fragattacks/patches/openssl-0.9.8g-tls-extensions.patch
Jouni Malinen fe2b7dda02 Fixed fallback to full handshake when server rejects PAC-Opaque
The TLS client changes in ssl3_get_server_hello() were based on the
pre-RFC 5077 version of OpenSSL and they hardcoded s->hit to 1 in case
PAC-Opaque was used. This prevented fallback to full TLS handshake in case
the server rejected PAC-Opaque in ClientHello. The fixed version simplifies
ssl3_get_server_hello() and uses the new RFC 5077 functionality in OpenSSL
(ssl3_check_finished) to allow the state machine handle start of
abbreviated handshake based on the used ticket.
2008-04-15 17:24:06 +03:00

331 lines
11 KiB
Diff

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 <akobozev@cisco.com>
(sent to openssl-dev mailing list on Tue, 07 Jun 2005 15:40:58 +0300).
OpenSSL 0.9.8g does not enable TLS extension support by default, so it
will need to be enabled by adding enable-tlsext to config script
command line.
diff -upr openssl-0.9.8g.orig/ssl/s3_clnt.c openssl-0.9.8g/ssl/s3_clnt.c
--- openssl-0.9.8g.orig/ssl/s3_clnt.c 2007-08-31 03:28:51.000000000 +0300
+++ openssl-0.9.8g/ssl/s3_clnt.c 2008-04-15 17:11:46.000000000 +0300
@@ -727,6 +727,20 @@ 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-0.9.8g.orig/ssl/s3_srvr.c openssl-0.9.8g/ssl/s3_srvr.c
--- openssl-0.9.8g.orig/ssl/s3_srvr.c 2007-09-30 21:55:59.000000000 +0300
+++ openssl-0.9.8g/ssl/s3_srvr.c 2008-04-15 17:10:37.000000000 +0300
@@ -928,6 +928,59 @@ 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
* options, we will now look for them. We have i-1 compression
@@ -1066,16 +1119,22 @@ 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-0.9.8g.orig/ssl/ssl.h openssl-0.9.8g/ssl/ssl.h
--- openssl-0.9.8g.orig/ssl/ssl.h 2007-10-19 10:42:38.000000000 +0300
+++ openssl-0.9.8g/ssl/ssl.h 2008-04-15 17:10:37.000000000 +0300
@@ -342,6 +342,7 @@ 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
@@ -363,6 +364,8 @@ 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
{
@@ -1004,6 +1007,14 @@ struct ssl_st
*/
/* RFC4507 session ticket expected to be received or sent */
int tlsext_ticket_expected;
+
+ /* 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
@@ -1589,6 +1600,12 @@ 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.
@@ -1778,6 +1795,7 @@ 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 -upr openssl-0.9.8g.orig/ssl/ssl_err.c openssl-0.9.8g/ssl/ssl_err.c
--- openssl-0.9.8g.orig/ssl/ssl_err.c 2007-10-11 17:36:59.000000000 +0300
+++ openssl-0.9.8g/ssl/ssl_err.c 2008-04-15 17:10:37.000000000 +0300
@@ -250,6 +250,7 @@ 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 -upr openssl-0.9.8g.orig/ssl/ssl_sess.c openssl-0.9.8g/ssl/ssl_sess.c
--- openssl-0.9.8g.orig/ssl/ssl_sess.c 2007-10-19 10:36:34.000000000 +0300
+++ openssl-0.9.8g/ssl/ssl_sess.c 2008-04-15 17:10:37.000000000 +0300
@@ -704,6 +704,52 @@ 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-0.9.8g.orig/ssl/t1_lib.c openssl-0.9.8g/ssl/t1_lib.c
--- openssl-0.9.8g.orig/ssl/t1_lib.c 2007-10-19 10:44:10.000000000 +0300
+++ openssl-0.9.8g/ssl/t1_lib.c 2008-04-15 17:10:37.000000000 +0300
@@ -105,6 +105,12 @@ 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);
}
@@ -174,8 +180,24 @@ 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
*/
@@ -189,6 +211,7 @@ unsigned char *ssl_add_clienthello_tlsex
ret += ticklen;
}
}
+ skip_ext:
if ((extdatalen = ret-p-2)== 0)
return p;
@@ -543,6 +566,8 @@ 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-0.9.8g.orig/ssl/tls1.h openssl-0.9.8g/ssl/tls1.h
--- openssl-0.9.8g.orig/ssl/tls1.h 2007-08-28 04:12:44.000000000 +0300
+++ openssl-0.9.8g/ssl/tls1.h 2008-04-15 17:10:37.000000000 +0300
@@ -365,6 +365,14 @@ SSL_CTX_ctrl(ctx,SSL_CTRL_SET_TLSEXT_SER
#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-0.9.8g.orig/util/ssleay.num openssl-0.9.8g/util/ssleay.num
--- openssl-0.9.8g.orig/util/ssleay.num 2007-08-13 01:31:16.000000000 +0300
+++ openssl-0.9.8g/util/ssleay.num 2008-04-15 17:10:37.000000000 +0300
@@ -241,3 +241,5 @@ SSL_CTX_sess_get_remove_cb
SSL_set_SSL_CTX 290 EXIST::FUNCTION:
SSL_get_servername 291 EXIST::FUNCTION:TLSEXT
SSL_get_servername_type 292 EXIST::FUNCTION:TLSEXT
+SSL_set_hello_extension 305 EXIST::FUNCTION:TLSEXT
+SSL_set_session_secret_cb 306 EXIST::FUNCTION:TLSEXT