From bbdc81631b6d322785d8e92788fd400e25a931e6 Mon Sep 17 00:00:00 2001 From: Ruslan Ermilov Date: Tue, 13 Aug 2019 15:43:40 +0300 Subject: [PATCH 3/3] HTTP/2: limited number of PRIORITY frames. Fixed excessive CPU usage caused by a peer that continuously shuffles priority of streams. Fix is to limit the number of PRIORITY frames. --- src/http/v2/ngx_http_v2.c | 10 ++++++++++ src/http/v2/ngx_http_v2.h | 1 + 2 files changed, 11 insertions(+) diff --git a/src/http/v2/ngx_http_v2.c b/src/http/v2/ngx_http_v2.c index 1b01f271..fd6ecb05 100644 --- a/src/http/v2/ngx_http_v2.c +++ b/src/http/v2/ngx_http_v2.c @@ -275,6 +275,7 @@ ngx_http_v2_init(ngx_event_t *rev) h2scf = ngx_http_get_module_srv_conf(hc->conf_ctx, ngx_http_v2_module); h2c->concurrent_pushes = h2scf->concurrent_pushes; + h2c->priority_limit = h2scf->concurrent_streams; h2c->pool = ngx_create_pool(h2scf->pool_size, h2c->connection->log); if (h2c->pool == NULL) { @@ -1806,6 +1807,13 @@ ngx_http_v2_state_priority(ngx_http_v2_connection_t *h2c, u_char *pos, return ngx_http_v2_connection_error(h2c, NGX_HTTP_V2_SIZE_ERROR); } + if (--h2c->priority_limit == 0) { + ngx_log_error(NGX_LOG_INFO, h2c->connection->log, 0, + "client sent too many PRIORITY frames"); + + return ngx_http_v2_connection_error(h2c, NGX_HTTP_V2_ENHANCE_YOUR_CALM); + } + if (end - pos < NGX_HTTP_V2_PRIORITY_SIZE) { return ngx_http_v2_state_save(h2c, pos, end, ngx_http_v2_state_priority); @@ -3120,6 +3128,8 @@ ngx_http_v2_create_stream(ngx_http_v2_connection_t *h2c, ngx_uint_t push) h2c->processing++; } + h2c->priority_limit += h2scf->concurrent_streams; + return stream; } diff --git a/src/http/v2/ngx_http_v2.h b/src/http/v2/ngx_http_v2.h index 715b7d30..69d55d1c 100644 --- a/src/http/v2/ngx_http_v2.h +++ b/src/http/v2/ngx_http_v2.h @@ -122,6 +122,7 @@ struct ngx_http_v2_connection_s { ngx_uint_t processing; ngx_uint_t frames; ngx_uint_t idle; + ngx_uint_t priority_limit; ngx_uint_t pushing; ngx_uint_t concurrent_pushes; -- 2.20.1