krackattacks/patches/openssl-0.9.8zf-tls-extensions.patch

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 0.9.8zf 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-0.9.8zf.orig/ssl/s3_clnt.c openssl-0.9.8zf/ssl/s3_clnt.c
--- openssl-0.9.8zf.orig/ssl/s3_clnt.c	2015-03-19 15:46:46.000000000 +0200
+++ openssl-0.9.8zf/ssl/s3_clnt.c	2015-03-24 16:19:14.043911769 +0200
@@ -760,6 +760,23 @@ 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);
+	    s->s3->flags |= SSL3_FLAGS_CCS_OK;
+	}
+    }
+#endif /* OPENSSL_NO_TLSEXT */
+
     if (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
@@ -2684,12 +2701,8 @@ 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,
diff -upr openssl-0.9.8zf.orig/ssl/s3_srvr.c openssl-0.9.8zf/ssl/s3_srvr.c
--- openssl-0.9.8zf.orig/ssl/s3_srvr.c	2015-03-19 15:46:46.000000000 +0200
+++ openssl-0.9.8zf/ssl/s3_srvr.c	2015-03-24 16:23:34.567909681 +0200
@@ -999,6 +999,59 @@ 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
@@ -1143,15 +1196,21 @@ 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-0.9.8zf.orig/ssl/ssl_err.c openssl-0.9.8zf/ssl/ssl_err.c
--- openssl-0.9.8zf.orig/ssl/ssl_err.c	2015-03-19 15:46:46.000000000 +0200
+++ openssl-0.9.8zf/ssl/ssl_err.c	2015-03-24 16:35:58.627903717 +0200
@@ -316,6 +316,7 @@ 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_SESSION_TICKET_EXT), "SSL_set_session_ticket_ext"},
     {0, NULL}
 };
 
diff -upr openssl-0.9.8zf.orig/ssl/ssl.h openssl-0.9.8zf/ssl/ssl.h
--- openssl-0.9.8zf.orig/ssl/ssl.h	2015-03-19 15:46:46.000000000 +0200
+++ openssl-0.9.8zf/ssl/ssl.h	2015-03-24 16:25:44.339908641 +0200
@@ -349,6 +349,7 @@ extern "C" {
  * function parameters used to prototype callbacks in SSL_CTX.
  */
 typedef struct ssl_st *ssl_crock_st;
+typedef struct tls_session_ticket_ext_st TLS_SESSION_TICKET_EXT;
 
 /* used to hold info on the particular ciphers used */
 typedef struct ssl_cipher_st {
@@ -366,6 +367,12 @@ typedef struct ssl_cipher_st {
 
 DECLARE_STACK_OF(SSL_CIPHER)
 
+typedef int (*tls_session_ticket_ext_cb_fn)(SSL *s, const unsigned char *data,
+					    int len, void *arg);
+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 {
     int version;
@@ -1116,6 +1123,18 @@ struct ssl_st {
     int tlsext_ocsp_resplen;
     /* RFC4507 session ticket expected to be received or sent */
     int tlsext_ticket_expected;
+
+    /* TLS Session Ticket extension override */
+    TLS_SESSION_TICKET_EXT *tlsext_session_ticket;
+
+    /* TLS Session Ticket extension callback */
+    tls_session_ticket_ext_cb_fn tls_session_ticket_ext_cb;
+    void *tls_session_ticket_ext_cb_arg;
+
+    /* 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
@@ -1772,6 +1791,17 @@ void *SSL_COMP_get_compression_methods(v
 int SSL_COMP_add_compression_method(int id, void *cm);
 # endif
 
+/* TLS extensions functions */
+int SSL_set_session_ticket_ext(SSL *s, void *ext_data, int ext_len);
+
+int SSL_set_session_ticket_ext_cb(SSL *s, tls_session_ticket_ext_cb_fn cb,
+				  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
@@ -1977,6 +2007,7 @@ 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_SESSION_TICKET_EXT                  213
 
 /* Reason codes. */
 # define SSL_R_APP_DATA_IN_HANDSHAKE                      100
diff -upr openssl-0.9.8zf.orig/ssl/ssl_sess.c openssl-0.9.8zf/ssl/ssl_sess.c
--- openssl-0.9.8zf.orig/ssl/ssl_sess.c	2015-03-19 15:46:46.000000000 +0200
+++ openssl-0.9.8zf/ssl/ssl_sess.c	2015-03-24 16:28:04.819907515 +0200
@@ -716,6 +716,61 @@ 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_session_ticket_ext_cb(SSL *s, tls_session_ticket_ext_cb_fn cb,
+				  void *arg)
+{
+    if (s == NULL)
+	    return 0;
+    s->tls_session_ticket_ext_cb = cb;
+    s->tls_session_ticket_ext_cb_arg = arg;
+    return 1;
+}
+
+int SSL_set_session_ticket_ext(SSL *s, void *ext_data, int ext_len)
+{
+    if (s->version >= TLS1_VERSION) {
+	if (s->tlsext_session_ticket) {
+	    OPENSSL_free(s->tlsext_session_ticket);
+	    s->tlsext_session_ticket = NULL;
+	}
+
+	s->tlsext_session_ticket = OPENSSL_malloc(
+		sizeof(TLS_SESSION_TICKET_EXT) + ext_len);
+	if (!s->tlsext_session_ticket) {
+	    SSLerr(SSL_F_SSL_SET_SESSION_TICKET_EXT, ERR_R_MALLOC_FAILURE);
+	    return 0;
+	}
+
+	if (ext_data) {
+	    s->tlsext_session_ticket->length = ext_len;
+	    s->tlsext_session_ticket->data = s->tlsext_session_ticket + 1;
+	    memcpy(s->tlsext_session_ticket->data, ext_data, ext_len);
+	} else {
+		s->tlsext_session_ticket->length = 0;
+		s->tlsext_session_ticket->data = NULL;
+	}
+
+	return 1;
+    }
+
+    return 0;
+}
+#endif /* OPENSSL_NO_TLSEXT */
+
 typedef struct timeout_param_st {
     SSL_CTX *ctx;
     long time;
diff -upr openssl-0.9.8zf.orig/ssl/t1_lib.c openssl-0.9.8zf/ssl/t1_lib.c
--- openssl-0.9.8zf.orig/ssl/t1_lib.c	2015-03-19 15:46:46.000000000 +0200
+++ openssl-0.9.8zf/ssl/t1_lib.c	2015-03-24 16:32:46.923905254 +0200
@@ -108,6 +108,11 @@ int tls1_new(SSL *s)
 
