Cactus pollinate - #12
Merged
Merged
Conversation
Generate §4.4 subtree consistency proofs from stored interior node hashes (the tlog.StoredHashIndex addressing scheme) instead of hashing every leaf. O(log n) node reads per proof makes generation over a remote tree practical: each read maps to a cached, authenticated hash-tile lookup rather than a replay of the whole log. The existing leaf-hashing generator is unchanged; both share the SUBTREE_PROOF skeleton, parameterised by a range-hash function.
A c2sp.org/tlog-cosignature log_origin is just the checkpoint origin string, and real-world MTC logs (e.g. Cloudflare's bootstrap CA, origin bootstrap-mtca.cloudflareresearch.com/logs/shard3) use plain hostname-path origins that TrustAnchorID cannot represent. Expose the §5.3.1 CosignedMessage construction with raw string names; MarshalSignatureInputAt becomes a thin wrapper.
Target.Origin overrides the oid/-derived checkpoint origin so the push client can serve logs whose origin is not a trust anchor ID, and VerifyCosignaturesForOrigin verifies mirror cosignatures against such origins (VerifyCosignatures delegates to it). The 404 responses from add-checkpoint and add-entries now wrap a new ErrUnknownOrigin sentinel, so a caller that pushes opportunistically can record "this mirror does not carry this log" with errors.Is instead of treating the response as an operator-facing fault.
cactus-pollinate follows the Chrome MTC cosigners list, watches every issuer's logs and every mirror's copy of them, and pushes missing entries (via the c2sp.org/tlog-mirror write API) to any mirror that has been lagging the log head for longer than a configured delay. CAs are expected to push on their own; pollinate is the backstop for mirrors they are failing to reach — including bootstrapping brand-new mirrors. Discovery probes both layouts seen in the wild: a single log at the bare CA base URL and mtc-tlog-profile logs at <CA prefix>/<n>. A log's identity is the origin its checkpoint declares, including non-oid/ origins. Reads go through tlog.TileHashReader, so every hash and entry is authenticated against the source checkpoint root without keeping a local replica (Cloudflare's bootstrap log has 229M entries); sources are picked freshest-first with random tie-breaks to spread read load, and verified tiles are shared through a bounded cache. Lag is measured against history, not the current head: the state file (pollinate/state.json) records when the head was first seen at each size, and a mirror is only pushed entries the head already had a full delay window ago. Mirrors that answer "unknown origin" on the submission API are recorded as not carrying the log and rechecked on an interval or when the cosigners list version changes. Issuer checkpoints are signature-verified when the key is ML-DSA-44; mirror cosignatures on push responses are always verified, with keys matched from the cosigners PEM bundle by key_sha256 (the SHA-256 of the SPKI DER). Prometheus metrics (cactus_pollinate_*) and slog JSON output follow the cactus server's conventions, including loopback-gated pprof. Tested end-to-end against a stub mirror that verifies every pushed subtree consistency proof, and live against a real Sunlight witness/mirror (562-entry bootstrap push, cosignature verified, mirror copy recomputes to the CA's signed root).
c2sp.org/tlog-tiles: clients SHOULD include a way for the operator to
contact them in the User-Agent (an email and/or a +https:// URL), and
logs MAY rate-limit anonymous or unreachable clients. Skylight enforces
this — anonymous entry-bundle reads get HTTP 429.
Stamp a contact UA on everything in the repo that talks to a log or
mirror: the cactus server's mirror_push client and sign-subtree quorum
requests ("cactus (+https://github.com/mcpherrinm/cactus)") and
cactus-cli's reads. cactus-pollinate already ships with its own. The
integration stub witness now records the User-Agent it sees so the
header cannot silently regress.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
This is a tool for syncing mirrors