Add basic ECH shared-mode via OpenSSL.

2 files changed, 177 insertions, 0 deletions

diff --git a/src/event/ngx_event_openssl.c b/src/event/ngx_event_openssl.c
index a5af0ed3d..fe2302966 100644
--- a/src/event/ngx_event_openssl.c
+++ b/src/event/ngx_event_openssl.c
@@ -1654,6 +1654,102 @@ ngx_ssl_dhparam(ngx_conf_t *cf, ngx_ssl_t *ssl, ngx_str_t *file)
 
 
 ngx_int_t
+ngx_ssl_ech_files(ngx_conf_t *cf, ngx_ssl_t *ssl, ngx_array_t *filenames)
+{
+#ifdef SSL_OP_ECH_GREASE
+    int             numkeys;
+    BIO            *in;
+    ngx_int_t       rc;
+    ngx_str_t      *filename;
+    ngx_uint_t      i;
+    OSSL_ECHSTORE  *es;
+
+    if (filenames == NULL) {
+        return NGX_OK;
+    }
+
+    es = OSSL_ECHSTORE_new(NULL, NULL);
+    if (es == NULL) {
+        ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0, "OSSL_ECHSTORE_new() failed");
+        return NGX_ERROR;
+    }
+
+    rc = NGX_ERROR;
+    filename = filenames->elts;
+
+    for (i = 0; i < filenames->nelts; i++) {
+
+        if (ngx_conf_full_name(cf->cycle, &filename[i], 1) != NGX_OK) {
+            goto cleanup;
+        }
+
+        in = BIO_new_file((char *) filename[i].data, "r");
+        if (in == NULL) {
+            ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
+                          "BIO_new_file(\"%s\") failed", filename[i].data);
+            goto cleanup;
+        }
+
+        /*
+         * We only set the ECHConfigList from the first file read to use
+         * in ECH retry-configs.
+         *
+         * That allows many sensible key rotation schemes so that the
+         * values sent in ECH retry-configs are smaller and current.
+         * For example, if the first file name has the current ECH
+         * private key, and a second one has the previously used key
+         * that some clients may still use due to DNS caching.
+         */
+
+         if (OSSL_ECHSTORE_read_pem(es, in, i ? OSSL_ECH_NO_RETRY
+                                              : OSSL_ECH_FOR_RETRY)
+             != 1)
+         {
+             ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
+                           "OSSL_ECHSTORE_read_pem(%s) failed",
+                           filename[i].data);
+             BIO_free(in);
+             goto cleanup;
+         }
+
+         BIO_free(in);
+    }
+
+    /*
+     * load the ECH store after checking there's at least one ECH
+     * private key in there (the PEM file spec allows zero or one
+     * private key per file)
+     */
+
+    if (OSSL_ECHSTORE_num_keys(es, &numkeys) != 1) {
+        ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
+                      "OSSL_ECHSTORE_num_keys(%s) failed");
+        goto cleanup;
+    }
+
+    if (numkeys > 0 && SSL_CTX_set1_echstore(ssl->ctx, es) != 1) {
+        ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
+                      "SSL_CTX_set1_echstore() failed");
+        goto cleanup;
+    }
+
+    rc = NGX_OK;
+
+cleanup:
+
+    OSSL_ECHSTORE_free(es);
+    return rc;
+
+#else
+    ngx_log_error(NGX_LOG_WARN, ssl->log, 0,
+                  "\"ssl_ech_file\" is not supported on this platform, "
+                  "ignored");
+    return NGX_OK;
+#endif
+}
+
+
+ngx_int_t
 ngx_ssl_ecdh_curve(ngx_conf_t *cf, ngx_ssl_t *ssl, ngx_str_t *name)
 {
 #ifndef OPENSSL_NO_ECDH
@@ -5709,6 +5805,81 @@ ngx_ssl_get_alpn_protocol(ngx_connection_t *c, ngx_pool_t *pool, ngx_str_t *s)
 
