HTTP/2: flood detection.

Fixed uncontrolled memory growth in case peer is flooding us with
some frames (e.g., SETTINGS and PING) and doesn't read data.  Fix
is to limit the number of allocated control frames.

2 files changed, 12 insertions, 1 deletions

diff --git a/src/http/v2/ngx_http_v2.c b/src/http/v2/ngx_http_v2.c
index 77ebb8474..17d7cad04 100644
--- a/src/http/v2/ngx_http_v2.c
+++ b/src/http/v2/ngx_http_v2.c
@@ -664,6 +664,7 @@ ngx_http_v2_handle_connection(ngx_http_v2_connection_t *h2c)
 
     h2c->pool = NULL;
     h2c->free_frames = NULL;
+    h2c->frames = 0;
     h2c->free_fake_connections = NULL;
 
 #if (NGX_HTTP_SSL)
@@ -2895,7 +2896,7 @@ ngx_http_v2_get_frame(ngx_http_v2_connection_t *h2c, size_t length,
 
         frame->blocked = 0;
 
-    } else {
+    } else if (h2c->frames < 10000) {
         pool = h2c->pool ? h2c->pool : h2c->connection->pool;
 
         frame = ngx_pcalloc(pool, sizeof(ngx_http_v2_out_frame_t));
@@ -2919,6 +2920,15 @@ ngx_http_v2_get_frame(ngx_http_v2_connection_t *h2c, size_t length,
         frame->last = frame->first;
 
         frame->handler = ngx_http_v2_frame_handler;
+
+        h2c->frames++;
+
+    } else {
+        ngx_log_error(NGX_LOG_INFO, h2c->connection->log, 0,
+                      "http2 flood detected");
+
+        h2c->connection->error = 1;
+        return NULL;
     }
 
 #if (NGX_DEBUG)
diff --git a/src/http/v2/ngx_http_v2.h b/src/http/v2/ngx_http_v2.h
index ebd0e77c0..e8eaebb25 100644
--- a/src/http/v2/ngx_http_v2.h
+++ b/src/http/v2/ngx_http_v2.h
@@ -120,6 +120,7 @@ struct ngx_http_v2_connection_s {
     ngx_http_connection_t           *http_connection;
 
     ngx_uint_t                       processing;
+    ngx_uint_t                       frames;
 
     ngx_uint_t                       pushing;
     ngx_uint_t                       concurrent_pushes;