- if (s->ctx->app_verify_cookie_cb != NULL) {
- if (s->ctx->app_verify_cookie_cb(s, s->d1->rcvd_cookie,
- cookie_len) == 0) {
- al = SSL_AD_HANDSHAKE_FAILURE;
- SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO,
- SSL_R_COOKIE_MISMATCH);
- goto f_err;
- }
- /* else cookie verification succeeded */
- }
- /* default verification */
- else if (memcmp(s->d1->rcvd_cookie, s->d1->cookie,
- s->d1->cookie_len) != 0) {
+ /*
+ * We don't allow resumption in a backwards compatible ClientHello.
+ * TODO(openssl-team): in TLS1.1+, session_id MUST be empty.
+ *
+ * Versions before 0.9.7 always allow clients to resume sessions in
+ * renegotiation. 0.9.7 and later allow this by default, but optionally
+ * ignore resumption requests with flag
+ * SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION (it's a new flag rather
+ * than a change to default behavior so that applications relying on
+ * this for security won't even compile against older library versions).
+ * 1.0.1 and later also have a function SSL_renegotiate_abbreviated() to
+ * request renegotiation but not a new session (s->new_session remains
+ * unset): for servers, this essentially just means that the
+ * SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION setting will be
+ * ignored.
+ */
+ if (is_v2_record ||
+ (s->new_session &&
+ (s->options & SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION))) {
+ if (!ssl_get_new_session(s, 1))
+ goto err;
+ } else {
+ i = ssl_get_prev_session(s, &extensions, &session_id);
+ /*
+ * Only resume if the session's version matches the negotiated
+ * version.
+ * RFC 5246 does not provide much useful advice on resumption
+ * with a different protocol version. It doesn't forbid it but
+ * the sanity of such behaviour would be questionable.
+ * In practice, clients do not accept a version mismatch and
+ * will abort the handshake with an error.
+ */
+ if (i == 1 && s->version == s->session->ssl_version) {
+ /* previous session */
+ s->hit = 1;
+ } else if (i == -1) {
+ goto err;
+ } else {
+ /* i == 0 */
+ if (!ssl_get_new_session(s, 1))
+ goto err;
+ }
+ }
+
+ if (SSL_IS_DTLS(s)) {
+ /* Empty cookie was already handled above by returning early. */
+ if (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE) {
+ if (s->ctx->app_verify_cookie_cb != NULL) {
+ if (s->ctx->app_verify_cookie_cb(s, PACKET_data(&cookie),
+ PACKET_remaining(&cookie)) == 0) {