mirror of
https://github.com/vanhoefm/fragattacks.git
synced 2024-12-01 11:48:23 -05:00
fe2b7dda02
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.
331 lines
11 KiB
Diff
331 lines
11 KiB
Diff
This patch adds support for TLS SessionTicket extension (RFC 5077) for
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the parts used by EAP-FAST (RFC 4851).
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This is based on the patch from Alexey Kobozev <akobozev@cisco.com>
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(sent to openssl-dev mailing list on Tue, 07 Jun 2005 15:40:58 +0300).
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OpenSSL 0.9.8g does not enable TLS extension support by default, so it
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will need to be enabled by adding enable-tlsext to config script
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command line.
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diff -upr openssl-0.9.8g.orig/ssl/s3_clnt.c openssl-0.9.8g/ssl/s3_clnt.c
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--- openssl-0.9.8g.orig/ssl/s3_clnt.c 2007-08-31 03:28:51.000000000 +0300
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+++ openssl-0.9.8g/ssl/s3_clnt.c 2008-04-15 17:11:46.000000000 +0300
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@@ -727,6 +727,20 @@ int ssl3_get_server_hello(SSL *s)
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goto f_err;
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}
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+#ifndef OPENSSL_NO_TLSEXT
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+ /* check if we want to resume the session based on external pre-shared secret */
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+ if (s->version >= TLS1_VERSION && s->tls_session_secret_cb)
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+ {
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+ SSL_CIPHER *pref_cipher=NULL;
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+ s->session->master_key_length=sizeof(s->session->master_key);
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+ if (s->tls_session_secret_cb(s, s->session->master_key, &s->session->master_key_length,
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+ NULL, &pref_cipher, s->tls_session_secret_cb_arg))
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+ {
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+ s->session->cipher=pref_cipher ? pref_cipher : ssl_get_cipher_by_char(s,p+j);
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+ }
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+ }
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+#endif /* OPENSSL_NO_TLSEXT */
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+
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if (j != 0 && j == s->session->session_id_length
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&& memcmp(p,s->session->session_id,j) == 0)
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{
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diff -upr openssl-0.9.8g.orig/ssl/s3_srvr.c openssl-0.9.8g/ssl/s3_srvr.c
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--- openssl-0.9.8g.orig/ssl/s3_srvr.c 2007-09-30 21:55:59.000000000 +0300
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+++ openssl-0.9.8g/ssl/s3_srvr.c 2008-04-15 17:10:37.000000000 +0300
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@@ -928,6 +928,59 @@ int ssl3_get_client_hello(SSL *s)
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SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO,SSL_R_CLIENTHELLO_TLSEXT);
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goto err;
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}
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+
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+ /* Check if we want to use external pre-shared secret for this
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+ * handshake for not reused session only. We need to generate
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+ * server_random before calling tls_session_secret_cb in order to allow
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+ * SessionTicket processing to use it in key derivation. */
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+ {
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+ unsigned long Time;
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+ unsigned char *pos;
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+ Time=(unsigned long)time(NULL); /* Time */
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+ pos=s->s3->server_random;
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+ l2n(Time,pos);
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+ if (RAND_pseudo_bytes(pos,SSL3_RANDOM_SIZE-4) <= 0)
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+ {
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+ al=SSL_AD_INTERNAL_ERROR;
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+ goto f_err;
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+ }
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+ }
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+
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+ if (!s->hit && s->version >= TLS1_VERSION && s->tls_session_secret_cb)
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+ {
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+ SSL_CIPHER *pref_cipher=NULL;
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+
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+ s->session->master_key_length=sizeof(s->session->master_key);
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+ if(s->tls_session_secret_cb(s, s->session->master_key, &s->session->master_key_length,
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+ ciphers, &pref_cipher, s->tls_session_secret_cb_arg))
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+ {
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+ s->hit=1;
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+ s->session->ciphers=ciphers;
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+ s->session->verify_result=X509_V_OK;
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+
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+ ciphers=NULL;
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+
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+ /* check if some cipher was preferred by call back */
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+ pref_cipher=pref_cipher ? pref_cipher : ssl3_choose_cipher(s, s->session->ciphers, SSL_get_ciphers(s));
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+ if (pref_cipher == NULL)
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+ {
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+ al=SSL_AD_HANDSHAKE_FAILURE;
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+ SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO,SSL_R_NO_SHARED_CIPHER);
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+ goto f_err;
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+ }
