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feat(spark): solver_integrity SPARK companion — run #2
SPARK 2014/2022 formal companion for src/rust/integrity/solver_integrity.rs, the SHAKE3-512 + BLAKE3 binary integrity layer. Advances the Rust→Rust/SPARK migration roadmap to run #2. Files - spark/solver_integrity/solver_integrity.ads — Ada spec, Pre/Post + ghost lemmas - spark/solver_integrity/solver_integrity.adb — body mirroring the 5-arm Rust decision tree - spark/solver_integrity/solver_integrity_proof.adb — 11 proof obligations catalogue - spark/solver_integrity/solver_integrity.gpr — GPRbuild project (gnat2022, --level=1) - spark/solver_integrity/alire.toml — Alire manifest pinning gnat_native ^14 / gprbuild ^22 - spark/solver_integrity/.gitignore — ignore .obj/ - spark/README.adoc — module index updated Proved - Total classification: Classify_Verification covers every input combination and never returns Unchecked (which is reserved for "no check done") - Hash-mismatch monotonicity: Binary_Found ∧ ¬Placeholder ∧ Compute_Succeeded ∧ ¬Hashes_Match ⇒ Tampered (issue #40 roadmap's load-bearing obligation) - Safety predicate exclusion: Is_Safe(S) = (S in {Verified, Uninitialized, Unchecked}) - Quick_Reverify: Unchanged ⇔ Cached_Match - Aggregate cap-at-Tampered: Has_Tampered(S) ⇒ ¬Aggregate_Safe(S) gnatprove summary: 11 checks, 0 unproved, 0 justified, max 53 steps. SPARK does not model file IO, async/tokio, or cryptographic primitives, so the companion is intentionally a pure-decision mirror. The Rust impl's find_solver_binary / compute_shake3_512 / compute_blake3 / RwLock layer is abstracted into the four boolean inputs of Classify_Verification, and the crypto guarantees come from the tiny_keccak (SHAKE3) and blake3 crates. SPARK's contribution is proving the decision tree *above* the crypto layer is correct and that hash mismatch unambiguously yields Tampered. 🤖 Generated with [Claude Code](https://claude.com/claude-code)
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‎spark/README.adoc‎

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| link:axiom_tracker/[axiom_tracker]
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| `src/rust/verification/axiom_tracker.rs`
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| Run #1 — proved
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| Run #1 — proved (18/0)
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| link:solver_integrity/[solver_integrity]
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| `src/rust/integrity/solver_integrity.rs`
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| Run #2 — proved (11/0)
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|===
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‎spark/solver_integrity/.gitignore‎

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.obj/

‎spark/solver_integrity/alire.toml‎

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name = "solver_integrity_spark"
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description = "SPARK companion for echidna solver_integrity module"
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version = "0.1.0"
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licenses = "PMPL-1.0-or-later"
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maintainers = ["hyperpolymath@users.noreply.github.com"]
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maintainers-logins = ["hyperpolymath"]
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[build-switches]
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"*".Ada_Version = "Ada2022"
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[[depends-on]]
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gnat_native = "^14"
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gprbuild = "^22"

‎spark/solver_integrity/solver_integrity.adb‎

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-- SPDX-License-Identifier: PMPL-1.0-or-later
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--
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-- SPARK companion body for solver_integrity.ads
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--
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-- Implementation strategy
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-- -----------------------
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-- Classify_Verification is a 5-arm if-chain mirroring the Rust decision tree
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-- top-to-bottom. Each return statement closes exactly one Post case;
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-- gnatprove substitutes the case-branch predicate at the return site and
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-- discharges at --level=0/1.
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--
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-- The ghost lemmas (Cap_At_Tampered, Hash_Mismatch_Means_Tampered) are
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-- named restatements with null bodies — gnatprove derives the conclusion
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-- from the spec's Post-condition + the standard quantifier dualities.
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pragma Ada_2022;
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package body Solver_Integrity
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with SPARK_Mode => On
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is
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function Classify_Verification
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(Binary_Found : Boolean;
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Expected_Is_Placeholder : Boolean;
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Compute_Succeeded : Boolean;
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Hashes_Match : Boolean) return Integrity_Status is
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begin
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-- (1) Mirrors Rust line 222: find_solver_binary returned None.
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if not Binary_Found then
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return Missing;
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end if;
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-- (2) Mirrors Rust line 240: entry.shake3_512.starts_with("PLACEHOLDER").
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if Expected_Is_Placeholder then
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return Uninitialized;
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end if;
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-- (3) Mirrors Rust line 298-309: compute_shake3_512 returned Err.
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if not Compute_Succeeded then
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return Missing;
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end if;
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-- (4) Mirrors Rust line 277-286: computed == expected.
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if Hashes_Match then
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return Verified;
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else
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return Tampered;
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end if;
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end Classify_Verification;
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function Quick_Reverify (Cached_Match : Boolean) return Reverify_Outcome is
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begin
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if Cached_Match then
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return Unchanged;
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else
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return Changed;
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end if;
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end Quick_Reverify;
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-- ── Cap_At_Tampered ────────────────────────────────────────────────
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-- Ghost lemma; gnatprove discharges from definitions:
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-- Has_Tampered (S) = (for some I, S(I) = Tampered)
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-- Is_Safe (Tampered) = False (by Is_Safe expression function)
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-- => (for some I, not Is_Safe (S(I)))
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-- => not (for all I, Is_Safe (S(I)))
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-- => not Aggregate_Safe (S).
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-- Null body is sufficient — Post follows from Pre by SMT.
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procedure Cap_At_Tampered (Statuses : Status_Array) is
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begin
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null;
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end Cap_At_Tampered;
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-- ── Hash_Mismatch_Means_Tampered ───────────────────────────────────
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-- Ghost lemma; the four-fold conjunction in Pre is exactly the case
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-- arm of Classify_Verification's Post that maps to Tampered, so the
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-- conclusion follows by post-condition application + the disjointness
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-- of the case arms.
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procedure Hash_Mismatch_Means_Tampered
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(Binary_Found : Boolean;
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Expected_Is_Placeholder : Boolean;
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Compute_Succeeded : Boolean;
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Hashes_Match : Boolean) is
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begin
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null;
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end Hash_Mismatch_Means_Tampered;
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end Solver_Integrity;

