Back in the before time, the best practices surrounding usage of Context
weren't quite worked out. We defined our own type to make usage easier.
As this packaged was used elsewhere, it make it more and more
challenging to integrate with the forked `Context` type. Now that it is
available in the standard library, we can just use that one directly.
To make usage more consistent, we now use `dcontext` when referring to
the distribution context package.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
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>
A change in #763 to address review comments caused problems. Originally,
instrumentedResponseWriter implemented the CloseNotifier interface, and
would panic if it was wrapping something that did not implement that
interface. This was split into a separate instrumentedResponseWriterCN
type that implements CloseNotifier, so there's a fallback if
instrumentedResponseWriter ever needs to wrap something that does not
implement this interface.
instrumentedResponseWriter's Value method would end up upcasting either
type back to instrumentedResponseWriter, which does not implement the
interface. In effect, instrumentedResponseWriterCN was never visible to
the handler.
This fixes the problem by implementing a wrapper Value method for
instrumentedResponseWriterCN.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
Instead, provide a variant of instrumentedResponseWriter that does not
implement CloseNotifier, and use that when necessary. In
copyFullPayload, log instead of panicing when we encounter something
that doesn't implement CloseNotifier.
This is more complicated than I'd like, but it's necessary because
instrumentedResponseWriter must not embed CloseNotifier unless there's
really a CloseNotifier to embed.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
The response code isn't actually sent to the client, because the
connection has already closed by this point. But it causes the status
code to appear as 499 in the logs instead of 0.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
This changeset provides a common http handler for serving errcodes. This should
unify http responses across webservices in the face of errors.
Several type assertions have been added, as well, to ensure the error interface
is implemented.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
The goal is to free up the distribution/registry package to include common
registry types. This moves the webapp definitions out of the way to allow for
this change in the future.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
