diff src/event/quic/ngx_event_quic_output.c @ 9169:60c4e8d3151f

QUIC: added safety belt to prevent using discarded keys. In addition to triggering alert, it ensures that such packets won't be sent. With the previous change that marks server keys as discarded by zeroing the key lengh, it is now an error to send packets with discarded keys. OpenSSL based stacks tolerate such behaviour because key length isn't used in packet protection, but BoringSSL will raise the UNSUPPORTED_KEY_SIZE cipher error. It won't be possible to use discarded keys with reused crypto contexts as it happens in subsequent changes.
author Sergey Kandaurov <pluknet@nginx.com>
date Fri, 20 Oct 2023 18:05:07 +0400
parents 58afcd72446f
children 4ccb0d973206
line wrap: on
line diff
--- a/src/event/quic/ngx_event_quic_output.c
+++ b/src/event/quic/ngx_event_quic_output.c
@@ -519,6 +519,21 @@ ngx_quic_output_packet(ngx_connection_t 
 
     qc = ngx_quic_get_connection(c);
 
+    if (!ngx_quic_keys_available(qc->keys, ctx->level, 1)) {
+        ngx_log_error(NGX_LOG_ALERT, c->log, 0, "quic %s write keys discarded",
+                      ngx_quic_level_name(ctx->level));
+
+        while (!ngx_queue_empty(&ctx->frames)) {
+            q = ngx_queue_head(&ctx->frames);
+            ngx_queue_remove(q);
+
+            f = ngx_queue_data(q, ngx_quic_frame_t, queue);
+            ngx_quic_free_frame(c, f);
+        }
+
+        return 0;
+    }
+
     ngx_quic_init_packet(c, ctx, &pkt, qc->path);
 
     min_payload = ngx_quic_payload_size(&pkt, min);