auth/internal/domain/code_challenge_method.go

125 lines
3.1 KiB
Go

package domain
import (
"crypto/md5"
"crypto/sha1"
"crypto/sha256"
"crypto/sha512"
"encoding/base64"
"fmt"
"hash"
"strconv"
"strings"
)
// CodeChallengeMethod represent a PKCE challenge method for validate verifier.
//
// NOTE(toby3d): Encapsulate enums in structs for extra compile-time safety:
// https://threedots.tech/post/safer-enums-in-go/#struct-based-enums
type CodeChallengeMethod struct {
hash hash.Hash
uid string
}
//nolint: gochecknoglobals // NOTE(toby3d): structs cannot be constants
var (
CodeChallengeMethodUndefined = CodeChallengeMethod{
uid: "",
hash: nil,
}
CodeChallengeMethodPLAIN = CodeChallengeMethod{
uid: "PLAIN",
hash: nil,
}
CodeChallengeMethodMD5 = CodeChallengeMethod{
uid: "MD5",
hash: md5.New(),
}
CodeChallengeMethodS1 = CodeChallengeMethod{
uid: "S1",
hash: sha1.New(),
}
CodeChallengeMethodS256 = CodeChallengeMethod{
uid: "S256",
hash: sha256.New(),
}
CodeChallengeMethodS512 = CodeChallengeMethod{
uid: "S512",
hash: sha512.New(),
}
)
var ErrCodeChallengeMethodUnknown error = NewError(ErrorCodeInvalidRequest, "unknown code_challene_method")
//nolint: gochecknoglobals // NOTE(toby3d): maps cannot be constants
var slugsMethods = map[string]CodeChallengeMethod{
CodeChallengeMethodMD5.uid: CodeChallengeMethodMD5,
CodeChallengeMethodPLAIN.uid: CodeChallengeMethodPLAIN,
CodeChallengeMethodS1.uid: CodeChallengeMethodS1,
CodeChallengeMethodS256.uid: CodeChallengeMethodS256,
CodeChallengeMethodS512.uid: CodeChallengeMethodS512,
}
// ParseCodeChallengeMethod parse string identifier of code challenge method
// into struct enum.
func ParseCodeChallengeMethod(uid string) (CodeChallengeMethod, error) {
if method, ok := slugsMethods[strings.ToUpper(uid)]; ok {
return method, nil
}
return CodeChallengeMethodUndefined, fmt.Errorf("%w: %s", ErrCodeChallengeMethodUnknown, uid)
}
// UnmarshalForm implements custom unmarshler for form values.
func (ccm *CodeChallengeMethod) UnmarshalForm(v []byte) error {
method, err := ParseCodeChallengeMethod(string(v))
if err != nil {
return fmt.Errorf("UnmarshalForm: %w", err)
}
*ccm = method
return nil
}
// UnmarshalJSON implements custom unmarshler for JSON.
func (ccm *CodeChallengeMethod) UnmarshalJSON(v []byte) error {
src, err := strconv.Unquote(string(v))
if err != nil {
return fmt.Errorf("UnmarshalJSON: %w", err)
}
method, err := ParseCodeChallengeMethod(src)
if err != nil {
return fmt.Errorf("UnmarshalJSON: %w", err)
}
*ccm = method
return nil
}
// String returns string representation of code challenge method.
func (ccm CodeChallengeMethod) String() string {
return ccm.uid
}
// Validate checks for a match to the verifier with the hashed version of the
// challenge via the chosen method.
func (ccm CodeChallengeMethod) Validate(codeChallenge, verifier string) bool {
if ccm.uid == CodeChallengeMethodUndefined.uid {
return false
}
if ccm.uid == CodeChallengeMethodPLAIN.uid {
return codeChallenge == verifier
}
return codeChallenge == base64.RawURLEncoding.EncodeToString(ccm.hash.Sum([]byte(verifier)))
}