From c9c7807bf0f068474ce5c853244bcb392bdfcce3 Mon Sep 17 00:00:00 2001 From: tv Date: Sun, 8 Nov 2026 19:16:10 +0000 Subject: roots: an epoch's root pinned, and named in every handshake Review 2, N7, the care it raised: a joining node's empty document took as the first epoch's root whatever dependency-less change came first, from whichever peer it joined through; the first epoch's ID is all zeros, so nothing pinned it. A remake's epoch has its ID, the snapshot change's hash, which the rules hold its root to. * Every node names its epoch's root in HELLO and HELLO_REPLY (the epoch's ID for a remake's, its genesis change for the first; wire version 45). A node whose document starts from another root of the same epoch refuses the handshake, logging it: another history under the swarm's ID, a forged root or a genesis started again. * A joining node with an empty document takes as its root only the one it was given (--genesis-root, new), else the one its peers name, and none while they name different ones (access::screen::RootPin, kept in Screening across documents): one peer hands it another root only if it is all the joiner hears, or never, with --genesis-root. A root refused is listed with the refused, what builds on it with it. * The genesis node logs the root (`The swarm's root`); GET /admin/epochs shows it (`root`). A genesis started again under a remembered swarm ID used to merge with the nodes of it still running; they now refuse it (another root), and the docs say to join them with seeds instead. The epoch's identity stays as it is (generation 0 all zeros): records and epoch metadata name it so, and every comparison of epochs with them. --- src/config/mod.rs | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) (limited to 'src/config/mod.rs') diff --git a/src/config/mod.rs b/src/config/mod.rs index 0352832..f6d3e15 100644 --- a/src/config/mod.rs +++ b/src/config/mod.rs @@ -179,6 +179,13 @@ pub(crate) const OPTIONS: &[OptionSpec] = &[ None, "With bootstrap-users: their SSH keys, as authorized_keys lines (ssh-ed25519 [comment], named by the comment), recorded in their entries: to log in by key and sign values (docs/access.md), so a swarm can be strict from its start.", ), + option( + "genesis-root", + Kind::Text, + "HASH", + None, + "The hash of the swarm's genesis change (hex, as its genesis node logs it and GET /admin/epochs shows it): joining with an empty document, the only root this node takes. Without, the one its peers name, none while they name different ones (docs/access.md).", + ), option( "strict-keys", Kind::List, @@ -219,7 +226,7 @@ pub(crate) const OPTIONS: &[OptionSpec] = &[ Kind::Flag, "BOOL", Some("false"), - "Start a new swarm, as its genesis node, instead of joining one through seeds. Every start with it starts another new swarm: drop it once the swarm exists, and give the node seeds instead. Can't be combined with seeds. With a --state-file that remembers a swarm, it starts that swarm again instead (empty; nodes of it still running merge with this one).", + "Start a new swarm, as its genesis node, instead of joining one through seeds. Every start with it starts another new swarm: drop it once the swarm exists, and give the node seeds instead. Can't be combined with seeds. With a --state-file that remembers a swarm, it starts that swarm again instead (empty, from a new root, which nodes of it still running refuse: to join them, give seeds).", ), option( "force", @@ -601,6 +608,7 @@ pub(crate) struct Settings { pub(crate) bootstrap_users: Vec, #[serde(default)] pub(crate) bootstrap_keys: Vec, + pub(crate) genesis_root: Option, #[serde(default)] pub(crate) strict_keys: Vec, @@ -881,6 +889,11 @@ impl Settings { { bail!("{why}"); } + if let Some(root) = &self.genesis_root + && crate::swarm::roots::parse(root).is_none() + { + bail!("genesis-root: {root:?} isn't a change hash (64 hex digits)"); + } if let Some(why) = self .strict_keys .iter() -- cgit v1.3.1