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>
If the client doesn't support manifest lists, the registry will
rewrite a manifest list into the old format. The Docker-Content-Digest
header should be updated in this case.
Signed-off-by: Oleg Bulatov <oleg@bulatov.me>
In some conditions, regulator.exit may not send a signal to blocked
regulator.enter.
Let's assume we are in the critical section of regulator.exit and r.available
is equal to 0. And there are three more gorotines. One goroutine also executes
regulator.exit and waits for the lock. Rest run regulator.enter and wait for
the signal.
We send the signal, and after releasing the lock, there will be lock
contention:
1. Wait from regulator.enter
2. Lock from regulator.exit
If the winner is Lock from regulator.exit, we will not send another signal to
unlock the second Wait.
Signed-off-by: Oleg Bulatov <obulatov@redhat.com>
Add build args. Defaults to Linux/x64 so no change to existing image, but can build for other platforms - e.g.
```
docker build --build-arg GOOS=windows -t distribution-builder:windows .
```
Signed-off-by: Elton Stoneman <elton@sixeyed.com>
Updates resumable hash implementation to Go 1.8 equivalent. This should
be a major speedup, since it includes a number of optimizations from Go
1.7.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
This updates the grammar to allow more than one digest algorithm
separator, matching the regular expression and intended grammar.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
