False Start support.
(Called "cut through" for historical reasons in this patch.)
Enables SSL3+ clients to send application data immediately following the
Finished message even when negotiating full-handshakes. With this
patch, clients can negotiate SSL connections in 1-RTT even when
performing full-handshakes.
diff --git a/ssl/s3_clnt.c b/ssl/s3_clnt.c
index 9698916..ba0410a 100644
--- a/ssl/s3_clnt.c
+++ b/ssl/s3_clnt.c
@@ -209,6 +209,12 @@
}
#endif
+ if (SSL_get_mode(s) & SSL_MODE_HANDSHAKE_CUTTHROUGH)
+ {
+ /* Send app data along with CCS/Finished */
+ s->s3->flags |= SSL3_FLAGS_DELAY_CLIENT_FINISHED;
+ }
+
for (;;)
{
state=s->state;
@@ -518,14 +524,32 @@
}
else
{
-#ifndef OPENSSL_NO_TLSEXT
- /* Allow NewSessionTicket if ticket expected */
- if (s->tlsext_ticket_expected)
- s->s3->tmp.next_state=SSL3_ST_CR_SESSION_TICKET_A;
+ if ((SSL_get_mode(s) & SSL_MODE_HANDSHAKE_CUTTHROUGH)
+ && ssl3_can_cutthrough(s)
+ && s->s3->previous_server_finished_len == 0 /* no cutthrough on renegotiation (would complicate the state machine) */
+ )
+ {
+ if (s->s3->flags & SSL3_FLAGS_DELAY_CLIENT_FINISHED)
+ {
+ s->state=SSL3_ST_CUTTHROUGH_COMPLETE;
+ s->s3->flags|=SSL3_FLAGS_POP_BUFFER;
+ s->s3->delay_buf_pop_ret=0;
+ }
+ else
+ {
+ s->s3->tmp.next_state=SSL3_ST_CUTTHROUGH_COMPLETE;
+ }
+ }
else
+ {
+#ifndef OPENSSL_NO_TLSEXT
+ /* Allow NewSessionTicket if ticket expected */
+ if (s->tlsext_ticket_expected)
+ s->s3->tmp.next_state=SSL3_ST_CR_SESSION_TICKET_A;
+ else
#endif
-
- s->s3->tmp.next_state=SSL3_ST_CR_FINISHED_A;
+ s->s3->tmp.next_state=SSL3_ST_CR_FINISHED_A;
+ }
}
s->init_num=0;
break;
@@ -573,6 +597,24 @@
s->state=s->s3->tmp.next_state;
break;
+ case SSL3_ST_CUTTHROUGH_COMPLETE:
+#ifndef OPENSSL_NO_TLSEXT
+ /* Allow NewSessionTicket if ticket expected */
+ if (s->tlsext_ticket_expected)
+ s->state=SSL3_ST_CR_SESSION_TICKET_A;
+ else
+#endif
+ s->state=SSL3_ST_CR_FINISHED_A;
+
+ /* SSL_write() will take care of flushing buffered data if
+ * DELAY_CLIENT_FINISHED is set.
+ */
+ if (!(s->s3->flags & SSL3_FLAGS_DELAY_CLIENT_FINISHED))
+ ssl_free_wbio_buffer(s);
+ ret = 1;
+ goto end;
+ /* break; */
+
case SSL_ST_OK:
/* clean a few things up */
ssl3_cleanup_key_block(s);
diff --git a/ssl/s3_lib.c b/ssl/s3_lib.c
index 3a53c68..edffd21 100644
--- a/ssl/s3_lib.c
+++ b/ssl/s3_lib.c
@@ -3963,9 +3963,22 @@
static int ssl3_read_internal(SSL *s, void *buf, int len, int peek)
{
- int ret;
+ int n,ret;
ERR_clear_system_error();
+ if ((s->s3->flags & SSL3_FLAGS_POP_BUFFER) && (s->wbio == s->bbio))
+ {
+ /* Deal with an application that calls SSL_read() when handshake data
+ * is yet to be written.
+ */
+ if (BIO_wpending(s->wbio) > 0)
+ {
+ s->rwstate=SSL_WRITING;
+ n=BIO_flush(s->wbio);
+ if (n <= 0) return(n);
+ s->rwstate=SSL_NOTHING;
+ }
+ }
if (s->s3->renegotiate) ssl3_renegotiate_check(s);
s->s3->in_read_app_data=1;
ret=s->method->ssl_read_bytes(s,SSL3_RT_APPLICATION_DATA,buf,len,peek);
diff --git a/ssl/ssl.h b/ssl/ssl.h
index 91f52ce..e5aa03a 100644
--- a/ssl/ssl.h
+++ b/ssl/ssl.h
@@ -689,6 +689,7 @@
* TLS only.) "Released" buffers are put onto a free-list in the context
* or just freed (depending on the context's setting for freelist_max_len). */
#define SSL_MODE_RELEASE_BUFFERS 0x00000010L
+
/* Send the current time in the Random fields of the ClientHello and
* ServerHello records for compatibility with hypothetical implementations
* that require it.
