Plugin fixes (#562)

* Plugins: Remove support for V1 manifests

* Plugins: Make proxy endpoints not leak sensitive HTTP headers

* Security: Fix do not forward login cookie in outgoing requests

pkg/api/datasources.go

@@ -827,7 +827,7 @@ func (hs *HTTPServer) checkDatasourceHealth(c *models.ReqContext, ds *datasource
 		}
 	}
 
-	proxyutil.ClearCookieHeader(c.Req, ds.AllowedCookies())
+	proxyutil.ClearCookieHeader(c.Req, ds.AllowedCookies(), []string{hs.Cfg.LoginCookieName})
 	if cookieStr := c.Req.Header.Get("Cookie"); cookieStr != "" {
 		req.Headers["Cookie"] = cookieStr
 	}

pkg/api/metrics_test.go

@@ -26,6 +26,7 @@ import (
 	"github.com/grafana/grafana/pkg/services/query"
 	"github.com/grafana/grafana/pkg/services/quota/quotatest"
 	"github.com/grafana/grafana/pkg/services/user"
+	"github.com/grafana/grafana/pkg/setting"
 	"github.com/grafana/grafana/pkg/util/errutil"
 	"github.com/grafana/grafana/pkg/web/webtest"
 )
@@ -59,7 +60,7 @@ func (ts *fakeOAuthTokenService) IsOAuthPassThruEnabled(*datasources.DataSource)
 // `/ds/query` endpoint test
 func TestAPIEndpoint_Metrics_QueryMetricsV2(t *testing.T) {
 	qds := query.ProvideService(
-		nil,
+		setting.NewCfg(),
 		nil,
 		nil,
 		&fakePluginRequestValidator{},
@@ -108,7 +109,7 @@ func TestAPIEndpoint_Metrics_QueryMetricsV2(t *testing.T) {
 
 func TestAPIEndpoint_Metrics_PluginDecryptionFailure(t *testing.T) {
 	qds := query.ProvideService(
-		nil,
+		setting.NewCfg(),
 		nil,
 		nil,
 		&fakePluginRequestValidator{},
@@ -271,7 +272,7 @@ func TestDataSourceQueryError(t *testing.T) {
 				err := r.Add(context.Background(), p)
 				require.NoError(t, err)
 				hs.queryDataService = query.ProvideService(
-					nil,
+					setting.NewCfg(),
 					&fakeDatasources.FakeCacheService{},
 					nil,
 					&fakePluginRequestValidator{},

pkg/api/plugin_resource.go

@@ -14,6 +14,7 @@ import (
 
 	"github.com/grafana/grafana/pkg/models"
 	"github.com/grafana/grafana/pkg/plugins/backendplugin"
+	"github.com/grafana/grafana/pkg/services/contexthandler"
 	"github.com/grafana/grafana/pkg/services/datasources"
 	"github.com/grafana/grafana/pkg/util/proxyutil"
 	"github.com/grafana/grafana/pkg/web"
@@ -117,7 +118,15 @@ func (hs *HTTPServer) makePluginResourceRequest(w http.ResponseWriter, req *http
 			hs.log.Warn("failed to unpack JSONData in datasource instance settings", "err", err)
 		}
 	}
-	proxyutil.ClearCookieHeader(req, keepCookieModel.KeepCookies)
+
+	list := contexthandler.AuthHTTPHeaderListFromContext(req.Context())
+	if list != nil {
+		for _, name := range list.Items {
+			req.Header.Del(name)
+		}
+	}
+
+	proxyutil.ClearCookieHeader(req, keepCookieModel.KeepCookies, []string{hs.Cfg.LoginCookieName})
 	proxyutil.PrepareProxyRequest(req)
 
 	body, err := io.ReadAll(req.Body)

pkg/api/pluginproxy/ds_proxy.go

@@ -224,7 +224,7 @@ func (proxy *DataSourceProxy) director(req *http.Request) {
 
 	applyUserHeader(proxy.cfg.SendUserHeader, req, proxy.ctx.SignedInUser)
 
