Prepare ticket structure for securing
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 1059efc..ad9142c 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -147,6 +147,106 @@
return( 0 );
}
+/*
+ * Create session ticket, secured as recommended in RFC 5077 section 4:
+ *
+ * struct {
+ * opaque key_name[16];
+ * opaque iv[16];
+ * opaque encrypted_state<0..2^16-1>;
+ * opaque mac[32];
+ * } ticket;
+ *
+ * (the internal state structure differs, however).
+ */
+static int ssl_write_ticket( ssl_context *ssl, size_t *tlen )
+{
+ unsigned char * const start = ssl->out_msg + 10;
+ unsigned char *p = start;
+ size_t clear_len, enc_len;
+
+ memset( p, 0, 16 ); // TODO: key_name
+ p += 16;
+
+ memset( p, 0, 16 ); // TODO: iv
+ p += 16;
+
+ ssl_save_session( ssl->session_negotiate, p + 2, &clear_len );
+ SSL_DEBUG_BUF( 4, "session ticket cleartext", p, clear_len );
+
+ // TODO: encrypt ticket
+ enc_len = clear_len;
+ (void) enc_len;
+
+ *p++ = (unsigned char)( ( clear_len >> 8 ) & 0xFF );
+ *p++ = (unsigned char)( ( clear_len ) & 0xFF );
+ p += clear_len;
+
+ memset( p, 0, 32 ); // TODO: mac
+ p += 32;
+
+ *tlen = p - start;
+
+ SSL_DEBUG_BUF( 4, "final session ticket", start, *tlen );
+
+ return( 0 );
+}
+
+/*
+ * Load session ticket (see ssl_write_ticket for structure)
+ */
+static int ssl_parse_ticket( ssl_context *ssl,
+ const unsigned char *buf,
+ size_t len )
+{
+ int ret;
+ ssl_session session;
+ const unsigned char *key_name = buf;
+ const unsigned char *iv = buf + 16;
+ const unsigned char *enc_len_p = iv + 16;
+ const unsigned char *ticket = enc_len_p + 2;
+ const unsigned char *mac;
+ size_t enc_len, clear_len;
+
+ if( len < 34 )
+ return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+
+ enc_len = ( enc_len_p[0] << 8 ) | enc_len_p[1];
+ mac = ticket + enc_len;
+
+ if( len != enc_len + 66 )
+ return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+
+ // TODO: check key_name
+ (void) key_name;
+
+ // TODO: check hmac
+ (void) mac;
+
+ // TODO: decrypt ticket
+ clear_len = enc_len;
+
+ if( ( ret = ssl_load_session( &session, ticket, clear_len ) ) != 0 )
+ {
+ SSL_DEBUG_MSG( 1, ( "failed to parse ticket content" ) );
+ memset( &session, 0, sizeof( ssl_session ) );
+ return( ret );
+ }
+
+ /*
+ * Keep the session ID sent by the client, since we MUST send it back to
+ * inform him we're accepting the ticket (RFC 5077 section 3.4)
+ */
+ session.length = ssl->session_negotiate->length;
+ memcpy( &session.id, ssl->session_negotiate->id, session.length );
+
+ ssl_session_free( ssl->session_negotiate );
+ memcpy( ssl->session_negotiate, &session, sizeof( ssl_session ) );
+ memset( &session, 0, sizeof( ssl_session ) );
+
+ return( 0 );
+}
+
static int ssl_parse_servername_ext( ssl_context *ssl,
const unsigned char *buf,
size_t len )
@@ -434,9 +534,7 @@
const unsigned char *buf,
size_t len )
{
- ssl_session session;
-
- /* Remember the client asked us to send a ticket */
+ /* Remember the client asked us to send a new ticket */
ssl->handshake->new_session_ticket = 1;
SSL_DEBUG_MSG( 3, ( "ticket length: %d", len ) );
@@ -451,35 +549,18 @@
}
/*
- * Use a temporary session to preserve the current one of failures.
* Failures are ok: just ignore the ticket and proceed.
*/
- if( ssl_load_session( &session, buf, len ) != 0 )
- {
- SSL_DEBUG_MSG( 3, ( "failed to load ticket" ) );
+ if( ssl_parse_ticket( ssl, buf, len ) != 0 )
return( 0 );
- }
SSL_DEBUG_MSG( 3, ( "session successfully restored from ticket" ) );
- /*
- * Don't send a new ticket after all, this one is OK
- */
- ssl->handshake->new_session_ticket = 0;
-
- /*
- * Keep the session ID sent by the client, since we MUST send it back to
- * inform him we're accepting the ticket (RFC 5077 section 3.4)
- */
- session.length = ssl->session_negotiate->length;
- memcpy( &session.id, ssl->session_negotiate->id, session.length );
-
- ssl_session_free( ssl->session_negotiate );
- memcpy( ssl->session_negotiate, &session, sizeof( ssl_session ) );
- memset( &session, 0, sizeof( ssl_session ) );
-
ssl->handshake->resume = 1;
+ /* Don't send a new ticket after all, this one is OK */
+ ssl->handshake->new_session_ticket = 0;
+
return( 0 );
}
@@ -2351,7 +2432,7 @@
ssl->out_msg[6] = 0x00;
ssl->out_msg[7] = 0x00;
- ssl_save_session( ssl->session_negotiate, ssl->out_msg + 10, &tlen );
+ ssl_write_ticket( ssl, &tlen );
ssl->out_msg[8] = (unsigned char)( ( tlen >> 8 ) & 0xFF );
ssl->out_msg[9] = (unsigned char)( ( tlen ) & 0xFF );