Agent-Skills.md

Agent Skills: zeroize-audit — Claude Skill

Detects missing zeroization of sensitive data in source code and identifies zeroization removed by compiler optimizations, with assembly-level analysis, and control-flow verification. Use for auditing C/C++/Rust code handling secrets, keys, passwords, or other sensitive data.

UncategorizedID: sickn33/antigravity-awesome-skills/zeroize-audit

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sickn33/antigravity-awesome-skills
sickn33License: MIT
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skills/zeroize-audit/SKILL.md

Skill Metadata

Name
zeroize-audit
Description
"Detects missing zeroization of sensitive data in source code and identifies zeroization removed by compiler optimizations, with assembly-level analysis, and control-flow verification. Use for auditing C/C++/Rust code handling secrets, keys, passwords, or other sensitive data."

zeroize-audit — Claude Skill

When to Use

  • Auditing cryptographic implementations (keys, seeds, nonces, secrets)
  • Reviewing authentication systems (passwords, tokens, session data)
  • Analyzing code that handles PII or sensitive credentials
  • Verifying secure cleanup in security-critical codebases
  • Investigating memory safety of sensitive data handling

When NOT to Use

  • General code review without security focus
  • Performance optimization (unless related to secure wiping)
  • Refactoring tasks not related to sensitive data
  • Code without identifiable secrets or sensitive values

Purpose

Detect missing zeroization of sensitive data in source code and identify zeroization that is removed or weakened by compiler optimizations (e.g., dead-store elimination), with mandatory LLVM IR/asm evidence. Capabilities include:

  • Assembly-level analysis for register spills and stack retention
  • Data-flow tracking for secret copies
  • Heap allocator security warnings
  • Semantic IR analysis for loop unrolling and SSA form
  • Control-flow graph analysis for path coverage verification
  • Runtime validation test generation

Scope

  • Read-only against the target codebase (does not modify audited code; writes analysis artifacts to a temporary working directory).
  • Produces a structured report (JSON).
  • Requires valid build context (compile_commands.json) and compilable translation units.
  • "Optimized away" findings only allowed with compiler evidence (IR/asm diff).

Inputs

See {baseDir}/schemas/input.json for the full schema. Key fields:

| Field | Required | Default | Description | |---|---|---|---| | path | yes | — | Repo root | | compile_db | no | null | Path to compile_commands.json for C/C++ analysis. Required if cargo_manifest is not set. | | cargo_manifest | no | null | Path to Cargo.toml for Rust crate analysis. Required if compile_db is not set. | | config | no | — | YAML defining heuristics and approved wipes | | opt_levels | no | ["O0","O1","O2"] | Optimization levels for IR comparison. O1 is the diagnostic level: if a wipe disappears at O1 it is simple DSE; O2 catches more aggressive eliminations. | | languages | no | ["c","cpp","rust"] | Languages to analyze | | max_tus | no | — | Limit on translation units processed from compile DB | | mcp_mode | no | prefer | off, prefer, or require — controls Serena MCP usage | | mcp_required_for_advanced | no | true | Downgrade SECRET_COPY, MISSING_ON_ERROR_PATH, and NOT_DOMINATING_EXITS to needs_review when MCP is unavailable | | mcp_timeout_ms | no | — | Timeout budget for MCP semantic queries | | poc_categories | no | all 11 exploitable | Finding categories for which to generate PoCs. C/C++ findings: all 11 categories supported. Rust findings: only MISSING_SOURCE_ZEROIZE, SECRET_COPY, and PARTIAL_WIPE are supported; other Rust categories are marked poc_supported=false. | | poc_output_dir | no | generated_pocs/ | Output directory for generated PoCs | | enable_asm | no | true | Enable assembly emission and analysis (Step 8); produces STACK_RETENTION, REGISTER_SPILL. Auto-disabled if emit_asm.sh is missing. | | enable_semantic_ir | no | false | Enable semantic LLVM IR analysis (Step 9); produces LOOP_UNROLLED_INCOMPLETE | | enable_cfg | no | false | Enable control-flow graph analysis (Step 10); produces MISSING_ON_ERROR_PATH, NOT_DOMINATING_EXITS | | enable_runtime_tests | no | false | Enable runtime test harness generation (Step 11) |

Prerequisites

Before running, verify the following. Each has a defined failure mode.