-	proxyutil.ClearCookieHeader(req, proxy.ds.AllowedCookies())
+	proxyutil.ClearCookieHeader(req, proxy.ds.AllowedCookies(), []string{proxy.cfg.LoginCookieName})
 	req.Header.Set("User-Agent", fmt.Sprintf("Grafana/%s", setting.BuildVersion))
 
 	jsonData := make(map[string]interface{})

pkg/api/plugins_test.go

@@ -23,6 +23,7 @@ import (
 	"github.com/grafana/grafana/pkg/models"
 	"github.com/grafana/grafana/pkg/plugins"
 	ac "github.com/grafana/grafana/pkg/services/accesscontrol"
+	"github.com/grafana/grafana/pkg/services/contexthandler"
 	"github.com/grafana/grafana/pkg/services/org"
 	"github.com/grafana/grafana/pkg/services/pluginsettings"
 	"github.com/grafana/grafana/pkg/services/quota/quotatest"
@@ -320,6 +321,12 @@ func TestMakePluginResourceRequest(t *testing.T) {
 		pluginClient: &fakePluginClient{},
 	}
 	req := httptest.NewRequest(http.MethodGet, "/", nil)
+
+	const customHeader = "X-CUSTOM"
+	req.Header.Set(customHeader, "val")
+	ctx := contexthandler.WithAuthHTTPHeader(req.Context(), customHeader)
+	req = req.WithContext(ctx)
+
 	resp := httptest.NewRecorder()
 	pCtx := backend.PluginContext{}
 	err := hs.makePluginResourceRequest(resp, req, pCtx)
@@ -332,6 +339,7 @@ func TestMakePluginResourceRequest(t *testing.T) {
 	}
 
 	require.Equal(t, "sandbox", resp.Header().Get("Content-Security-Policy"))
+	require.Empty(t, req.Header.Get(customHeader))
 }
 
 func callGetPluginAsset(sc *scenarioContext) {

pkg/infra/httpclient/httpclientprovider/forwarded_cookie_middleware_test.go

@@ -13,6 +13,7 @@ func TestForwardedCookiesMiddleware(t *testing.T) {
 	tcs := []struct {
 		desc                 string
 		allowedCookies       []string
+		disallowedCookies    []string
 		expectedCookieHeader string
 	}{
 		{
@@ -30,6 +31,12 @@ func TestForwardedCookiesMiddleware(t *testing.T) {
 			allowedCookies:       []string{"c1", "c3"},
 			expectedCookieHeader: "c1=1; c3=3",
 		},
+		{
+			desc:                 "When provided with allowed and not allowed cookies should populate Cookie header",
+			allowedCookies:       []string{"c1", "c3"},
+			disallowedCookies:    []string{"c1"},
+			expectedCookieHeader: "c3=3",
+		},
 	}
 
 	for _, tc := range tcs {
@@ -41,7 +48,7 @@ func TestForwardedCookiesMiddleware(t *testing.T) {
 				{Name: "c2", Value: "2"},
 				{Name: "c3", Value: "3"},
 			}
-			mw := httpclientprovider.ForwardedCookiesMiddleware(forwarded, tc.allowedCookies)
+			mw := httpclientprovider.ForwardedCookiesMiddleware(forwarded, tc.allowedCookies, tc.disallowedCookies)
 			opts := httpclient.Options{}
 			rt := mw.CreateMiddleware(opts, finalRoundTripper)
 			require.NotNil(t, rt)

pkg/infra/httpclient/httpclientprovider/forwarded_cookies_middleware.go

@@ -11,13 +11,13 @@ const ForwardedCookiesMiddlewareName = "forwarded-cookies"
 
