPHER **cipher, void *arg);
+
 /* Used to hold functions for SSLv2 or SSLv3/TLSv1 functions */
 typedef struct ssl_method_st
 	{
@@ -968,6 +971,15 @@ struct ssl_st
 	int first_packet;
 	int client_version;	/* what was passed, used for
 				 * SSLv3/TLS rollback check */
+
+	/* TLS externsions */
+	TLS_EXTENSION *tls_extension;
+	int (*tls_extension_cb)(SSL *s, TLS_EXTENSION *tls_ext, void *arg);
+	void *tls_extension_cb_arg;
+
+	/* TLS pre-shared secret session resumption */
+	tls_session_secret_cb_fn tls_session_secret_cb;
+	void *tls_session_secret_cb_arg;
 	};
 
 #ifdef __cplusplus
@@ -1533,6 +1545,13 @@ void *SSL_COMP_get_compression_methods(v
 int SSL_COMP_add_compression_method(int id,void *cm);
 #endif
 
+/* TLS extensions functions */
+int SSL_set_hello_extension(SSL *s, int ext_type, void *ext_data, int ext_len);
+int SSL_set_hello_extension_cb(SSL *s, int (*cb)(SSL *, TLS_EXTENSION *, void *), void *arg);
+
+/* Pre-shared secret session resumption functions */
+int SSL_set_session_secret_cb(SSL *s, tls_session_secret_cb_fn tls_session_secret_cb, void *arg);
+
 /* BEGIN ERROR CODES */
 /* The following lines are auto generated by the script mkerr.pl. Any changes
  * made after this point may be overwritten when the script is next run.
@@ -1714,6 +1733,7 @@ void ERR_load_SSL_strings(void);
 #define SSL_F_TLS1_ENC					 210
 #define SSL_F_TLS1_SETUP_KEY_BLOCK			 211
 #define SSL_F_WRITE_PENDING				 212
+#define SSL_F_SSL_SET_HELLO_EXTENSION	 213
 
 /* Reason codes. */
 #define SSL_R_APP_DATA_IN_HANDSHAKE			 100
diff -uprN openssl-0.9.8.orig/include/openssl/tls1.h openssl-0.9.8/include/openssl/tls1.h
--- openssl-0.9.8.orig/include/openssl/tls1.h	2003-07-22 05:34:21.000000000 -0700
+++ openssl-0.9.8/include/openssl/tls1.h	2005-07-19 20:02:15.000000000 -0700
@@ -282,6 +282,14 @@ extern "C" {
 #define TLS_MD_MASTER_SECRET_CONST    "\x6d\x61\x73\x74\x65\x72\x20\x73\x65\x63\x72\x65\x74"  /*master secret*/
 #endif
 
