fix: token endpoint must not accept params as query string args (#1321)

backend/internal/controller/oidc_controller.go

@@ -1,6 +1,7 @@
 package controller
 
 import (
+	"context"
 	"errors"
 	"log/slog"
 	"net/http"
@@ -24,7 +25,11 @@ import (
 // @Description Initializes all OIDC-related API endpoints for authentication and client management
 // @Tags OIDC
 func NewOidcController(group *gin.RouterGroup, authMiddleware *middleware.AuthMiddleware, fileSizeLimitMiddleware *middleware.FileSizeLimitMiddleware, oidcService *service.OidcService, jwtService *service.JwtService) {
-	oc := &OidcController{oidcService: oidcService, jwtService: jwtService}
+	oc := &OidcController{
+		oidcService:  oidcService,
+		jwtService:   jwtService,
+		createTokens: oidcService.CreateTokens,
+	}
 
 	group.POST("/oidc/authorize", authMiddleware.WithAdminNotRequired().Add(), oc.authorizeHandler)
 	group.POST("/oidc/authorization-required", authMiddleware.WithAdminNotRequired().Add(), oc.authorizationConfirmationRequiredHandler)
@@ -70,6 +75,7 @@ func NewOidcController(group *gin.RouterGroup, authMiddleware *middleware.AuthMi
 type OidcController struct {
 	oidcService  *service.OidcService
 	jwtService   *service.JwtService
+	createTokens func(context.Context, dto.OidcCreateTokensDto) (service.CreatedTokens, error)
 }
 
 // authorizeHandler godoc
@@ -144,8 +150,13 @@ func (oc *OidcController) authorizationConfirmationRequiredHandler(c *gin.Contex
 // @Success 200 {object} dto.OidcTokenResponseDto "Token response with access_token and optional id_token and refresh_token"
 // @Router /api/oidc/token [post]
 func (oc *OidcController) createTokensHandler(c *gin.Context) {
+	// Per RFC-6749, parameters passed to the /token endpoint MUST be passed in the body of the request
+	// Gin's "ShouldBind" by default reads from the query string too, so we need to reset all query string args before invoking ShouldBind
+	c.Request.URL.RawQuery = ""
+
 	var input dto.OidcCreateTokensDto
-	if err := c.ShouldBind(&input); err != nil {
+	err := c.ShouldBind(&input)
+	if err != nil {
 		_ = c.Error(err)
 		return
 	}
@@ -167,7 +178,7 @@ func (oc *OidcController) createTokensHandler(c *gin.Context) {
 		input.ClientID, input.ClientSecret, _ = utils.OAuthClientBasicAuth(c.Request)
 	}
 
-	tokens, err := oc.oidcService.CreateTokens(c.Request.Context(), input)
+	tokens, err := oc.createTokens(c.Request.Context(), input)
 
 	switch {
 	case errors.Is(err, &common.OidcAuthorizationPendingError{}):