 // ForwardedCookiesMiddleware middleware that sets Cookie header on the
 // outgoing request, if forwarded cookies configured/provided.
-func ForwardedCookiesMiddleware(forwardedCookies []*http.Cookie, allowedCookies []string) httpclient.Middleware {
+func ForwardedCookiesMiddleware(forwardedCookies []*http.Cookie, allowedCookies []string, disallowedCookies []string) httpclient.Middleware {
 	return httpclient.NamedMiddlewareFunc(ForwardedCookiesMiddlewareName, func(opts httpclient.Options, next http.RoundTripper) http.RoundTripper {
 		return httpclient.RoundTripperFunc(func(req *http.Request) (*http.Response, error) {
 			for _, cookie := range forwardedCookies {
 				req.AddCookie(cookie)
 			}
-			proxyutil.ClearCookieHeader(req, allowedCookies)
+			proxyutil.ClearCookieHeader(req, allowedCookies, disallowedCookies)
 			return next.RoundTrip(req)
 		})
 	})

pkg/middleware/middleware_basic_auth_test.go

@@ -38,6 +38,9 @@ func TestMiddlewareBasicAuth(t *testing.T) {
 		assert.True(t, sc.context.IsSignedIn)
 		assert.Equal(t, orgID, sc.context.OrgID)
 		assert.Equal(t, org.RoleEditor, sc.context.OrgRole)
+		list := contexthandler.AuthHTTPHeaderListFromContext(sc.context.Req.Context())
+		require.NotNil(t, list)
+		require.EqualValues(t, []string{"Authorization"}, list.Items)
 	}, configure)
 
 	middlewareScenario(t, "Handle auth", func(t *testing.T, sc *scenarioContext) {
@@ -71,6 +74,9 @@ func TestMiddlewareBasicAuth(t *testing.T) {
 
 		assert.True(t, sc.context.IsSignedIn)
 		assert.Equal(t, id, sc.context.UserID)
+		list := contexthandler.AuthHTTPHeaderListFromContext(sc.context.Req.Context())
+		require.NotNil(t, list)
+		require.EqualValues(t, []string{"Authorization"}, list.Items)
 	}, configure)
 
 	middlewareScenario(t, "Should return error if user is not found", func(t *testing.T, sc *scenarioContext) {

pkg/middleware/middleware_jwt_auth_test.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/grafana/grafana/pkg/services/org"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 
 	"github.com/grafana/grafana/pkg/models"
 	"github.com/grafana/grafana/pkg/services/contexthandler"
@@ -75,6 +76,9 @@ func TestMiddlewareJWTAuth(t *testing.T) {
 		assert.Equal(t, orgID, sc.context.OrgID)
 		assert.Equal(t, id, sc.context.UserID)
 		assert.Equal(t, myUsername, sc.context.Login)
+		list := contexthandler.AuthHTTPHeaderListFromContext(sc.context.Req.Context())
+		require.NotNil(t, list)
+		require.EqualValues(t, []string{sc.cfg.JWTAuthHeaderName}, list.Items)
 	}, configure, configureUsernameClaim)
 
 	middlewareScenario(t, "Valid token with bearer in authorization header", func(t *testing.T, sc *scenarioContext) {

pkg/middleware/middleware_test.go

@@ -422,6 +422,11 @@ func TestMiddlewareContext(t *testing.T) {
 			assert.True(t, sc.context.IsSignedIn)
 			assert.Equal(t, userID, sc.context.UserID)
 			assert.Equal(t, orgID, sc.context.OrgID)
+			list := contexthandler.AuthHTTPHeaderListFromContext(sc.context.Req.Context())
+			require.NotNil(t, list)
+			require.Contains(t, list.Items, sc.cfg.AuthProxyHeaderName)
+			require.Contains(t, list.Items, "X-WEBAUTH-GROUPS")
+			require.Contains(t, list.Items, "X-WEBAUTH-ROLE")
 		}, func(cfg *setting.Cfg) {
 			configure(cfg)
 			cfg.LDAPEnabled = false