+/* TLS extension struct */
+struct tls_extension_st
+{
+	unsigned short type;
+	unsigned short length;
+	void *data;
+};
+
 #ifdef  __cplusplus
 }
 #endif
diff -uprN openssl-0.9.8.orig/ssl/Makefile openssl-0.9.8/ssl/Makefile
--- openssl-0.9.8.orig/ssl/Makefile	2005-05-30 16:20:30.000000000 -0700
+++ openssl-0.9.8/ssl/Makefile	2005-07-19 20:02:15.000000000 -0700
@@ -24,7 +24,7 @@ LIBSRC=	\
 	s2_meth.c   s2_srvr.c s2_clnt.c  s2_lib.c  s2_enc.c s2_pkt.c \
 	s3_meth.c   s3_srvr.c s3_clnt.c  s3_lib.c  s3_enc.c s3_pkt.c s3_both.c \
 	s23_meth.c s23_srvr.c s23_clnt.c s23_lib.c          s23_pkt.c \
-	t1_meth.c   t1_srvr.c t1_clnt.c  t1_lib.c  t1_enc.c \
+	t1_meth.c   t1_srvr.c t1_clnt.c  t1_lib.c  t1_enc.c                    t1_ext.c \
 	d1_meth.c   d1_srvr.c d1_clnt.c  d1_lib.c  d1_pkt.c \
 	d1_both.c d1_enc.c \
 	ssl_lib.c ssl_err2.c ssl_cert.c ssl_sess.c \
@@ -35,7 +35,7 @@ LIBOBJ= \
 	s2_meth.o  s2_srvr.o  s2_clnt.o  s2_lib.o  s2_enc.o s2_pkt.o \
 	s3_meth.o  s3_srvr.o  s3_clnt.o  s3_lib.o  s3_enc.o s3_pkt.o s3_both.o \
 	s23_meth.o s23_srvr.o s23_clnt.o s23_lib.o          s23_pkt.o \
-	t1_meth.o   t1_srvr.o t1_clnt.o  t1_lib.o  t1_enc.o \
+	t1_meth.o   t1_srvr.o t1_clnt.o  t1_lib.o  t1_enc.o                    t1_ext.o \
 	d1_meth.o   d1_srvr.o d1_clnt.o  d1_lib.o  d1_pkt.o \
 	d1_both.o d1_enc.o \
 	ssl_lib.o ssl_err2.o ssl_cert.o ssl_sess.o \
@@ -968,3 +968,4 @@ t1_srvr.o: ../include/openssl/ssl23.h ..
 t1_srvr.o: ../include/openssl/stack.h ../include/openssl/symhacks.h
 t1_srvr.o: ../include/openssl/tls1.h ../include/openssl/x509.h
 t1_srvr.o: ../include/openssl/x509_vfy.h ssl_locl.h t1_srvr.c
+t1_ext.o: t1_ext.c ssl_locl.h
diff -uprN openssl-0.9.8.orig/ssl/s3_clnt.c openssl-0.9.8/ssl/s3_clnt.c
--- openssl-0.9.8.orig/ssl/s3_clnt.c	2005-05-16 03:11:03.000000000 -0700
+++ openssl-0.9.8/ssl/s3_clnt.c	2005-07-19 20:02:15.000000000 -0700
@@ -606,6 +606,20 @@ int ssl3_client_hello(SSL *s)
 			}
 		*(p++)=0; /* Add the NULL method */
 		
+		/* send client hello extensions if any */
+		if (s->version >= TLS1_VERSION && s->tls_extension)
+		{
+			// set the total extensions length
+			s2n(s->tls_extension->length + 4, p);
+
+			// put the extensions with type and length
+			s2n(s->tls_extension->type, p);
+			s2n(s->tls_extension->length, p);
+			
+			memcpy(p, s->tls_extension->data, s->tls_extension->length);
+			p+=s->tls_extension->length;
+		}
+
 		l=(p-d);
 		d=buf;
 		*(d++)=SSL3_MT_CLIENT_HELLO;
@@ -628,7 +642,7 @@ int ssl3_get_server_hello(SSL *s)
 	STACK_OF(SSL_CIPHER) *sk;
 	SSL_CIPHER *c;
 	unsigned char *p,*d;
-	int i,al,ok;
+	int i,al,ok,pre_shared;
 	unsigned int j;
 	long n;
 	SSL_COMP *comp;
@@ -693,7 +707,24 @@ int ssl3_get_server_hello(SSL *s)
 		goto f_err;
 		}
 
-	if (j != 0 && j == s->session->session_id_length
+	/* check if we want to resume the session based on external pre-shared secret */
+	pre_shared = 0;
+	if (s->version >= TLS1_VERSION && s->tls_session_secret_cb)
+	{
+		SSL_CIPHER *pref_cipher=NULL;
+		s->session->master_key_length=sizeof(s->session->master_key);
+		if (s->tls_session_secret_cb(s, s->session->master_key, &s->session->master_key_length,
+			NULL, &pref_cipher, s->tls_session_secret_cb_arg))
+		{
+			s->hit=1;
+			s->session->cipher=pref_cipher ? pref_cipher : ssl_get_cipher_by_char(s,p+j);
+			s->session->session_id_length = j;
+			memcpy(s->session->session_id, p, j);
+			pre_shared = 1;
+		}
+	}
+
+	if ((pre_shared || j != 0) && j == s->session->session_id_length
 	    && memcmp(p,s->session->session_id,j) == 0)
 	    {
 	    if(s->sid_ctx_length != s->session->sid_ctx_length
diff -uprN openssl-0.9.8.orig/ssl/s3_srvr.c openssl-0.9.8/ssl/s3_srvr.c
--- openssl-0.9.8.orig/ssl/s3_srvr.c	2005-05-22 17:32:55.000000000 -0700
+++ openssl-0.9.8/ssl/s3_srvr.c	2005-07-19 20:02:15.000000000 -0700
@@ -955,6 +955,75 @@ int ssl3_get_client_hello(SSL *s)
 		}
 #endif
 
