Two HIGH validator-side bugs + several MED/LOW off-chain issues found
in the subagent-driven audit on this branch. New validator hash:
a8081acef26935d9b5f44b92052178e17301b6d6e6808c91c5b56f5d.
## HIGH-1: Deposit redeemer let depositors drain tokens
aiken-escrow/validators/escrow.ak Deposit branch now requires
`value_geq_value(new_value, in_value)` before computing net_added.
Previously net_added could carry negative quantities (when new_value
< in_value component-wise), letting a depositor write a matching
new_d.deposits with reduced values and pocket the difference as
wallet change. Latent under v1 ADA-only MCP usage but the validator
must hold against all callers.
## HIGH-2: Empty/partial deposits enabled funds drain via Veto/Refund
Veto and Refund branches now require
`value_eq(deposits_to_value(d.deposits), in_value)` — the tracked
deposits must account for the full locked value. Previously
`refund_outputs_satisfy(_, [])` was vacuously true on empty deposits,
so a driver could fire Veto/Refund on an escrow opened with
`initial_contributor=None` (deposits=[], in_value>0) and pocket the
input's lovelace as change.
Defense in depth: escrow_open builder now refuses
`initial_contributor=None`. New helper `deposits_to_value` folds
deposit FlatValues into a Value via `assets.add` for the equality
check.
## MED: off-chain fixes
- escrow_open min-utxo bumped 1M → 2M (Conway-era inline-datum
+ script-address outputs need ~1.4-1.7 ADA, NOT the 1 ADA default).
- escrow_settle_unsigned + escrow_refund_timeout_unsigned now derive
`validity_lower_ms` via slot_to_posix_ms(network, slot) instead of
Koios's `block_time*1000` — the chain reconstructs `lower` from the
slot, so Koios's ~1s drift could pass off-chain preflight while the
chain rejects at the strict-`>` boundary.
- escrow_open_unsigned MCP tool no longer accepts (and silently
discards) `fee_lovelace` — the unsigned-tx builder auto-estimates.
## LOW: defensive depth
- escrow_veto + escrow_refund_timeout: `qty as u64` → `u64::try_from`
so a corrupt or adversarial datum with negative i128 qty can't slip
through with a wraparound.
## Tests
- 36 escrow builder tests pass (added rejects_no_initial_contributor)
- 132 dao tests pass under --features escrow_wip
- aldabra-mcp release build clean
## Infra
- Validator artifact files (plutus.json, validator.cbor.hex)
regenerated. Dockerfile already wired to bake them at
/etc/aldabra/escrow/ for MCP tools' validator_script_path arg.
- Internal audit findings written up at
audits/2026-05-09-escrow-internal-audit.md including the v2-deferred
items (multi-asset spend-input, lovelace-not-cross-checked, etc.)
Third-party audit still required before any mainnet deployment.