‎spark/solver_integrity/solver_integrity.ads‎

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-- SPDX-License-Identifier: PMPL-1.0-or-later
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--
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-- SPARK companion spec for src/rust/integrity/solver_integrity.rs
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--
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-- Proved properties
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-- 1. Classify_Verification is total over (Binary_Found, Expected_Is_Placeholder,
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-- Compute_Succeeded, Hashes_Match) and never returns Unchecked.
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-- 2. Hash mismatch monotonicity: binary found AND expected is a real hash
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-- AND compute succeeded AND hashes don't match => status is Tampered.
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-- (This is the load-bearing "hash mismatch => Failed" obligation from
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-- hyperpolymath/echidna#40 roadmap.)
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-- 3. Is_Safe excludes Tampered and Missing exactly:
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-- Is_Safe(S) = (S in {Verified, Uninitialized, Unchecked}).
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-- 4. Quick_Reverify is the boolean-pure restatement of BLAKE3 cached==current.
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-- 5. Aggregate_Safe is cap-at-Tampered monotonic: any Tampered member
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-- forces the aggregate unsafe (Has_Tampered => not Aggregate_Safe).
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--
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-- SPARK does not model file IO, async, tokio, or cryptographic primitives,
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-- so this companion is intentionally a pure-decision mirror. The Rust impl's
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-- find_solver_binary / compute_shake3_512 / compute_blake3 / RwLock layer is
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-- abstracted into the four boolean inputs of Classify_Verification, and the
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-- crypto guarantees come from the Keccak / BLAKE3 crates. The SPARK proof
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-- establishes that the *decision tree above the crypto layer* is correct.
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pragma Ada_2022;
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package Solver_Integrity
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with SPARK_Mode => On
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is
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-- ── IntegrityStatus ────────────────────────────────────────────────
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-- Mirrors Rust enum IntegrityStatus (declared in the same positional
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-- order: Verified, Tampered, Missing, Uninitialized, Unchecked).
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type Integrity_Status is
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(Verified, Tampered, Missing, Uninitialized, Unchecked);
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-- ── Reverify_Outcome ───────────────────────────────────────────────
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-- Quick_reverify returns a Result<bool, _> in Rust; the pure logical
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-- content is a two-valued outcome.
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type Reverify_Outcome is (Unchanged, Changed);
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-- ── Classify_Verification ──────────────────────────────────────────
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-- Mirrors verify_solver's decision tree from src/rust/integrity/
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-- solver_integrity.rs:212-311.
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--
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-- Inputs encode the verify_solver pipeline:
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-- Binary_Found -- find_solver_binary returned Some(_)
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-- Expected_Is_Placeholder -- entry.shake3_512.starts_with("PLACEHOLDER")
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-- Compute_Succeeded -- compute_shake3_512(actual_path).is_ok()
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-- Hashes_Match -- computed == entry.shake3_512
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--
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-- Decision tree (top-to-bottom precedence, mirroring the Rust source):
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-- 1. not Binary_Found => Missing (line 222)
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-- 2. Expected_Is_Placeholder => Uninitialized (line 257)
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-- 3. not Compute_Succeeded => Missing (line 302)
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-- 4. Hashes_Match => Verified (line 279)
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-- 5. otherwise (computed /= expected) => Tampered (line 285)
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function Classify_Verification
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(Binary_Found : Boolean;
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Expected_Is_Placeholder : Boolean;
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Compute_Succeeded : Boolean;
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Hashes_Match : Boolean) return Integrity_Status
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with Post =>
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(case Classify_Verification'Result is
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when Verified =>
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Binary_Found and not Expected_Is_Placeholder
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and Compute_Succeeded and Hashes_Match,
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when Tampered =>
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Binary_Found and not Expected_Is_Placeholder
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and Compute_Succeeded and not Hashes_Match,
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when Uninitialized =>
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Binary_Found and Expected_Is_Placeholder,
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when Missing =>
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(not Binary_Found)
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or (Binary_Found and not Expected_Is_Placeholder
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and not Compute_Succeeded),
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when Unchecked => False);
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-- ── Is_Safe ────────────────────────────────────────────────────────
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-- Mirrors IntegrityChecker::is_solver_safe (Rust line 355-361):
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-- matches!(status, Verified | Uninitialized | Unchecked)
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--
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-- Expressed as an expression function so callers can use it freely
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-- in their own Pre/Post contracts.
