[release/2.6] Add GOARM flag to dockerfile

When building with arm on alpine, GOARM should
be set to 6 by default.

Signed-off-by: Derek McGowan <derek@mcgstyle.net>

[release/2.6] Add go arguments to dockerfile

Signed-off-by: Derek McGowan <derek@mcgstyle.net>

[release/2.6] integration tests: update certificates

Set expiration to 10 years

Signed-off-by: Derek McGowan <derek@mcgstyle.net>

[release/2.6] Cherry-Pick commits for release 2.6.3

Remove EndpointConfig.Transport from the return value of the
registry.notifications.endpoints expvar.Func.  It results in an empty
value for that expvar variable under Go 1.7 because it is a non-nil
*http.Transport, which Go 1.7 can no longer encode as JSON.

Signed-off-by: Noah Treuhaft <noah.treuhaft@docker.com>
(cherry picked from commit 9a58c910)

Signed-off-by: Wenkai Yin <yinw@vmware.com>
(cherry picked from commit 005c6e02)

Signed-off-by: Stephen J Day <stephen.day@docker.com>
(cherry picked from commit 1ba5b3b5)

[2.6] registry: feed the linter by removing redundant err check

Signed-off-by: Stephen J Day <stephen.day@docker.com>
(cherry picked from commit 4abf680c)
Signed-off-by: Stephen J Day <stephen.day@docker.com>

Fix keyword format for downstream docs

Signed-off-by: Misty Stanley-Jones <misty@docker.com>

[release/2.6] Put back v2-registry-auth.png

Signed-off-by: Misty Stanley-Jones <misty@docker.com>
(cherry picked from commit 1d957167)
Signed-off-by: Stephen J Day <stephen.day@docker.com>

[release/2.6] release: prepare for 2.6.2 release

Signed-off-by: Stephen J Day <stephen.day@docker.com>

[release/2.6] registry/{storage,handlers}: limit content sizes

Under certain circumstances, the use of `StorageDriver.GetContent` can
result in unbounded memory allocations. In particualr, this happens when
accessing a layer through the manifests endpoint.

This problem is mitigated by setting a 4MB limit when using to access
content that may have been accepted from a user. In practice, this means
setting the limit with the use of `BlobProvider.Get` by wrapping
`StorageDriver.GetContent` in a helper that uses `StorageDriver.Reader`
with a `limitReader` that returns an error.

When mitigating this security issue, we also noticed that the size of
manifests uploaded to the registry is also unlimited. We apply similar
logic to the request body of payloads that are full buffered.

Signed-off-by: Stephen J Day <stephen.day@docker.com>
(cherry picked from commit 55ea4404)
Signed-off-by: Stephen J Day <stephen.day@docker.com>

Put architecture.md back into distribution repo

Signed-off-by: Misty Stanley-Jones <misty@docker.com>

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

`app.driver.List` on `"/"` is very expensive if registry contains significant amount of images. And the result isn't used anyways.
In most (if not all) storage drivers, `Stat` has a cheaper implementation, so use it instead to achieve the same goal.

Signed-off-by: yixi zhang <yixi@memsql.com>

Release notes for forwarded header fix patch release

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

Partially reverts change adding support for X-Forwarded-Port.
Changes the logic to prefer the standard Forwarded header over
X-Forwarded headers. Prefer forwarded "host" over "for" since
"for" represents the client and not the client's request.

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

Signed-off-by: Troels Thomsen <troels@thomsen.io>
Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

Backport #2116 to releases/2.6

Signed-off-by: Misty Stanley-Jones <misty@docker.com>
(cherry picked from commit 6ee03f5d)
Signed-off-by: Misty Stanley-Jones <misty@docker.com>

Signed-off-by: Joao Fernandes <joao.fernandes@docker.com>

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

Use whitelist of allowed repository classes to enforce.
By default all repository classes are allowed.

Add authorized resources to context after authorization.

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

Update grammar to support a resource class. Add
example for plugin repository class.

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

Golint now checks for new lines at the end of go error strings,
remove these unneeded new lines.

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

Release notes for v2.6.0-rc1

Signed-off-by: Richard Scothern <richard.scothern@docker.com>