# HG changeset patch
# User Roman Arutyunyan <arut@nginx.com>
# Date 1605128928 0
# Node ID 831d1960826f2de7958a5d9d2f0462e23ff63def
# Parent  d8b01c2b89315216aa424759600f0704aa3dcbed
QUIC: generate default stateless reset token key.

Previously, if quic_stateless_reset_token_key was empty or unspecified,
initial stateless reset token was not generated.  However subsequent tokens
were generated with empty key, which resulted in error with certain SSL
libraries, for example OpenSSL.

Now a random 32-byte stateless reset token key is generated if none is
specified in the configuration.  As a result, stateless reset tokens are now
generated for all server ids.

diff --git a/src/event/ngx_event_quic.c b/src/event/ngx_event_quic.c
--- a/src/event/ngx_event_quic.c
+++ b/src/event/ngx_event_quic.c
@@ -1133,10 +1133,6 @@ ngx_quic_send_stateless_reset(ngx_connec
     ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, 0,
                    "quic handle stateless reset output");
 
-    if (conf->sr_token_key.len == 0) {
-        return NGX_DECLINED;
-    }
-
     if (pkt->len <= NGX_QUIC_MIN_PKT_LEN) {
         return NGX_DECLINED;
     }
@@ -1573,19 +1569,15 @@ ngx_quic_init_connection(ngx_connection_
     }
 #endif
 
-    if (qc->conf->sr_token_key.len) {
-        qc->tp.sr_enabled = 1;
-
-        if (ngx_quic_new_sr_token(c, &qc->dcid, &qc->conf->sr_token_key,
-                                  qc->tp.sr_token)
-            != NGX_OK)
-        {
-            return NGX_ERROR;
-        }
-
-        ngx_quic_hexdump(c->log, "quic stateless reset token",
-                         qc->tp.sr_token, (size_t) NGX_QUIC_SR_TOKEN_LEN);
-    }
+    if (ngx_quic_new_sr_token(c, &qc->dcid, &qc->conf->sr_token_key,
+                              qc->tp.sr_token)
+        != NGX_OK)
+    {
+        return NGX_ERROR;
+    }
+
+    ngx_quic_hexdump(c->log, "quic stateless reset token",
+                     qc->tp.sr_token, (size_t) NGX_QUIC_SR_TOKEN_LEN);
 
     len = ngx_quic_create_transport_params(NULL, NULL, &qc->tp, &clen);
     /* always succeeds */
diff --git a/src/event/ngx_event_quic.h b/src/event/ngx_event_quic.h
--- a/src/event/ngx_event_quic.h
+++ b/src/event/ngx_event_quic.h
@@ -27,6 +27,7 @@
 
 #define NGX_QUIC_DEFAULT_ACK_DELAY_EXPONENT  3
 #define NGX_QUIC_DEFAULT_MAX_ACK_DELAY       25
+#define NGX_QUIC_DEFAULT_SRT_KEY_LEN         32
 
 #define NGX_QUIC_RETRY_TIMEOUT               3000
 #define NGX_QUIC_RETRY_LIFETIME              30000
@@ -82,7 +83,6 @@ typedef struct {
     ngx_str_t                  initial_scid;
     ngx_str_t                  retry_scid;
     u_char                     sr_token[NGX_QUIC_SR_TOKEN_LEN];
-    ngx_uint_t                 sr_enabled;
 
     /* TODO */
     void                      *preferred_address;
diff --git a/src/event/ngx_event_quic_transport.c b/src/event/ngx_event_quic_transport.c
--- a/src/event/ngx_event_quic_transport.c
+++ b/src/event/ngx_event_quic_transport.c
@@ -1883,11 +1883,9 @@ ngx_quic_create_transport_params(u_char 
     }
 #endif
 
-    if (tp->sr_enabled) {
-        len += ngx_quic_varint_len(NGX_QUIC_TP_SR_TOKEN);
-        len += ngx_quic_varint_len(NGX_QUIC_SR_TOKEN_LEN);
-        len += NGX_QUIC_SR_TOKEN_LEN;
-    }
+    len += ngx_quic_varint_len(NGX_QUIC_TP_SR_TOKEN);
+    len += ngx_quic_varint_len(NGX_QUIC_SR_TOKEN_LEN);
+    len += NGX_QUIC_SR_TOKEN_LEN;
 
     if (pos == NULL) {
         return len;
@@ -1935,11 +1933,9 @@ ngx_quic_create_transport_params(u_char 
     }
 #endif
 
-    if (tp->sr_enabled) {
-        ngx_quic_build_int(&p, NGX_QUIC_TP_SR_TOKEN);
-        ngx_quic_build_int(&p, NGX_QUIC_SR_TOKEN_LEN);
-        p = ngx_cpymem(p, tp->sr_token, NGX_QUIC_SR_TOKEN_LEN);
-    }
+    ngx_quic_build_int(&p, NGX_QUIC_TP_SR_TOKEN);
+    ngx_quic_build_int(&p, NGX_QUIC_SR_TOKEN_LEN);
+    p = ngx_cpymem(p, tp->sr_token, NGX_QUIC_SR_TOKEN_LEN);
 
     return p - pos;
 }
diff --git a/src/http/modules/ngx_http_quic_module.c b/src/http/modules/ngx_http_quic_module.c
--- a/src/http/modules/ngx_http_quic_module.c
+++ b/src/http/modules/ngx_http_quic_module.c
@@ -317,6 +317,19 @@ ngx_http_quic_merge_srv_conf(ngx_conf_t 
 
     ngx_conf_merge_str_value(conf->sr_token_key, prev->sr_token_key, "");
 
+    if (conf->sr_token_key.len == 0) {
+        conf->sr_token_key.len = NGX_QUIC_DEFAULT_SRT_KEY_LEN;
+
+        conf->sr_token_key.data = ngx_pnalloc(cf->pool, conf->sr_token_key.len);
+        if (conf->sr_token_key.data == NULL) {
+            return NGX_CONF_ERROR;
+        }
+
+        if (RAND_bytes(conf->sr_token_key.data, conf->sr_token_key.len) <= 0) {
+            return NGX_CONF_ERROR;
+        }
+    }
+
     sscf = ngx_http_conf_get_module_srv_conf(cf, ngx_http_ssl_module);
     conf->ssl = &sscf->ssl;
 
diff --git a/src/stream/ngx_stream_quic_module.c b/src/stream/ngx_stream_quic_module.c
--- a/src/stream/ngx_stream_quic_module.c
+++ b/src/stream/ngx_stream_quic_module.c
@@ -313,6 +313,19 @@ ngx_stream_quic_merge_srv_conf(ngx_conf_
 
     ngx_conf_merge_str_value(conf->sr_token_key, prev->sr_token_key, "");
 
+    if (conf->sr_token_key.len == 0) {
+        conf->sr_token_key.len = NGX_QUIC_DEFAULT_SRT_KEY_LEN;
+
+        conf->sr_token_key.data = ngx_pnalloc(cf->pool, conf->sr_token_key.len);
+        if (conf->sr_token_key.data == NULL) {
+            return NGX_CONF_ERROR;
+        }
+
+        if (RAND_bytes(conf->sr_token_key.data, conf->sr_token_key.len) <= 0) {
+            return NGX_CONF_ERROR;
+        }
+    }
+
     scf = ngx_stream_conf_get_module_srv_conf(cf, ngx_stream_ssl_module);
     conf->ssl = &scf->ssl;