The attached patch is an updated version of the EAP-FAST specific
submission for OpenSSL 0.9.9. This fixes fallback to full TLS handshake
in case the server rejects PAC-Opaque from the client. This change
cleans up the modifications to ssl3_get_server_hello() that were
leftover from the old patch (that was made before TLS SessionTicket
support was added to OpenSSL). The new version uses the
ssl3_check_finished() function to allow the state machine to handle
PAC-Opaque -based abbreviated handshake.
I haven't received much comments on the EAP-FAST support from OpenSSL
developers, but I would really appreciate getting this type of
functionality included with OpenSSL in order to get rid of the need to
maintain an external patch for OpenSSL (the original patch was submitted
almost three years ago). Consequently, any comments on how to get this
(or something similar) merged into OpenSSL would be very helpful.
--
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).
diff -upr openssl-SNAP-20080415.orig/ssl/s3_clnt.c
openssl-SNAP-20080415/ssl/s3_clnt.c
--- openssl-SNAP-20080415.orig/ssl/s3_clnt.c 2008-01-06 00:00:33.000000000
+0200
+++ openssl-SNAP-20080415/ssl/s3_clnt.c 2008-04-15 16:58:39.000000000 +0300
@@ -785,6 +785,20 @@ 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)
{
diff -upr openssl-SNAP-20080415.orig/ssl/s3_srvr.c
openssl-SNAP-20080415/ssl/s3_srvr.c
--- openssl-SNAP-20080415.orig/ssl/s3_srvr.c 2007-10-26 16:00:29.000000000
+0300
+++ openssl-SNAP-20080415/ssl/s3_srvr.c 2008-04-15 16:32:08.000000000 +0300
@@ -992,6 +992,59 @@ 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);
+ }
+ }
#endif
/* Worst case, we will use the NULL compression, but if we have other
@@ -1118,16 +1171,22 @@ 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]);
diff -upr openssl-SNAP-20080415.orig/ssl/ssl.h openssl-SNAP-20080415/ssl/ssl.h
--- openssl-SNAP-20080415.orig/ssl/ssl.h 2007-10-27 03:01:28.000000000
+0300
+++ openssl-SNAP-20080415/ssl/ssl.h 2008-04-15 16:32:08.000000000 +0300
@@ -353,6 +353,7 @@ 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
@@ -379,6 +380,8 @@ 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
{
@@ -1121,6 +1124,13 @@ 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
@@ -1721,6 +1731,12 @@ 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.
@@ -1920,6 +1936,7 @@ 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
diff -upr openssl-SNAP-20080415.orig/ssl/ssl_err.c
openssl-SNAP-20080415/ssl/ssl_err.c
--- openssl-SNAP-20080415.orig/ssl/ssl_err.c 2007-10-27 03:01:29.000000000
+0300
+++ openssl-SNAP-20080415/ssl/ssl_err.c 2008-04-15 16:32:08.000000000 +0300
@@ -260,6 +260,7 @@ 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}
};
diff -upr openssl-SNAP-20080415.orig/ssl/ssl_sess.c
openssl-SNAP-20080415/ssl/ssl_sess.c
--- openssl-SNAP-20080415.orig/ssl/ssl_sess.c 2007-10-17 21:00:45.000000000
+0300
+++ openssl-SNAP-20080415/ssl/ssl_sess.c 2008-04-15 16:32:08.000000000
+0300
@@ -831,6 +831,52 @@ 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;
diff -upr openssl-SNAP-20080415.orig/ssl/t1_lib.c
openssl-SNAP-20080415/ssl/t1_lib.c
--- openssl-SNAP-20080415.orig/ssl/t1_lib.c 2008-03-17 00:00:10.000000000
+0200
+++ openssl-SNAP-20080415/ssl/t1_lib.c 2008-04-15 16:32:08.000000000 +0300
@@ -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)
@@ -1425,6 +1448,8 @@ int tls1_process_ticket(SSL *s, unsigned
s->tlsext_ticket_expected = 1;
return 0; /* Cache miss */
}
+ if (s->tls_session_secret_cb)
+ return 0;
return tls_decrypt_ticket(s, p, size, session_id, len,
ret);
}
diff -upr openssl-SNAP-20080415.orig/ssl/tls1.h openssl-SNAP-20080415/ssl/tls1.h
--- openssl-SNAP-20080415.orig/ssl/tls1.h 2007-09-27 01:01:39.000000000
+0300
+++ openssl-SNAP-20080415/ssl/tls1.h 2008-04-15 16:32:08.000000000 +0300
@@ -509,6 +509,14 @@ SSL_CTX_ctrl(ctx,SSL_CTRL_SET_TLSEXT_OPA
#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 -upr openssl-SNAP-20080415.orig/util/ssleay.num
openssl-SNAP-20080415/util/ssleay.num
--- openssl-SNAP-20080415.orig/util/ssleay.num 2007-08-31 16:03:14.000000000
+0300
+++ openssl-SNAP-20080415/util/ssleay.num 2008-04-15 16:32:08.000000000
+0300
@@ -253,3 +253,5 @@ PEM_write_bio_SSL_SESSION
PEM_read_SSL_SESSION 302 EXIST:!WIN16:FUNCTION:
PEM_read_bio_SSL_SESSION 303 EXIST::FUNCTION:
PEM_write_SSL_SESSION 304 EXIST:!WIN16:FUNCTION:
+SSL_set_hello_extension 305 EXIST::FUNCTION:TLSEXT
+SSL_set_session_secret_cb 306 EXIST::FUNCTION:TLSEXT
