df94136727
- Add RpmVersionComparer for RPM version comparison with epoch, version, and release handling. - Introduce DebianVersion for parsing Debian EVR (Epoch:Version-Release) strings. - Create ApkVersion for parsing Alpine APK version strings with suffix support. - Define IVersionComparator interface for version comparison with proof-line generation. - Implement VersionComparisonResult struct to encapsulate comparison results and proof lines. - Add tests for Debian and RPM version comparers to ensure correct functionality and edge case handling. - Create project files for the version comparison library and its tests.
288 lines
8.6 KiB
Markdown
288 lines
8.6 KiB
Markdown
# Reachability Slice Schema
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_Last updated: 2025-12-22. Owner: Scanner Guild._
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This document defines the **Reachability Slice** schema—a minimal, attestable proof unit that answers whether a vulnerable symbol is reachable from application entrypoints.
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---
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## 1. Overview
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A **slice** is a focused subgraph extracted from a full reachability graph, containing only the nodes and edges relevant to answering a specific reachability query (e.g., "Is CVE-2024-1234's vulnerable function reachable?").
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### Key Properties
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| Property | Description |
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|----------|-------------|
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| **Minimal** | Contains only nodes/edges on paths between entrypoints and targets |
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| **Attestable** | DSSE-signed with in-toto predicate format |
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| **Reproducible** | Same inputs → same bytes (deterministic) |
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| **Content-addressed** | Retrieved by BLAKE3 digest |
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---
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## 2. Schema Definition
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### 2.1 DSSE Predicate Type
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```
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https://stellaops.dev/predicates/reachability-slice/v1
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```
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### 2.2 Full Schema
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```json
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{
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"$schema": "https://json-schema.org/draft/2020-12/schema",
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"$id": "https://stellaops.dev/schemas/reachability-slice.v1.schema.json",
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"title": "Reachability Slice",
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"type": "object",
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"required": ["_type", "inputs", "query", "subgraph", "verdict", "manifest"],
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"properties": {
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"_type": {
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"const": "https://stellaops.dev/predicates/reachability-slice/v1"
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},
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"inputs": { "$ref": "#/$defs/SliceInputs" },
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"query": { "$ref": "#/$defs/SliceQuery" },
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"subgraph": { "$ref": "#/$defs/SliceSubgraph" },
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"verdict": { "$ref": "#/$defs/SliceVerdict" },
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"manifest": { "$ref": "#/$defs/ScanManifest" }
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},
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"$defs": {
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"SliceInputs": {
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"type": "object",
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"required": ["graphDigest", "binaryDigests"],
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"properties": {
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"graphDigest": { "type": "string", "pattern": "^blake3:[a-f0-9]{64}$" },
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"binaryDigests": {
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"type": "array",
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"items": { "type": "string", "pattern": "^sha256:[a-f0-9]{64}$" }
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},
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"sbomDigest": { "type": "string" },
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"layerDigests": { "type": "array", "items": { "type": "string" } }
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}
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},
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"SliceQuery": {
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"type": "object",
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"properties": {
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"cveId": { "type": "string", "pattern": "^CVE-\\d{4}-\\d+$" },
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"targetSymbols": { "type": "array", "items": { "type": "string" } },
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"entrypoints": { "type": "array", "items": { "type": "string" } },
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"policyHash": { "type": "string" }
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}
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},
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"SliceSubgraph": {
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"type": "object",
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"required": ["nodes", "edges"],
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"properties": {
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"nodes": {
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"type": "array",
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"items": { "$ref": "#/$defs/SliceNode" }
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},
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"edges": {
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"type": "array",
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"items": { "$ref": "#/$defs/SliceEdge" }
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}
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}
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},
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"SliceNode": {
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"type": "object",
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"required": ["id", "symbol", "kind"],
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"properties": {
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"id": { "type": "string" },
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"symbol": { "type": "string" },
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"kind": { "enum": ["entrypoint", "intermediate", "target", "unknown"] },
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"file": { "type": "string" },
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"line": { "type": "integer" },
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"purl": { "type": "string" },
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"attributes": { "type": "object" }
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}
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},
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"SliceEdge": {
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"type": "object",
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"required": ["from", "to", "confidence"],
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"properties": {
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"from": { "type": "string" },
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"to": { "type": "string" },
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"kind": { "enum": ["direct", "plt", "iat", "dynamic", "unknown"] },
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"confidence": { "type": "number", "minimum": 0, "maximum": 1 },
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"evidence": { "type": "string" },
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"gate": { "$ref": "#/$defs/GateInfo" },
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"observed": { "$ref": "#/$defs/ObservedInfo" }
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}
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},
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"GateInfo": {
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"type": "object",
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"properties": {
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"type": { "enum": ["feature_flag", "auth", "config", "admin_only"] },
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"condition": { "type": "string" },
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"satisfied": { "type": "boolean" }
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}
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},
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"ObservedInfo": {
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"type": "object",
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"properties": {
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"firstObserved": { "type": "string", "format": "date-time" },
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"lastObserved": { "type": "string", "format": "date-time" },
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"count": { "type": "integer" }
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}
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},
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"SliceVerdict": {
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"type": "object",
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"required": ["status", "confidence"],
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"properties": {
