xs/vendor/gopkg.in/hlandau/passlib.v1/hash/sha2crypt/raw/parse.go

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package raw
import "fmt"
import "strings"
import "strconv"
// Indicates that a password hash or stub is invalid.
var ErrInvalidStub = fmt.Errorf("invalid stub")
// Indicates that the number of rounds specified is not in the valid range.
var ErrInvalidRounds = fmt.Errorf("invalid number of rounds")
// Scans a sha256-crypt or sha512-crypt modular crypt stub or modular crypt hash
// to determine configuration parameters.
func Parse(stub string) (isSHA512 bool, salt, hash string, rounds int, err error) {
// $5$
if len(stub) < 3 || stub[0] != '$' || stub[2] != '$' {
err = ErrInvalidStub
return
}
if stub[1] == '6' {
isSHA512 = true
} else if stub[1] != '5' {
err = ErrInvalidStub
return
}
rest := stub[3:]
parts := strings.Split(rest, "$")
roundsStr := ""
switch len(parts) {
case 1:
// $5$
// $5$salt
salt = parts[0]
case 2:
// $5$salt$hash
// $5$rounds=1000$salt
if strings.HasPrefix(parts[0], "rounds=") {
roundsStr = parts[0]
salt = parts[1]
} else {
salt = parts[0]
hash = parts[1]
}
case 3:
// $5$rounds=1000$salt$hash
roundsStr = parts[0]
salt = parts[1]
hash = parts[2]
default:
err = ErrInvalidStub
}
if roundsStr != "" {
if !strings.HasPrefix(roundsStr, "rounds=") {
err = ErrInvalidStub
return
}
roundsStr = roundsStr[7:]
var n uint64
n, err = strconv.ParseUint(roundsStr, 10, 31)
if err != nil {
err = ErrInvalidStub
return
}
rounds = int(n)
if rounds < MinimumRounds || rounds > MaximumRounds {
err = ErrInvalidRounds
return
}
} else {
rounds = DefaultRounds
}
return
}