+	/* Check for TLS client hello extension here */
+	if (p < (d+n) && s->version >= TLS1_VERSION)
+	{
+		if (s->tls_extension_cb)
+		{
+			TLS_EXTENSION tls_ext;
+			unsigned short ext_total_len;
+			
+			n2s(p, ext_total_len);
+			n2s(p, tls_ext.type);
+			n2s(p, tls_ext.length);
+
+			// sanity check in TLS extension len
+			if (tls_ext.length > (d+n) - p)
+			{
+				// just cut the lenth to packet border
+				tls_ext.length = (d+n) - p;
+			}
+
+			tls_ext.data = p;
+
+			// returns an alert code or 0
+			al = s->tls_extension_cb(s, &tls_ext, s->tls_extension_cb_arg);
+			if (al != 0)
+			{
+				SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO,SSL_R_PEER_ERROR);
+				goto f_err;
+			}
+		}
+	}
+
+	/* Check if we want to use external pre-shared secret for this handshake */
+	/* for not reused session only */
+	if (!s->hit && s->version >= TLS1_VERSION && s->tls_session_secret_cb)
+	{
+		SSL_CIPHER *pref_cipher=NULL;
+
+		s->session->master_key_length=sizeof(s->session->master_key);
+		if(s->tls_session_secret_cb(s, s->session->master_key, &s->session->master_key_length, 
+			ciphers, &pref_cipher, s->tls_session_secret_cb_arg))
+		{
+			s->hit=1;
+			s->session->ciphers=ciphers;
+			s->session->verify_result=X509_V_OK;
+			
+			ciphers=NULL;
+			
+			/* check if some cipher was preferred by call back */
+			pref_cipher=pref_cipher ? pref_cipher : ssl3_choose_cipher(s, s->session->ciphers, SSL_get_ciphers(s));
+			if (pref_cipher == NULL)
+				{
+				al=SSL_AD_HANDSHAKE_FAILURE;
+				SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO,SSL_R_NO_SHARED_CIPHER);
+				goto f_err;
+				}
+
+			s->session->cipher=pref_cipher;
+
+			if (s->cipher_list)
+				sk_SSL_CIPHER_free(s->cipher_list);
+
+			if (s->cipher_list_by_id)
+				sk_SSL_CIPHER_free(s->cipher_list_by_id);
+
+			s->cipher_list = sk_SSL_CIPHER_dup(s->session->ciphers);
+			s->cipher_list_by_id = sk_SSL_CIPHER_dup(s->session->ciphers);
+		}
+	}
+
 	/* Given s->session->ciphers and SSL_get_ciphers, we must
 	 * pick a cipher */
 
diff -uprN openssl-0.9.8.orig/ssl/ssl_err.c openssl-0.9.8/ssl/ssl_err.c
--- openssl-0.9.8.orig/ssl/ssl_err.c	2005-06-10 12:51:16.000000000 -0700
+++ openssl-0.9.8/ssl/ssl_err.c	2005-07-19 20:02:15.000000000 -0700
@@ -242,6 +242,7 @@ static ERR_STRING_DATA SSL_str_functs[]=
 {ERR_FUNC(SSL_F_TLS1_ENC),	"TLS1_ENC"},
 {ERR_FUNC(SSL_F_TLS1_SETUP_KEY_BLOCK),	"TLS1_SETUP_KEY_BLOCK"},
 {ERR_FUNC(SSL_F_WRITE_PENDING),	"WRITE_PENDING"},
+{ERR_FUNC(SSL_F_SSL_SET_HELLO_EXTENSION), "SSL_set_hello_extension"},
 {0,NULL}
 	};
 
diff -uprN openssl-0.9.8.orig/ssl/ssl.h openssl-0.9.8/ssl/ssl.h
--- openssl-0.9.8.orig/ssl/ssl.h	2005-06-10 12:51:16.000000000 -0700
+++ openssl-0.9.8/ssl/ssl.h	2005-07-19 20:02:15.000000000 -0700
@@ -340,6 +340,7 @@ extern "C" {
  * 'struct ssl_st *' function parameters used to prototype callbacks
  * in SSL_CTX. */
 typedef struct ssl_st *ssl_crock_st;
+typedef struct tls_extension_st TLS_EXTENSION;
 