pkg/plugins/manager/loader/loader_test.go

@@ -298,7 +298,7 @@ func TestLoader_Load(t *testing.T) {
 			},
 		},
 		{
-			name:        "Load an unsigned plugin with modified signature (production)",
+			name:        "Load a plugin with v1 manifest should return signatureInvalid",
 			class:       plugins.External,
 			cfg:         &config.Cfg{},
 			pluginPaths: []string{"../testdata/lacking-files"},
@@ -306,12 +306,12 @@ func TestLoader_Load(t *testing.T) {
 			pluginErrors: map[string]*plugins.Error{
 				"test-datasource": {
 					PluginID:  "test-datasource",
-					ErrorCode: "signatureModified",
+					ErrorCode: "signatureInvalid",
 				},
 			},
 		},
 		{
-			name:  "Load an unsigned plugin with modified signature using PluginsAllowUnsigned config (production) still includes a signing error",
+			name:  "Load a plugin with v1 manifest using PluginsAllowUnsigned config (production) should return signatureInvali",
 			class: plugins.External,
 			cfg: &config.Cfg{
 				PluginsAllowUnsigned: []string{"test-datasource"},
@@ -321,7 +321,7 @@ func TestLoader_Load(t *testing.T) {
 			pluginErrors: map[string]*plugins.Error{
 				"test-datasource": {
 					PluginID:  "test-datasource",
-					ErrorCode: "signatureModified",
+					ErrorCode: "signatureInvalid",
 				},
 			},
 		},

pkg/plugins/manager/signature/manifest.go

@@ -132,6 +132,12 @@ func Calculate(mlog log.Logger, plugin *plugins.Plugin) (plugins.Signature, erro
 		}, nil
 	}
 
+	if !manifest.isV2() {
+		return plugins.Signature{
+			Status: plugins.SignatureInvalid,
+		}, nil
+	}
+
 	// Make sure the versions all match
 	if manifest.Plugin != plugin.ID || manifest.Version != plugin.Info.Version {
 		return plugins.Signature{
@@ -167,21 +173,19 @@ func Calculate(mlog log.Logger, plugin *plugins.Plugin) (plugins.Signature, erro
 		manifestFiles[p] = struct{}{}
 	}
 
-	if manifest.isV2() {
-		// Track files missing from the manifest
-		var unsignedFiles []string
-		for _, f := range pluginFiles {
-			if _, exists := manifestFiles[f]; !exists {
-				unsignedFiles = append(unsignedFiles, f)
-			}
+	// Track files missing from the manifest
+	var unsignedFiles []string
+	for _, f := range pluginFiles {
+		if _, exists := manifestFiles[f]; !exists {
+			unsignedFiles = append(unsignedFiles, f)
 		}
+	}
 
-		if len(unsignedFiles) > 0 {
-			mlog.Warn("The following files were not included in the signature", "plugin", plugin.ID, "files", unsignedFiles)
-			return plugins.Signature{
-				Status: plugins.SignatureModified,
-			}, nil
-		}
+	if len(unsignedFiles) > 0 {
+		mlog.Warn("The following files were not included in the signature", "plugin", plugin.ID, "files", unsignedFiles)
+		return plugins.Signature{
+			Status: plugins.SignatureModified,
+		}, nil
 	}
 
 	mlog.Debug("Plugin signature valid", "id", plugin.ID)

pkg/services/contexthandler/auth_jwt.go

@@ -142,6 +142,9 @@ func (h *ContextHandler) initContextWithJWT(ctx *models.ReqContext, orgId int64)
 		return true
 	}
 
+	newCtx := WithAuthHTTPHeader(ctx.Req.Context(), h.Cfg.JWTAuthHeaderName)
+	*ctx.Req = *ctx.Req.WithContext(newCtx)
+
 	ctx.SignedInUser = queryResult
 	ctx.IsSignedIn = true
 

pkg/services/contexthandler/contexthandler.go

@@ -258,6 +258,9 @@ func (h *ContextHandler) initContextWithAPIKey(reqContext *models.ReqContext) bo
 	_, span := h.tracer.Start(reqContext.Req.Context(), "initContextWithAPIKey")
 	defer span.End()
 
