feat(s137): the toolchain floor refused at boot, and ML-DSA-87 known-answer tests through :crypto

.github/workflows/gate.yml

@@ -101,6 +101,21 @@ jobs:
 
       - run: mix gate
 
+      # Slice 137, AC2: a real boot on an Erlang runtime below the CVE-2026-55737 floor refuses.
+      # OTP 28.5.0.3 (erts 16.4.0.3) is the release just before the fix, prebuilt by Hex for this
+      # runner's OS and pinned by the sha256 builds.hex.pm publishes in builds.txt. The tree is the
+      # one `mix gate` just compiled on the pinned OTP; only the runtime is older. `--only` with a
+      # tag that selects nothing makes `mix test` exit non-zero, so this cannot pass by running
+      # no test.
+      - name: A boot on OTP 28.5.0.3, below the floor, refuses
+        run: |
+          curl -fsSL -o /tmp/otp-28.5.0.3.tar.gz https://builds.hex.pm/builds/otp/ubuntu-24.04/OTP-28.5.0.3.tar.gz
+          echo "d4116a141da5081b849bd057a30679b48f229fb41dbe88da171739883a4797fb  /tmp/otp-28.5.0.3.tar.gz" | sha256sum -c -
+          mkdir -p /tmp/otp-28.5.0.3
+          tar -xzf /tmp/otp-28.5.0.3.tar.gz -C /tmp/otp-28.5.0.3 --strip-components=1
+          (cd /tmp/otp-28.5.0.3 && ./Install -minimal "$PWD" > /dev/null)
+          TRINITY_BELOW_FLOOR_OTP=/tmp/otp-28.5.0.3/bin mix test --only below_floor_otp test/trinity/toolchain_node_test.exs
+
       # Slice 120 AC1. `reuse lint` is a Python tool and this is the only leg that installs one,
       # deliberately: `mix gate` has to stay runnable inside the FIPS container and on a developer's
       # machine without a Python environment, so the REUSE check is a step here rather than a row in
@@ -360,3 +375,23 @@ jobs:
         run: |
           mix test --trace test/fips
           mix test --cover | grep -E 'Result:|\| *Total'
+
+      # Slice 137, AC5 and AC7: ML-DSA-87 with the mode off. This image links OpenSSL 3.5, the only
+      # runtime in CI that signs ML-DSA-87 (the gate runners link 3.0; in the mode, Red Hat's
+      # provider refuses it), so the ML-DSA-87 path runs here end to end: the planted-step cases,
+      # a regulated node that boots with ML-DSA-87 receipts and whose boot receipt verifies, and the
+      # signer's key shapes. TRINITY_REQUIRE_MLDSA87_RUNTIME makes test_helper raise if the runtime
+      # cannot sign, rather than excluding the cases it came to run.
+      #
+      # It runs last, from a fresh suite state. The suite keeps its receipt keys in tmp/test_keys
+      # and its receipts in trinity_test_receipts.db across runs, so a run with the mode off leaves
+      # Ed25519 and ML-DSA-87 keys and rows that the mode refuses to verify. Run before `mix gate`,
+      # it turned five of the gate's tests red on PR #132 (`:notsup`, "Unsupported algorithm in
+      # FIPS mode"; three receipt keys in one export). Nothing in the mode runs after this step.
+      - name: ML-DSA-87 end to end (FIPS mode off)
+        env:
+          ERL_AFLAGS: "-eval application:load(crypto)"
+          TRINITY_REQUIRE_MLDSA87_RUNTIME: "1"
+        run: |
+          rm -rf tmp trinity_test.db* trinity_test_receipts.db*
+          mix test test/trinity/crypto/preflight_test.exs test/trinity/toolchain_node_test.exs test/trinity/receipts/signer_test.exs

CHANGELOG.md

@@ -22,6 +22,31 @@ evidence for each increment is retained by the maintainers and summarised here.
   tree, engineering rules consolidated into `docs/03-conventions.md`, and this changelog added as
   the public record of delivered work.
 
