diff options
author | Ruslan Ermilov <ru@nginx.com> | 2018-11-06 16:29:49 +0300 |
---|---|---|
committer | Ruslan Ermilov <ru@nginx.com> | 2018-11-06 16:29:49 +0300 |
commit | b5802dbf51cf713f84c763180bc45069fb3bf320 (patch) | |
tree | 9ed4b8c7bf4dd9508713994fba8ead78a3c8863a | |
parent | 65b2c00d624f17892c777f8fb5bb9c623cff5188 (diff) |
HTTP/2: limit the number of idle state switches.
An attack that continuously switches HTTP/2 connection between
idle and active states can result in excessive CPU usage.
This is because when a connection switches to the idle state,
all of its memory pool caches are freed.
This change limits the maximum allowed number of idle state
switches to 10 * http2_max_requests (i.e., 10000 by default).
This limits possible CPU usage in one connection, and also
imposes a limit on the maximum lifetime of a connection.
Initially reported by Gal Goldshtein from F5 Networks.
-rw-r--r-- | src/http/v2/ngx_http_v2.c | 13 | ||||
-rw-r--r-- | src/http/v2/ngx_http_v2.h | 1 |
2 files changed, 11 insertions, 3 deletions
diff --git a/src/http/v2/ngx_http_v2.c b/src/http/v2/ngx_http_v2.c index 17d7cad04..12214e157 100644 --- a/src/http/v2/ngx_http_v2.c +++ b/src/http/v2/ngx_http_v2.c @@ -4481,12 +4481,19 @@ ngx_http_v2_idle_handler(ngx_event_t *rev) #endif - c->destroyed = 0; - ngx_reusable_connection(c, 0); - h2scf = ngx_http_get_module_srv_conf(h2c->http_connection->conf_ctx, ngx_http_v2_module); + if (h2c->idle++ > 10 * h2scf->max_requests) { + ngx_log_error(NGX_LOG_INFO, h2c->connection->log, 0, + "http2 flood detected"); + ngx_http_v2_finalize_connection(h2c, NGX_HTTP_V2_NO_ERROR); + return; + } + + c->destroyed = 0; + ngx_reusable_connection(c, 0); + h2c->pool = ngx_create_pool(h2scf->pool_size, h2c->connection->log); if (h2c->pool == NULL) { ngx_http_v2_finalize_connection(h2c, NGX_HTTP_V2_INTERNAL_ERROR); diff --git a/src/http/v2/ngx_http_v2.h b/src/http/v2/ngx_http_v2.h index e8eaebb25..bec22160e 100644 --- a/src/http/v2/ngx_http_v2.h +++ b/src/http/v2/ngx_http_v2.h @@ -121,6 +121,7 @@ struct ngx_http_v2_connection_s { ngx_uint_t processing; ngx_uint_t frames; + ngx_uint_t idle; ngx_uint_t pushing; ngx_uint_t concurrent_pushes; |