The attached patch is an updated version of the EAP-FAST (RFC 4851)
specific changes to TLS SessionTicket (RFC 5077) processing. This
updates the patch to work with the current 0.9.9 snapshots.
The original patch for making it possible to use OpenSSL for EAP-FAST
implementation was posted more than three years ago. So far, there has
been next to no comments from the OpenSSL team on the changes. I would
really appreciate getting some feedback on the proposed changes and
feasibility of finally getting them included into the OpenSSL releases.
Maintaining an external patch for a standard system component makes it
much harder for users and distributions to handle the current situation
if they need EAP-FAST support. Getting the changes, or something else
providing similar functionality, included in the OpenSSL would be very
helpful in avoiding these issues. Any advice on how to contribute to
OpenSSL development as someone outside the core development team would
also be appreciated if no one in the core team is interested in looking
into this or providing comments.
--
Jouni Malinen PGP id EFC895FA
This patch adds support for TLS SessionTicket extension (RFC 5077) for
the parts used by EAP-FAST (RFC 4851).
This is based on the patch from Alexey Kobozev <[EMAIL PROTECTED]>
(sent to openssl-dev mailing list on Tue, 07 Jun 2005 15:40:58 +0300).
Index: openssl-SNAP-20080822/ssl/s3_clnt.c
===================================================================
--- openssl-SNAP-20080822.orig/ssl/s3_clnt.c
+++ openssl-SNAP-20080822/ssl/s3_clnt.c
@@ -788,6 +788,20 @@ int ssl3_get_server_hello(SSL *s)
goto f_err;
}
+#ifndef OPENSSL_NO_TLSEXT
+ /* check if we want to resume the session based on external pre-shared
secret */
+ 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->session->cipher=pref_cipher ? pref_cipher :
ssl_get_cipher_by_char(s,p+j);
+ }
+ }
+#endif /* OPENSSL_NO_TLSEXT */
+
if (j != 0 && j == s->session->session_id_length
&& memcmp(p,s->session->session_id,j) == 0)
{
@@ -2927,11 +2941,8 @@ static int ssl3_check_finished(SSL *s)
{
int ok;
long n;
- /* If we have no ticket or session ID is non-zero length (a match of
- * a non-zero session length would never reach here) it cannot be a
- * resumed session.
- */
- if (!s->session->tlsext_tick || s->session->session_id_length)
+ /* If we have no ticket it cannot be a resumed session. */
+ if (!s->session->tlsext_tick)
return 1;
/* this function is called when we really expect a Certificate
* message, so permit appropriate message length */
Index: openssl-SNAP-20080822/ssl/s3_srvr.c
===================================================================
--- openssl-SNAP-20080822.orig/ssl/s3_srvr.c
+++ openssl-SNAP-20080822/ssl/s3_srvr.c
@@ -1004,6 +1004,61 @@ int ssl3_get_client_hello(SSL *s)
SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO,SSL_R_CLIENTHELLO_TLSEXT);
goto err;
}
+
+ /* Check if we want to use external pre-shared secret for this
+ * handshake for not reused session only. We need to generate
+ * server_random before calling tls_session_secret_cb in order to allow
+ * SessionTicket processing to use it in key derivation. */
+ {
+ unsigned long Time;
+ unsigned char *pos;
+ Time=(unsigned long)time(NULL); /* Time */
+ pos=s->s3->server_random;
+ l2n(Time,pos);
+ if (RAND_pseudo_bytes(pos,SSL3_RANDOM_SIZE-4) <= 0)
+ {
+ al=SSL_AD_INTERNAL_ERROR;
+ goto f_err;
+ }
+ }
+
+ 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);
+ s->s3->tmp.new_cipher = pref_cipher;
+ ssl3_digest_cached_records(s);
+ }
+ }
#endif
/* Worst case, we will use the NULL compression, but if we have other
@@ -1130,16 +1185,22 @@ int ssl3_send_server_hello(SSL *s)
unsigned char *buf;
unsigned char *p,*d;
int i,sl;
- unsigned long l,Time;
+ unsigned long l;
+#ifdef OPENSSL_NO_TLSEXT
+ unsigned long Time;
+#endif
if (s->state == SSL3_ST_SW_SRVR_HELLO_A)
{
buf=(unsigned char *)s->init_buf->data;
+#ifdef OPENSSL_NO_TLSEXT
p=s->s3->server_random;
+ /* Generate server_random if it was not needed previously */
Time=(unsigned long)time(NULL); /* Time */
l2n(Time,p);
if (RAND_pseudo_bytes(p,SSL3_RANDOM_SIZE-4) <= 0)
return -1;
+#endif
/* Do the message type and length last */
d=p= &(buf[4]);
Index: openssl-SNAP-20080822/ssl/ssl_err.c
===================================================================
--- openssl-SNAP-20080822.orig/ssl/ssl_err.c
+++ openssl-SNAP-20080822/ssl/ssl_err.c
@@ -263,6 +263,7 @@ static ERR_STRING_DATA SSL_str_functs[]=
{ERR_FUNC(SSL_F_TLS1_PRF), "tls1_prf"},
{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}
};
Index: openssl-SNAP-20080822/ssl/ssl.h
===================================================================
--- openssl-SNAP-20080822.orig/ssl/ssl.h
+++ openssl-SNAP-20080822/ssl/ssl.h
@@ -354,6 +354,7 @@ 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
@@ -377,6 +378,8 @@ typedef struct ssl_cipher_st
DECLARE_STACK_OF(SSL_CIPHER)
+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
{
@@ -1144,6 +1147,13 @@ struct ssl_st
void *tlsext_opaque_prf_input;
size_t tlsext_opaque_prf_input_len;
+ /* TLS extensions */
+ TLS_EXTENSION *tls_extension;
+
+ /* TLS pre-shared secret session resumption */
+ tls_session_secret_cb_fn tls_session_secret_cb;
+ void *tls_session_secret_cb_arg;
+
SSL_CTX * initial_ctx; /* initial ctx, used to store sessions */
#define session_ctx initial_ctx
#else
@@ -1745,6 +1755,12 @@ 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);
+
+/* 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.
