mirror of
https://github.com/wneessen/go-mail.git
synced 2024-11-21 21:30:50 +01:00
Winni Neessen
19330fc108
Removed error handling from `randNum` in `random_test.go` and introduced new `randNum` implementations for different Go versions (1.19, 1.20-1.21, 1.22+). This ensures compatibility with different versions of Go and utilizes the appropriate version-specific random number generation methods. We are using math/rand instead crypto/rand. For our needs this should be sufficient.
52 lines
1.4 KiB
Go
52 lines
1.4 KiB
Go
// SPDX-FileCopyrightText: 2022-2023 The go-mail Authors
|
|
//
|
|
// SPDX-License-Identifier: MIT
|
|
|
|
package mail
|
|
|
|
import (
|
|
"crypto/rand"
|
|
"encoding/binary"
|
|
"strings"
|
|
)
|
|
|
|
// Range of characters for the secure string generation
|
|
const cr = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890"
|
|
|
|
// Bitmask sizes for the string generators (based on 93 chars total)
|
|
const (
|
|
letterIdxBits = 7 // 7 bits to represent a letter index
|
|
letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
|
|
letterIdxMax = 63 / letterIdxBits // # of letter indices fitting in 63 bits
|
|
)
|
|
|
|
// randomStringSecure returns a random, string of length characters. This method uses the
|
|
// crypto/random package and therfore is cryptographically secure
|
|
func randomStringSecure(length int) (string, error) {
|
|
randString := strings.Builder{}
|
|
randString.Grow(length)
|
|
charRangeLength := len(cr)
|
|
|
|
randPool := make([]byte, 8)
|
|
_, err := rand.Read(randPool)
|
|
if err != nil {
|
|
return randString.String(), err
|
|
}
|
|
for idx, char, rest := length-1, binary.BigEndian.Uint64(randPool), letterIdxMax; idx >= 0; {
|
|
if rest == 0 {
|
|
_, err = rand.Read(randPool)
|
|
if err != nil {
|
|
return randString.String(), err
|
|
}
|
|
char, rest = binary.BigEndian.Uint64(randPool), letterIdxMax
|
|
}
|
|
if i := int(char & letterIdxMask); i < charRangeLength {
|
|
randString.WriteByte(cr[i])
|
|
idx--
|
|
}
|
|
char >>= letterIdxBits
|
|
rest--
|
|
}
|
|
|
|
return randString.String(), nil
|
|
}
|