Opened 6 years ago

Closed 6 years ago

#598 closed defect (duplicate)

ngx_proxy_protocol "broken header" error writes unescaped bytes to error log

Reported by: jstangroome.pip.verisignlabs.com Owned by:
Priority: minor Milestone: 1.7
Component: nginx-core Version: 1.7.x
Keywords: Cc:
uname -a: Linux ip-10-0-0-25 3.13.0-29-generic #53-Ubuntu SMP Wed Jun 4 21:00:20 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
nginx -V: nginx version: nginx/1.7.1
TLS SNI support enabled
configure arguments: --with-cc-opt='-g -O2 -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security -D_FORTIFY_SOURCE=2' --with-ld-opt='-Wl,-Bsymbolic-functions -Wl,-z,relro' --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 --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_addition_module --with-http_dav_module --with-http_geoip_module --with-http_gzip_static_module --with-http_image_filter_module --with-http_spdy_module --with-http_sub_module --with-http_xslt_module --with-mail --with-mail_ssl_module --add-module=/build/buildd/nginx-1.7.1/debian/modules/nginx-auth-pam --add-module=/build/buildd/nginx-1.7.1/debian/modules/nginx-dav-ext-module --add-module=/build/buildd/nginx-1.7.1/debian/modules/nginx-echo --add-module=/build/buildd/nginx-1.7.1/debian/modules/nginx-upstream-fair --add-module=/build/buildd/nginx-1.7.1/debian/modules/ngx_http_substitutions_filter_module

Description

When using the 'proxy_protocol' parameter on 'listen' directives, any connections that do not begin with a valid proxy protocol line will log an ERR-level message containing the raw unescaped request to the error.log file. This leads to difficult to parse multi-line log entries and binary data in an otherwise text-only file.

The offending code is here:
http://trac.nginx.org/nginx/browser/nginx/src/core/ngx_proxy_protocol.c#L88

A workable solution may include:

  • only logging the message length and origin and excluding the actual data.
  • logging only the first N bytes of the actual data and escaping any bytes that break the log format (eg control chars, high-bits).
  • only writing the actual data to a debug log.

Change History (1)

comment:1 by Maxim Dounin, 6 years ago

Resolution: duplicate
Status: newclosed

Duplicate of ticket #191.

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