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+
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+ s->session->cipher=pref_cipher;
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+
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+ if (s->cipher_list)
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+ sk_SSL_CIPHER_free(s->cipher_list);
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+
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+ if (s->cipher_list_by_id)
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+ sk_SSL_CIPHER_free(s->cipher_list_by_id);
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+
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+ s->cipher_list = sk_SSL_CIPHER_dup(s->session->ciphers);
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+ s->cipher_list_by_id = sk_SSL_CIPHER_dup(s->session->ciphers);
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+ }
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+ }
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#endif
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/* Worst case, we will use the NULL compression, but if we have other
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* options, we will now look for them. We have i-1 compression
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@@ -1066,16 +1119,22 @@ int ssl3_send_server_hello(SSL *s)
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unsigned char *buf;
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unsigned char *p,*d;
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int i,sl;
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- unsigned long l,Time;
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+ unsigned long l;
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+#ifdef OPENSSL_NO_TLSEXT
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+ unsigned long Time;
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+#endif
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if (s->state == SSL3_ST_SW_SRVR_HELLO_A)
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{
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buf=(unsigned char *)s->init_buf->data;
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+#ifdef OPENSSL_NO_TLSEXT
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p=s->s3->server_random;
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+ /* Generate server_random if it was not needed previously */
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Time=(unsigned long)time(NULL); /* Time */
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l2n(Time,p);
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if (RAND_pseudo_bytes(p,SSL3_RANDOM_SIZE-4) <= 0)
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return -1;
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+#endif
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/* Do the message type and length last */
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d=p= &(buf[4]);
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diff -upr openssl-0.9.8g.orig/ssl/ssl.h openssl-0.9.8g/ssl/ssl.h
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--- openssl-0.9.8g.orig/ssl/ssl.h 2007-10-19 10:42:38.000000000 +0300
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+++ openssl-0.9.8g/ssl/ssl.h 2008-04-15 17:10:37.000000000 +0300
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@@ -342,6 +342,7 @@ extern "C" {
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* 'struct ssl_st *' function parameters used to prototype callbacks
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* in SSL_CTX. */
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typedef struct ssl_st *ssl_crock_st;
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+typedef struct tls_extension_st TLS_EXTENSION;
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/* used to hold info on the particular ciphers used */
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typedef struct ssl_cipher_st
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@@ -363,6 +364,8 @@ DECLARE_STACK_OF(SSL_CIPHER)
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typedef struct ssl_st SSL;
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typedef struct ssl_ctx_st SSL_CTX;
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+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);
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+
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/* Used to hold functions for SSLv2 or SSLv3/TLSv1 functions */
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typedef struct ssl_method_st
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{
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@@ -1004,6 +1007,14 @@ struct ssl_st
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*/
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/* RFC4507 session ticket expected to be received or sent */
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int tlsext_ticket_expected;
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+
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+ /* TLS extensions */
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+ TLS_EXTENSION *tls_extension;
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+
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+ /* TLS pre-shared secret session resumption */
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+ tls_session_secret_cb_fn tls_session_secret_cb;
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+ void *tls_session_secret_cb_arg;
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+
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SSL_CTX * initial_ctx; /* initial ctx, used to store sessions */
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#define session_ctx initial_ctx
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#else
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@@ -1589,6 +1600,12 @@ void *SSL_COMP_get_compression_methods(v
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int SSL_COMP_add_compression_method(int id,void *cm);
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#endif
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+/* TLS extensions functions */
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+int SSL_set_hello_extension(SSL *s, int ext_type, void *ext_data, int ext_len);
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+
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+/* Pre-shared secret session resumption functions */
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+int SSL_set_session_secret_cb(SSL *s, tls_session_secret_cb_fn tls_session_secret_cb, void *arg);
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+
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/* BEGIN ERROR CODES */
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/* The following lines are auto generated by the script mkerr.pl. Any changes
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* made after this point may be overwritten when the script is next run.
