Add lsquic_conn_get_full_cert_chain to obtain certs including leaf on server side

docs/apiref.rst

@@ -1970,6 +1970,13 @@ Miscellaneous Connection Functions
 
     The caller releases the stack using sk_X509_free().
 
+.. function:: struct stack_st_X509 * lsquic_conn_get_full_cert_chain (lsquic_conn_t *conn)
+
+    Get full certificate chain returned by the server/client.  This can be used for
+    server/client certificate verification.
+
+    The caller releases the stack using sk_X509_free().
+
 .. function:: lsquic_conn_ctx_t * lsquic_conn_get_ctx (const lsquic_conn_t *conn)
 
     Get user-supplied context associated with the connection.

include/lsquic.h

@@ -1784,6 +1784,16 @@ lsquic_stream_has_unacked_data (lsquic_stream_t *s);
 struct stack_st_X509 *
 lsquic_conn_get_server_cert_chain (lsquic_conn_t *);
 
+/**
+ * Get the full certificate chain returned by the server/lient.
+ * This can be used for server/client certificate verification.
+ *
+ * The caller releases the stack using sk_X509_free().
+ */
+struct stack_st_X509 *
+lsquic_conn_get_full_cert_chain (lsquic_conn_t *);
+
+
 /** Returns ID of the stream */
 lsquic_stream_id_t
 lsquic_stream_id (const lsquic_stream_t *s);

src/liblsquic/lsquic_conn.c

@@ -138,6 +138,16 @@ lsquic_conn_get_server_cert_chain (struct lsquic_conn *lconn)
 }
 
 
+struct stack_st_X509 *
+lsquic_conn_get_full_cert_chain (struct lsquic_conn *lconn)
+{
+    if (lconn->cn_enc_session)
+        return lconn->cn_esf_c->esf_get_full_cert_chain(lconn->cn_enc_session);
+    else
+        return NULL;
+}
+
+
 void
 lsquic_conn_make_stream (struct lsquic_conn *lconn)
 {

src/liblsquic/lsquic_enc_sess.h

@@ -118,6 +118,9 @@ struct enc_session_funcs_common
     struct stack_st_X509 *
     (*esf_get_server_cert_chain) (enc_session_t *);
 
+    struct stack_st_X509 *
+    (*esf_get_full_cert_chain) (enc_session_t *);
+
     int
     (*esf_verify_reset_token) (enc_session_t *, const unsigned char *, size_t);
 

src/liblsquic/lsquic_enc_sess_ietf.c

@@ -89,6 +89,9 @@ free_handshake_keys (struct enc_sess_iquic *);
 static struct stack_st_X509 *
 iquic_esf_get_server_cert_chain (enc_session_t *);
 
+static struct stack_st_X509 *
+iquic_esf_get_full_cert_chain (enc_session_t *);
+
 static void
 maybe_drop_SSL (struct enc_sess_iquic *);
 
@@ -2612,6 +2615,22 @@ iquic_esf_get_server_cert_chain (enc_session_t *enc_session_p)
 }
 
 
+static struct stack_st_X509 *
+iquic_esf_get_full_cert_chain (enc_session_t *enc_session_p)
+{
+    struct enc_sess_iquic *const enc_sess = enc_session_p;
+    STACK_OF(X509) *chain;
+
+    if (enc_sess->esi_ssl)
+    {
+        chain = SSL_get_peer_full_cert_chain(enc_sess->esi_ssl);
+        return X509_chain_up_ref(chain);
+    }
+    else
+        return NULL;
+}
+
+
 static const char *
 iquic_esf_cipher (enc_session_t *enc_session_p)
 {
@@ -2864,6 +2883,8 @@ const struct enc_session_funcs_common lsquic_enc_session_common_ietf_v1 =
     .esf_tag_len         = IQUIC_TAG_LEN,
     .esf_get_server_cert_chain
                          = iquic_esf_get_server_cert_chain,
+    .esf_get_full_cert_chain
+                         = iquic_esf_get_full_cert_chain,
     .esf_get_sni         = iquic_esf_get_sni,
     .esf_cipher          = iquic_esf_cipher,
     .esf_keysize         = iquic_esf_keysize,
@@ -2883,6 +2904,8 @@ const struct enc_session_funcs_common lsquic_enc_session_common_ietf_v1_no_flush
     .esf_tag_len         = IQUIC_TAG_LEN,
     .esf_get_server_cert_chain
                          = iquic_esf_get_server_cert_chain,
+    .esf_get_full_cert_chain
+                         = iquic_esf_get_full_cert_chain,
     .esf_get_sni         = iquic_esf_get_sni,
     .esf_cipher          = iquic_esf_cipher,
     .esf_keysize         = iquic_esf_keysize,