flood detected with file uploads over http2

[Ruslan Ermilov]

On Mon, Dec 16, 2019 at 05:45:55PM +0000, Jasper Wallace wrote:
> We are having intermittent problems uploading files via nginx to a
> flask backend over http2:
> 
> 2019/12/16 16:07:08 [debug] 27658#27658: *1 event timer: 3, old:
> 1576512608187, new: 1576512608301
> 2019/12/16 16:07:08 [debug] 27658#27658: *1 http2 idle handler
> 2019/12/16 16:07:08 [info] 27658#27658: *1 http2 flood detected while
> processing HTTP/2 connection, client: x.x.x.x, server: 0.0.0.0:443
> 2019/12/16 16:07:08 [debug] 27658#27658: *1 http2 send GOAWAY frame, status:0
> 2019/12/16 16:07:08 [debug] 27658#27658: *1 posix_memalign:
> 0000563642B8EE20:512 @16
> 2019/12/16 16:07:08 [debug] 27658#27658: *1 http2 frame out:
> 0000563642B8EE40 sid:0 bl:0 len:8
> 2019/12/16 16:07:08 [debug] 27658#27658: *1 malloc: 0000563642D0A870:16384
> 2019/12/16 16:07:08 [debug] 27658#27658: *1 SSL buf copy: 17
> 2019/12/16 16:07:08 [debug] 27658#27658: *1 SSL to write: 17
> 
> Is there anyway of getting information on what might be triggering this?
> 
> We've changed some defaults:
> 
> client_max_body_size 10m;
> http2_body_preread_size 256k;
> http2_recv_buffer_size 1m;
> proxy_headers_hash_max_size 512;
> proxy_headers_hash_bucket_size 128;
> 
> Client is Chrome:
> 
> Version 78.0.3904.97 (Developer Build) built on Debian 10.1, running
> on Debian 10.2 (64-bit)
> 
> openssl:
> 
> OpenSSL 1.1.0l  10 Sep 2019
> 
> nginx:
> 
> nginx version: nginx/1.10.3
> built with OpenSSL 1.1.0k  28 May 2019 (running with OpenSSL 1.1.0l
> 10 Sep 2019)
> TLS SNI support enabled
> configure arguments: --with-cc-opt='-g -O2
> -fdebug-prefix-map=/build/nginx-DhOtPd/nginx-1.10.3=.
> -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time
> -D_FORTIFY_SOURCE=2' --with-ld-opt='-Wl,-z,relro -Wl,-z,now'
> --prefix=/usr/share/nginx --conf-path=/etc/nginx/nginx.conf
> --http-log-path=/var/log/nginx/access.log
> --error-log-path=/var/log/nginx/error.log
> --lock-path=/var/lock/nginx.lock --pid-path=/run/nginx.pid
> --modules-path=/usr/lib/nginx/modules
> --http-client-body-temp-path=/var/lib/nginx/body
> --http-fastcgi-temp-path=/var/lib/nginx/fastcgi
> --http-proxy-temp-path=/var/lib/nginx/proxy
> --http-scgi-temp-path=/var/lib/nginx/scgi
> --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --with-debug
> --with-pcre-jit --with-ipv6 --with-http_ssl_module
> --with-http_stub_status_module --with-http_realip_module
> --with-http_auth_request_module --with-http_v2_module
> --with-http_dav_module --with-http_slice_module --with-threads
> --with-http_addition_module --with-http_flv_module
> --with-http_geoip_module=dynamic --with-http_gunzip_module
> --with-http_gzip_static_module --with-http_image_filter_module=dynamic
> --with-http_mp4_module --with-http_perl_module=dynamic
> --with-http_random_index_module --with-http_secure_link_module
> --with-http_sub_module --with-http_xslt_module=dynamic
> --with-mail=dynamic --with-mail_ssl_module --with-stream=dynamic
> --with-stream_ssl_module
> --add-dynamic-module=/build/nginx-DhOtPd/nginx-1.10.3/debian/modules/headers-more-nginx-module
> --add-dynamic-module=/build/nginx-DhOtPd/nginx-1.10.3/debian/modules/nginx-auth-pam
> --add-dynamic-module=/build/nginx-DhOtPd/nginx-1.10.3/debian/modules/nginx-cache-purge
> --add-dynamic-module=/build/nginx-DhOtPd/nginx-1.10.3/debian/modules/nginx-dav-ext-module
> --add-dynamic-module=/build/nginx-DhOtPd/nginx-1.10.3/debian/modules/nginx-development-kit
> --add-dynamic-module=/build/nginx-DhOtPd/nginx-1.10.3/debian/modules/nginx-echo
> --add-dynamic-module=/build/nginx-DhOtPd/nginx-1.10.3/debian/modules/ngx-fancyindex
> --add-dynamic-module=/build/nginx-DhOtPd/nginx-1.10.3/debian/modules/nchan
> --add-dynamic-module=/build/nginx-DhOtPd/nginx-1.10.3/debian/modules/nginx-lua
> --add-dynamic-module=/build/nginx-DhOtPd/nginx-1.10.3/debian/modules/nginx-upload-progress
> --add-dynamic-module=/build/nginx-DhOtPd/nginx-1.10.3/debian/modules/nginx-upstream-fair
> --add-dynamic-module=/build/nginx-DhOtPd/nginx-1.10.3/debian/modules/ngx_http_substitutions_filter_module

nginx/1.10.3 doesn't have HTTP/2 flood detection.  It appeared
in later versions.