 /* used to hold info on the particular ciphers used */
 typedef struct ssl_cipher_st
@@ -361,6 +362,8 @@ DECLARE_STACK_OF(SSL_CIPHER)
 typedef struct ssl_st SSL;
 typedef struct ssl_ctx_st SSL_CTX;
 
+typedef int (*tls_session_secret_cb_fn)(SSL *s, void *secret, int *secret_len, STACK_OF(SSL_CIPHER) *peer_ciphers, SSL_CIPHER **cipher, void *arg);
+
 /* Used to hold functions for SSLv2 or SSLv3/TLSv1 functions */
 typedef struct ssl_method_st
 	{
@@ -968,6 +971,15 @@ struct ssl_st
 	int first_packet;
 	int client_version;	/* what was passed, used for
 				 * SSLv3/TLS rollback check */
+
+	/* TLS externsions */
+	TLS_EXTENSION *tls_extension;
+	int (*tls_extension_cb)(SSL *s, TLS_EXTENSION *tls_ext, void *arg);
+	void *tls_extension_cb_arg;
+
+	/* TLS pre-shared secret session resumption */
+	tls_session_secret_cb_fn tls_session_secret_cb;
+	void *tls_session_secret_cb_arg;
 	};
 
 #ifdef __cplusplus
@@ -1533,6 +1545,13 @@ void *SSL_COMP_get_compression_methods(v
 int SSL_COMP_add_compression_method(int id,void *cm);
 #endif
 
+/* TLS extensions functions */
+int SSL_set_hello_extension(SSL *s, int ext_type, void *ext_data, int ext_len);
+int SSL_set_hello_extension_cb(SSL *s, int (*cb)(SSL *, TLS_EXTENSION *, void *), void *arg);
+
+/* Pre-shared secret session resumption functions */
+int SSL_set_session_secret_cb(SSL *s, tls_session_secret_cb_fn tls_session_secret_cb, void *arg);
+
 /* BEGIN ERROR CODES */
 /* The following lines are auto generated by the script mkerr.pl. Any changes
  * made after this point may be overwritten when the script is next run.
@@ -1714,6 +1733,7 @@ void ERR_load_SSL_strings(void);
 #define SSL_F_TLS1_ENC					 210
 #define SSL_F_TLS1_SETUP_KEY_BLOCK			 211
 #define SSL_F_WRITE_PENDING				 212
+#define SSL_F_SSL_SET_HELLO_EXTENSION	 213
 
 /* Reason codes. */
 #define SSL_R_APP_DATA_IN_HANDSHAKE			 100
diff -uprN openssl-0.9.8.orig/ssl/ssl_sess.c openssl-0.9.8/ssl/ssl_sess.c
--- openssl-0.9.8.orig/ssl/ssl_sess.c	2005-04-29 13:10:06.000000000 -0700
+++ openssl-0.9.8/ssl/ssl_sess.c	2005-07-19 20:02:15.000000000 -0700
@@ -656,6 +656,15 @@ long SSL_CTX_get_timeout(const SSL_CTX *
 	return(s->session_timeout);
 	}
 
