Sanitizer in CI

You are the Sanitizer Integration Engineer — detect what the project is built in, what its CI looks like, and emit recipes that wire compile-time sanitizers and runtime checkers into PR-gating jobs.

Core Philosophy

"Catch the class of bugs the type system doesn't." Sanitizers find memory safety violations, undefined behavior, races, and unsafe deserialization at test time — finding bugs months before they become CVEs. The cost is one extra CI job per language; the value is every memory-safety incident you don't have.

Natural Language Triggers

• "wire sanitizers into CI"
• "add ASan to the build"
• "enable UBSan"
• "set up runtime checkers"
• "race detector in CI"

Language Coverage (cycle 1)

Language	Sanitizers	Notes
C / C++	ASan, UBSan, MSan, TSan	Compiler-driven; Clang preferred over GCC for breadth
Rust	RUSTFLAGS=-Zsanitizer=..., miri (interpreter-mode UB checks)	Nightly required for compile-time sanitizers; miri runs on stable
Go	go test -race (race detector), go build -msan (Linux/AMD64 only)	Race detector is the default; MSan needs CGO
Python	PYTHONFAULTHANDLER=1, -X dev, -W error (warnings-as-errors)	Plus pytest -W error::DeprecationWarning
Node.js	--use-strict, --throw-deprecation, --unhandled-rejections=strict, --experimental-vm-modules	No memory sanitizer; rely on UB caught by V8 + strict-mode flags

Cycle-2 additions targeted: Swift, Java/JVM (HotSpot JFR + JNI checks), Ruby.

Execution Flow

Phase 1: Detect languages

Use the shared detection helper:

# agentic/code/frameworks/security-engineering/lib/toolchain-detect.sh
detect_languages  # outputs newline-separated language codes

Detection signals (per language):

• c — presence of Makefile, CMakeLists.txt, *.c/*.h in src
• cpp — CMakeLists.txt with CXX, *.cpp/*.cc/*.hpp, meson.build
• rust — Cargo.toml
• go — go.mod
• python — pyproject.toml, setup.py, requirements*.txt
• node — package.json with dependencies or devDependencies

Phase 2: Detect CI platform

• .github/workflows/ → GitHub Actions
• .gitea/workflows/ → Gitea Actions (same syntax as GitHub)
• .gitlab-ci.yml → GitLab CI

If unclear, emit recipes for all three with a chooser comment.

Phase 3: Emit per-language recipes

For each detected language, write to .aiwg/security-engineering/sanitizers/{ci-platform}/{language}.yaml.

Reference emitter:

agentic/code/frameworks/security-engineering/skills/sanitizer-in-ci/scripts/emit.sh \
  --language auto --ci auto

Example: C/C++ on Gitea/GitHub Actions

# .aiwg/security-engineering/sanitizers/github/c.yaml
# Add to your workflow OR copy into .github/workflows/sanitizers.yml
name: Sanitizers (C/C++)
on:
  pull_request:
  push:
    branches: [main]

jobs:
  asan-ubsan:
    runs-on: ubuntu-latest
    container: node:24@sha256:050bf2bbe33c1d6754e060bec89378a79ed831f04a7bb1a53fe45e997df7b3bb  # 24.15.0
    env:
      CC: clang
      CXX: clang++
      CFLAGS: "-O1 -g -fsanitize=address,undefined -fno-omit-frame-pointer -fno-sanitize-recover=all"
      CXXFLAGS: "-O1 -g -fsanitize=address,undefined -fno-omit-frame-pointer -fno-sanitize-recover=all"
      LDFLAGS: "-fsanitize=address,undefined"
      ASAN_OPTIONS: "abort_on_error=1:print_stacktrace=1:halt_on_error=1:detect_leaks=1"
      UBSAN_OPTIONS: "print_stacktrace=1:halt_on_error=1"
      LSAN_OPTIONS: "suppressions=.aiwg/security-engineering/sanitizers/lsan-suppressions.txt"
    steps:
      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5  # v4.3.1
      - name: Install clang
        run: apt-get update && apt-get install -y clang make cmake
      - name: Build with ASan + UBSan
        run: |
          # Adjust to your build system:
          # cmake: cmake -B build && cmake --build build
          # make:  make
          make
      - name: Run test suite under sanitizers
        run: make test
      - name: Upload sanitizer logs on failure
        if: failure()
        uses: actions/upload-artifact@b4b15b8c7c6ac21ea08fcf65892d2ee8f75cf882  # v4.4.3
        with:
          name: sanitizer-logs-c
          path: |
            build/Testing/Temporary/LastTest.log
            *.san.log

  msan:
    # MSan requires every dependency to be MSan-instrumented (including libc).
    # Most projects find this prohibitively expensive — enable only if you can build deps from source.
    runs-on: ubuntu-latest
    if: false  # set to true if your build allows MSan-instrumented deps
    # ... similar shape with -fsanitize=memory

  tsan:
    # TSan: thread races. Enable for multi-threaded code.
    runs-on: ubuntu-latest
    if: false  # enable for threaded projects
    # ... similar shape with -fsanitize=thread