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@@ -1778,6 +1795,7 @@ void ERR_load_SSL_strings(void);
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#define SSL_F_TLS1_ENC 210
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#define SSL_F_TLS1_SETUP_KEY_BLOCK 211
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#define SSL_F_WRITE_PENDING 212
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+#define SSL_F_SSL_SET_HELLO_EXTENSION 213
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/* Reason codes. */
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#define SSL_R_APP_DATA_IN_HANDSHAKE 100
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diff -upr openssl-0.9.8g.orig/ssl/ssl_err.c openssl-0.9.8g/ssl/ssl_err.c
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--- openssl-0.9.8g.orig/ssl/ssl_err.c 2007-10-11 17:36:59.000000000 +0300
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+++ openssl-0.9.8g/ssl/ssl_err.c 2008-04-15 17:10:37.000000000 +0300
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@@ -250,6 +250,7 @@ static ERR_STRING_DATA SSL_str_functs[]=
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{ERR_FUNC(SSL_F_TLS1_ENC), "TLS1_ENC"},
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{ERR_FUNC(SSL_F_TLS1_SETUP_KEY_BLOCK), "TLS1_SETUP_KEY_BLOCK"},
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{ERR_FUNC(SSL_F_WRITE_PENDING), "WRITE_PENDING"},
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+{ERR_FUNC(SSL_F_SSL_SET_HELLO_EXTENSION), "SSL_set_hello_extension"},
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{0,NULL}
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};
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diff -upr openssl-0.9.8g.orig/ssl/ssl_sess.c openssl-0.9.8g/ssl/ssl_sess.c
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--- openssl-0.9.8g.orig/ssl/ssl_sess.c 2007-10-19 10:36:34.000000000 +0300
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+++ openssl-0.9.8g/ssl/ssl_sess.c 2008-04-15 17:10:37.000000000 +0300
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@@ -704,6 +704,52 @@ long SSL_CTX_get_timeout(const SSL_CTX *
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return(s->session_timeout);
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}
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+#ifndef OPENSSL_NO_TLSEXT
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+int SSL_set_session_secret_cb(SSL *s, int (*tls_session_secret_cb)(SSL *s, void *secret, int *secret_len,
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+ STACK_OF(SSL_CIPHER) *peer_ciphers, SSL_CIPHER **cipher, void *arg), void *arg)
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+{
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+ if (s == NULL) return(0);
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+ s->tls_session_secret_cb = tls_session_secret_cb;
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+ s->tls_session_secret_cb_arg = arg;
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+ return(1);
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+}
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+
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+int SSL_set_hello_extension(SSL *s, int ext_type, void *ext_data, int ext_len)
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+{
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+ if(s->version >= TLS1_VERSION)
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+ {
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+ if(s->tls_extension)
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+ {
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+ OPENSSL_free(s->tls_extension);
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+ s->tls_extension = NULL;
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+ }
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+
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+ s->tls_extension = OPENSSL_malloc(sizeof(TLS_EXTENSION) + ext_len);
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+ if(!s->tls_extension)
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+ {
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+ SSLerr(SSL_F_SSL_SET_HELLO_EXTENSION, ERR_R_MALLOC_FAILURE);
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+ return 0;
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+ }
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+
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+ s->tls_extension->type = ext_type;
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+
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+ if(ext_data)
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+ {
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+ s->tls_extension->length = ext_len;
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+ s->tls_extension->data = s->tls_extension + 1;
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+ memcpy(s->tls_extension->data, ext_data, ext_len);
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+ } else {
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+ s->tls_extension->length = 0;
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+ s->tls_extension->data = NULL;
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+ }
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+
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+ return 1;
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+ }
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+
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+ return 0;
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+}
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+#endif /* OPENSSL_NO_TLSEXT */
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+
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typedef struct timeout_param_st
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{
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SSL_CTX *ctx;
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diff -upr openssl-0.9.8g.orig/ssl/t1_lib.c openssl-0.9.8g/ssl/t1_lib.c
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--- openssl-0.9.8g.orig/ssl/t1_lib.c 2007-10-19 10:44:10.000000000 +0300
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+++ openssl-0.9.8g/ssl/t1_lib.c 2008-04-15 17:10:37.000000000 +0300
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@@ -105,6 +105,12 @@ int tls1_new(SSL *s)
