Remove cipher from SSL_SESSION.

For a long time SSL_SESSION has had both a cipher ID and a pointer to
an SSL_CIPHER (and not both are guaranteed to be populated). There is also
a pointer to an SSL_CIPHER in the SSL_HANDSHAKE that denotes the cipher
being used for this connection. Some code has been using the cipher from
SSL_SESSION and some code has been using the cipher from SSL_HANDSHAKE.

Remove cipher from SSL_SESSION and use the version in SSL_HANDSHAKE
everywhere. If resuming from a session then we need to use the SSL_SESSION
cipher ID to set the SSL_HANDSHAKE cipher. And we still need to ensure that
we update the cipher ID in the SSL_SESSION whenever the SSL_HANDSHAKE
cipher changes (this only occurs in a few places).

ok tb@

1 files changed, 2 insertions, 9 deletions

diff --git a/src/lib/libssl/ssl_sess.c b/src/lib/libssl/ssl_sess.c
index 76f194ca78..c2bd1bf135 100644
--- a/src/lib/libssl/ssl_sess.c
+++ b/src/lib/libssl/ssl_sess.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_sess.c,v 1.126 2024/07/19 08:54:31 jsing Exp $ */
+/* $OpenBSD: ssl_sess.c,v 1.127 2024/07/20 04:04:23 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -287,7 +287,6 @@ ssl_session_dup(SSL_SESSION *sess, int include_ticket)
         copy->time = sess->time;
         copy->references = 1;
 
-        copy->cipher = sess->cipher;
         copy->cipher_id = sess->cipher_id;
 
         if (sess->tlsext_hostname != NULL) {
@@ -707,12 +706,6 @@ ssl_get_prev_session(SSL *s, CBS *session_id, CBS *ext_block, int *alert)
                 goto err;
         }
 
-        if (sess->cipher == NULL) {
-                sess->cipher = ssl3_get_cipher_by_id(sess->cipher_id);
-                if (sess->cipher == NULL)
-                        goto err;
-        }
-
         if (sess->timeout < (time(NULL) - sess->time)) {
                 s->session_ctx->stats.sess_timeout++;
                 if (!ticket_decrypted) {
@@ -991,7 +984,7 @@ LSSL_ALIAS(SSL_SESSION_get_protocol_version);
 const SSL_CIPHER *
 SSL_SESSION_get0_cipher(const SSL_SESSION *s)
 {
-        return s->cipher;
+        return ssl3_get_cipher_by_id(s->cipher_id);
 }
 LSSL_ALIAS(SSL_SESSION_get0_cipher);