Stop when the backend is not following BLAKE2b - #21
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lightningdonly checks that its backend reportschain = main, which a bitcoind that never switched to BLAKE2b also reports. Block headers are parsed by their own version bit, so a node pointed at such a backend followed it without complaint.new_block()now stops the node when a block at or above the BLAKE2b activation height (the chain parameter, or--dev-blake2b-activation-height) has an 80-byte header. Every block passes through it, including the startup scan and reorg replacements. Regtest has no activation height, so nothing changes there unless the developer option is set.doc/blake2b-upgrade.mddescribed this check as already present; it now describes it as it is.SECURITY.mdwas upstream's, sending reports for this code to upstream's maintainers and listing their release keys. It now sends them to security@privkey.io, sends upstream-only issues upstream, and names the key these releases are signed with.Tests
In
tests/test_blake2b_differentiation.py, against a backend whose activation never arrives:test_backend_without_blake2b_at_startup: the node refuses to start past the activation height.test_backend_without_blake2b_at_activation: a running node stops at the first block past it.test_backend_with_blake2b_passes_activation: a BLAKE2b backend crosses it untouched.The first two fail on the current release, where the node keeps running.
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