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void tls1_free(SSL *s)
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{
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+#ifndef OPENSSL_NO_TLSEXT
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+ if(s->tls_extension)
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+ {
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+ OPENSSL_free(s->tls_extension);
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+ }
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+#endif
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ssl3_free(s);
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}
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@@ -174,8 +180,24 @@ unsigned char *ssl_add_clienthello_tlsex
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int ticklen;
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if (s->session && s->session->tlsext_tick)
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ticklen = s->session->tlsext_ticklen;
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+ else if (s->session && s->tls_extension &&
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+ s->tls_extension->type == TLSEXT_TYPE_session_ticket &&
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+ s->tls_extension->data)
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+ {
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+ ticklen = s->tls_extension->length;
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+ s->session->tlsext_tick = OPENSSL_malloc(ticklen);
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+ if (!s->session->tlsext_tick)
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+ return NULL;
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+ memcpy(s->session->tlsext_tick, s->tls_extension->data,
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+ ticklen);
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+ s->session->tlsext_ticklen = ticklen;
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+ }
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else
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ticklen = 0;
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+ if (ticklen == 0 && s->tls_extension &&
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+ s->tls_extension->type == TLSEXT_TYPE_session_ticket &&
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+ s->tls_extension->data == NULL)
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+ goto skip_ext;
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/* Check for enough room 2 for extension type, 2 for len
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* rest for ticket
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*/
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@@ -189,6 +211,7 @@ unsigned char *ssl_add_clienthello_tlsex
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ret += ticklen;
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}
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}
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+ skip_ext:
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if ((extdatalen = ret-p-2)== 0)
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return p;
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@@ -543,6 +566,8 @@ int tls1_process_ticket(SSL *s, unsigned
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s->tlsext_ticket_expected = 1;
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return 0; /* Cache miss */
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}
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+ if (s->tls_session_secret_cb)
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+ return 0;
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return tls_decrypt_ticket(s, p, size, session_id, len,
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ret);
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}
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diff -upr openssl-0.9.8g.orig/ssl/tls1.h openssl-0.9.8g/ssl/tls1.h
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--- openssl-0.9.8g.orig/ssl/tls1.h 2007-08-28 04:12:44.000000000 +0300
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+++ openssl-0.9.8g/ssl/tls1.h 2008-04-15 17:10:37.000000000 +0300
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@@ -365,6 +365,14 @@ SSL_CTX_ctrl(ctx,SSL_CTRL_SET_TLSEXT_SER
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#define TLS_MD_MASTER_SECRET_CONST "\x6d\x61\x73\x74\x65\x72\x20\x73\x65\x63\x72\x65\x74" /*master secret*/
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#endif
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+/* TLS extension struct */
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+struct tls_extension_st
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+{
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+ unsigned short type;
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+ unsigned short length;
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+ void *data;
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+};
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+
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#ifdef __cplusplus
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}
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#endif
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diff -upr openssl-0.9.8g.orig/util/ssleay.num openssl-0.9.8g/util/ssleay.num
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--- openssl-0.9.8g.orig/util/ssleay.num 2007-08-13 01:31:16.000000000 +0300
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+++ openssl-0.9.8g/util/ssleay.num 2008-04-15 17:10:37.000000000 +0300
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@@ -241,3 +241,5 @@ SSL_CTX_sess_get_remove_cb
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SSL_set_SSL_CTX 290 EXIST::FUNCTION:
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SSL_get_servername 291 EXIST::FUNCTION:TLSEXT
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SSL_get_servername_type 292 EXIST::FUNCTION:TLSEXT
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+SSL_set_hello_extension 305 EXIST::FUNCTION:TLSEXT
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+SSL_set_session_secret_cb 306 EXIST::FUNCTION:TLSEXT
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