Make PermissionBackend#ForRef authoritative

This change fixes a misconception that leads to data being accessible
through Gerrit APIs that should be locked down.

Gerrit had two components for determining if a Git ref is visible to a
user: (Default)RefFilter and PermissionBackend#ForRef (ex RefControl).
The former was always capable of providing correct results for all refs.
The latter only had logic to decide if a Git ref is visible according to
the Gerrit READ permissions. This includes all refs under refs/heads as
well as any other ref that isn't a database ref or a Git tag. This
component was unware of Git tags and database references. Hence, when
asked for a database reference such as refs/changes/xx/yyyyxx/meta the
logic would allow access if the user has READ permissions on any of the
ref prefixes, such as the default "read refs/* Anonymous Users".

That is problematic, because it bypasses documented behavior [1] where
a user should only have access to a change if they can see the destination
ref. The same goes for other database references.

This change fixes the problem. It is intentionally kept to a minimally
invasive code change so that it's easier to backport it.

Add tests to assert the correct behavior. These tests would fail before
this fix. We have included them in this change to be able to backport
just a single commit.


Change-Id: Ice3a756cf573dd9b38e3f198ccc44899ccf65f75
11 files changed
tree: 81d483ea3348eb3607333375bc9b4ae43c6c5fd4
  1. .settings/
  2. antlr3/
  3. contrib/
  4. Documentation/
  5. e2e-tests/
  6. java/
  7. javatests/
  8. lib/
  9. modules/
  10. plugins/
  11. polygerrit-ui/
  12. prolog/
  13. prologtests/
  14. proto/
  15. resources/
  16. tools/
  17. webapp/
  18. .bazelignore
  19. .bazelproject
  20. .bazelrc
  21. .bazelversion
  22. .editorconfig
  23. .git-blame-ignore-revs
  24. .gitignore
  25. .gitmodules
  26. .gitreview
  27. .mailmap
  28. .pydevproject
  29. .zuul.yaml
  30. BUILD
  33. Jenkinsfile
  34. package.json
  37. version.bzl
  39. yarn.lock

Gerrit Code Review

Gerrit is a code review and project management tool for Git based projects.

Build Status


Gerrit makes reviews easier by showing changes in a side-by-side display, and allowing inline comments to be added by any reviewer.

Gerrit simplifies Git based project maintainership by permitting any authorized user to submit changes to the master Git repository, rather than requiring all approved changes to be merged in by hand by the project maintainer.


For information about how to install and use Gerrit, refer to the documentation.


Our canonical Git repository is located on There is a mirror of the repository on Github.

Reporting bugs

Please report bugs on the issue tracker.


Gerrit is the work of hundreds of contributors. We appreciate your help!

Please read the contribution guidelines.

Note that we do not accept Pull Requests via the Github mirror.

Getting in contact

The Developer Mailing list is repo-discuss on Google Groups.


Gerrit is provided under the Apache License 2.0.


Install Bazel and run the following:

    git clone --recurse-submodules
    cd gerrit && bazel build release

Install binary packages (Deb/Rpm)

The instruction how to configure GerritForge/BinTray repositories is here

On Debian/Ubuntu run:

    apt-get update & apt-get install gerrit=<version>-<release>

NOTE: release is a counter that starts with 1 and indicates the number of packages that have been released with the same version of the software.

On CentOS/RedHat run:

    yum clean all && yum install gerrit-<version>[-<release>]

On Fedora run:

    dnf clean all && dnf install gerrit-<version>[-<release>]

Use pre-built Gerrit images on Docker

Docker images of Gerrit are available on DockerHub

To run a CentOS 7 based Gerrit image:

    docker run -p 8080:8080 gerritforge/gerrit-centos7[:version]

To run a Ubuntu 15.04 based Gerrit image:

    docker run -p 8080:8080 gerritforge/gerrit-ubuntu15.04[:version]

NOTE: release is optional. Last released package of the version is installed if the release number is omitted.