Provide SSL_OP_NO_RENEGOTIATION and SSL_OP_ALLOW_CLIENT_RENEGOTIATION.

In January 2017 we added SSL_OP_NO_CLIENT_RENEGOTIATION, which results in a
SSL_AD_NO_RENEGOTIATION fatal alert if a ClientHello message is seen on an
active connection (client initiated renegotation). Then in May 2017 OpenSSL
added SSL_OP_NO_RENEGOTIATION, which results in a SSL_AD_NO_RENEGOTIATION
warning alert if a server receives a ClientHello on an active connection
(client initiated renegotation), or a client receives a HelloRequest
(server requested renegotation). This option also causes calls to
SSL_renegotiate() and SSL_renegotiate_abbreviated() to fail. Then in 2021,
OpenSSL also added SSL_OP_ALLOW_CLIENT_RENEGOTIATION, which trumps
SSL_OP_NO_RENEGOTIATION but only for incoming ClientHello messages
(apparently unsetting SSL_OP_NO_RENEGOTIATION is too hard).

Provide SSL_OP_NO_RENEGOTIATION and SSL_OP_ALLOW_CLIENT_RENEGOTIATION,
primarily to make life easier for ports. If SSL_OP_NO_CLIENT_RENEGOTIATION
is set it will take precedence and render SSL_OP_ALLOW_CLIENT_RENEGOTIATION
ineffective. The rest of the behaviour should match OpenSSL, with the
exception of ClientHellos triggering fatal alerts instead of warnings.

ok tb@

1 files changed, 5 insertions, 1 deletions

diff --git a/src/lib/libssl/ssl.h b/src/lib/libssl/ssl.h
index 062c6dcbb9..a1ed22b778 100644
--- a/src/lib/libssl/ssl.h
+++ b/src/lib/libssl/ssl.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl.h,v 1.246 2025/03/09 15:53:36 tb Exp $ */
+/* $OpenBSD: ssl.h,v 1.247 2025/03/12 14:03:55 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -389,6 +389,10 @@ typedef int (*tls_session_secret_cb_fn)(SSL *s, void *secret, int *secret_len,
 #define SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION   0x00010000L
 /* Disallow client initiated renegotiation. */
 #define SSL_OP_NO_CLIENT_RENEGOTIATION                  0x00020000L
+/* Disallow client and server initiated renegotiation. */
+#define SSL_OP_NO_RENEGOTIATION                         0x00040000L
+/* Allow client initiated renegotiation. */
+#define SSL_OP_ALLOW_CLIENT_RENEGOTIATION               0x00080000L
 /* If set, always create a new key when using tmp_dh parameters */
 #define SSL_OP_SINGLE_DH_USE                            0x00100000L
 /* Set on servers to choose the cipher according to the server's