C/C++ prerequisites:

| Prerequisite | Failure mode if missing | |---|---| | compile_commands.json at compile_db path | Fail fast — do not proceed | | clang on PATH | Fail fast — IR/ASM analysis impossible | | uvx on PATH (for Serena) | If mcp_mode=require: fail. If mcp_mode=prefer: continue without MCP; downgrade affected findings per Confidence Gating rules. | | {baseDir}/tools/extract_compile_flags.py | Fail fast — cannot extract per-TU flags | | {baseDir}/tools/emit_ir.sh | Fail fast — IR analysis impossible | | {baseDir}/tools/emit_asm.sh | Warn and skip assembly findings (STACK_RETENTION, REGISTER_SPILL) | | {baseDir}/tools/mcp/check_mcp.sh | Warn and treat as MCP unavailable | | {baseDir}/tools/mcp/normalize_mcp_evidence.py | Warn and use raw MCP output |

Rust prerequisites:

| Prerequisite | Failure mode if missing | |---|---| | Cargo.toml at cargo_manifest path | Fail fast — do not proceed | | cargo check passes | Fail fast — crate must be buildable | | cargo +nightly on PATH | Fail fast — nightly required for MIR and LLVM IR emission | | uv on PATH | Fail fast — required to run Python analysis scripts | | {baseDir}/tools/validate_rust_toolchain.sh | Warn — run preflight manually. Checks all tools, scripts, nightly, and optionally cargo check. Use --json for machine-readable output, --manifest to also validate the crate builds. | | {baseDir}/tools/emit_rust_mir.sh | Fail fast — MIR analysis impossible (--opt, --crate, --bin/--lib supported; --out can be file or directory) | | {baseDir}/tools/emit_rust_ir.sh | Fail fast — LLVM IR analysis impossible (--opt required; --crate, --bin/--lib supported; --out must be .ll) | | {baseDir}/tools/emit_rust_asm.sh | Warn and skip assembly findings (STACK_RETENTION, REGISTER_SPILL). Supports --opt, --crate, --bin/--lib, --target, --intel-syntax; --out can be .s file or directory. | | {baseDir}/tools/diff_rust_mir.sh | Warn and skip MIR-level optimization comparison. Accepts 2+ MIR files, normalizes, diffs pairwise, and reports first opt level where zeroize/drop-glue patterns disappear. | | {baseDir}/tools/scripts/semantic_audit.py | Warn and skip semantic source analysis | | {baseDir}/tools/scripts/find_dangerous_apis.py | Warn and skip dangerous API scan | | {baseDir}/tools/scripts/check_mir_patterns.py | Warn and skip MIR analysis | | {baseDir}/tools/scripts/check_llvm_patterns.py | Warn and skip LLVM IR analysis | | {baseDir}/tools/scripts/check_rust_asm.py | Warn and skip Rust assembly analysis (STACK_RETENTION, REGISTER_SPILL, drop-glue checks). Dispatches to check_rust_asm_x86.py (production) or check_rust_asm_aarch64.py (EXPERIMENTAL — AArch64 findings require manual verification). | | {baseDir}/tools/scripts/check_rust_asm_x86.py | Required by check_rust_asm.py for x86-64 analysis; warn and skip if missing | | {baseDir}/tools/scripts/check_rust_asm_aarch64.py | Required by check_rust_asm.py for AArch64 analysis (EXPERIMENTAL); warn and skip if missing |

Common prerequisite:

| Prerequisite | Failure mode if missing | |---|---| | {baseDir}/tools/generate_poc.py | Fail fast — PoC generation is mandatory |

Approved Wipe APIs

The following are recognized as valid zeroization. Configure additional entries in {baseDir}/configs/.

C/C++

  • explicit_bzero
  • memset_s
  • SecureZeroMemory
  • OPENSSL_cleanse
  • sodium_memzero
  • Volatile wipe loops (pattern-based; see volatile_wipe_patterns in {baseDir}/configs/default.yaml)
  • In IR: llvm.memset with volatile flag, volatile stores, or non-elidable wipe call

Rust

  • zeroize::Zeroize trait (zeroize() method)
  • Zeroizing<T> wrapper (drop-based)
  • ZeroizeOnDrop derive macro

Finding Capabilities

Findings are grouped by required evidence. Only attempt findings for which the required tooling is available.

