Updating with Seb's comments
Updating with comments from review

Signed-off-by: Mary Anthony <mary@docker.com>
This commit is contained in:
Mary Anthony 2015-09-13 13:22:04 -07:00
Родитель 552c361f39
Коммит a2f545c86d
1 изменённых файлов: 59 добавлений и 49 удалений

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@ -16,19 +16,19 @@ particular, when communicating over an untrusted medium such as the internet, it
is critical to ensure the integrity and publisher of all the data a system
operates on. You use Docker to push and pull images (data) to a registry. Content trust
gives you the ability to both verify the integrity and the publisher of all the
data received from a registry over any channel.
data received from a registry over any channel.
Content trust is currently only available for users of the public Docker Hub. It
is currently not available for the Docker Trusted Registry or for private
registries.
## Understand trust in Docker
## Understand trust in Docker
Content trust allows operations with a remote Docker registry to enforce
client-side signing and verification of image tags. Content trust provides the
ability to use digital signatures for data sent to and received from remote
Docker registries. These signatures allow client-side verification of the
integrity and publisher of specific image tags.
integrity and publisher of specific image tags.
Currently, content trust is disabled by default. You must enabled it by setting
the `DOCKER_CONTENT_TRUST` environment variable.
@ -36,7 +36,7 @@ the `DOCKER_CONTENT_TRUST` environment variable.
Once content trust is enabled, image publishers can sign their images. Image consumers can
ensure that the images they use are signed. publishers and consumers can be
individuals alone or in organizations. Docker's content trust supports users and
automated processes such as builds.
automated processes such as builds.
### Image tags and content trust
@ -48,7 +48,7 @@ An individual image record has the following identifier:
A particular image `REPOSITORY` can have multiple tags. For example, `latest` and
`3.1.2` are both tags on the `mongo` image. An image publisher can build an image
and tag combination many times changing the image with each build.
and tag combination many times changing the image with each build.
Content trust is associated with the `TAG` portion of an image. Each image
repository has a set of keys that image publishers use to sign an image tag.
@ -67,7 +67,7 @@ Publishers can choose to sign a specific tag or not. As a result, the content of
an unsigned tag and that of a signed tag with the same name may not match. For
example, a publisher can push a tagged image `someimage:latest` and sign it.
Later, the same publisher can push an unsigned `someimage:latest` image. This second
push replaces the last unsigned tag `latest` but does not affect the signed `latest` version.
push replaces the last unsigned tag `latest` but does not affect the signed `latest` version.
The ability to choose which tags they can sign, allows publishers to iterate over
the unsigned version of an image before officially signing it.
@ -92,9 +92,9 @@ operate with content trust are:
* `push`
* `build`
* `create`
* `create`
* `pull`
* `run`
* `run`
For example, with content trust enabled a `docker pull someimage:latest` only
succeeds if `someimage:latest` is signed. However, an operation with an explicit
@ -105,7 +105,7 @@ $ docker pull someimage@sha256:d149ab53f8718e987c3a3024bb8aa0e2caadf6c0328f1d9d8
```
Trust for an image tag is managed through the use of signing keys. Docker's content
trust makes use four different keys:
trust makes use four different keys:
| Key | Description |
|---------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------|
@ -126,25 +126,25 @@ The following image depicts the various signing keys and their relationships:
>Correcting this loss requires intervention from [Docker
>Support](https://support.docker.com) to reset the repository state. This loss
>also requires **manual intervention** from every consumer that used a signed
>tag from this repository prior to the loss.
>tag from this repository prior to the loss.
You should backup the offline key somewhere safe. Given that it is only required
to create new repositories, it is a good idea to store it offline. Make sure you
read [Manage keys for content trust](/security/trust/trust_key_mng) information
for details on creating, securing, and backing up your keys.
for details on creating, securing, and backing up your keys.
## Survey of typical content trust operations
This section surveys the typical trusted operations users perform with Docker
images.
### Enable content trust
### Enable and disable content trust per-shell or per-invocation
Enable content trust by setting the `DOCKER_CONTENT_TRUST` environment variable.
Enabling per-shell is useful because you can have one shell configured for
trusted operations and another terminal shell for untrusted operations. You can
also add this declaration to your shell profile to have it turned on always by
default.
In a shell, you can enable content trust by setting the `DOCKER_CONTENT_TRUST`
environment variable. Enabling per-shell is useful because you can have one
shell configured for trusted operations and another terminal shell for untrusted
operations. You can also add this declaration to your shell profile to have it
turned on always by default.
To enable content trust in a `bash` shell enter the following command:
@ -152,23 +152,36 @@ To enable content trust in a `bash` shell enter the following command:
export DOCKER_CONTENT_TRUST=1
```
Once set, each of the "tag" operations require key for trusted tag. All of these
commands also support the `--disable-content-trust` flag. This flag allows
publishers to run individual operations on tagged images without content trust on an
as-needed basis.
Once set, each of the "tag" operations requires a key for a trusted tag.
In an environment where `DOCKER_CONTENT_TRUST` is set, you can use the
`--disable-content-trust` flag to run individual operations on tagged images
without content trust on an as-needed basis.