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function Is_Safe (S : Integrity_Status) return Boolean is
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(S = Verified or S = Uninitialized or S = Unchecked);
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-- ── Quick_Reverify ─────────────────────────────────────────────────
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-- Mirrors IntegrityChecker::quick_reverify's decision (Rust line 334):
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-- if current_hash != cached_hash { Changed } else { Unchanged }
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--
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-- SPARK abstracts the actual BLAKE3 comparison into Cached_Match.
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function Quick_Reverify (Cached_Match : Boolean) return Reverify_Outcome
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with Post =>
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(Quick_Reverify'Result = Unchanged) = Cached_Match;
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-- ── Bounded status array ───────────────────────────────────────────
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-- Mirrors verify_all's Vec<SolverIntegrityReport>, projected to just
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-- the status field (the rest is informational). 256 solvers covers
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-- any realistic deployment.
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Max_Solvers : constant := 256;
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subtype Solver_Index is Positive range 1 .. Max_Solvers;
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type Status_Array is array (Solver_Index range <>) of Integrity_Status;
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-- ── Aggregate_Safe ─────────────────────────────────────────────────
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-- A set of solvers is safe iff every member is safe. Expression
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-- function — the body IS the postcondition, no separate VC needed.
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function Aggregate_Safe (Statuses : Status_Array) return Boolean is
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(for all I in Statuses'Range => Is_Safe (Statuses (I)));
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-- ── Has_Tampered (ghost) ───────────────────────────────────────────
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-- Predicate: does any solver in the set have status Tampered?
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-- Stated as ghost so callers can use it in their own contracts.
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function Has_Tampered (Statuses : Status_Array) return Boolean is
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(for some I in Statuses'Range => Statuses (I) = Tampered)
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with Ghost;
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-- ── Cap_At_Tampered (ghost lemma) ──────────────────────────────────
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-- Cap-at-Tampered monotonicity: if any solver is Tampered, the
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-- aggregate is unsafe. Mirrors axiom_tracker's cap-at-Reject
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-- monotonicity for the integrity domain.
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--
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-- Proof: Has_Tampered (S) => (exists I, S(I) = Tampered)
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-- => (exists I, not Is_Safe (S(I)))
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-- => not (forall I, Is_Safe (S(I)))
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-- => not Aggregate_Safe (S).
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procedure Cap_At_Tampered (Statuses : Status_Array)
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with Ghost,
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Pre => Has_Tampered (Statuses),
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Post => not Aggregate_Safe (Statuses);
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-- ── Hash_Mismatch_Means_Tampered (ghost lemma) ─────────────────────
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-- Direct named restatement of issue #40's load-bearing obligation
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-- ("hash mismatch => Failed"). Proof: Classify_Verification's Post.
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procedure Hash_Mismatch_Means_Tampered
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(Binary_Found : Boolean;
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Expected_Is_Placeholder : Boolean;
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Compute_Succeeded : Boolean;
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Hashes_Match : Boolean)
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with Ghost,
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Pre => Binary_Found and not Expected_Is_Placeholder
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and Compute_Succeeded and not Hashes_Match,
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Post => Classify_Verification
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(Binary_Found, Expected_Is_Placeholder,
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Compute_Succeeded, Hashes_Match) = Tampered;
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end Solver_Integrity;

‎spark/solver_integrity/solver_integrity.gpr‎

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-- GPRbuild project for solver_integrity SPARK companion
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project Solver_Integrity is
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for Source_Dirs use (".");
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for Object_Dir use ".obj";
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for Main use ();
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package Compiler is
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for Switches ("Ada") use
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("-gnat2022", -- Ada 2022 syntax
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"-gnatX", -- experimental Ada extensions (quantified exprs)
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"-O1",
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"-gnatn");
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end Compiler;
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package Prove is
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-- gnatprove settings:
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-- --mode=prove run full proof (not just flow analysis)
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-- --level=1 CVC5 + Z3, medium timeout
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-- --counterexamples=on surface failing inputs when a VC fails
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-- -j0 use all available cores
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for Proof_Switches ("Ada") use
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("--mode=prove",
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"--level=1",
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"--counterexamples=on",
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"-j0",
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"--report=all");
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end Prove;
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end Solver_Integrity;

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