Certificate Transparency: Go Code
This repository holds Go code related to Certificate Transparency (CT). The repository requires Go version 1.9.
- Repository Structure
- Trillian CT Personality
- Working on the Code
- Running Codebase Checks
- Rebuilding Generated Code
- Updating Vendor Code
The main parts of the repository are:
- Encoding libraries:
x509/are forks of the upstream Go
crypto/x509libraries. We maintain separate forks of these packages because CT is intended to act as an observatory of certificates across the ecosystem; as such, we need to be able to process somewhat-malformed certificates that the stricter upstream code would (correctly) reject. Our
x509fork also includes code for working with the pre-certificates defined in RFC 6962.
tlsholds a library for processing TLS-encoded data as described in RFC 5246.
x509util/provides additional utilities for dealing with
- CT client libraries:
- The top-level
.) holds types and utilities for working with CT data structures defined in RFC 6962.
jsonclient/hold libraries that allow access to CT Logs via HTTP entrypoints described in section 4 of RFC 6962.
dnsclient/has a library that allows access to CT Logs over DNS.
scanner/holds a library for scanning the entire contents of an existing CT Log.
- The top-level
- CT Personality for Trillian:
trillian/holds code that allows a Certificate Transparency Log to be run using a Trillian Log as its back-end – see below.
- Command line tools:
./client/ctclientallows interaction with a CT Log.
./ctutil/sctcheckallows SCTs (signed certificate timestamps) from a CT Log to be verified.
./scanner/scanlogallows an existing CT Log to be scanned for certificates of interest; please be polite when running this tool against a Log.
./x509util/certcheckallows display and verification of certificates
./x509util/crlcheckallows display and verification of certificate revocation lists (CRLs).
- Other libraries related to CT:
ctutil/holds utility functions for validating and verifying CT data structures.
loglist/has a library for reading JSON lists of CT Logs.
Trillian CT Personality
trillian/ subdirectory holds code and scripts for running a CT Log based
on the Trillian general transparency Log,
and is documented separately.
Working on the Code
Developers who want to make changes to the codebase need some additional dependencies and tools, described in the following sections. The Travis configuration for the codebase is also useful reference for the required tools and scripts, as it may be more up-to-date than this document.
In order for the
go generate command to work properly, the code must
be checked out to the following location:
Running Codebase Checks
scripts/presubmit.sh script runs various tools
and tests over the codebase; please ensure this script passes before sending
pull requests for review.
# Install golangci-lint go get -u github.com/golangci/golangci-lint/cmd/golangci-lint cd $GOPATH/src/github.com/golangci/golangci-lint/cmd/golangci-lint go install -ldflags "-X 'main.version=$(git describe --tags)' -X 'main.commit=$(git rev-parse --short HEAD)' -X 'main.date=$(date)'" cd - # Run code generation, build, test and linters ./scripts/presubmit.sh # Run build, test and linters but skip code generation ./scripts/presubmit.sh --no-generate # Or just run the linters alone: golangci-lint run
Rebuilding Generated Code
Some of the CT Go code is autogenerated from other files:
- Protocol buffer message
definitions are converted to
- A mock implementation of the Trillian gRPC API (in
trillian/mockclient) is created with GoMock.
Re-generating mock or protobuffer files is only needed if you’re changing the original files; if you do, you’ll need to install the prerequisites:
mockgentool from https://github.com/golang/mock
protoc, Go support for protoc (see documentation linked from the protobuf site)
and run the following:
go generate -x ./... # hunts for //go:generate comments and runs them
Updating Vendor Code
The codebase includes a couple of external projects under the
subdirectory, to ensure that builds use a fixed version (typically because the
upstream repository does not guarantee back-compatibility between the tip
master branch and the current stable release). See
instructions in the Trillian repo
for how to update vendored subtrees.