go-avahi: Add initial fuzzing harness for DomainNormalize

projects/go-avahi/README.md

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+# Fuzzing Harness for go-avahi
+
+This directory contains fuzzers for the [`go-avahi`](https://github.com/OpenPrinting/go-avahi) project.
+
+## Fuzzers
+
+- `fuzz_domain.go`: Fuzzes the `DomainNormalize` function to validate the CGo boundary and `unsafe.Pointer` usage.
+
+## Build with OSS-Fuzz locally:
+1. Clone the OSS-Fuzz repo:
+
+```bash
+git clone https://github.com/google/oss-fuzz
+```
+
+2. Navigate into oss-fuzz directory:
+
+```bash
+cd oss-fuzz
+```
+
+3. Build the fuzzers:
+```bash
+python3 infra/helper.py build_fuzzers go-avahi
+```
+
+4. Run the fuzzer:
+```bash
+python3 infra/helper.py run_fuzzer go-avahi fuzz_domain_normalize
+```

projects/go-avahi/fuzzer/fuzz_domain.go

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+/*
+ * Fuzz target for go-avahi's DomainNormalize function.
+ */
+
+package fuzzer
+
+import (
+	"testing"
+
+	"github.com/OpenPrinting/go-avahi"
+)
+
+func FuzzDomainNormalize(f *testing.F) {
+	f.Add("example.local")
+	f.Add("printer._ipp._tcp.local")
+	f.Add("My\\.Printer._ipp._tcp.local")
+	f.Fuzz(func(t *testing.T, data string) {
+		_ = avahi.DomainNormalize(data)
+	})
+}

projects/go-avahi/oss_fuzz_build.sh

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+#!/bin/bash -eu
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+################################################################################
+
+# Copy fuzzer source into the target library tree
+mkdir -p $SRC/go-avahi/fuzzer
+cp $SRC/fuzzing/projects/go-avahi/fuzzer/fuzz_domain.go $SRC/go-avahi/fuzzer/
+
+# Package seed corpus
+mkdir -p $WORK/domain_seed_corpus
+cp $SRC/fuzzing/projects/go-avahi/seeds/domain_seed_corpus/* $WORK/domain_seed_corpus/
+cd $WORK
+zip -r $OUT/fuzz_domain_normalize_seed_corpus.zip domain_seed_corpus/
+
+# CGo environment: use pkg-config for architecture-agnostic library resolution
+export CGO_ENABLED=1
+export CGO_CFLAGS="-D_REENTRANT"
+export CGO_LDFLAGS="$(pkg-config --libs avahi-client) -lpthread -lresolv"
+
+# Append avahi libs to CXXFLAGS so compile_native_go_fuzzer's final
+# clang++ link step can resolve the C symbols from the .a archive.
+export CXXFLAGS="${CXXFLAGS:-} $(pkg-config --libs avahi-client) -lpthread -lresolv"
+
+# Build dependencies and fuzzers
+cd $SRC/go-avahi
+go mod tidy
+go install github.com/AdamKorcz/go-118-fuzz-build@latest
+go get github.com/AdamKorcz/go-118-fuzz-build/testing
+
+compile_native_go_fuzzer ./fuzzer FuzzDomainNormalize fuzz_domain_normalize

projects/go-avahi/seeds/domain_seed_corpus/valid_domain

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+printer._ipp._tcp.local