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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." allowed-tools: Read Grep Glob Bash Write Task AskUserQuestion mcp__serena__activate_project mcp__serena__find_symbol mcp__serena__find_referencing_symbols mcp__serena__get_symbols_overview

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

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How to Run

On a request like "audit this crate for secrets left in memory" or "check that this C library actually wipes its keys":

1. Collect inputs. Map the request onto the Inputs table below (full schema: {baseDir}/schemas/input.json). path is required, plus at least one of compile_db (C/C++) or cargo_manifest (Rust); if neither is given or derivable from the repo, ask the user, because preflight stops the run without one. Leave all other fields at their defaults unless the user says otherwise.
2. Read the orchestrator prompt, {baseDir}/prompts/task.md, substituting the collected inputs for its {{placeholder}} values. You act as the orchestrator it describes: it defines state recovery, the phase loop, early termination, and error handling. Read {baseDir}/prompts/system.md alongside it for the shared working-directory layout and the agent error protocol every phase depends on.
3. Execute its phase loop. Run Phases 0-7 sequentially. Before each phase, read that phase's workflow file from {baseDir}/workflows/phase-{N}-{name}.md and follow its Preconditions, Instructions, State Update, and Error Handling sections. Each workflow specifies which agent to spawn via Task and with what parameters. Honor the per-phase skip conditions and the early-termination rules in task.md.
4. Return the report (Phase 8, inline): read {workdir}/report/final-report.md and return its contents as the skill output.

To resume an interrupted run: if a workdir is known from prior context, read {workdir}/orchestrator-state.json and continue from its current_phase instead of starting at Phase 0 (see the Recovery section of task.md).

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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).

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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 | 50 | 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 | 10000 | 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) |

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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 |

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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

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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 |

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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,