forked from klauspost/compress
/
fuzz.go
211 lines (196 loc) · 4.31 KB
/
fuzz.go
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// Copyright (c) 2024+ Klaus Post. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package fuzz provides a way to add test cases to a testing.F instance from a zip file.
package fuzz
import (
"archive/zip"
"bytes"
"encoding/binary"
"fmt"
"go/ast"
"go/parser"
"go/token"
"io"
"os"
"strconv"
"testing"
)
type InputType uint8
const (
// TypeRaw indicates that files are raw bytes.
TypeRaw InputType = iota
// TypeGoFuzz indicates files are from Go Fuzzer.
TypeGoFuzz
// TypeOSSFuzz indicates that files are from OSS fuzzer with size before data.
TypeOSSFuzz
)
// AddFromZip will read the supplied zip and add all as corpus for f.
// Byte slices only.
func AddFromZip(f *testing.F, filename string, t InputType, short bool) {
file, err := os.Open(filename)
if err != nil {
f.Fatal(err)
}
fi, err := file.Stat()
if err != nil {
f.Fatal(err)
}
zr, err := zip.NewReader(file, fi.Size())
if err != nil {
f.Fatal(err)
}
for i, file := range zr.File {
if short && i%10 != 0 {
continue
}
rc, err := file.Open()
if err != nil {
f.Fatal(err)
}
b, err := io.ReadAll(rc)
if err != nil {
f.Fatal(err)
}
rc.Close()
t := t
if t == TypeOSSFuzz {
t = TypeRaw // Fallback
if len(b) >= 4 {
sz := binary.BigEndian.Uint32(b)
if sz <= uint32(len(b))-4 {
f.Add(b[4 : 4+sz])
continue
}
}
}
if bytes.HasPrefix(b, []byte("go test fuzz")) {
t = TypeGoFuzz
} else {
t = TypeRaw
}
if t == TypeRaw {
f.Add(b)
continue
}
vals, err := unmarshalCorpusFile(b)
if err != nil {
f.Fatal(err)
}
for _, v := range vals {
f.Add(v)
}
}
}
// ReturnFromZip will read the supplied zip and add all as corpus for f.
// Byte slices only.
func ReturnFromZip(tb testing.TB, filename string, t InputType, fn func([]byte)) {
file, err := os.Open(filename)
if err != nil {
tb.Fatal(err)
}
fi, err := file.Stat()
if err != nil {
tb.Fatal(err)
}
zr, err := zip.NewReader(file, fi.Size())
if err != nil {
tb.Fatal(err)
}
for _, file := range zr.File {
rc, err := file.Open()
if err != nil {
tb.Fatal(err)
}
b, err := io.ReadAll(rc)
if err != nil {
tb.Fatal(err)
}
rc.Close()
t := t
if t == TypeOSSFuzz {
t = TypeRaw // Fallback
if len(b) >= 4 {
sz := binary.BigEndian.Uint32(b)
if sz <= uint32(len(b))-4 {
fn(b[4 : 4+sz])
continue
}
}
}
if bytes.HasPrefix(b, []byte("go test fuzz")) {
t = TypeGoFuzz
} else {
t = TypeRaw
}
if t == TypeRaw {
fn(b)
continue
}
vals, err := unmarshalCorpusFile(b)
if err != nil {
tb.Fatal(err)
}
for _, v := range vals {
fn(v)
}
}
}
// unmarshalCorpusFile decodes corpus bytes into their respective values.
func unmarshalCorpusFile(b []byte) ([][]byte, error) {
if len(b) == 0 {
return nil, fmt.Errorf("cannot unmarshal empty string")
}
lines := bytes.Split(b, []byte("\n"))
if len(lines) < 2 {
return nil, fmt.Errorf("must include version and at least one value")
}
var vals = make([][]byte, 0, len(lines)-1)
for _, line := range lines[1:] {
line = bytes.TrimSpace(line)
if len(line) == 0 {
continue
}
v, err := parseCorpusValue(line)
if err != nil {
return nil, fmt.Errorf("malformed line %q: %v", line, err)
}
vals = append(vals, v)
}
return vals, nil
}
// parseCorpusValue
func parseCorpusValue(line []byte) ([]byte, error) {
fs := token.NewFileSet()
expr, err := parser.ParseExprFrom(fs, "(test)", line, 0)
if err != nil {
return nil, err
}
call, ok := expr.(*ast.CallExpr)
if !ok {
return nil, fmt.Errorf("expected call expression")
}
if len(call.Args) != 1 {
return nil, fmt.Errorf("expected call expression with 1 argument; got %d", len(call.Args))
}
arg := call.Args[0]
if arrayType, ok := call.Fun.(*ast.ArrayType); ok {
if arrayType.Len != nil {
return nil, fmt.Errorf("expected []byte or primitive type")
}
elt, ok := arrayType.Elt.(*ast.Ident)
if !ok || elt.Name != "byte" {
return nil, fmt.Errorf("expected []byte")
}
lit, ok := arg.(*ast.BasicLit)
if !ok || lit.Kind != token.STRING {
return nil, fmt.Errorf("string literal required for type []byte")
}
s, err := strconv.Unquote(lit.Value)
if err != nil {
return nil, err
}
return []byte(s), nil
}
return nil, fmt.Errorf("expected []byte")
}