Fix some bugs in the TLSv1.3 PSK code

Found while developing the PSK tests
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3670)

ssl/statem/extensions_clnt.c

@@ -898,7 +898,7 @@ EXT_RETURN tls_construct_ctos_psk(SSL *s, WPACKET *pkt, unsigned int context,
             goto err;
         }
 
-        if (s->hello_retry_request && mdres != handmd) {
+        if (s->hello_retry_request && mdpsk != handmd) {
             /*
              * Selected ciphersuite hash does not match the hash for the PSK
              * session. This is an application bug.
@@ -971,12 +971,15 @@ EXT_RETURN tls_construct_ctos_psk(SSL *s, WPACKET *pkt, unsigned int context,
 
     if (dores)
         s->session->ext.tick_identity = 0;
+    SSL_SESSION_free(s->psksession);
     s->psksession = psksess;
     if (psksess != NULL)
         s->psksession->ext.tick_identity = (dores ? 1 : 0);
+    psksess = NULL;
 
     ret = EXT_RETURN_SENT;
  err:
+    SSL_SESSION_free(psksess);
     return ret;
 #else
     return 1;

ssl/statem/extensions_srvr.c

@@ -713,8 +713,15 @@ int tls_parse_ctos_psk(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
         }
 
         if (s->psk_find_session_cb != NULL
-                && s->psk_find_session_cb(s, PACKET_data(&identity),
-                                          PACKET_remaining(&identity), &sess)) {
+                && !s->psk_find_session_cb(s, PACKET_data(&identity),
+                                           PACKET_remaining(&identity),
+                                           &sess)) {
+            *al = SSL_AD_INTERNAL_ERROR;
+            return 0;
+        }
+
+        if (sess != NULL) {
+            /* We found a PSK */
             SSL_SESSION *sesstmp = ssl_session_dup(sess, 0);
 
             if (sesstmp == NULL) {