feat: add PKCE for non public clients

backend/internal/dto/oidc_dto.go

@@ -10,6 +10,7 @@ type OidcClientDto struct {
 	PublicOidcClientDto
 	CallbackURLs []string `json:"callbackURLs"`
 	IsPublic     bool     `json:"isPublic"`
+	PkceEnabled  bool     `json:"pkceEnabled"`
 	CreatedBy    UserDto  `json:"createdBy"`
 }
 
@@ -17,6 +18,7 @@ type OidcClientCreateDto struct {
 	Name         string   `json:"name" binding:"required,max=50"`
 	CallbackURLs []string `json:"callbackURLs" binding:"required,urlList"`
 	IsPublic     bool     `json:"isPublic"`
+	PkceEnabled  bool     `json:"pkceEnabled"`
 }
 
 type AuthorizeOidcClientRequestDto struct {

backend/internal/model/oidc.go

@@ -42,6 +42,7 @@ type OidcClient struct {
 	ImageType    *string
 	HasLogo      bool `gorm:"-"`
 	IsPublic     bool
+	PkceEnabled  bool
 
 	CreatedByID string
 	CreatedBy   User

backend/internal/service/oidc_service.go

@@ -131,8 +131,8 @@ func (s *OidcService) CreateTokens(code, grantType, clientID, clientSecret, code
 		return "", "", &common.OidcInvalidAuthorizationCodeError{}
 	}
 
-	// If the client is public, the code verifier must match the code challenge
-	if client.IsPublic {
+	// If the client is public or PKCE is enabled, the code verifier must match the code challenge
+	if client.IsPublic || client.PkceEnabled {
 		if !s.validateCodeVerifier(codeVerifier, *authorizationCodeMetaData.CodeChallenge, *authorizationCodeMetaData.CodeChallengeMethodSha256) {
 			return "", "", &common.OidcInvalidCodeVerifierError{}
 		}
@@ -189,6 +189,8 @@ func (s *OidcService) CreateClient(input dto.OidcClientCreateDto, userID string)
 		Name:         input.Name,
 		CallbackURLs: input.CallbackURLs,
 		CreatedByID:  userID,
+		IsPublic:     input.IsPublic,
+		PkceEnabled:  input.IsPublic || input.PkceEnabled,
 	}
 
 	if err := s.db.Create(&client).Error; err != nil {
@@ -207,6 +209,7 @@ func (s *OidcService) UpdateClient(clientID string, input dto.OidcClientCreateDt
 	client.Name = input.Name
 	client.CallbackURLs = input.CallbackURLs
 	client.IsPublic = input.IsPublic
+	client.PkceEnabled = input.IsPublic || input.PkceEnabled
 
 	if err := s.db.Save(&client).Error; err != nil {
 		return model.OidcClient{}, err
@@ -406,6 +409,10 @@ func (s *OidcService) createAuthorizationCode(clientID string, userID string, sc
 }
 
 func (s *OidcService) validateCodeVerifier(codeVerifier, codeChallenge string, codeChallengeMethodSha256 bool) bool {
+	if codeVerifier == "" || codeChallenge == "" {
+		return false
+	}
+
 	if !codeChallengeMethodSha256 {
 		return codeVerifier == codeChallenge
 	}