backend/internal/controller/oidc_controller_test.go

@@ -0,0 +1,227 @@
+package controller
+
+import (
+	"context"
+	"encoding/base64"
+	"encoding/json"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/pocket-id/pocket-id/backend/internal/common"
+	"github.com/pocket-id/pocket-id/backend/internal/dto"
+	"github.com/pocket-id/pocket-id/backend/internal/service"
+)
+
+func TestCreateTokensHandler(t *testing.T) {
+	createTestContext := func(t *testing.T, rawURL string, form url.Values, authHeader string, noCT bool) (*gin.Context, *httptest.ResponseRecorder) {
+		t.Helper()
+
+		mode := gin.Mode()
+		gin.SetMode(gin.TestMode)
+		t.Cleanup(func() { gin.SetMode(mode) })
+
+		recorder := httptest.NewRecorder()
+		c, _ := gin.CreateTestContext(recorder)
+
+		req, err := http.NewRequestWithContext(t.Context(), http.MethodPost, rawURL, strings.NewReader(form.Encode()))
+		require.NoError(t, err)
+
+		if !noCT {
+			req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+		}
+		if authHeader != "" {
+			req.Header.Set("Authorization", authHeader)
+		}
+
+		c.Request = req
+		return c, recorder
+	}
+
+	t.Run("Ignores Query String Parameters For Binding", func(t *testing.T) {
+		oc := &OidcController{}
+
+		c, _ := createTestContext(
+			t,
+			"http://example.com/oidc/token?grant_type=refresh_token&refresh_token=query-value",
+			url.Values{},
+			"",
+			false,
+		)
+
+		oc.createTokensHandler(c)
+
+		require.Len(t, c.Errors, 1)
+		assert.Contains(t, c.Errors[0].Err.Error(), "GrantType")
+	})
+
+	t.Run("Missing Authorization Code", func(t *testing.T) {
+		oc := &OidcController{}
+
+		c, _ := createTestContext(
+			t,
+			"http://example.com/oidc/token",
+			url.Values{
+				"grant_type": {service.GrantTypeAuthorizationCode},
+			},
+			"",
+			false,
+		)
+
+		oc.createTokensHandler(c)
+
+		require.Len(t, c.Errors, 1)
+		var missingCodeErr *common.OidcMissingAuthorizationCodeError
+		require.ErrorAs(t, c.Errors[0].Err, &missingCodeErr)
+	})
+
+	t.Run("Missing Refresh Token", func(t *testing.T) {
+		oc := &OidcController{}
+
+		c, _ := createTestContext(
+			t,
+			"http://example.com/oidc/token",
+			url.Values{
+				"grant_type": {service.GrantTypeRefreshToken},
+			},
+			"",
+			false,
+		)
+
+		oc.createTokensHandler(c)
+
+		require.Len(t, c.Errors, 1)
+		var missingRefreshErr *common.OidcMissingRefreshTokenError
+		require.ErrorAs(t, c.Errors[0].Err, &missingRefreshErr)
+	})
+
+	t.Run("Uses Basic Auth Credentials When Body Credentials Missing", func(t *testing.T) {
+		var capturedInput dto.OidcCreateTokensDto
+		oc := &OidcController{
+			createTokens: func(_ context.Context, input dto.OidcCreateTokensDto) (service.CreatedTokens, error) {
+				capturedInput = input
+				return service.CreatedTokens{
+					AccessToken:  "access-token",
+					IdToken:      "id-token",
+					RefreshToken: "refresh-token",
+					ExpiresIn:    2 * time.Minute,
+				}, nil
+			},
+		}
+
+		basicAuth := "Basic " + base64.StdEncoding.EncodeToString([]byte("client-id:client-secret"))
+		c, recorder := createTestContext(
+			t,
+			"http://example.com/oidc/token",
+			url.Values{
+				"grant_type":    {service.GrantTypeRefreshToken},
+				"refresh_token": {"input-refresh-token"},
+			},
+			basicAuth,
+			false,
+		)
+
+		oc.createTokensHandler(c)
+
+		require.Empty(t, c.Errors)
+		assert.Equal(t, "client-id", capturedInput.ClientID)
+		assert.Equal(t, "client-secret", capturedInput.ClientSecret)
+		assert.Equal(t, "input-refresh-token", capturedInput.RefreshToken)
+
+		require.Equal(t, http.StatusOK, recorder.Code)
+		var response dto.OidcTokenResponseDto
+		require.NoError(t, json.Unmarshal(recorder.Body.Bytes(), &response))
+		assert.Equal(t, "access-token", response.AccessToken)
+		assert.Equal(t, "Bearer", response.TokenType)
+		assert.Equal(t, "id-token", response.IdToken)
+		assert.Equal(t, "refresh-token", response.RefreshToken)
+		assert.Equal(t, 120, response.ExpiresIn)
+	})
+
+	t.Run("Maps Authorization Pending Error", func(t *testing.T) {
+		oc := &OidcController{
+			createTokens: func(context.Context, dto.OidcCreateTokensDto) (service.CreatedTokens, error) {
+				return service.CreatedTokens{}, &common.OidcAuthorizationPendingError{}
+			},
+		}
+
+		c, recorder := createTestContext(
+			t,
+			"http://example.com/oidc/token",
+			url.Values{
+				"grant_type":    {service.GrantTypeRefreshToken},
+				"refresh_token": {"input-refresh-token"},
+			},
+			"",
+			false,
+		)
+
+		oc.createTokensHandler(c)
+
+		require.Empty(t, c.Errors)
+		require.Equal(t, http.StatusBadRequest, recorder.Code)
+		var response map[string]string
+		require.NoError(t, json.Unmarshal(recorder.Body.Bytes(), &response))
+		assert.Equal(t, "authorization_pending", response["error"])
+	})
+
+	t.Run("Maps Slow Down Error", func(t *testing.T) {
+		oc := &OidcController{
+			createTokens: func(context.Context, dto.OidcCreateTokensDto) (service.CreatedTokens, error) {
+				return service.CreatedTokens{}, &common.OidcSlowDownError{}
+			},
+		}
+
+		c, recorder := createTestContext(
+			t,
+			"http://example.com/oidc/token",
+			url.Values{
+				"grant_type":    {service.GrantTypeRefreshToken},
+				"refresh_token": {"input-refresh-token"},
+			},
+			"",
+			false,
+		)
+
+		oc.createTokensHandler(c)
+
+		require.Empty(t, c.Errors)
+		require.Equal(t, http.StatusBadRequest, recorder.Code)
+		var response map[string]string
+		require.NoError(t, json.Unmarshal(recorder.Body.Bytes(), &response))
+		assert.Equal(t, "slow_down", response["error"])
+	})
+
+	t.Run("Returns Generic Service Error In Context", func(t *testing.T) {
+		expectedErr := errors.New("boom")
+		oc := &OidcController{
+			createTokens: func(context.Context, dto.OidcCreateTokensDto) (service.CreatedTokens, error) {
+				return service.CreatedTokens{}, expectedErr
+			},
+		}
+
+		c, _ := createTestContext(
+			t,
+			"http://example.com/oidc/token",
+			url.Values{
+				"grant_type":    {service.GrantTypeRefreshToken},
+				"refresh_token": {"input-refresh-token"},
+			},
+			"",
+			false,
+		)
+
+		oc.createTokensHandler(c)
+
+		require.Len(t, c.Errors, 1)
+		assert.ErrorIs(t, c.Errors[0].Err, expectedErr)
+	})
+}

backend/internal/service/geolite_service.go

@@ -162,6 +162,8 @@ func (s *GeoLiteService) extractDatabase(reader io.Reader) error {
 	}
 
 	// Check if the file starts with the gzip magic number
+	// Gosec returns false positive for "G602: slice index out of range"
+	//nolint:gosec
 	isGzip := buf[0] == 0x1f && buf[1] == 0x8b
 
 	if !isGzip {