+### `slice/137`: Trinity refuses a runtime it should not trust
+
+A node now refuses to start, before anything else runs, on an Erlang runtime that still carries
+CVE-2026-55737 (heap corruption when a malformed external term is decoded) or on Elixir older than
+1.20.x. The floor is the release that fixed it on each Erlang/OTP line (27.3.4.15, 28.5.0.4,
+29.0.4), whose rows of Erlang/OTP's own version table are checked in verbatim: the runtime and every
+loaded Erlang/OTP application, ssl and crypto among them, are compared with that release's
+versions. Every pinned build is above it; a release copied onto an older runtime is what it stops.
+
+Whether ML-DSA-87 can be used is now answered by doing it at boot, against published answers (a
+NIST key-generation case and three Wycheproof verification cases) and then with a fresh key,
+rather than by asking whether the runtime lists the algorithm.
+Erlang/OTP lists no ML-DSA type in FIPS mode whatever the cryptographic provider can do, so the
+listing would have told a FIPS node with a capable provider that it could not sign. A regulated
+node configured to sign receipts with ML-DSA-87 that fails the check refuses to boot and says
+which step failed; a default node keeps running with effects denied, as it does for any signer
+fault. The boot receipt records the runtime's erts and Elixir versions and the check's answer.
+ML-DSA-87 receipt keys made by Erlang/OTP 28.5.0.8, which returns the private key in a different
+shape from earlier releases, no longer stop the node from starting.
+
+Verified by the test suite: a real boot on Erlang/OTP 28.5.0.3, the release before the fix,
+refusing in its own operating system process; the floor at every boundary and a property over
+generated versions; every step of the ML-DSA-87 check failing by name; and, on the FIPS image with
+the mode off, the planted failures against the real cryptographic library.
+
 ## 2026-10-08
 
 ### `slice/136`: the web pages ask who is there

REUSE.toml

@@ -67,3 +67,20 @@ path = ["test/support/fixtures/nist/**"]
 precedence = "override"
 SPDX-FileCopyrightText = "National Institute of Standards and Technology"
 SPDX-License-Identifier = "CC0-1.0"
+
+# Slice 137. **Not ours.** The ML-DSA-87 known-answer vectors the boot preflight checks against.
+# `priv/kat/acvp/` is one case from NIST's ACVP-Server (`usnistgov/ACVP-Server`), a work of the US
+# Government, annotated CC0-1.0 as the NIST catalogues above are. `priv/kat/wycheproof/` is three
+# cases from C2SP's Wycheproof, Apache-2.0. Each file names its source commit and the SHA-256 of the
+# file it was cut from. The `**/*.json` line above would otherwise assign them to this project.
+[[annotations]]
+path = ["priv/kat/acvp/**"]
+precedence = "override"
+SPDX-FileCopyrightText = "National Institute of Standards and Technology"
+SPDX-License-Identifier = "CC0-1.0"
+
+[[annotations]]
+path = ["priv/kat/wycheproof/**"]
+precedence = "override"
+SPDX-FileCopyrightText = "Google LLC and the C2SP Wycheproof contributors"
+SPDX-License-Identifier = "Apache-2.0"

docs/07-security-model.md

@@ -522,6 +522,30 @@ where the runtime carries it; the boot receipt names the choice and the authorit
 hash in unsigned metadata (the R21 default). `bin/verify_receipt.exs` verifies an export with `elixir` alone,
 from an empty directory, with the exit vocabulary 0, 1, 2, 5, 6.
 