 
 ngx_int_t
+ngx_ssl_get_ech_status(ngx_connection_t *c, ngx_pool_t *pool, ngx_str_t *s)
+{
+#ifdef SSL_OP_ECH_GREASE
+    int    echrv;
+    char  *inner_sni, *outer_sni;
+
+    inner_sni = NULL;
+    outer_sni = NULL;
+
+    echrv = SSL_ech_get1_status(c->ssl->connection, &inner_sni, &outer_sni);
+
+    switch (echrv) {
+    case SSL_ECH_STATUS_NOT_TRIED:
+        ngx_str_set(s, "NOT_TRIED");
+        break;
+    case SSL_ECH_STATUS_SUCCESS:
+        ngx_str_set(s, "SUCCESS");
+        break;
+    case SSL_ECH_STATUS_GREASE:
+        ngx_str_set(s, "GREASE");
+        break;
+    case SSL_ECH_STATUS_BACKEND:
+        ngx_str_set(s, "BACKEND");
+        break;
+    default:
+        ngx_str_set(s, "FAILED");
+        break;
+    }
+
+    OPENSSL_free(inner_sni);
+    OPENSSL_free(outer_sni);
+#else
+    s->len = 0;
+#endif
+    return NGX_OK;
+}
+
+
+ngx_int_t
+ngx_ssl_get_ech_outer_server_name(ngx_connection_t *c, ngx_pool_t *pool,
+    ngx_str_t *s)
+{
+#if defined(SSL_OP_ECH_GREASE)
+    int    echrv;
+    char  *inner_sni, *outer_sni;
+
+    inner_sni = NULL;
+    outer_sni = NULL;
+
+    echrv = SSL_ech_get1_status(c->ssl->connection, &inner_sni, &outer_sni);
+
+    if (echrv == SSL_ECH_STATUS_SUCCESS && outer_sni) {
+        s->len = ngx_strlen(outer_sni);
+
+        s->data = ngx_pnalloc(pool, s->len);
+        if (s->data == NULL) {
+            return NGX_ERROR;
+        }
+
+        ngx_memcpy(s->data, outer_sni, s->len);
+
+    } else {
+        s->len = 0;
+    }
+
+    OPENSSL_free(inner_sni);
+    OPENSSL_free(outer_sni);
+#else
+    s->len = 0;
+#endif
+    return NGX_OK;
+}
+
+
+ngx_int_t
 ngx_ssl_get_raw_certificate(ngx_connection_t *c, ngx_pool_t *pool, ngx_str_t *s)
 {
     size_t   len;
diff --git a/src/event/ngx_event_openssl.h b/src/event/ngx_event_openssl.h
index a156c4bb9..d86ffb8da 100644
--- a/src/event/ngx_event_openssl.h
+++ b/src/event/ngx_event_openssl.h
@@ -271,6 +271,8 @@ ngx_array_t *ngx_ssl_read_password_file(ngx_conf_t *cf, ngx_str_t *file);
 ngx_array_t *ngx_ssl_preserve_passwords(ngx_conf_t *cf,
     ngx_array_t *passwords);
 ngx_int_t ngx_ssl_dhparam(ngx_conf_t *cf, ngx_ssl_t *ssl, ngx_str_t *file);
+ngx_int_t ngx_ssl_ech_files(ngx_conf_t *cf, ngx_ssl_t *ssl,
+    ngx_array_t *filename);
 ngx_int_t ngx_ssl_ecdh_curve(ngx_conf_t *cf, ngx_ssl_t *ssl, ngx_str_t *name);
 ngx_int_t ngx_ssl_early_data(ngx_conf_t *cf, ngx_ssl_t *ssl,
     ngx_uint_t enable);
@@ -338,6 +340,10 @@ ngx_int_t ngx_ssl_get_early_data(ngx_connection_t *c, ngx_pool_t *pool,
     ngx_str_t *s);
 ngx_int_t ngx_ssl_get_server_name(ngx_connection_t *c, ngx_pool_t *pool,
     ngx_str_t *s);
+ngx_int_t ngx_ssl_get_ech_status(ngx_connection_t *c, ngx_pool_t *pool,
+    ngx_str_t *s);
+ngx_int_t ngx_ssl_get_ech_outer_server_name(ngx_connection_t *c,
+    ngx_pool_t *pool, ngx_str_t *s);
 ngx_int_t ngx_ssl_get_alpn_protocol(ngx_connection_t *c, ngx_pool_t *pool,
     ngx_str_t *s);
 ngx_int_t ngx_ssl_get_raw_certificate(ngx_connection_t *c, ngx_pool_t *pool,