nginx (container image)

Built-from-source container image of the NGINX HTTP server

Available at ricardbejarano/nginx.

Tags

1.15.12-glibc, 1.15.12, glibc, latest (glibc/Dockerfile)

1.15.12-musl, musl (musl/Dockerfile)

Features

• Super tiny (glibc-based is ~13.2MB and musl-based is ~12.5MB)
• Built from source, including libraries
• Built FROM scratch, see the Filesystem section below for an exhaustive list of the image's contents
• Reduced attack surface (no bash, no UNIX tools, no package manager...)
• Built with exploit mitigations enabled (see Security)

Building

To build the glibc-based image:

docker build -t nginx:glibc -f glibc/Dockerfile .

To build the musl-based image:

docker build -t nginx:musl -f musl/Dockerfile .

Security

This image attempts to build a secure NGINX container image.

It does so by the following ways:

• downloading and verifying the source code of NGINX and every library it is built with,
• packaging the image with only those files required during runtime (see Filesystem),
• by enforcing a series of exploit mitigations (PIE, full RELRO, full SSP, NX and Fortify)

Verifying the presence of exploit mitigations

To check whether a binary in a container image has those mitigations enabled, use tests/checksec.sh.

Usage

usage: checksec.sh docker_image executable_path

Container-based wrapper for checksec.sh.
Requires a running Docker daemon.

Example:

  $ checksec.sh ricardbejarano/nginx:glibc /nginx

  Extracts the '/nginx' binary from the 'ricardbejarano/nginx:glibc' image,
  downloads checksec (github.com/slimm609/checksec.sh) and runs it on the
  binary.
  Everything runs inside containers.

Example:

Testing the /nginx binary in ricardbejarano/nginx:glibc:

$ bash tests/checksec.sh ricardbejarano/nginx:glibc /nginx
Downloading ricardbejarano/nginx:glibc...Done!
Extracting ricardbejarano/nginx:glibc:/nginx...Done!
Downloading checksec.sh...Done!
Running checksec.sh:
RELRO        STACK CANARY   NX           PIE           RPATH      RUNPATH      Symbols         FORTIFY   Fortified   Fortifiable   FILE
Full RELRO   Canary found   NX enabled   PIE enabled   No RPATH   No RUNPATH   11563 Symbols   Yes       0           34            /tmp/.checksec-ui8eKi3Q
Cleaning up...Done!

This wrapper script works with any binary in a container image. Feel free to use it with any other image.

Other examples:

• bash tests/checksec.sh debian /bin/bash
• bash tests/checksec.sh alpine /bin/sh
• bash tests/checksec.sh nginx /usr/sbin/nginx

Volumes

• Bind your configuration file at /etc/nginx/nginx.conf.

Filesystem

The images' contents are:

glibc

Based on the glibc implementation of libc. Dynamically linked.

/
├── etc/
│   ├── group/
│   ├── nginx/
│   │   ├── html/
│   │   │   ├── 50x.html
│   │   │   └── index.html
│   │   ├── mime.types
│   │   └── nginx.conf
│   └── passwd
├── lib/
│   └── x86_64-linux-gnu/
│       ├── libc.so.6
│       ├── libcrypt.so.1
│       ├── libdl.so.2
│       ├── libnss_dns.so.2
│       ├── libnss_files.so.2
│       ├── libpthread.so.0
│       └── libresolv.so.2
├── lib64/
│   └── ld-linux-x86-64.so.2
├── nginx
└── tmp/
    └── .keep

musl

Based on the musl implementation of libc. Statically linked.

/
├── etc/
│   ├── group
│   ├── nginx/
│   │   ├── html/
│   │   │   ├── 50x.html
│   │   │   └── index.html
│   │   ├── mime.types
│   │   └── nginx.conf
│   └── passwd
├── nginx
└── tmp/
    └── .keep

License

See LICENSE.