+## The runtime floor, and ML-DSA-87 by doing it (Slice 137, as built)
+
+Before anything else starts, and in every profile, `Trinity.Application` refuses a runtime below
+the fix for CVE-2026-55737 ("heap corruption when an invalidly encoded tuple with an arity of 2^31
+or larger is decoded from Erlang's External Term Format"). The defect is in erts, so erts is what
+is compared: `Trinity.Toolchain.floor/0` holds the fixed erts per OTP line, read from
+`otp_versions.table`. An assembled release has no `OTP_VERSION` file, and `:erlang.system_info(:version)`
+answers in every runtime. The same releases fix CVEs in ssl, public_key, crypto, ssh and stdlib,
+so erts is not enough: `priv/otp_floor.table` holds the three fixing releases' rows of
+`otp_versions.table` verbatim, with their source commit and SHA-256, and every loaded application
+the row names must be at or above its version there. Elixir outside 1.20.x is refused the same way.
+
+`crypto:supports/0` cannot say whether ML-DSA-87 is usable in FIPS mode: OTP's
+`build_pkey_type_list/3` omits every ML-DSA and SLH-DSA type whenever the mode is on, whatever the
+loaded provider can do. `Trinity.Crypto.Preflight.mldsa87/1` asks the provider by doing the
+operation: NIST's ACVP keyGen case (the published secret key must yield the published public key),
+Wycheproof's valid, bit-flipped and malformed-hints verify cases, then a fresh key. The ML-DSA-87
+receipts signer reports itself available exactly when that passes.
+Under `:regulated`, a node configured for ML-DSA-87 receipts that fails it refuses to boot with
+`{:mldsa87_preflight_failed, step, reason}`; under `:default` the receipts supervisor stays
+fail-open. Where it signs today: a runtime linked to OpenSSL 3.5 or later with the mode off. In the
+mode, on the image's current FIPS provider, it does not; a provider validated with ML-DSA-87
+(CMVP #5523) is what would change that.
+
 ## The effect population, published (Slice 027, as built)
 
 The set of things that can cause an effect is small, derived from the tree, and published as

