details: https://hg.nginx.org/nginx/rev/a23a7e6edac4 branches: stable-1.16 changeset: 7556:a23a7e6edac4 user: Ruslan Ermilov <r...@nginx.com> date: Tue Aug 13 15:43:40 2019 +0300 description: 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. diffstat: src/http/v2/ngx_http_v2.c | 10 ++++++++++ src/http/v2/ngx_http_v2.h | 1 + 2 files changed, 11 insertions(+), 0 deletions(-) diffs (45 lines): diff --git a/src/http/v2/ngx_http_v2.c b/src/http/v2/ngx_http_v2.c --- a/src/http/v2/ngx_http_v2.c +++ b/src/http/v2/ngx_http_v2.c @@ -273,6 +273,7 @@ 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) { @@ -1804,6 +1805,13 @@ ngx_http_v2_state_priority(ngx_http_v2_c 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_co 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 --- 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; _______________________________________________ nginx-devel mailing list nginx-devel@nginx.org http://mailman.nginx.org/mailman/listinfo/nginx-devel