syntaqxBrokered secrets work on self-hosted runners whose jobs run on Linux or macOS, and the value still never reaches the runner's computer. The job keeps its stand-in; a harness that can broker says so when it fetches its spec (`broker`), and the spec then lists each stand-in's hosts (`brokered`), never a value. The harness runs a proxy for the job on 127.0.0.1 and gives the steps HTTPS_PROXY, NODE_USE_ENV_PROXY and the trusted-certificate variables g1t's own sandboxes set (SSL_CERT_FILE, NODE_EXTRA_CA_CERTS, REQUESTS_CA_BUNDLE, CURL_CA_BUNDLE, PIP_CERT, GIT_SSL_CAINFO, CARGO_HTTP_CAINFO), each pointing at what it pointed at before with the job's certificate added. HTTPS to any other host is a plain tunnel. HTTPS to a brokered host is opened with a certificate from an authority made for that job alone, name-constrained to the brokered hosts and with its key only in memory; each request on it that carries one of the job's stand-ins goes to POST /actions/jobs/{job}/broker with the job's current token in Authorization, and a request without one goes straight to the host on a connection of its own.c1606d3History