docs/regulated/control-mapping.md

@@ -117,11 +117,13 @@ register does not claim is never Trinity's.
 | `SC-12` | Keys pass through one behaviour, so a KMS or HSM adapter is a module and a configuration line; none ships in this tree | `lib/trinity/keys.ex` | `test/trinity/keys/signer_seam_test.exs` "a sealed key still signs, which is the point of sealing it" | shared | A KMS or HSM adapter, where one is required | CRM "A KMS or HSM adapter" |
 | `SC-12` | Custody of the signing key is not addressed: a key in a file shows the records were not altered by anything without read access to it, and nothing about who held it | `docs/10-assurance-case.md` | none | the deployment's | Custody of the signing key | CRM "Custody of the signing key" |
 | `SC-13` | Signing picks its algorithm by the runtime's mode: Ed25519 by default, ECDSA P-384 with SHA-384 in FIPS mode, where Ed25519 reports itself unavailable. The gate and the suite run in FIPS mode on every push | `lib/trinity/receipts/signer.ex`, `docs/fips-leg.md`, `docs/regulated/crypto-inventory.md` | `test/trinity/receipts/signer_test.exs` "outside FIPS mode the default is Ed25519; in FIPS mode (the fips leg) it is P-384"; `test/fips/receipts_test.exs` "the mode is on, Ed25519 reports unavailable, P-384 is selected and the boot receipt names it" | shared | A validated cryptographic module on the host, established from its certificate and the running binary | Register "FIPS 140-3 validated cryptography in FIPS mode": :unknown; Register "FIPS 140-2 certificates on the Historical list from 2026-09-22": real-world dependency |
+| `SC-13` | ML-DSA-87 is offered for receipts only where a known-answer check passes through `:crypto` in the mode the node is in: NIST's ACVP keyGen case (the published secret key yields the published public key), Wycheproof's verify cases (a valid signature, a bit-flipped one and one with malformed hints), then a fresh key. Not where the algorithm is merely listed: OTP lists no ML-DSA type in FIPS mode whatever the provider can do. A regulated node configured for ML-DSA-87 that fails the check refuses to boot naming the step; the boot receipt records the check's answer | `lib/trinity/crypto/preflight.ex`, `priv/kat/`, `lib/trinity/receipts/signer/mldsa87.ex`, `lib/trinity/receipts/key_custody.ex` | `Trinity.Crypto.Preflight.mldsa87/1`; `test/trinity/crypto/preflight_test.exs` "a provider that derives the wrong public key fails at :keygen_kat"; `test/trinity/crypto/preflight_test.exs` "a verifier that accepts Wycheproof's bit-flipped signature fails at :sigver_kat, naming the case"; `test/trinity/crypto/preflight_test.exs` "the ML-DSA-87 signer is available exactly when the preflight passes (F-137-1)"; `test/trinity/toolchain_node_test.exs` "a failing preflight refuses the boot, naming the step" | Trinity's | none | none |
 | `SC-23` | A request whose `Host` is not the loopback or the configured host is refused before routing, and the websocket origin check is an explicit list in every environment; under `TRINITY_PROFILE=regulated` an origin check of `false` or `:conn` refuses to boot, because a DNS rebinding page controls both | `lib/trinity_web/plugs/host_allow_list.ex`, `lib/trinity/profile.ex` | `Trinity.Profile.check_origin/2`; `test/trinity_web/auth/host_and_origin_test.exs` "a foreign Host is 403 before routing, wherever it points"; `test/trinity_web/auth/host_and_origin_test.exs` "check_origin is an explicit list in dev, test and prod" | shared | Setting `PHX_HOST` to the host users reach | CRM "Refusing a request whose Host is not this deployment's" |
 | `SC-23` | The state an MCP client carries between rounds is sealed with AES-256-GCM: a replay, one tampered byte, an expired envelope and a state bound to other arguments are refused | `lib/trinity/mcp/server/envelope.ex` | `test/trinity/mcp/server_mrtr_test.exs` "a replay inside the partition, one tampered byte, an expired envelope and a state bound to other arguments are refused; a missing state is a first call" | Trinity's | none | Register "Envelope MAC in FIPS mode is an approved algorithm": :unknown |
 | `SC-24` | Failure denies: an unavailable signer denies every effect, a tool absent from the catalogue or a decision other than allow is denied before anything runs, and an authority adapter that cannot be loaded refuses the boot | `lib/trinity/effects.ex`, `lib/trinity/authority/selection.ex` | `test/trinity/effects/membrane_test.exs` "a :catalog tool absent from the catalog, or a decision other than allow, is denied before anything runs"; `test/trinity/authority/selection_test.exs` "an absent module is refused as not loaded, by name" | Trinity's | none | Register "Nothing fails open": :unknown |
 | `SC-28` | Anything SQLite indexes is left unencrypted by design, for the volume beneath it | `docs/encryption-at-rest.md` | none | the deployment's | Volume or page-level encryption below SQLite | CRM "Encryption of everything SQLite indexes" |
 | `SC-28(1)` | Blobs nothing indexes (skill files, staged changes, archives) are sealed with AES-256-GCM under a fresh data key each | `lib/trinity/vault.ex` | `test/trinity/vault_test.exs` "a sealed blob is ciphertext: the plaintext does not appear in it"; `test/trinity/vault_test.exs` "every blob gets its own data key, so one compromise does not open the next" | Trinity's | none | CRM "Envelope encryption of blobs"; Register "Encryption of data at rest with deployment-controlled keys": :unknown |
+| `SI-2` | Every profile refuses to boot, before any child starts, on a runtime below the release that fixed CVE-2026-55737 for its line (OTP 27.3.4.15, 28.5.0.4 or 29.0.4): erts and every loaded application are compared with that release's row of `otp_versions.table`, checked in verbatim with its source commit and SHA-256. Elixir outside 1.20.x is refused the same way, and the boot receipt records the erts and Elixir it ran on | `lib/trinity/toolchain.ex`, `priv/otp_floor.table`, `lib/trinity/application.ex`, `lib/trinity/effects/boot.ex` | `Trinity.Toolchain.check_otp/3`; `Trinity.Toolchain.check_otp/2`; `Trinity.Toolchain.check_elixir/1`; `test/trinity/toolchain_node_test.exs` "the line the child prints names the refusal, the runtime's erts and the floor"; `test/trinity/toolchain_test.exs` "erts at the floor with an application below it refuses, naming the application"; `test/trinity/toolchain_node_test.exs` "a default node boots" | Trinity's | none | none |
 | `SI-4` | Documented telemetry events an operator can subscribe to; Trinity emits them and alerts no one | `lib/trinity/telemetry.ex`, `docs/telemetry.md` | `test/trinity/telemetry/telemetry_test.exs` "every event the catalogue lists appears in docs/telemetry.md" | shared | Collecting the events, and alerting on them | CRM "Telemetry events an operator can subscribe to" |
 | `SI-7` | A changed MCP tool definition is held, not called, until the owner accepts it; the first sighting is the baseline | `lib/trinity/tools/surface.ex`, `lib/trinity/tools/definition_digest.ex` | `test/trinity/mcp/surface_drift_test.exs` "a description change alone holds the tool, with the schema untouched" | Trinity's | none | none |
 | `SI-7` | Every input to the image build that is not a UBI package is declared with its digest and copied only if declared, and the published bases are pinned by digest | `ci/ironbank/hardening_manifest.yaml`, `lib/mix/tasks/trinity.ironbank.lint.ex` | `mix trinity.ironbank.lint`; `test/ironbank_submission_test.exs` "copying a file no resource declares is refused"; `test/ironbank_submission_test.exs` "a published base pinned by tag and not by digest is refused (planted red)" | Trinity's | none | none |

