Opened 5 years ago

Closed 5 years ago

#1812 closed defect (invalid)

NGINX does not reply with HTTP Headers on broken request line

Reported by: archmalet@… Owned by:
Priority: minor Milestone:
Component: nginx-core Version: 1.17.x
Keywords: Cc:
uname -a:
nginx -V: nginx version: nginx/1.17.1
built by gcc 6.3.0 20170516 (Debian 6.3.0-18+deb9u1)
built with OpenSSL 1.1.0j 20 Nov 2018
TLS SNI support enabled
configure arguments: --prefix=/etc/nginx --sbin-path=/usr/sbin/nginx --modules-path=/usr/lib/nginx/modules --conf-path=/etc/nginx/nginx.conf --error-log-path=/var/log/nginx/error.log --http-log-path=/var/log/nginx/access.log --pid-path=/var/run/nginx.pid --lock-path=/var/run/nginx.lock --http-client-body-temp-path=/var/cache/nginx/client_temp --http-proxy-temp-path=/var/cache/nginx/proxy_temp --http-fastcgi-temp-path=/var/cache/nginx/fastcgi_temp --http-uwsgi-temp-path=/var/cache/nginx/uwsgi_temp --http-scgi-temp-path=/var/cache/nginx/scgi_temp --user=nginx --group=nginx --with-compat --with-file-aio --with-threads --with-http_addition_module --with-http_auth_request_module --with-http_dav_module --with-http_flv_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_mp4_module --with-http_random_index_module --with-http_realip_module --with-http_secure_link_module --with-http_slice_module --with-http_ssl_module --with-http_stub_status_module --with-http_sub_module --with-http_v2_module --with-mail --with-mail_ssl_module --with-stream --with-stream_realip_module --with-stream_ssl_module --with-stream_ssl_preread_module --with-cc-opt='-g -O2 -fdebug-prefix-map=/data/builder/debuild/nginx-1.17.1/debian/debuild-base/nginx-1.17.1=. -fstack-protector-strong -Wformat -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fPIC' --with-ld-opt='-Wl,-z,relro -Wl,-z,now -Wl,--as-needed -pie'

Description

NGINX does reply without HTTP Response Headers when there is a newline character in the HTTP request line before the HTTP version.

With an example valid request (NGINX listens on port 8080 here):

GET /foobar HTTP/1.1
Host: localhost:8080
User-Agent: A user agent
Pragma: no-cache
Cache-Control: no-cache

NGINX responds with:

HTTP/1.1 404 Not Found
Server: nginx/1.17.1
Date: Mon, 15 Jul 2019 15:59:40 GMT
Content-Type: text/html
Content-Length: 153
Connection: keep-alive

<html>
<head><title>404 Not Found</title></head>
<body>
<center><h1>404 Not Found</h1></center>
<hr><center>nginx/1.17.1</center>
</body>
</html>

With a newline in the request line like in the following example:

GET /foobar
HTTP/1.1
Host: localhost:8080
User-Agent: A user agent
Pragma: no-cache
Cache-Control: no-cache

the response (note that the response headers are missing here) is:

<html>
<head><title>404 Not Found</title></head>
<body>
<center><h1>404 Not Found</h1></center>
<hr><center>nginx/1.17.1</center>
</body>
</html>

Putting the newline inside the HTTP version like in the following request does return a 400 Bad Request with headers

GET /foobar HTT
P/1.1
Host: localhost:8080
User-Agent: A user agent
Pragma: no-cache
Cache-Control: no-cache

I'm guessing that the newline character before the HTTP version messes up the state machine of HTTP Request parsing in NGINX.

Change History (1)

comment:1 by Sergey Kandaurov, 5 years ago

Resolution: → invalid
Status: new → closed

HTTP/0.9 requests are not expected to contain the protocol version token.
See ​http://tools.ietf.org/html/rfc1945#section-4.1 for details.

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