| Finding ID | Description | Requires | PoC Support | |---|---|---|---| | MISSING_SOURCE_ZEROIZE | No zeroization found in source | Source only | Yes (C/C++ + Rust) | | PARTIAL_WIPE | Incorrect size or incomplete wipe | Source only | Yes (C/C++ + Rust) | | NOT_ON_ALL_PATHS | Zeroization missing on some control-flow paths (heuristic) | Source only | Yes (C/C++ only) | | SECRET_COPY | Sensitive data copied without zeroization tracking | Source + MCP preferred | Yes (C/C++ + Rust) | | INSECURE_HEAP_ALLOC | Secret uses insecure allocator (malloc vs. secure_malloc) | Source only | Yes (C/C++ only) | | OPTIMIZED_AWAY_ZEROIZE | Compiler removed zeroization | IR diff required (never source-only) | Yes | | STACK_RETENTION | Stack frame may retain secrets after return | Assembly required (C/C++); LLVM IR alloca+lifetime.end evidence (Rust); assembly corroboration upgrades to confirmed | Yes (C/C++ only) | | REGISTER_SPILL | Secrets spilled from registers to stack | Assembly required (C/C++); LLVM IR load+call-site evidence (Rust); assembly corroboration upgrades to confirmed | Yes (C/C++ only) | | MISSING_ON_ERROR_PATH | Error-handling paths lack cleanup | CFG or MCP required | Yes | | NOT_DOMINATING_EXITS | Wipe doesn't dominate all exits | CFG or MCP required | Yes | | LOOP_UNROLLED_INCOMPLETE | Unrolled loop wipe is incomplete | Semantic IR required | Yes |

Agent Architecture

The analysis pipeline uses 11 agents across 8 phases, invoked by the orchestrator ({baseDir}/prompts/task.md) via Task. Agents write persistent finding files to a shared working directory (/tmp/zeroize-audit-{run_id}/), enabling parallel execution and protecting against context pressure.

| Agent | Phase | Purpose | Output Directory | |---|---|---|---| | 0-preflight | Phase 0 | Preflight checks (tools, toolchain, compile DB, crate build), config merge, workdir creation, TU enumeration | {workdir}/ | | 1-mcp-resolver | Phase 1, Wave 1 (C/C++ only) | Resolve symbols, types, and cross-file references via Serena MCP | mcp-evidence/ | | 2-source-analyzer | Phase 1, Wave 2a (C/C++ only) | Identify sensitive objects, detect wipes, validate correctness, data-flow/heap | source-analysis/ | | 2b-rust-source-analyzer | Phase 1, Wave 2b (Rust only, parallel with 2a) | Rustdoc JSON trait-aware analysis + dangerous API grep | source-analysis/ | | 3-tu-compiler-analyzer | Phase 2, Wave 3 (C/C++ only, N parallel) | Per-TU IR diff, assembly, semantic IR, CFG analysis | compiler-analysis/{tu_hash}/ | | 3b-rust-compiler-analyzer | Phase 2, Wave 3R (Rust only, single agent) | Crate-level MIR, LLVM IR, and assembly analysis | rust-compiler-analysis/ | | 4-report-assembler | Phase 3 (interim) + Phase 6 (final) | Collect findings from all agents, apply confidence gates; merge PoC results and produce final report | report/ | | 5-poc-generator | Phase 4 | Craft bespoke proof-of-concept programs (C/C++: all categories; Rust: MISSING_SOURCE_ZEROIZE, SECRET_COPY, PARTIAL_WIPE) | poc/ | | 5b-poc-validator | Phase 5 | Compile and run all PoCs | poc/ | | 5c-poc-verifier | Phase 5 | Verify each PoC proves its claimed finding | poc/ | | 6-test-generator | Phase 7 (optional) | Generate runtime validation test harnesses | tests/ |

The orchestrator reads one per-phase workflow file from {baseDir}/workflows/ at a time, and maintains orchestrator-state.json for recovery after context compression. Agents receive configuration by file path (config_path), not by value.