@@ -1947,6 +1963,7 @@ void ERR_load_SSL_strings(void);
#define SSL_F_TLS1_PRF 284
#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
Index: openssl-SNAP-20080822/ssl/ssl_sess.c
===================================================================
--- openssl-SNAP-20080822.orig/ssl/ssl_sess.c
+++ openssl-SNAP-20080822/ssl/ssl_sess.c
@@ -834,6 +834,52 @@ long SSL_CTX_get_timeout(const SSL_CTX *
return(s->session_timeout);
}
+#ifndef OPENSSL_NO_TLSEXT
+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);
+}
+
+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;
+ }
+
+ 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;
+
+ if(ext_data)
+ {
+ s->tls_extension->length = ext_len;
+ s->tls_extension->data = s->tls_extension + 1;
+ memcpy(s->tls_extension->data, ext_data, ext_len);
+ } else {
+ s->tls_extension->length = 0;
+ s->tls_extension->data = NULL;
+ }
+
+ return 1;
+ }
+
+ return 0;
+}
+#endif /* OPENSSL_NO_TLSEXT */
+
typedef struct timeout_param_st
{
SSL_CTX *ctx;
Index: openssl-SNAP-20080822/ssl/t1_lib.c
===================================================================
--- openssl-SNAP-20080822.orig/ssl/t1_lib.c
+++ openssl-SNAP-20080822/ssl/t1_lib.c
@@ -154,6 +154,12 @@ int tls1_new(SSL *s)
void tls1_free(SSL *s)
{
+#ifndef OPENSSL_NO_TLSEXT
+ if(s->tls_extension)
+ {
+ OPENSSL_free(s->tls_extension);
+ }
+#endif
ssl3_free(s);
}
@@ -357,8 +363,24 @@ unsigned char *ssl_add_clienthello_tlsex
int ticklen;
if (s->session && s->session->tlsext_tick)
ticklen = s->session->tlsext_ticklen;
+ else if (s->session && s->tls_extension &&
+ s->tls_extension->type == TLSEXT_TYPE_session_ticket &&
+ s->tls_extension->data)
+ {
+ ticklen = s->tls_extension->length;
+ s->session->tlsext_tick = OPENSSL_malloc(ticklen);
+ if (!s->session->tlsext_tick)
+ return NULL;
+ memcpy(s->session->tlsext_tick, s->tls_extension->data,
+ ticklen);
+ s->session->tlsext_ticklen = ticklen;
+ }
else
ticklen = 0;
+ if (ticklen == 0 && s->tls_extension &&
+ s->tls_extension->type == TLSEXT_TYPE_session_ticket &&
+ s->tls_extension->data == NULL)
+ goto skip_ext;
/* Check for enough room 2 for extension type, 2 for len
* rest for ticket
*/
@@ -371,6 +393,7 @@ unsigned char *ssl_add_clienthello_tlsex
ret += ticklen;
}
}
+ skip_ext:
#ifdef TLSEXT_TYPE_opaque_prf_input
if (s->s3->client_opaque_prf_input != NULL)
@@ -1428,6 +1451,15 @@ int tls1_process_ticket(SSL *s, unsigned
s->tlsext_ticket_expected = 1;
return 0; /* Cache miss */
}
+ if (s->tls_session_secret_cb)
+ {
+ /* Indicate cache miss here and instead of
+ * generating the session from ticket now,
+ * trigger abbreviated handshake based on
+ * external mechanism to calculate the master
+ * secret later. */
+ return 0;
+ }
return tls_decrypt_ticket(s, p, size, session_id, len,
ret);
}
Index: openssl-SNAP-20080822/ssl/tls1.h
===================================================================
--- openssl-SNAP-20080822.orig/ssl/tls1.h
+++ openssl-SNAP-20080822/ssl/tls1.h
@@ -512,6 +512,14 @@ SSL_CTX_callback_ctrl(ssl,SSL_CTRL_SET_T
#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
Index: openssl-SNAP-20080822/util/ssleay.num
===================================================================
--- openssl-SNAP-20080822.orig/util/ssleay.num
+++ openssl-SNAP-20080822/util/ssleay.num
@@ -254,3 +254,5 @@ PEM_read_bio_SSL_SESSION
SSL_CTX_set_psk_server_callback 303 EXIST::FUNCTION:PSK
SSL_get_psk_identity 304 EXIST::FUNCTION:PSK
PEM_write_SSL_SESSION 305 EXIST:!WIN16:FUNCTION:
+SSL_set_hello_extension 306 EXIST::FUNCTION:TLSEXT
+SSL_set_session_secret_cb 307 EXIST::FUNCTION:TLSEXT
