Fix early_data age calculation

The ticket_age/age_add values use ms granualarity. We were incorrectly
treating them as seconds and so the ticket was always being rejected for
early data. We also clarify a comment which could have been the source of
the confusion.

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/20387)

diff --git a/ssl/statem/extensions_srvr.c b/ssl/statem/extensions_srvr.c
index a0a48e405fb2ed821a43692817169ab4014177df..ff1f2a77e06a6eecead5c0a0017ad55977fe4e58 100644 (file)
--- a/ssl/statem/extensions_srvr.c
+++ b/ssl/statem/extensions_srvr.c
@@ -1155,16 +1155,18 @@ int tls_parse_ctos_psk(SSL_CONNECTION *s, PACKET *pkt, unsigned int context,
                 continue;
             }
 
-            age = ossl_time_subtract(ossl_seconds2time(ticket_agel),
-                                     ossl_seconds2time(sess->ext.tick_age_add));
+            age = ossl_time_subtract(ossl_ms2time(ticket_agel),
+                                     ossl_ms2time(sess->ext.tick_age_add));
             t = ossl_time_subtract(ossl_time_now(), sess->time);
 
             /*
-             * Beause we use second granuality, it could appear that
-             * the client's ticket age is longer than ours (our ticket
-             * age calculation should always be slightly longer than the
-             * client's due to the network latency).  Therefore we add
-             * 1000ms to our age calculation to adjust for rounding errors.
+             * Although internally we use OSS_TIME which has ns granularity,
+             * when SSL_SESSION structures are serialised/deserialised we use
+             * second granularity for the sess->time field. Therefore it could
+             * appear that the client's ticket age is longer than ours (our
+             * ticket age calculation should always be slightly longer than the
+             * client's due to the network latency). Therefore we add 1000ms to
+             * our age calculation to adjust for rounding errors.
              */
             expire = ossl_time_add(t, ossl_ms2time(1000));