nuclei/pkg/templates/preprocessors.go

70 lines
1.8 KiB
Go

package templates
import (
"bytes"
"regexp"
"strings"
"github.com/segmentio/ksuid"
)
type Preprocessor interface {
// Process processes the data and returns the processed data.
Process(data []byte) []byte
// Exists check if the preprocessor exists in the data.
Exists(data []byte) bool
}
var (
preprocessorRegex = regexp.MustCompile(`{{([a-z0-9_]+)}}`)
defaultPreprocessors = []Preprocessor{
&randStrPreprocessor{},
}
)
func getPreprocessors(preprocessor Preprocessor) []Preprocessor {
if preprocessor != nil {
// append() function adds the elements to existing slice if space is available
// else it creates a new slice and copies the elements to new slice
// this may cause race-conditions hence we do it explicitly
tmp := make([]Preprocessor, 0, len(defaultPreprocessors)+1)
tmp = append(tmp, preprocessor)
tmp = append(tmp, defaultPreprocessors...)
return tmp
}
return defaultPreprocessors
}
var _ Preprocessor = &randStrPreprocessor{}
type randStrPreprocessor struct{}
// Process processes the data and returns the processed data.
func (r *randStrPreprocessor) Process(data []byte) []byte {
foundMap := make(map[string]struct{})
for _, expression := range preprocessorRegex.FindAllStringSubmatch(string(data), -1) {
if len(expression) != 2 {
continue
}
value := expression[1]
if strings.Contains(value, "(") || strings.Contains(value, ")") {
continue
}
if _, ok := foundMap[value]; ok {
continue
}
foundMap[value] = struct{}{}
if strings.EqualFold(value, "randstr") || strings.HasPrefix(value, "randstr_") {
data = bytes.ReplaceAll(data, []byte(expression[0]), []byte(ksuid.New().String()))
}
}
return data
}
// Exists check if the preprocessor exists in the data.
func (r *randStrPreprocessor) Exists(data []byte) bool {
return bytes.Contains(data, []byte("randstr"))
}