wolfTPM/.github/workflows/fuzz.yml

name: Fuzz Testing

on:
  schedule:
    - cron: '0 4 * * *'  # Nightly 4am UTC
  workflow_dispatch:       # Manual trigger
  pull_request:
    branches: [ '*' ]
    types: [opened, reopened, ready_for_review]
  push:
    branches: [ master ]

jobs:
  # The matrix context is not available in a job-level if:, so route by run
  # type here instead: 600s full runs go to the nightly schedule / manual
  # dispatch; 60s smoke runs go to non-draft PR open/reopen/ready and merges
  # to master. Intermediate PR pushes (synchronize) are not a trigger.
  select:
    if: github.event_name != 'pull_request' || github.event.pull_request.draft == false
    runs-on: ubuntu-latest
    outputs:
      matrix: ${{ steps.pick.outputs.matrix }}
    steps:
      - name: Pick fuzz matrix for ${{ github.event_name }}
        id: pick
        run: |
          # schedule / dispatch -> full (600s); PR / push -> smoke (60s).
          case "${{ github.event_name }}" in
            schedule|workflow_dispatch) WANT=false ;;
            *)                          WANT=true  ;;
          esac
          PQC="--enable-dilithium --enable-mlkem --enable-experimental --enable-harden"
          MATRIX=$(jq -nc --argjson want "$WANT" --arg pqc "$PQC" '{
            include: [
              {name:"fuzz-full",      fuzz_time:600, smoke_only:false, wolfssl_extra_flags:"",   wolftpm_extra_flags:"",              max_len:4096},
              {name:"fuzz-smoke",     fuzz_time:60,  smoke_only:true,  wolfssl_extra_flags:"",   wolftpm_extra_flags:"",              max_len:4096},
              {name:"fuzz-full-pqc",  fuzz_time:600, smoke_only:false, wolfssl_extra_flags:$pqc, wolftpm_extra_flags:"--enable-v185", max_len:8192},
              {name:"fuzz-smoke-pqc", fuzz_time:60,  smoke_only:true,  wolfssl_extra_flags:$pqc, wolftpm_extra_flags:"--enable-v185", max_len:8192}
            ] | map(select(.smoke_only == $want))
          }')
          echo "matrix=$MATRIX" >> "$GITHUB_OUTPUT"          

  fuzz:
    needs: select
    runs-on: ubuntu-latest
    timeout-minutes: 30
    strategy:
      fail-fast: false
      matrix: ${{ fromJson(needs.select.outputs.matrix) }}

    steps:
      - name: Checkout wolfTPM
        uses: actions/checkout@v4

      - name: ASLR workaround
        run: sudo sysctl vm.mmap_rnd_bits=28

      - name: Setup wolfSSL with fuzzer support
        uses: ./.github/actions/setup-wolfssl
        with:
          cc: clang
          configure-flags: --enable-wolftpm --enable-pkcallbacks --enable-keygen ${{ matrix.wolfssl_extra_flags }}
          cflags: -fsanitize=fuzzer-no-link,address -fno-omit-frame-pointer -g -O1 -DWC_RSA_NO_PADDING
          ldflags: -fsanitize=address

      - name: Build fuzz target
        run: |
          ./autogen.sh
          CC=clang ./configure --enable-fwtpm --enable-fuzz \
            ${{ matrix.wolftpm_extra_flags }} \
            CFLAGS="-fsanitize=fuzzer-no-link,address -fno-omit-frame-pointer -g -O1" \
            LDFLAGS="-fsanitize=address"
          make -j$(nproc)          

      - name: Generate seed corpus
        run: python3 tests/fuzz/gen_corpus.py

      - name: Verify v1.85 PQC opcode coverage in corpus
        if: contains(matrix.name, 'pqc')
        run: |
          # Without this guard, fuzz-*-pqc could spend 10 minutes fuzzing
          # classical paths with -DWOLFTPM_V185 set and never exercise an
          # Encapsulate or SignSequenceComplete opcode. Fail fast if any of
          # the 8 new v1.85 command codes is absent from the seed corpus.
          # Seeds are binary; opcodes appear as raw 4-byte big-endian
          # sequences. Hex-dump the concatenated corpus and grep the
          # resulting hex stream for each opcode's bytes.
          CORPUS_HEX=$(cat tests/fuzz/corpus/*.bin | xxd -p | tr -d '\n')
          MISSING=()
          for cc in 000001a3 000001a4 000001a5 000001a6 \
                    000001a7 000001a8 000001a9 000001aa; do
            if ! echo "$CORPUS_HEX" | grep -q "$cc"; then
              MISSING+=("0x${cc^^}")
            fi
          done
          if [ ${#MISSING[@]} -gt 0 ]; then
            echo "ERROR: PQC seed corpus missing the following command codes:"
            printf '  %s\n' "${MISSING[@]}"
            echo "Update tests/fuzz/gen_corpus.py to emit a seed for each."
            exit 1
          fi
          echo "All 8 v1.85 PQC opcodes (0x1A3-0x1AA) present in seed corpus."          

      - name: Run fuzzer
        env:
          ASAN_OPTIONS: "detect_leaks=1:abort_on_error=1:symbolize=1"
        run: |
          echo "Fuzzing for ${{ matrix.fuzz_time }} seconds..."
          timeout ${{ matrix.fuzz_time }} \
            ./tests/fuzz/fwtpm_fuzz \
              tests/fuzz/corpus/ \
              -dict=tests/fuzz/tpm2.dict \
              -max_len=${{ matrix.max_len }} \
              -timeout=30 \
              -rss_limit_mb=2048 \
              -print_final_stats=1 \
            || FUZZ_RC=$?
          # timeout returns 124 on normal expiry, fuzzer returns 0 on no crash
          if [ "${FUZZ_RC:-0}" -eq 124 ] || [ "${FUZZ_RC:-0}" -eq 0 ]; then
            echo "Fuzzer completed without crashes"
          else
            echo "Fuzzer found crashes (exit code $FUZZ_RC)"
            ls -la crash-* 2>/dev/null || true
            exit 1
          fi          

      - name: Upload crash artifacts
        if: failure()
        uses: actions/upload-artifact@v4
        with:
          name: fuzz-crashes-${{ matrix.name }}
          path: |
            crash-*
            oom-*
            timeout-*            
          retention-days: 30
          if-no-files-found: ignore