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"status": { "enum": ["reachable", "unreachable", "unknown", "gated"] },
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"confidence": { "type": "number", "minimum": 0, "maximum": 1 },
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"reasons": { "type": "array", "items": { "type": "string" } },
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"pathWitnesses": { "type": "array", "items": { "type": "string" } },
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"unknownCount": { "type": "integer" },
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"gatedPaths": { "type": "array", "items": { "$ref": "#/$defs/GateInfo" } }
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}
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},
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"ScanManifest": {
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"type": "object",
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"required": ["analyzerVersion", "createdAt"],
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"properties": {
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"analyzerVersion": { "type": "string" },
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"rulesetHash": { "type": "string" },
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"feedVersions": { "type": "object" },
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"createdAt": { "type": "string", "format": "date-time" },
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"toolchain": { "type": "string" }
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}
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}
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}
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}
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```
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---
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## 3. Verdict Status Definitions
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| Status | Meaning | Confidence Range |
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|--------|---------|------------------|
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| `reachable` | Path exists from entrypoint to target | ≥0.7 |
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| `unreachable` | No path found, no unknowns | ≥0.9 |
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| `unknown` | Unknowns present on potential paths | 0.3–0.7 |
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| `gated` | Path exists but gated by feature flag/auth | 0.5–0.8 |
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### Verdict Computation Rules
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```
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reachable := path_exists AND min(path_confidence) ≥ 0.7 AND unknown_edges = 0
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unreachable := NOT path_exists AND unknown_edges = 0
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gated := path_exists AND all_paths_gated AND gates_not_satisfied
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unknown := unknown_edges > 0 OR min(path_confidence) < 0.5
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```
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---
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## 4. Example Slice
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```json
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{
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"_type": "https://stellaops.dev/predicates/reachability-slice/v1",
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"inputs": {
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"graphDigest": "blake3:a1b2c3d4e5f6789012345678901234567890123456789012345678901234abcd",
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"binaryDigests": ["sha256:deadbeef..."],
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"sbomDigest": "sha256:cafebabe..."
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},
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"query": {
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"cveId": "CVE-2024-1234",
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"targetSymbols": ["openssl:EVP_PKEY_decrypt"],
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"entrypoints": ["main", "http_handler"]
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},
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"subgraph": {
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"nodes": [
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{"id": "node:1", "symbol": "main", "kind": "entrypoint", "file": "/app/main.c", "line": 42},
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{"id": "node:2", "symbol": "process_request", "kind": "intermediate", "file": "/app/handler.c", "line": 100},
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{"id": "node:3", "symbol": "decrypt_data", "kind": "intermediate", "file": "/app/crypto.c", "line": 55},
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{"id": "node:4", "symbol": "EVP_PKEY_decrypt", "kind": "target", "purl": "pkg:generic/openssl@3.0.0"}
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],
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"edges": [
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{"from": "node:1", "to": "node:2", "kind": "direct", "confidence": 1.0},
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{"from": "node:2", "to": "node:3", "kind": "direct", "confidence": 0.95},
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{"from": "node:3", "to": "node:4", "kind": "plt", "confidence": 0.9}
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]
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},
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"verdict": {
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"status": "reachable",
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"confidence": 0.9,
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"reasons": ["Direct call path from main() to EVP_PKEY_decrypt()"],
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"pathWitnesses": ["main → process_request → decrypt_data → EVP_PKEY_decrypt"]
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},
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"manifest": {
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"analyzerVersion": "scanner.native:1.2.0",
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"rulesetHash": "sha256:...",
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"createdAt": "2025-12-22T10:00:00Z",
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"toolchain": "iced-x86:1.21.0"
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}
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}
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```
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---
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## 5. DSSE Envelope Format
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Slices are wrapped in DSSE envelopes for attestation:
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```json
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{
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"payloadType": "application/vnd.in-toto+json",
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"payload": "<base64-encoded slice JSON>",
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"signatures": [
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{
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"keyid": "sha256:abc123...",
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"sig": "<base64-encoded signature>"
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}
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]
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}
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```
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---
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## 6. Storage & Retrieval
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### CAS URI Format
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```
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cas://slices/blake3:<digest>
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```
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### OCI Artifact Format
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```json
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{
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"mediaType": "application/vnd.stellaops.slice.v1+json",
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"digest": "sha256:...",
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"annotations": {
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"org.stellaops.slice.cve": "CVE-2024-1234",
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"org.stellaops.slice.verdict": "reachable"
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}
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}
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```
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---
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## 7. Determinism Requirements
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For reproducible slices:
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1. **Node ordering**: Sort by `id` lexicographically
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2. **Edge ordering**: Sort by `(from, to)` tuple
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3. **Timestamps**: Use UTC ISO-8601 with Z suffix
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4. **Floating point**: Round to 6 decimal places
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5. **JSON serialization**: No whitespace, sorted keys
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---
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## 8. Related Documentation
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- [Binary Reachability Schema](./binary-reachability-schema.md)
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- [RichGraph Contract](../contracts/richgraph-v1.md)
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- [Function-Level Evidence](./function-level-evidence.md)
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- [Replay Verification](./replay-verification.md)
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---
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_Created: 2025-12-22. See Sprint 3810 for implementation details._
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