Documentation

Overview

    Package vmtoken implements parsing and verification of signed GCE VM metadata tokens.

    See https://cloud.google.com/compute/docs/instances/verifying-instance-identity

    Intended to be used from a server environment (e.g. from a GAE), since it depends on a bunch of luci/server packages that require a properly configured context.

    Index

    Constants

    View Source
    const Header = "X-Luci-Gce-Vm-Token"

      Header is the name of the HTTP header where the GCE VM metadata token is expected.

      Variables

      This section is empty.

      Functions

      func Clear

      func Clear(c context.Context) context.Context

        Clear returns a new context without a GCE VM metadata token installed.

        func CurrentIdentity

        func CurrentIdentity(c context.Context) string

          CurrentIdentity returns the identity of the VM stored in the current context.

          func Has

          func Has(c context.Context) bool

            Has returns whether the current context contains a valid GCE VM metadata token.

            func Hostname

            func Hostname(c context.Context) string

              Hostname returns the hostname of the VM stored in the current context.

              func Matches

              func Matches(c context.Context, host, zone, proj string) bool

                Matches returns whether the current context contains a GCE VM metadata token matching the given identity.

                func Middleware

                func Middleware(c *router.Context, next router.Handler)

                  Middleware embeds a Payload in the context if the request contains a GCE VM metadata token.

                  Types

                  type Payload

                  type Payload struct {
                  	Project  string // GCE project name, e.g. "my-bots" or "domain.com:my-bots"
                  	Zone     string // GCE zone name where the VM is, e.g. "us-central1-b"
                  	Instance string // VM instance name, e.g. "my-instance-1"
                  	Audience string // 'aud' field inside the token, usually the server URL
                  }

                    Payload is extracted from a verified GCE VM metadata token.

                    It identifies a VM that produced the token and the target audience for the token (as it was supplied to the GCE metadata endpoint via 'audience' request parameter when generating the token).

                    func Verify

                    func Verify(c context.Context, jwt string) (*Payload, error)

                      Verify parses a GCE VM metadata token, verifies its signature and expiration time, and extracts interesting parts of it into Payload struct.

                      Does NOT verify the audience field. This is responsibility of the caller.

                      The token is in JWT form (three dot-separated base64-encoded strings). It is expected to be signed by Google OAuth2 backends using RS256 algo.

                      Source Files

                      Directories

                      Path Synopsis
                      Package client implements client-side fetch and transmission of signed GCE VM metadata tokens.
                      Package client implements client-side fetch and transmission of signed GCE VM metadata tokens.