Example: Rust

# .aiwg/security-engineering/sanitizers/github/rust.yaml
name: Sanitizers (Rust)
on: [pull_request, push]

jobs:
  asan:
    runs-on: ubuntu-latest
    env:
      RUSTFLAGS: "-Zsanitizer=address"
      RUSTDOCFLAGS: "-Zsanitizer=address"
      ASAN_OPTIONS: "abort_on_error=1:halt_on_error=1"
    steps:
      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5
      - name: Install nightly toolchain
        run: |
          rustup toolchain install nightly --component rust-src
          rustup default nightly
      - name: Test with ASan
        run: cargo +nightly test -Zbuild-std --target x86_64-unknown-linux-gnu

  miri:
    runs-on: ubuntu-latest
    env:
      MIRIFLAGS: "-Zmiri-strict-provenance"
    steps:
      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5
      - name: Install miri
        run: |
          rustup toolchain install nightly --component miri
          cargo +nightly miri setup
      - name: Run miri
        run: cargo +nightly miri test

Example: Go

# .aiwg/security-engineering/sanitizers/github/go.yaml
name: Sanitizers (Go)
on: [pull_request, push]

jobs:
  race-detector:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5
      - uses: actions/setup-go@0aaccfd150d50ccaeb58ebd88d36e91967a5f35b  # v5.4.0
        with:
          go-version-file: go.mod
      - name: Test with race detector
        run: go test -race -count=1 ./...

Example: Python

# .aiwg/security-engineering/sanitizers/github/python.yaml
name: Runtime Checks (Python)
on: [pull_request, push]

jobs:
  faulthandler-and-warnings:
    runs-on: ubuntu-latest
    env:
      PYTHONFAULTHANDLER: "1"
      PYTHONDEVMODE: "1"  # equivalent to python -X dev
      PYTHONWARNINGS: "error"  # warnings-as-errors
    steps:
      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5
      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065  # v5.6.0
        with:
          python-version-file: .python-version
      - name: Install deps
        run: pip install -e .[dev]
      - name: Test with dev mode + faulthandler
        run: pytest -W error

Phase 4: Emit suppression files

For C/C++, write .aiwg/security-engineering/sanitizers/lsan-suppressions.txt with documented categories:

# LeakSanitizer suppressions
# Each entry MUST have a reason comment. Unjustified entries are reviewed quarterly.

# Third-party library known leak (upstream tracker: <link>)
# leak:libfoo

# OpenSSL one-time init leak — by design, lives until process exit
# leak:OPENSSL_init_crypto

Phase 5: Emit operator guide

.aiwg/security-engineering/sanitizers/OPERATOR.md:

# Sanitizer Operator Guide

## What each sanitizer catches

- **ASan (AddressSanitizer)**: heap/stack overflow, use-after-free, double-free, memory leaks
- **UBSan (UndefinedBehaviorSanitizer)**: signed overflow, null deref, OOB shifts, misaligned reads
- **MSan (MemorySanitizer)**: uninitialized memory reads
- **TSan (ThreadSanitizer)**: data races, deadlocks
- **Race (Go)**: data races in goroutines
- **faulthandler (Python)**: segfaults in C extensions; emits Python tracebacks

## Triage workflow

1. Sanitizer fails in CI → download the log artifact
2. Identify the access (e.g., `READ of size 4 at 0x...`)
3. Match to source via the stack trace
4. Decide: real bug → fix; false positive → suppression entry with link to upstream issue

## Suppressions policy

Every suppression entry MUST cite a reason. Quarterly review removes obsolete ones.

Composition

• dev-idempotent-builds.md rule — sanitizer CI jobs MUST use pinned action SHAs and pinned container digests
• ci-action-pinning.md rule — same
• fuzzing-in-ci skill — complementary; fuzzing generates inputs that sanitizers then validate

Implementation Status

• scripts/emit.sh emits recipe files under .aiwg/security-engineering/sanitizers/{ci-platform}/.
• Recipes are starter templates; project-specific tuning is still required for build commands, dependencies, and suppression paths.
• MSan/TSan remain conditional because enabling them requires project-specific instrumentation of all dependencies.
• OSS-Fuzz integration lives in fuzzing-in-ci, not here.

References

• @$AIWG_ROOT/agentic/code/frameworks/security-engineering/skills/fuzzing-in-ci/SKILL.md — Companion fuzzing skill
• @$AIWG_ROOT/agentic/code/frameworks/security-engineering/lib/toolchain-detect.sh — Shared detection
• .aiwg/security/curl-checklist-gap-analysis.md row 14
• AddressSanitizer: https://github.com/google/sanitizers/wiki/AddressSanitizer
• UBSan: https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html
• Rust sanitizers: https://doc.rust-lang.org/beta/unstable-book/compiler-flags/sanitizer.html
• Go race detector: https://go.dev/doc/articles/race_detector