vault/plugins/database/postgresql/scram/scram.go

87 lines
2.6 KiB
Go

package scram
//
// @see https://github.com/postgres/postgres/blob/c30f54ad732ca5c8762bb68bbe0f51de9137dd72/src/interfaces/libpq/fe-auth.c#L1167-L1285
// @see https://github.com/postgres/postgres/blob/e6bdfd9700ebfc7df811c97c2fc46d7e94e329a2/src/interfaces/libpq/fe-auth-scram.c#L868-L905
// @see https://github.com/postgres/postgres/blob/c30f54ad732ca5c8762bb68bbe0f51de9137dd72/src/port/pg_strong_random.c#L66-L96
// @see https://github.com/postgres/postgres/blob/e6bdfd9700ebfc7df811c97c2fc46d7e94e329a2/src/common/scram-common.c#L160-L274
// @see https://github.com/postgres/postgres/blob/e6bdfd9700ebfc7df811c97c2fc46d7e94e329a2/src/common/scram-common.c#L27-L85
// Implementation from https://github.com/supercaracal/scram-sha-256/blob/d3c05cd927770a11c6e12de3e3a99c3446a1f78d/main.go
import (
"crypto/hmac"
"crypto/rand"
"crypto/sha256"
"encoding/base64"
"fmt"
"io"
"golang.org/x/crypto/pbkdf2"
)
const (
// @see https://github.com/postgres/postgres/blob/e6bdfd9700ebfc7df811c97c2fc46d7e94e329a2/src/include/common/scram-common.h#L36-L41
saltSize = 16
// @see https://github.com/postgres/postgres/blob/c30f54ad732ca5c8762bb68bbe0f51de9137dd72/src/include/common/sha2.h#L22
digestLen = 32
// @see https://github.com/postgres/postgres/blob/e6bdfd9700ebfc7df811c97c2fc46d7e94e329a2/src/include/common/scram-common.h#L43-L47
iterationCnt = 4096
)
var (
clientRawKey = []byte("Client Key")
serverRawKey = []byte("Server Key")
)
func genSalt(size int) ([]byte, error) {
salt := make([]byte, size)
if _, err := io.ReadFull(rand.Reader, salt); err != nil {
return nil, err
}
return salt, nil
}
func encodeB64(src []byte) (dst []byte) {
dst = make([]byte, base64.StdEncoding.EncodedLen(len(src)))
base64.StdEncoding.Encode(dst, src)
return
}
func getHMACSum(key, msg []byte) []byte {
h := hmac.New(sha256.New, key)
_, _ = h.Write(msg)
return h.Sum(nil)
}
func getSHA256Sum(key []byte) []byte {
h := sha256.New()
_, _ = h.Write(key)
return h.Sum(nil)
}
func hashPassword(rawPassword, salt []byte, iter, keyLen int) string {
digestKey := pbkdf2.Key(rawPassword, salt, iter, keyLen, sha256.New)
clientKey := getHMACSum(digestKey, clientRawKey)
storedKey := getSHA256Sum(clientKey)
serverKey := getHMACSum(digestKey, serverRawKey)
return fmt.Sprintf("SCRAM-SHA-256$%d:%s$%s:%s",
iter,
string(encodeB64(salt)),
string(encodeB64(storedKey)),
string(encodeB64(serverKey)),
)
}
func Hash(password string) (string, error) {
salt, err := genSalt(saltSize)
if err != nil {
return "", err
}
hashedPassword := hashPassword([]byte(password), salt, iterationCnt, digestLen)
return hashedPassword, nil
}