id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	uname	nginx_version
2287	fastcgi: CONTENT_LENGTH parameter missing for chunked requests	SiebelsTim@…		"When disabling `fastcgi_request_buffering` and receiving a request with chunked transfer encoding, nginx does not pass a CONTENT_LENGTH parameter to the fastcgi responder.

As a result, we must disable `fastcgi_request_buffering` entirely, rather than having nginx handle it itself regarding the request type.

The specification  says:

> Next the Responder application receives CGI/1.1 stdin data from the Web server over FCGI_STDIN. The application receives at most CONTENT_LENGTH bytes from this stream before receiving the end-of-stream indication. (The application receives less than CONTENT_LENGTH bytes only if the HTTP client fails to provide them, e.g. because the client crashed.)

Furthermore, the CGI specification  says:

> The server MUST set this meta-variable if and only if the request is accompanied by a message-body entity.  The CONTENT_LENGTH value must reflect the length of the message-body after the server has removed any transfer-codings or content-codings.

Therefore, I think nginx is supposed to buffer all chunked requests and calculate the content length to pass it to the fastcgi responder.


Apache had similar problems. They solved it by buffering all chunked requests: https://bz.apache.org/bugzilla/show_bug.cgi?id=53332, https://bz.apache.org/bugzilla/show_bug.cgi?id=57087


I reproduced this with different systems and nginx versions:

Linux $hostname 5.13.0-21-generic #21-Ubuntu SMP Tue Oct 19 08:59:28 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

nginx version: nginx/1.21.3
built by gcc 9.3.0 (Ubuntu 9.3.0-17ubuntu1~20.04)
built with OpenSSL 1.1.1f  31 Mar 2020
TLS SNI support enabled
configure arguments: --with-cc-opt='-g -O2 -ffile-prefix-map=/build/nginx-q9LD4J/nginx-1.18.0=. -fstack-protector-strong -Wformat -Werror=format-security -fPIC -Wdate-time -D_FORTIFY_SOURCE=2' --with-ld-opt='-Wl,-z,relro -Wl,-z,now -fPIC' --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-compat --with-debug --with-pcre-jit --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_geoip_module=dynamic --with-stream_ssl_module --with-stream_ssl_preread_module --with-debug 

Linux $hostname 5.10.0-8-amd64 #1 SMP Debian 5.10.46-4 (2021-08-03) x86_64 GNU/Linux

nginx version: nginx/1.18.0
built with OpenSSL 1.1.1k  25 Mar 2021
TLS SNI support enabled
configure arguments: --with-cc-opt='-g -O2 -ffile-prefix-map=/build/nginx-q9LD4J/nginx-1.18.0=. -fstack-protector-strong -Wformat -Werror=format-security -fPIC -Wdate-time -D_FORTIFY_SOURCE=2' --with-ld-opt='-Wl,-z,relro -Wl,-z,now -fPIC' --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-compat --with-debug --with-pcre-jit --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_geoip_module=dynamic --with-stream_ssl_module --with-stream_ssl_preread_module --add-dynamic-module=/build/nginx-q9LD4J/nginx-1.18.0/debian/modules/http-headers-more-filter --add-dynamic-module=/build/nginx-q9LD4J/nginx-1.18.0/debian/modules/http-auth-pam --add-dynamic-module=/build/nginx-q9LD4J/nginx-1.18.0/debian/modules/http-cache-purge --add-dynamic-module=/build/nginx-q9LD4J/nginx-1.18.0/debian/modules/http-dav-ext --add-dynamic-module=/build/nginx-q9LD4J/nginx-1.18.0/debian/modules/http-ndk --add-dynamic-module=/build/nginx-q9LD4J/nginx-1.18.0/debian/modules/http-echo --add-dynamic-module=/build/nginx-q9LD4J/nginx-1.18.0/debian/modules/http-fancyindex --add-dynamic-module=/build/nginx-q9LD4J/nginx-1.18.0/debian/modules/http-geoip2 --add-dynamic-module=/build/nginx-q9LD4J/nginx-1.18.0/debian/modules/nchan --add-dynamic-module=/build/nginx-q9LD4J/nginx-1.18.0/debian/modules/http-lua --add-dynamic-module=/build/nginx-q9LD4J/nginx-1.18.0/debian/modules/rtmp --add-dynamic-module=/build/nginx-q9LD4J/nginx-1.18.0/debian/modules/http-uploadprogress --add-dynamic-module=/build/nginx-q9LD4J/nginx-1.18.0/debian/modules/http-upstream-fair --add-dynamic-module=/build/nginx-q9LD4J/nginx-1.18.0/debian/modules/http-subs-filter
"	defect	closed	minor		nginx-module		wontfix	fastcgi	SiebelsTim@…	Linux $hostname 5.13.0-21-generic #21-Ubuntu SMP Tue Oct 19 08:59:28 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux	"nginx version: nginx/1.21.3
built by gcc 9.3.0 (Ubuntu 9.3.0-17ubuntu1~20.04)
built with OpenSSL 1.1.1f  31 Mar 2020
TLS SNI support enabled
configure arguments: --with-cc-opt='-g -O2 -ffile-prefix-map=/build/nginx-q9LD4J/nginx-1.18.0=. -fstack-protector-strong -Wformat -Werror=format-security -fPIC -Wdate-time -D_FORTIFY_SOURCE=2' --with-ld-opt='-Wl,-z,relro -Wl,-z,now -fPIC' --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-compat --with-debug --with-pcre-jit --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_geoip_module=dynamic --with-stream_ssl_module --with-stream_ssl_preread_module --with-debug "