# Patch-Oracles QA Pattern

Patch oracles define expected functions and edges that must be present (or absent) in generated reachability graphs. The CI pipeline uses these oracles to ensure that:

1. Critical vulnerability paths are correctly identified as reachable
2. Mitigated paths are correctly identified as unreachable
3. Graph generation remains deterministic and complete

This document covers both the **JSON-based harness** (for reachbench integration) and the **YAML-based format** (for binary patch testing).

---

## Part A: JSON Patch-Oracle Harness (v1)

The JSON-based patch-oracle harness integrates with the reachbench fixture system for CI graph validation.

### A.1 Schema Overview

Patch-oracle fixtures follow the `patch-oracle/v1` schema:

```json
{
  "schema_version": "patch-oracle/v1",
  "id": "curl-CVE-2023-38545-socks5-heap-reachable",
  "case_ref": "curl-CVE-2023-38545-socks5-heap",
  "variant": "reachable",
  "description": "Validates SOCKS5 heap overflow path is reachable",
  "expected_functions": [...],
  "expected_edges": [...],
  "expected_roots": [...],
  "forbidden_functions": [...],
  "forbidden_edges": [...],
  "min_confidence": 0.5,
  "strict_mode": false
}
```

### A.2 Expected Functions

Define functions that MUST be present in the graph:

```json
{
  "symbol_id": "sym://curl:curl.c#sink",
  "lang": "c",
  "kind": "function",
  "purl_pattern": "pkg:github/curl/*",
  "required": true,
  "reason": "Vulnerable buffer handling function"
}
```

### A.3 Expected Edges

Define edges that MUST be present in the graph:

```json
{
  "from": "sym://net:handler#read",
  "to": "sym://curl:curl.c#entry",
  "kind": "call",
  "min_confidence": 0.8,
  "required": true,
  "reason": "Data flows from network to SOCKS5 handler"
}
```

### A.4 Forbidden Elements (for unreachable variants)

```json
{
  "forbidden_functions": [
    {
      "symbol_id": "sym://dangerous#sink",
      "reason": "Should not be reachable when feature disabled"
    }
  ],
  "forbidden_edges": [
    {
      "from": "sym://entry",
      "to": "sym://sink",
      "reason": "Path should be blocked by feature flag"
    }
  ]
}
```

### A.5 Wildcard Patterns

Symbol IDs support `*` wildcards:
- `sym://test#func1` - exact match
- `sym://test#*` - matches any symbol starting with `sym://test#`
- `*` - matches anything

### A.6 Directory Structure

```
tests/reachability/fixtures/patch-oracles/
├── INDEX.json                    # Oracle index
├── schema/
│   └── patch-oracle-v1.json      # JSON Schema
└── cases/
    ├── curl-CVE-2023-38545-socks5-heap/
    │   ├── reachable.oracle.json
    │   └── unreachable.oracle.json
    └── java-log4j-CVE-2021-44228-log4shell/
        └── reachable.oracle.json
```

### A.7 Usage in Tests

```csharp
var loader = new PatchOracleLoader(fixtureRoot);
var oracle = loader.LoadOracle("curl-CVE-2023-38545-socks5-heap-reachable");

var comparer = new PatchOracleComparer(oracle);
var result = comparer.Compare(richGraph);

if (!result.Success)
{
    foreach (var violation in result.Violations)
    {
        Console.WriteLine($"[{violation.Type}] {violation.From} -> {violation.To}");
    }
}
```

### A.8 Violation Types

| Type | Description |
|------|-------------|
| `MissingFunction` | Required function not found |
| `MissingEdge` | Required edge not found |
| `MissingRoot` | Required root not found |
| `ForbiddenFunctionPresent` | Forbidden function found |
| `ForbiddenEdgePresent` | Forbidden edge found |
| `UnexpectedFunction` | Unexpected function in strict mode |
| `UnexpectedEdge` | Unexpected edge in strict mode |

---

## Part B: YAML Binary Patch-Oracles

The YAML-based format is used for paired vulnerable/fixed binary testing.

### B.1 Workflow (per CVE)

1) Pick a CVE with a small, clean fix (e.g., OpenSSL, zlib, BusyBox). Identify vulnerable commit `A` and fixed commit `B`.
2) Build two stripped binaries (`vuln`, `fixed`) with identical toolchains/flags; keep a tiny harness that exercises the affected path.
3) Run Scanner binary analyzers to emit `richgraph-v1` for each binary.
4) Diff graphs: expect new/removed functions and edges to match the patch (e.g., `foo_parse -> validate_len` added; `foo_parse -> memcpy` removed).
5) Fail the test if expected functions/edges are absent or unchanged.

### B.2 Oracle manifest (YAML)

```yaml
cve: CVE-YYYY-XXXX
target: libfoo 1.2.3
build:
  cc: clang
  cflags: [-O2, -fno-omit-frame-pointer]
  ldflags: []
  strip: true
expect:
  functions_added: [validate_len]
  functions_removed: [unsafe_copy]
  edges_added:
    - { caller: foo_parse, callee: validate_len }
  edges_removed:
    - { caller: foo_parse, callee: memcpy }
tolerances:
  allow_unresolved_symbols: 0
  allow_extra_funcs: 2
```

Place manifests under `tests/reachability/patch-oracles/<cve>/oracle.yml` next to the sources/build scripts.

## 3. Repository layout

```
tests/reachability/patch-oracles/
  CVE-YYYY-XXXX-foo/
    src/            # vuln + fixed sources + harness
    build.sh        # produces ./out/vuln ./out/fixed
    oracle.yml
```

## 4. Harness rules

- Output binaries to `out/vuln` and `out/fixed` with deterministic flags and stripped symbols.
- Record toolchain version in a sidecar `build-meta.json` so Replay captures provenance.
- Never download from the internet during CI; vendor tiny sources into the fixture folder.

## 5. Test runner expectations

- Runs Scanner binary analyzers on both binaries; emits `richgraph-v1` CAS entries.
- Compares graphs against `oracle.yml` expectations (functions/edges added/removed, tolerances).
- Fails when deltas are missing; succeeds when expected guards/edges are present.

## 6. Integration points

- **Scanner**: add fixture runner under `tests/reachability/StellaOps.Scanner.Binary.PatchOracleTests`.
- **CI**: wire into reachbench/patch-oracles job; ensure artifacts are small and deterministic.
- **Docs**: link this file from reachability delivery guide once tests are live.

### B.7 Acceptance criteria

- At least three seed oracles (e.g., zlib overflow, OpenSSL length guard, BusyBox ash fix) committed with passing expectations.
- CI job proves deterministic hashes across reruns.
- Failures emit clear diffs (`expected edge foo->validate_len missing`).

---

## Related Documentation

- [Reachability Evidence Chain](./function-level-evidence.md)
- [RichGraph Schema](../contracts/richgraph-v1.md)
- [Ground Truth Schema](./ground-truth-schema.md)
- [Lattice States](./lattice.md)
- [Reachability Delivery Guide](./DELIVERY_GUIDE.md)