Deduplicate peer certificate chain processing code.

Rather than reimplement this in each TLS client and server, deduplicate it
into a single function. Furthermore, rather than dealing with the API
hazard that is SSL_get_peer_cert_chain() in this code, simply produce two
chains - one that has the leaf and one that does not.
SSL_get_peer_cert_chain() can then return the appropriate one.

This also moves the peer cert chain from the SSL_SESSION to the
SSL_HANDSHAKE, which makes more sense since it is not available on
resumption.

ok tb@

1 files changed, 8 insertions, 5 deletions

diff --git a/src/lib/libssl/ssl_lib.c b/src/lib/libssl/ssl_lib.c
index e346e3cf7f..9af1934dd6 100644
--- a/src/lib/libssl/ssl_lib.c
+++ b/src/lib/libssl/ssl_lib.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_lib.c,v 1.300 2022/07/24 15:05:16 jsing Exp $ */
+/* $OpenBSD: ssl_lib.c,v 1.301 2022/08/17 07:39:19 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -880,14 +880,17 @@ SSL_get_peer_certificate(const SSL *s)
 STACK_OF(X509) *
 SSL_get_peer_cert_chain(const SSL *s)
 {
-        if (s == NULL || s->session == NULL)
+        if (s == NULL)
                 return NULL;
 
         /*
-         * If we are a client, cert_chain includes the peer's own
-         * certificate; if we are a server, it does not.
+         * Achtung! Due to API inconsistency, a client includes the peer's leaf
+         * certificate in the peer certificate chain, while a server does not.
          */
-        return s->session->cert_chain;
+        if (!s->server)
+                return s->s3->hs.peer_certs;
+
+        return s->s3->hs.peer_certs_no_leaf;
 }
 
 STACK_OF(X509) *