On Tue, Jun 07, 2005 at 03:40:58PM +0300, Alexey Kobozev wrote:
> I've checked your patch and seems like you're not fully aware of what
> actually needed to support EAP-FAST in OpenSSL. There are actually
> two things:
> 1. TLS client hello extension support
> 2. Ability to perform the TLS session resume based on externally
> negotiated pre-shared key material.
Unfortunately, I missed your email to the mailing list and it took this
long to finally notice it.
I was doing the same part of copying s->session->master_key, but not as
a callback. This made me miss the part of setting s->hit and having to
workaround the other parts of the message processing. Your patch was
quite helpful in understanding how this can be done properly.
> Attached is the patch made for OpenSSL 0.9.8 beta 2, which includes the
> following modifications and updates for both server and client:
>
> - Client can attach additional data (PAC) to client hello using the newly
> added
> SSL_set_hello_extension() function.
This worked nicely and is certainly more generic way of doing this than
the quick test version I was using.
> - Client and server can register the callback, which will be called while
> creating
> TLS session. This callback provides the pre-shared secret for TLS session.
> This callback has cipher suites input and output parameters, which can be used
> to affect the cipher suite choice.
I needed to modify this part a bit to get EAP-FAST working. First, I was
triggering a segfault since my callback function did not set pref_cipher
to NULL and the variable happened to get non-NULL value.. I changed your
code for the client case to set pref_cipher=NULL before calling the
callback. Actually, this was already done in the server case.
After this, I was hitting a problem where the server was setting Session
ID length to zero and s->hit was cleared immediately after having been
set after successful tls_session_secret_cb call. ssl3_get_server_hello()
seems to be requiring that Session ID length is non-zero (j != 0 after
the tls_session_secret_cb). I don't know whether the EAP server was
supposed to set this to non-zero, but at least it did not seem to do
this in my tests, so I added some more code to allow s->hit being set
even if Session ID length is zero, but tls_session_secret_cb is
completed successfully. This allowed me to complete EAP-FAST
authentication. I changed wpa_supplicant to use this patch.
> P.S. I'd like this patch (with some modifications maybe) to be considered for
> committing
> it to current or future versions of OpenSSL.
I'd second this. The attached patch is a combination of your separate
t1_ext.c file and the other changes with the small modifications
mentioned above. This is against OpenSSL 0.9.8 beta 6.
--
Jouni Malinen PGP id EFC895FA
diff -uprN openssl-0.9.8-beta6.orig/include/openssl/ssl.h
openssl-0.9.8-beta6/include/openssl/ssl.h
--- openssl-0.9.8-beta6.orig/include/openssl/ssl.h 2005-06-10
12:51:16.000000000 -0700
+++ openssl-0.9.8-beta6/include/openssl/ssl.h 2005-06-29 22:17:29.000000000
-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-beta6.orig/include/openssl/tls1.h
openssl-0.9.8-beta6/include/openssl/tls1.h
--- openssl-0.9.8-beta6.orig/include/openssl/tls1.h 2003-07-22
05:34:21.000000000 -0700
+++ openssl-0.9.8-beta6/include/openssl/tls1.h 2005-06-29 22:17:29.000000000
-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-beta6.orig/ssl/Makefile
openssl-0.9.8-beta6/ssl/Makefile
--- openssl-0.9.8-beta6.orig/ssl/Makefile 2005-05-30 16:20:30.000000000
-0700
+++ openssl-0.9.8-beta6/ssl/Makefile 2005-06-29 22:17:29.000000000 -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-beta6.orig/ssl/s3_clnt.c
openssl-0.9.8-beta6/ssl/s3_clnt.c
--- openssl-0.9.8-beta6.orig/ssl/s3_clnt.c 2005-05-16 03:11:03.000000000
-0700
+++ openssl-0.9.8-beta6/ssl/s3_clnt.c 2005-06-30 20:52:03.000000000 -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-beta6.orig/ssl/s3_srvr.c
openssl-0.9.8-beta6/ssl/s3_srvr.c
--- openssl-0.9.8-beta6.orig/ssl/s3_srvr.c 2005-05-22 17:32:55.000000000
-0700
+++ openssl-0.9.8-beta6/ssl/s3_srvr.c 2005-06-29 22:17:29.000000000 -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-beta6.orig/ssl/ssl_err.c
openssl-0.9.8-beta6/ssl/ssl_err.c
--- openssl-0.9.8-beta6.orig/ssl/ssl_err.c 2005-06-10 12:51:16.000000000
-0700
+++ openssl-0.9.8-beta6/ssl/ssl_err.c 2005-06-29 22:17:29.000000000 -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-beta6.orig/ssl/ssl.h openssl-0.9.8-beta6/ssl/ssl.h
--- openssl-0.9.8-beta6.orig/ssl/ssl.h 2005-06-10 12:51:16.000000000 -0700
+++ openssl-0.9.8-beta6/ssl/ssl.h 2005-06-29 22:17:29.000000000 -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-beta6.orig/ssl/ssl_sess.c
openssl-0.9.8-beta6/ssl/ssl_sess.c
--- openssl-0.9.8-beta6.orig/ssl/ssl_sess.c 2005-04-29 13:10:06.000000000
-0700
+++ openssl-0.9.8-beta6/ssl/ssl_sess.c 2005-06-29 22:17:29.000000000 -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-beta6.orig/ssl/t1_ext.c
openssl-0.9.8-beta6/ssl/t1_ext.c
--- openssl-0.9.8-beta6.orig/ssl/t1_ext.c 1969-12-31 16:00:00.000000000
-0800
+++ openssl-0.9.8-beta6/ssl/t1_ext.c 2005-06-29 22:30:22.000000000 -0700
@@ -0,0 +1,45 @@
+
+#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;
+ }
+
+ 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-beta6.orig/ssl/t1_lib.c
openssl-0.9.8-beta6/ssl/t1_lib.c
--- openssl-0.9.8-beta6.orig/ssl/t1_lib.c 2005-04-26 09:02:40.000000000
-0700
+++ openssl-0.9.8-beta6/ssl/t1_lib.c 2005-06-29 22:17:29.000000000 -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-beta6.orig/ssl/tls1.h openssl-0.9.8-beta6/ssl/tls1.h
--- openssl-0.9.8-beta6.orig/ssl/tls1.h 2003-07-22 05:34:21.000000000 -0700
+++ openssl-0.9.8-beta6/ssl/tls1.h 2005-06-29 22:17:29.000000000 -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-beta6.orig/util/ssleay.num
openssl-0.9.8-beta6/util/ssleay.num
--- openssl-0.9.8-beta6.orig/util/ssleay.num 2005-05-08 17:22:02.000000000
-0700
+++ openssl-0.9.8-beta6/util/ssleay.num 2005-06-29 22:17:29.000000000 -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:
