fix: Modify the pure-ftpd encryption method (#8312)

Author: ssongliu

agent/utils/toolbox/helper/sha512_crypt.go

@@ -0,0 +1,224 @@
+package helper
+
+import (
+	"bytes"
+	"crypto/rand"
+	"crypto/sha512"
+	"errors"
+	"strconv"
+)
+
+const (
+	SaltLenMin    = 1
+	SaltLenMax    = 16
+	RoundsMin     = 1000
+	RoundsMax     = 999999999
+	RoundsDefault = 5000
+)
+
+var _rounds = []byte("rounds=")
+
+func Generate(key []byte) (string, error) {
+	var rounds int
+	var isRoundsDef bool
+
+	salt := generateWRounds()
+	magicPrefix := []byte("$6$")
+	if !bytes.HasPrefix(salt, magicPrefix) {
+		return "", errors.New("invalid magic prefix")
+	}
+
+	saltItem := bytes.Split(salt, []byte{'$'})
+	if len(saltItem) < 3 {
+		return "", errors.New("invalid salt format")
+	}
+
+	if bytes.HasPrefix(saltItem[2], _rounds) {
+		isRoundsDef = true
+		pr, err := strconv.ParseInt(string(saltItem[2][7:]), 10, 32)
+		if err != nil {
+			return "", errors.New("invalid rounds")
+		}
+		rounds = int(pr)
+		if rounds < RoundsMin {
+			rounds = RoundsMin
+		} else if rounds > RoundsMax {
+			rounds = RoundsMax
+		}
+		salt = saltItem[3]
+	} else {
+		rounds = RoundsDefault
+		salt = saltItem[2]
+	}
+
+	if len(salt) > SaltLenMax {
+		salt = salt[0:SaltLenMax]
+	}
+
+	Alternate := sha512.New()
+	Alternate.Write(key)
+	Alternate.Write(salt)
+	Alternate.Write(key)
+	AlternateSum := Alternate.Sum(nil)
+
+	A := sha512.New()
+	A.Write(key)
+	A.Write(salt)
+	i := len(key)
+	for ; i > 64; i -= 64 {
+		A.Write(AlternateSum)
+	}
+	A.Write(AlternateSum[0:i])
+
+	for i = len(key); i > 0; i >>= 1 {
+		if (i & 1) != 0 {
+			A.Write(AlternateSum)
+		} else {
+			A.Write(key)
+		}
+	}
+	A_sum := A.Sum(nil)
+
+	P := sha512.New()
+	for i = 0; i < len(key); i++ {
+		P.Write(key)
+	}
+	P_sum := P.Sum(nil)
+	P_seq := make([]byte, 0, len(key))
+	for i = len(key); i > 64; i -= 64 {
+		P_seq = append(P_seq, P_sum...)
+	}
+	P_seq = append(P_seq, P_sum[0:i]...)
+
+	S := sha512.New()
+	for i = 0; i < (16 + int(A_sum[0])); i++ {
+		S.Write(salt)
+	}
+	S_sum := S.Sum(nil)
+	S_seq := make([]byte, 0, len(salt))
+	for i = len(salt); i > 64; i -= 64 {
+		S_seq = append(S_seq, S_sum...)
+	}
+	S_seq = append(S_seq, S_sum[0:i]...)
+
+	C_sum := A_sum
+
+	for i = 0; i < rounds; i++ {
+		C := sha512.New()
+		if (i & 1) != 0 {
+			C.Write(P_seq)
+		} else {
+			C.Write(C_sum)
+		}
+		if (i % 3) != 0 {
+			C.Write(S_seq)
+		}
+		if (i % 7) != 0 {
+			C.Write(P_seq)
+		}
+		if (i & 1) != 0 {
+			C.Write(C_sum)
+		} else {
+			C.Write(P_seq)
+		}
+
+		C_sum = C.Sum(nil)
+	}
+
+	out := make([]byte, 0, 123)
+	out = append(out, magicPrefix...)
+	if isRoundsDef {
+		out = append(out, []byte("rounds="+strconv.Itoa(rounds)+"$")...)
+	}
+	out = append(out, salt...)
+	out = append(out, '$')
+	out = append(out, base64_24Bit([]byte{
+		C_sum[42], C_sum[21], C_sum[0],
+		C_sum[1], C_sum[43], C_sum[22],
+		C_sum[23], C_sum[2], C_sum[44],
+		C_sum[45], C_sum[24], C_sum[3],
+		C_sum[4], C_sum[46], C_sum[25],
+		C_sum[26], C_sum[5], C_sum[47],
+		C_sum[48], C_sum[27], C_sum[6],
+		C_sum[7], C_sum[49], C_sum[28],
+		C_sum[29], C_sum[8], C_sum[50],
+		C_sum[51], C_sum[30], C_sum[9],
+		C_sum[10], C_sum[52], C_sum[31],
+		C_sum[32], C_sum[11], C_sum[53],
+		C_sum[54], C_sum[33], C_sum[12],
+		C_sum[13], C_sum[55], C_sum[34],
+		C_sum[35], C_sum[14], C_sum[56],
+		C_sum[57], C_sum[36], C_sum[15],
+		C_sum[16], C_sum[58], C_sum[37],
+		C_sum[38], C_sum[17], C_sum[59],
+		C_sum[60], C_sum[39], C_sum[18],
+		C_sum[19], C_sum[61], C_sum[40],
+		C_sum[41], C_sum[20], C_sum[62],
+		C_sum[63],
+	})...)
+
+	A.Reset()
+	Alternate.Reset()
+	P.Reset()
+	for i = 0; i < len(A_sum); i++ {
+		A_sum[i] = 0
+	}
+	for i = 0; i < len(AlternateSum); i++ {
+		AlternateSum[i] = 0
+	}
+	for i = 0; i < len(P_seq); i++ {
+		P_seq[i] = 0
+	}
+
+	return string(out), nil
+}
+
+func generateWRounds() []byte {
+	salt := make([]byte, 16)
+	_, _ = rand.Read(salt)
+
+	magicPrefix := "$6$"
+	out := make([]byte, len(magicPrefix)+5000)
+	copy(out, magicPrefix)
+	copy(out[len(magicPrefix):], base64_24Bit(salt))
+	return out
+}
+
+func base64_24Bit(src []byte) (hash []byte) {
+	if len(src) == 0 {
+		return []byte{}
+	}
+	alphabet := "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
+
+	hashSize := (len(src) * 8) / 6
+	if (len(src) % 6) != 0 {
+		hashSize += 1
+	}
+	hash = make([]byte, hashSize)
+
+	dst := hash
+	for len(src) > 0 {
+		switch len(src) {
+		default:
+			dst[0] = alphabet[src[0]&0x3f]
+			dst[1] = alphabet[((src[0]>>6)|(src[1]<<2))&0x3f]
+			dst[2] = alphabet[((src[1]>>4)|(src[2]<<4))&0x3f]
+			dst[3] = alphabet[(src[2]>>2)&0x3f]
+			src = src[3:]
+			dst = dst[4:]
+		case 2:
+			dst[0] = alphabet[src[0]&0x3f]
+			dst[1] = alphabet[((src[0]>>6)|(src[1]<<2))&0x3f]
+			dst[2] = alphabet[(src[1]>>4)&0x3f]
+			src = src[2:]
+			dst = dst[3:]
+		case 1:
+			dst[0] = alphabet[src[0]&0x3f]
+			dst[1] = alphabet[(src[0]>>6)&0x3f]
+			src = src[1:]
+			dst = dst[2:]
+		}
+	}
+
+	return
+}