Chainguard Container for glibc-openssl

The GNU C Library (glibc) is a C standard library implementation maintained by the GNU Project. This container image also contains OpenSSL, a software library for applications providing secure communications over a network.

Chainguard Containers are regularly-updated, secure-by-default container images.

Download this Container Image

For those with access, this container image is available on cgr.dev:

docker pull cgr.dev/ORGANIZATION/glibc-openssl:latest

Be sure to replace the ORGANIZATION placeholder with the name used for your organization's private repository within the Chainguard Registry.

Compatibility Notes

This image is generally meant to be used only as a base image. It does, however, contain the openssl program which you can run.

You must bring your own artifacts to use this image, such as with a Docker multi-stage build. If you want locale support other than C.UTF-8, you must bring your own locale data as well. This may change in the future based on user feedback.

Getting Started

To illustrate how you can use Chainguard's glibc-openssl container image, start by creating the following Go program:

cat > main.go <<EOF
package main

import (
	"fmt"
	"net/http"
)

func main() {
	http.Get("http://www.google.com")
	fmt.Println("Hello, world!")
}
EOF

This is a Hello, world! program, but it includes the line http.Get("http://www.google.com") which will require glibc.

Next, create a Dockerfile that uses the glibc-openssl container image as a base image:

cat > Dockerfile <<EOF
FROM cgr.dev/chainguard/go AS builder
ADD main.go .
RUN CGO_ENABLED=1 go build -o /tmp/foo main.go

# Use this image as a base image.
FROM cgr.dev/ORGANIZATION/glibc-openssl
COPY --from=builder /tmp/foo /foo
ENTRYPOINT ["/foo"]
EOF

Note that this example Dockerfile uses the public Chainguard go image and a private glibc-openssl image. You will need to change ORGANIZATION to reflect your organization's private repository within the Chainguard registry.

Using this Dockerfile, build an image:

docker build -t glibc-openssl .

Then run the newly-built image:

docker run --rm glibc-openssl

This will return the following output, indicating the program was run successfully and the glibc base image worked as expected:

Hello, world!

Testing OpenSSL

As mentioned previously, the glibc-openssl image comes with OpenSSL. To test this out, first create a sample file:

echo "sample text" > sample.txt

Then mount this file to the glibc-openssl container and use the sha512 digest function to output the digest of the sample file:

docker run -v $(pwd):/tmp cgr.dev/chainguard-private/glibc-openssl openssl sha512 /tmp/sample.txt

SHA2-512(stdin)= cf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce47d0d13c5d85f2b0ff8318d2877eec2f63b931bd47417a81a538327af927da3e

Documentation and Resources

• glibc Project Website
• Chainguard Academy: glibc vs. musl
• OpenSSL Documentation

What are Chainguard Containers?

Chainguard Containers are minimal container images that are secure by default.

In many cases, the Chainguard Containers tagged as :latest contain only an open-source application and its runtime dependencies. These minimal container images typically do not contain a shell or package manager. Chainguard Containers are built with Wolfi, our Linux undistro designed to produce container images that meet the requirements of a more secure software supply chain.

The main features of Chainguard Containers include:

• Minimal design, without unnecessary software bloat
• Daily builds to ensure container images are up-to-date with available security patches
• High quality build-time SBOMs attesting to the provenance of all artifacts within the image
• Verifiable signatures provided by Sigstore
• Reproducible builds with Cosign and apko (read more about reproducibility)

For cases where you need container images with shells and package managers to build or debug, most Chainguard Containers come paired with a -dev variant.

Although the -dev container image variants have similar security features as their more minimal versions, they feature additional software that is typically not necessary in production environments. We recommend using multi-stage builds to leverage the -dev variants, copying application artifacts into a final minimal container that offers a reduced attack surface that won’t allow package installations or logins.

Learn More

To better understand how to work with Chainguard Containers, please visit Chainguard Academy and Chainguard Courses.

In addition to Containers, Chainguard offers VMs and Libraries. Contact Chainguard to access additional products.

Trademarks

This software listing is packaged by Chainguard. The trademarks set forth in this offering are owned by their respective companies, and use of them does not imply any affiliation, sponsorship, or endorsement by such companies.