@@ -752,6 +753,11 @@
#define SSL_CONF_TYPE_FILE 0x2
#define SSL_CONF_TYPE_DIR 0x3
+/* When set, clients may send application data before receipt of CCS
+ * and Finished. This mode enables full-handshakes to 'complete' in
+ * one RTT. */
+#define SSL_MODE_HANDSHAKE_CUTTHROUGH 0x00000080L
+
/* Note: SSL[_CTX]_set_{options,mode} use |= op on the previous value,
* they cannot be used to clear bits. */
@@ -1560,10 +1566,12 @@
/* Is the SSL_connection established? */
#define SSL_get_state(a) SSL_state(a)
#define SSL_is_init_finished(a) (SSL_state(a) == SSL_ST_OK)
-#define SSL_in_init(a) (SSL_state(a)&SSL_ST_INIT)
+#define SSL_in_init(a) ((SSL_state(a)&SSL_ST_INIT) && \
+ !SSL_cutthrough_complete(a))
#define SSL_in_before(a) (SSL_state(a)&SSL_ST_BEFORE)
#define SSL_in_connect_init(a) (SSL_state(a)&SSL_ST_CONNECT)
#define SSL_in_accept_init(a) (SSL_state(a)&SSL_ST_ACCEPT)
+int SSL_cutthrough_complete(const SSL *s);
/* The following 2 states are kept in ssl->rstate when reads fail,
* you should not need these */
diff --git a/ssl/ssl3.h b/ssl/ssl3.h
index e2bb36f..eb179e2 100644
--- a/ssl/ssl3.h
+++ b/ssl/ssl3.h
@@ -597,6 +597,7 @@
/*client */
/* extra state */
#define SSL3_ST_CW_FLUSH (0x100|SSL_ST_CONNECT)
+#define SSL3_ST_CUTTHROUGH_COMPLETE (0x101|SSL_ST_CONNECT)
/* write to server */
#define SSL3_ST_CW_CLNT_HELLO_A (0x110|SSL_ST_CONNECT)
#define SSL3_ST_CW_CLNT_HELLO_B (0x111|SSL_ST_CONNECT)
diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index eec32b2..c536600 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -3308,6 +3308,48 @@
SSL_callback_ctrl(ssl, SSL_CTRL_SET_MSG_CALLBACK, (void (*)(void))cb);
}
+int SSL_cutthrough_complete(const SSL *s)
+ {
+ return (!s->server && /* cutthrough only applies to clients */
+ !s->hit && /* full-handshake */
+ s->version >= SSL3_VERSION &&
+ s->s3->in_read_app_data == 0 && /* cutthrough only applies to write() */
+ (SSL_get_mode((SSL*)s) & SSL_MODE_HANDSHAKE_CUTTHROUGH) && /* cutthrough enabled */
+ ssl3_can_cutthrough(s) && /* cutthrough allowed */
+ s->s3->previous_server_finished_len == 0 && /* not a renegotiation handshake */
+ (s->state == SSL3_ST_CR_SESSION_TICKET_A || /* ready to write app-data*/
+ s->state == SSL3_ST_CR_FINISHED_A));
+ }
+
+int ssl3_can_cutthrough(const SSL *s)
+ {
+ const SSL_CIPHER *c;
+
+ /* require a strong enough cipher */
+ if (SSL_get_cipher_bits(s, NULL) < 128)
+ return 0;
+
+ /* require ALPN or NPN extension */
+ if (!s->s3->alpn_selected
+#ifndef OPENSSL_NO_NEXTPROTONEG
+ && !s->s3->next_proto_neg_seen
+#endif
+ )
+ {
+ return 0;
+ }
+
+ /* require a forward-secret cipher */
+ c = SSL_get_current_cipher(s);
+ if (!c || (c->algorithm_mkey != SSL_kEDH &&
+ c->algorithm_mkey != SSL_kEECDH))
+ {
+ return 0;
+ }
+
+ return 1;
+ }
+
/* Allocates new EVP_MD_CTX and sets pointer to it into given pointer
* vairable, freeing EVP_MD_CTX previously stored in that variable, if
* any. If EVP_MD pointer is passed, initializes ctx with this md
diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h
index f0b6d42..cbfa172 100644
--- a/ssl/ssl_locl.h
+++ b/ssl/ssl_locl.h
@@ -1294,6 +1294,8 @@
void tls1_set_cert_validity(SSL *s);
#endif
+
+int ssl3_can_cutthrough(const SSL *s);
EVP_MD_CTX* ssl_replace_hash(EVP_MD_CTX **hash,const EVP_MD *md) ;
void ssl_clear_hash_ctx(EVP_MD_CTX **hash);
int ssl_add_serverhello_renegotiate_ext(SSL *s, unsigned char *p, int *len,