Execution flow

Phase 0: 0-preflight agent — Preflight + config + create workdir + enumerate TUs
           → writes orchestrator-state.json, merged-config.yaml, preflight.json
Phase 1: Wave 1:  1-mcp-resolver              (skip if mcp_mode=off OR language_mode=rust)
         Wave 2a: 2-source-analyzer           (C/C++ only; skip if no compile_db)  ─┐ parallel
         Wave 2b: 2b-rust-source-analyzer     (Rust only; skip if no cargo_manifest) ─┘
Phase 2: Wave 3:  3-tu-compiler-analyzer x N  (C/C++ only; parallel per TU)
         Wave 3R: 3b-rust-compiler-analyzer   (Rust only; single crate-level agent)
Phase 3: Wave 4:  4-report-assembler          (mode=interim → findings.json; reads all agent outputs)
Phase 4: Wave 5:  5-poc-generator             (C/C++: all categories; Rust: MISSING_SOURCE_ZEROIZE, SECRET_COPY, PARTIAL_WIPE; other Rust findings: poc_supported=false)
Phase 5: PoC Validation & Verification
           Step 1: 5b-poc-validator agent      (compile and run all PoCs)
           Step 2: 5c-poc-verifier agent       (verify each PoC proves its claimed finding)
           Step 3: Orchestrator presents verification failures to user via AskUserQuestion
           Step 4: Orchestrator merges all results into poc_final_results.json
Phase 6: Wave 6: 4-report-assembler           (mode=final → merge PoC results, final-report.md)
Phase 7: Wave 7: 6-test-generator             (optional)
Phase 8: Orchestrator — Return final-report.md

Cross-Reference Convention

IDs are namespaced per agent to prevent collisions during parallel execution:

| Entity | Pattern | Assigned By | |---|---|---| | Sensitive object (C/C++) | SO-0001–SO-4999 | 2-source-analyzer | | Sensitive object (Rust) | SO-5000–SO-9999 (Rust namespace) | 2b-rust-source-analyzer | | Source finding (C/C++) | F-SRC-NNNN | 2-source-analyzer | | Source finding (Rust) | F-RUST-SRC-NNNN | 2b-rust-source-analyzer | | IR finding (C/C++) | F-IR-{tu_hash}-NNNN | 3-tu-compiler-analyzer | | ASM finding (C/C++) | F-ASM-{tu_hash}-NNNN | 3-tu-compiler-analyzer | | CFG finding | F-CFG-{tu_hash}-NNNN | 3-tu-compiler-analyzer | | Semantic IR finding | F-SIR-{tu_hash}-NNNN | 3-tu-compiler-analyzer | | Rust MIR finding | F-RUST-MIR-NNNN | 3b-rust-compiler-analyzer | | Rust LLVM IR finding | F-RUST-IR-NNNN | 3b-rust-compiler-analyzer | | Rust assembly finding | F-RUST-ASM-NNNN | 3b-rust-compiler-analyzer | | Translation unit | TU-{hash} | Orchestrator | | Final finding | ZA-NNNN | 4-report-assembler |

Every finding JSON object includes related_objects, related_findings, and evidence_files fields for cross-referencing between agents.

Detection Strategy

Analysis runs in two phases. For complete step-by-step guidance, see {baseDir}/references/detection-strategy.md.

| Phase | Steps | Findings produced | Required tooling | |---|---|---|---| | Phase 1 (Source) | 1–6 | MISSING_SOURCE_ZEROIZE, PARTIAL_WIPE, NOT_ON_ALL_PATHS, SECRET_COPY, INSECURE_HEAP_ALLOC | Source + compile DB | | Phase 2 (Compiler) | 7–12 | OPTIMIZED_AWAY_ZEROIZE, STACK_RETENTION, REGISTER_SPILL, LOOP_UNROLLED_INCOMPLETE†, MISSING_ON_ERROR_PATH‡, NOT_DOMINATING_EXITS‡ | clang, IR/ASM tools |

* requires enable_asm=true (default) † requires enable_semantic_ir=true ‡ requires enable_cfg=true

Output Format

Each run produces two outputs:

  1. final-report.md — Comprehensive markdown report (primary human-readable output)
  2. findings.json — Structured JSON matching {baseDir}/schemas/output.json (for machine consumption and downstream tools)

Markdown Report Structure

The markdown report (final-report.md) contains these sections:

  • Header: Run metadata (run_id, timestamp, repo, compile_db, config summary)
  • Executive Summary: Finding counts by severity, confidence, and category
  • Sensitive Objects Inventory: Table of all identified objects with IDs, types, locations
  • Findings: Grouped by severity then confidence. Each finding includes location, object, all evidence (source/IR/ASM/CFG), compiler evidence details, and recommended fix
  • Superseded Findings: Source findings replaced by CFG-backed findings
  • Confidence Gate Summary: Downgrades applied and overrides rejected
  • Analysis Coverage: TUs analyzed, agent success/failure, features enabled
  • Appendix: Evidence Files: Mapping of finding IDs to evidence file paths

Structured JSON

The findings.json file follows the schema in {baseDir}/schemas/output.json. Each Finding object:

{
  "id": "ZA-0001",
  "category": "OPTIMIZED_AWAY_ZEROIZE",
  "severity": "high",
  "confidence": "confirmed",
  "language": "c",
  "file": "src/crypto.c",
  "line": 42,
  "symbol": "key_buf",
  "evidence": "store volatile i8 0 count: O0=32, O2=0 — wipe eliminated by DSE",
  "compiler_evidence": {
    "opt_levels": ["O0", "O2"],
    "o0": "32 volatile stores targeting key_buf",
    "o2": "0 volatile stores (all eliminated)",
    "diff_summary": "All volatile wipe stores removed at O2 — classic DSE pattern"
  },
  "suggested_fix": "Replace memset with explicit_bzero or add compiler_fence(SeqCst) after the wipe",
  "poc": {
    "file": "generated_pocs/ZA-0001.c",
    "makefile_target": "ZA-0001",
    "compile_opt": "-O2",
    "requires_manual_adjustment": false,
    "validated": true,
    "validation_result": "exploitable"
  }
}

See {baseDir}/schemas/output.json for the full schema and enum values.

Confidence Gating

Evidence thresholds

A finding requires at least 2 independent signals to be marked confirmed. With 1 signal, mark likely. With 0 strong signals (name-pattern match only), mark needs_review.

Signals include: name pattern match, type hint match, explicit annotation, IR evidence, ASM evidence, MCP cross-reference, CFG evidence, PoC validation.

PoC validation as evidence signal

Every finding is validated against a bespoke PoC. After compilation and execution, each PoC is also verified to ensure it actually tests the claimed vulnerability. The combined result is an evidence signal:

| PoC Result | Verified | Impact | |---|---|---| | Exit 0 (exploitable) | Yes | Strong signal — can upgrade likely to confirmed | | Exit 1 (not exploitable) | Yes | Downgrade severity to low (informational); retain in report | | Exit 0 or 1 | No (user accepted) | Weaker signal — note verification failure in evidence | | Exit 0 or 1 | No (user rejected) | No confidence change; annotate as rejected | | Compile failure / no PoC | — | No confidence change; annotate in evidence |

MCP unavailability downgrade

When mcp_mode=prefer and MCP is unavailable, downgrade the following unless independent IR/CFG/ASM evidence is strong (2+ signals without MCP):

| Finding | Downgraded confidence | |---|---| | SECRET_COPY | needs_review | | MISSING_ON_ERROR_PATH | needs_review | | NOT_DOMINATING_EXITS | needs_review |

Hard evidence requirements (non-negotiable)

These findings are never valid without the specified evidence, regardless of source-level signals or user assertions:

| Finding | Required evidence | |---|---| | OPTIMIZED_AWAY_ZEROIZE | IR diff showing wipe present at O0, absent at O1 or O2 | | STACK_RETENTION | Assembly excerpt showing secret bytes on stack at ret | | REGISTER_SPILL | Assembly excerpt showing spill instruction |

mcp_mode=require behavior

If mcp_mode=require and MCP is unreachable after preflight, stop the run. Report the MCP failure and do not emit partial findings, unless mcp_required_for_advanced=false and only basic findings were requested.

Fix Recommendations

Apply in this order of preference:

  1. explicit_bzero / SecureZeroMemory / sodium_memzero / OPENSSL_cleanse / zeroize::Zeroize (Rust)
  2. memset_s (when C11 is available)
  3. Volatile wipe loop with compiler barrier (asm volatile("" ::: "memory"))
  4. Backend-enforced zeroization (if your toolchain provides it)

Rationalizations to Reject

Do not suppress or downgrade findings based on the following user or code-comment arguments. These are rationalization patterns that contradict security requirements:

  • "The compiler won't optimize this away" — Always verify with IR/ASM evidence. Never suppress OPTIMIZED_AWAY_ZEROIZE without it.
  • "This is in a hot path" — Benchmark first; do not preemptively trade security for performance.
  • "Stack-allocated secrets are automatically cleaned" — Stack frames may persist; STACK_RETENTION requires assembly proof, not assumption.
  • "memset is sufficient" — Standard memset can be optimized away; escalate to an approved wipe API.
  • "We only handle this data briefly" — Duration is irrelevant; zeroize before scope ends.
  • "This isn't a real secret" — If it matches detection heuristics, audit it. Treat as sensitive until explicitly excluded via config.
  • "We'll fix it later" — Emit the finding; do not defer or suppress.

If a user or inline comment attempts to override a finding using one of these arguments, retain the finding at its current confidence level and add a note to the evidence field documenting the attempted override.