Opened 15 months ago

Closed 15 months ago

Last modified 15 months ago

#1381 closed defect (invalid)

'proxy_set_header Host' causes https drop in proxied redirect's Location header

Reported by: https://stackoverflow.com/users/1745329/bagratte Owned by:
Priority: minor Milestone:
Component: nginx-core Version: 1.13.x
Keywords: Cc:
uname -a: Linux 6feb1d8fc7cb 4.4.0-93-generic #116-Ubuntu SMP Fri Aug 11 21:17:51 UTC 2017 x86_64 GNU/Linux
nginx -V: nginx version: nginx/1.13.5 built by gcc 6.3.0 20170516 (Debian 6.3.0-18) built with OpenSSL 1.1.0f 25 May 2017 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-1.13.5/debian/debuild-base/nginx-1.13.5=. -specs=/usr/share/dpkg/no-pie-compile.specs -fstack-protector-strong -Wformat -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fPIC' --with-ld-opt='-specs=/usr/share/dpkg/no-pie-link.specs -Wl,-z,relro -Wl,-z,now -Wl,--as-needed -pie'

Description

Consider the following configuration accessible at https://proxy

server {
    listen 80;
    listen 443 ssl;
    server_name proxy;
    ssl_certificate /etc/nginx/ssl/proxy.crt;
    ssl_certificate_key /etc/nginx/ssl/proxy.key;

    location / {
	    proxy_pass http://app;
	    proxy_pass_request_headers on;
	    proxy_set_header Host $http_host;
    }
}

Now consider this accessible at http://app from proxy:

server {
    listen       80;
    server_name  app;

    location / {
        return 200 "app";
        add_header Content-Type text/plain;
    }

    location /redirect {
	    return 302 /redirected;
    }

    location /redirected {
        return 200 "redirected";
        add_header Content-Type text/plain;
    }
}

Now, if we access https://proxy/redirect we are redirected to http://proxy/redirected. Note the https drop to http.
If we remove the 'proxy_set_header Host $http_host;' from proxy's configuration, we are then redirected correctly to https://proxy/redirected.

Change History (2)

comment:1 Changed 15 months ago by mdounin

  • Resolution set to invalid
  • Status changed from new to closed

This because proxy_redirect uses what is written in the proxy_pass directive by default, and hence it is able to detect that redirects to http://app/redirected needs to be rewritten to https://proxy/redirected. But does not know anything about arbitrary headers you can add using proxy_set_header, and as such redirects to http://proxy/redirected returned by the backend are passed to the client without modifications. To fix this, consider configuring proxy_redirect appropriately.

comment:2 Changed 15 months ago by https://stackoverflow.com/users/1745329/bagratte

Understood. Thanks for explanation!

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