 void tls1_free(SSL *s)
 {
+#ifndef OPENSSL_NO_TLSEXT
+    if (s->tlsext_session_ticket) {
+	OPENSSL_free(s->tlsext_session_ticket);
+    }
+#endif
     ssl3_free(s);
 }
 
@@ -206,8 +211,20 @@ unsigned char *ssl_add_clienthello_tlsex
         int ticklen;
         if (!s->new_session && s->session && s->session->tlsext_tick)
             ticklen = s->session->tlsext_ticklen;
-        else
+	else if (s->session && s->tlsext_session_ticket &&
+		 s->tlsext_session_ticket->data) {
+	    ticklen = s->tlsext_session_ticket->length;
+	    s->session->tlsext_tick = OPENSSL_malloc(ticklen);
+	    if (!s->session->tlsext_tick)
+		return NULL;
+	    memcpy(s->session->tlsext_tick, s->tlsext_session_ticket->data,
+		   ticklen);
+	    s->session->tlsext_ticklen = ticklen;
+	} else
             ticklen = 0;
+	if (ticklen == 0 && s->tlsext_session_ticket &&
+	    s->tlsext_session_ticket->data == NULL)
+	    goto skip_ext;
         /*
          * Check for enough room 2 for extension type, 2 for len rest for
          * ticket
@@ -221,6 +238,7 @@ unsigned char *ssl_add_clienthello_tlsex
             ret += ticklen;
         }
     }
+skip_ext:
 
     if (s->tlsext_status_type == TLSEXT_STATUSTYPE_ocsp &&
         s->version != DTLS1_VERSION) {
@@ -560,6 +578,14 @@ int ssl_parse_clienthello_tlsext(SSL *s,
             if (!ssl_parse_clienthello_renegotiate_ext(s, data, size, al))
                 return 0;
             renegotiate_seen = 1;
+	} else if (type == TLSEXT_TYPE_session_ticket) {
+	    if (s->tls_session_ticket_ext_cb &&
+		!s->tls_session_ticket_ext_cb(s, data, size,
+					      s->tls_session_ticket_ext_cb_arg))
+	    {
+		*al = TLS1_AD_INTERNAL_ERROR;
+		return 0;
+	    }
         } else if (type == TLSEXT_TYPE_status_request &&
                    s->version != DTLS1_VERSION && s->ctx->tlsext_status_cb) {
 
@@ -710,6 +736,13 @@ int ssl_parse_serverhello_tlsext(SSL *s,
             }
             tlsext_servername = 1;
         } else if (type == TLSEXT_TYPE_session_ticket) {
+	    if (s->tls_session_ticket_ext_cb &&
+		!s->tls_session_ticket_ext_cb(
+			s, data, size,
+			s->tls_session_ticket_ext_cb_arg)) {
+		*al = TLS1_AD_INTERNAL_ERROR;
+		return 0;
+	    }
             if ((SSL_get_options(s) & SSL_OP_NO_TICKET)
                 || (size > 0)) {
                 *al = TLS1_AD_UNSUPPORTED_EXTENSION;
@@ -993,6 +1026,14 @@ 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);
         }
         p += size;
diff -upr openssl-0.9.8zf.orig/ssl/tls1.h openssl-0.9.8zf/ssl/tls1.h
--- openssl-0.9.8zf.orig/ssl/tls1.h	2015-03-19 15:46:46.000000000 +0200
+++ openssl-0.9.8zf/ssl/tls1.h	2015-03-24 16:33:31.855904894 +0200
@@ -460,6 +460,12 @@ 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"
 # endif
 
+/* TLS extension struct */
+struct tls_session_ticket_ext_st {
+    unsigned short length;
+    void *data;
+};
+
 #ifdef  __cplusplus
 }
 #endif
diff -upr openssl-0.9.8zf.orig/util/ssleay.num openssl-0.9.8zf/util/ssleay.num
--- openssl-0.9.8zf.orig/util/ssleay.num	2015-03-19 15:47:15.000000000 +0200
+++ openssl-0.9.8zf/util/ssleay.num	2015-03-24 16:33:51.127904739 +0200
@@ -242,3 +242,5 @@ SSL_set_SSL_CTX
 SSL_get_servername                      291	EXIST::FUNCTION:TLSEXT
 SSL_get_servername_type                 292	EXIST::FUNCTION:TLSEXT
 SSL_CTX_set_client_cert_engine          293	EXIST::FUNCTION:ENGINE
+SSL_set_session_ticket_ext		306	EXIST::FUNCTION:TLSEXT
+SSL_set_session_secret_cb		307	EXIST::FUNCTION:TLSEXT