```bash
$ docker pull --disable-content-trust docker/trusttest:untrusted
```
To invoke a command with content trust enabled regardless of whether or how the `DOCKER_CONTENT_TRUST` variable is set:
```bash
$ docker build --disable-content-trust=false -t docker/trusttest:testing .
```
All of the trusted operations support the `--disable-content-trust` flag.
### Push trusted content
To create signed content for a specific image tag, simply enable content trust and push
a tagged image. If this is the first time you have pushed an image using content trust
on your system, the session looks like this:
To create signed content for a specific image tag, simply enable content trust
and push a tagged image. If this is the first time you have pushed an image
using content trust on your system, the session looks like this:
```bash
$ docker push docker/trusttest:latest
The push refers to a repository [docker.io/docker/trusttest] (len: 1)
9a61b6b1315e: Image already exists
902b87aaaec9: Image already exists
9a61b6b1315e: Image already exists
902b87aaaec9: Image already exists
latest: digest: sha256:d02adacee0ac7a5be140adb94fa1dae64f4e71a68696e7f8e7cbf9db8dd49418 size: 3220
Signing and pushing trust metadata
You are about to create a new offline signing key passphrase. This passphrase
@ -177,31 +190,31 @@ choose a long, complex passphrase and be careful to keep the password and the
key file itself secure and backed up. It is highly recommended that you use a
password manager to generate the passphrase and keep it safe. There will be no
way to recover this key. You can find the key in your config directory.
Enter passphrase for new offline key with id a1d96fb:
Repeat passphrase for new offline key with id a1d96fb:
Enter passphrase for new tagging key with id docker.io/docker/trusttest (3a932f1):
Repeat passphrase for new tagging key with id docker.io/docker/trusttest (3a932f1):
Enter passphrase for new offline key with id a1d96fb:
Repeat passphrase for new offline key with id a1d96fb:
Enter passphrase for new tagging key with id docker.io/docker/trusttest (3a932f1):
Repeat passphrase for new tagging key with id docker.io/docker/trusttest (3a932f1):
Finished initializing "docker.io/docker/trusttest"
```
When you push your first tagged image with content trust enabled, the `docker` client
recognizes this is your first push and:
When you push your first tagged image with content trust enabled, the `docker`
client recognizes this is your first push and:
- alerts you that it will create a new offline key
- requests a passphrase for the key
- generates an offline key in the `~/.docker/trust` directory
- generates a tagging key for in the `~/.docker/trust` directory
The passphrase you chose for both the offline key and your content key-pair should
be randomly generated and stored in a *password manager*.
It is important to note, if you had left off the `latest` tag, content trust is skipped.
This is true even if content trust is enabled and even if this is your first push.
The passphrase you chose for both the offline key and your content key-pair
should be randomly generated and stored in a *password manager*.
> **NOTE**: If you omit the `latest` tag, content trust is skipped. This is true
even if content trust is enabled and even if this is your first push.
```bash
$ docker push docker/trusttest
The push refers to a repository [docker.io/docker/trusttest] (len: 1)
9a61b6b1315e: Image successfully pushed
902b87aaaec9: Image successfully pushed
9a61b6b1315e: Image successfully pushed
902b87aaaec9: Image successfully pushed
latest: digest: sha256:a9a9c4402604b703bed1c847f6d85faac97686e48c579bd9c3b0fa6694a398fc size: 3220
No tag specified, skipping trust metadata push
```
@ -215,13 +228,13 @@ you create can use that same offline key:
```bash
$ docker push docker.io/docker/seaside:latest
The push refers to a repository [docker.io/docker/seaside] (len: 1)
a9539b34a6ab: Image successfully pushed
b3dbab3810fc: Image successfully pushed
a9539b34a6ab: Image successfully pushed
b3dbab3810fc: Image successfully pushed
latest: digest: sha256:d2ba1e603661a59940bfad7072eba698b79a8b20ccbb4e3bfb6f9e367ea43939 size: 3346
Signing and pushing trust metadata
Enter key passphrase for offline key with id a1d96fb:
Enter passphrase for new tagging key with id docker.io/docker/seaside (bb045e3):
Repeat passphrase for new tagging key with id docker.io/docker/seaside (bb045e3):
Enter key passphrase for offline key with id a1d96fb:
Enter passphrase for new tagging key with id docker.io/docker/seaside (bb045e3):
Repeat passphrase for new tagging key with id docker.io/docker/seaside (bb045e3):
Finished initializing "docker.io/docker/seaside"
```
@ -232,7 +245,7 @@ these.
### Pull image content
A common way to consume an image is to `pull` it. With content trust enabled, the Docker
client only allows `docker pull` to retrieve signed images.
client only allows `docker pull` to retrieve signed images.
```
$ docker pull docker/seaside
@ -286,6 +299,3 @@ $ docker push --disable-content-trust docker/trusttest:untrusted
* [Manage keys for content trust](/security/trust/trust_key_mng)
* [Automation with content trust](/security/trust/trust_automation)
* [Play in a content trust sandbox](/security/trust/trust_sandbox)