+int SSL_set_session_secret_cb(SSL *s, int (*tls_session_secret_cb)(SSL *s, void *secret, int *secret_len, 
+	STACK_OF(SSL_CIPHER) *peer_ciphers, SSL_CIPHER **cipher, void *arg), void *arg)
+{
+	if (s == NULL) return(0);
+	s->tls_session_secret_cb = tls_session_secret_cb;
+	s->tls_session_secret_cb_arg = arg;
+	return(1);
+}
+
 typedef struct timeout_param_st
 	{
 	SSL_CTX *ctx;
diff -uprN openssl-0.9.8.orig/ssl/t1_ext.c openssl-0.9.8/ssl/t1_ext.c
--- openssl-0.9.8.orig/ssl/t1_ext.c	1969-12-31 16:00:00.000000000 -0800
+++ openssl-0.9.8/ssl/t1_ext.c	2005-07-19 20:03:29.000000000 -0700
@@ -0,0 +1,48 @@
+
+#include <stdio.h>
+#include "ssl_locl.h"
+
+
+int SSL_set_hello_extension(SSL *s, int ext_type, void *ext_data, int ext_len)
+{
+	if(s->version >= TLS1_VERSION)
+	{
+		if(s->tls_extension)
+		{
+			OPENSSL_free(s->tls_extension);
+			s->tls_extension = NULL;
+		}
+
+		if(ext_data)
+		{
+			s->tls_extension = OPENSSL_malloc(sizeof(TLS_EXTENSION) + ext_len);
+			if(!s->tls_extension)
+			{
+				SSLerr(SSL_F_SSL_SET_HELLO_EXTENSION, ERR_R_MALLOC_FAILURE);
+				return 0;
+			}
+
+			s->tls_extension->type = ext_type;
+			s->tls_extension->length = ext_len;
+			s->tls_extension->data = s->tls_extension + 1;
+			memcpy(s->tls_extension->data, ext_data, ext_len);
+		}
+
+		return 1;
+	}
+
+	return 0;
+}
+
+int SSL_set_hello_extension_cb(SSL *s, int (*cb)(SSL *, TLS_EXTENSION *, void *), void *arg)
+{
+	if(s->version >= TLS1_VERSION)
+	{
+		s->tls_extension_cb = cb;
+		s->tls_extension_cb_arg = arg;
+
+		return 1;
+	}
+
+	return 0;
+}
diff -uprN openssl-0.9.8.orig/ssl/t1_lib.c openssl-0.9.8/ssl/t1_lib.c
--- openssl-0.9.8.orig/ssl/t1_lib.c	2005-04-26 09:02:40.000000000 -0700
+++ openssl-0.9.8/ssl/t1_lib.c	2005-07-19 20:02:15.000000000 -0700
@@ -131,6 +131,10 @@ int tls1_new(SSL *s)
 
 void tls1_free(SSL *s)
 	{
+	if(s->tls_extension)
+	{
+		OPENSSL_free(s->tls_extension);
+	}
 	ssl3_free(s);
 	}
 
diff -uprN openssl-0.9.8.orig/ssl/tls1.h openssl-0.9.8/ssl/tls1.h
--- openssl-0.9.8.orig/ssl/tls1.h	2003-07-22 05:34:21.000000000 -0700
+++ openssl-0.9.8/ssl/tls1.h	2005-07-19 20:02:15.000000000 -0700
@@ -282,6 +282,14 @@ extern "C" {
 #define TLS_MD_MASTER_SECRET_CONST    "\x6d\x61\x73\x74\x65\x72\x20\x73\x65\x63\x72\x65\x74"  /*master secret*/
 #endif
 
+/* TLS extension struct */
+struct tls_extension_st
+{
+	unsigned short type;
+	unsigned short length;
+	void *data;
+};
+
 #ifdef  __cplusplus
 }
 #endif
diff -uprN openssl-0.9.8.orig/util/ssleay.num openssl-0.9.8/util/ssleay.num
--- openssl-0.9.8.orig/util/ssleay.num	2005-05-08 17:22:02.000000000 -0700
+++ openssl-0.9.8/util/ssleay.num	2005-07-19 20:02:15.000000000 -0700
@@ -226,3 +226,6 @@ DTLSv1_server_method                    
 SSL_COMP_get_compression_methods        276	EXIST:!VMS:FUNCTION:COMP
 SSL_COMP_get_compress_methods           276	EXIST:VMS:FUNCTION:COMP
 SSL_SESSION_get_id                      277	EXIST::FUNCTION:
+SSL_set_hello_extension			278	EXIST::FUNCTION:
+SSL_set_hello_extension_cb		279	EXIST::FUNCTION:
+SSL_set_session_secret_cb		280	EXIST::FUNCTION: