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// The MIT License (MIT)
// Copyright (c) 2011-2015 Michael Mitton (mmitton@gmail.com)
// Portions copyright (c) 2015-2016 go-ldap Authors
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
package ldap
import (
"encoding/hex"
"errors"
"fmt"
"strings"
ldap "github.com/go-ldap/ldap/v3"
)
// DecodeDN - remove leading and trailing spaces from the attribute type and value
// and unescape any escaped characters in these fields
//
// pulled from the go-ldap library
// https://github.com/go-ldap/ldap/blob/dbdc485259442f987d83e604cd4f5859cfc1be58/dn.go
func DecodeDN(str string) (string, error) {
s := []rune(stripLeadingAndTrailingSpaces(str))
builder := strings.Builder{}
for i := 0; i < len(s); i++ {
char := s[i]
// If the character is not an escape character, just add it to the
// builder and continue
if char != '\\' {
builder.WriteRune(char)
continue
}
// If the escape character is the last character, it's a corrupted
// escaped character
if i+1 >= len(s) {
return "", ldap.NewError(34, fmt.Errorf("got corrupted escaped character: '%s'", string(s)))
}
// If the escaped character is a special character, just add it to
// the builder and continue
switch s[i+1] {
case ' ', '"', '#', '+', ',', ';', '<', '=', '>', '\\':
builder.WriteRune(s[i+1])
i++
continue
}
// If the escaped character is not a special character, it should
// be a hex-encoded character of the form \XX if it's not at least
// two characters long, it's a corrupted escaped character
if i+2 >= len(s) {
return "", ldap.NewError(34, errors.New("unable to decode escaped character: encoding/hex: invalid byte: "+string(s[i+1])))
}
// Get the runes for the two characters after the escape character
// and convert them to a byte slice
xx := []byte(string(s[i+1 : i+3]))
// If the two runes are not hex characters and result in more than
// two bytes when converted to a byte slice, it's a corrupted
// escaped character
if len(xx) != 2 {
return "", ldap.NewError(34, fmt.Errorf("unable to decode escaped character: invalid byte: %s", string(xx)))
}
// Decode the hex-encoded character and add it to the builder
dst := []byte{0}
if n, err := hex.Decode(dst, xx); err != nil {
return "", ldap.NewError(34, errors.New("unable to decode escaped character: "+err.Error()))
} else if n != 1 {
return "", ldap.NewError(34, fmt.Errorf("unable to decode escaped character: encoding/hex: expected 1 byte when un-escaping, got %d", n))
}
builder.WriteByte(dst[0])
i += 2
}
return builder.String(), nil
}
func stripLeadingAndTrailingSpaces(inVal string) string {
noSpaces := strings.Trim(inVal, " ")
// Re-add the trailing space if it was an escaped space
if len(noSpaces) > 0 && noSpaces[len(noSpaces)-1] == '\\' && inVal[len(inVal)-1] == ' ' {
noSpaces += " "
}
return noSpaces
}
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