lib/trinity.ex

@@ -42,6 +42,11 @@ defmodule Trinity do
         # starts anything. Pure, so the refusals are unit testable and so this boundary does not
         # grow a dependency on Authority or Receipts to ask a question about a value.
         Profile,
+        # Slice 137: the runtime floor the application refuses to boot below, and the ML-DSA-87
+        # known-answer check the receipts signer and the boot receipt ask. Pure questions about
+        # the runtime, asked before anything starts.
+        Toolchain,
+        Crypto.Preflight,
         # Slice 136: the web authentication mode, its rules and the mode in force.
         WebAuth,
         UUID,

lib/trinity/application.ex

@@ -31,6 +31,11 @@ defmodule Trinity.Application do
     # project's rules about key material, and the filter is the last line for exactly that case.
     install_log_redaction()
 
+    # Slice 137, in every profile, before every other refusal and every child: a runtime below
+    # the CVE-2026-55737 floor, or an Elixir below 1.20, is not one this node trusts to decode
+    # anything. The floor is erts per OTP line (`Trinity.Toolchain.floor/0`).
+    verify_toolchain!()
+
     # Slice 135, in every profile: a filesystem root that is, contains or sits inside the data
     # directory or the secrets directory refuses the boot, before any child (and before the
     # regulated refusals, so the reason printed is this one when both apply).
@@ -184,6 +189,15 @@ defmodule Trinity.Application do
     :ok
   end
 
+  # Slice 137. The decision is `Trinity.Toolchain.check/0`'s, pure; the reason is raised in the
+  # shape `verify_web_auth!/0` uses, so a refused child prints it whole.
+  defp verify_toolchain! do
+    case Trinity.Toolchain.check() do
+      :ok -> :ok
+      {:error, reason} -> raise "Trinity refuses to boot: #{inspect(reason)}"
+    end
+  end
+
   # Slice 136 AC4, AC6 and AC13. The decisions are `Trinity.WebAuth`'s and `Trinity.Profile`'s,
   # both pure; this reads the endpoint's configuration and hands them the values.
   defp verify_web_auth! do