+	ctx := WithAuthHTTPHeader(reqContext.Req.Context(), "Authorization")
+	*reqContext.Req = *reqContext.Req.WithContext(ctx)
+
 	var (
 		apikey *apikey.APIKey
 		errKey error
@@ -347,7 +350,7 @@ func (h *ContextHandler) initContextWithBasicAuth(reqContext *models.ReqContext,
 		return false
 	}
 
-	ctx, span := h.tracer.Start(reqContext.Req.Context(), "initContextWithBasicAuth")
+	_, span := h.tracer.Start(reqContext.Req.Context(), "initContextWithBasicAuth")
 	defer span.End()
 
 	username, password, err := util.DecodeBasicAuthHeader(header)
@@ -356,12 +359,15 @@ func (h *ContextHandler) initContextWithBasicAuth(reqContext *models.ReqContext,
 		return true
 	}
 
+	ctx := WithAuthHTTPHeader(reqContext.Req.Context(), "Authorization")
+	*reqContext.Req = *reqContext.Req.WithContext(ctx)
+
 	authQuery := models.LoginUserQuery{
 		Username: username,
 		Password: password,
 		Cfg:      h.Cfg,
 	}
-	if err := h.authenticator.AuthenticateUser(reqContext.Req.Context(), &authQuery); err != nil {
+	if err := h.authenticator.AuthenticateUser(ctx, &authQuery); err != nil {
 		reqContext.Logger.Debug(
 			"Failed to authorize the user",
 			"username", username,
@@ -610,6 +616,15 @@ func (h *ContextHandler) initContextWithAuthProxy(reqContext *models.ReqContext,
 
 	logger.Debug("Successfully got user info", "userID", user.UserID, "username", user.Login)
 
+	ctx := WithAuthHTTPHeader(reqContext.Req.Context(), h.Cfg.AuthProxyHeaderName)
+	for _, header := range h.Cfg.AuthProxyHeaders {
+		if header != "" {
+			ctx = WithAuthHTTPHeader(ctx, header)
+		}
+	}
+
+	*reqContext.Req = *reqContext.Req.WithContext(ctx)
+
 	// Add user info to context
 	reqContext.SignedInUser = user
 	reqContext.IsSignedIn = true
@@ -629,3 +644,38 @@ func (h *ContextHandler) initContextWithAuthProxy(reqContext *models.ReqContext,
 
 	return true
 }
+
+type authHTTPHeaderListContextKey struct{}
+
+var authHTTPHeaderListKey = authHTTPHeaderListContextKey{}
+
+// AuthHTTPHeaderList used to record HTTP headers that being when verifying authentication
+// of an incoming HTTP request.
+type AuthHTTPHeaderList struct {
+	Items []string
+}
+
+// WithAuthHTTPHeader returns a copy of parent in which the named HTTP header will be included
+// and later retrievable by AuthHTTPHeaderListFromContext.
+func WithAuthHTTPHeader(parent context.Context, name string) context.Context {
+	list := AuthHTTPHeaderListFromContext(parent)
+
+	if list == nil {
+		list = &AuthHTTPHeaderList{
+			Items: []string{},
+		}
+	}
+
+	list.Items = append(list.Items, name)
+
+	return context.WithValue(parent, authHTTPHeaderListKey, list)
+}
+
+// AuthHTTPHeaderListFromContext returns the AuthHTTPHeaderList in a context.Context, if any,
+// and will include any HTTP headers used when verifying authentication of an incoming HTTP request.
+func AuthHTTPHeaderListFromContext(c context.Context) *AuthHTTPHeaderList {
+	if list, ok := c.Value(authHTTPHeaderListKey).(*AuthHTTPHeaderList); ok {
+		return list
+	}
+	return nil
+}

pkg/services/query/query.go

@@ -171,7 +171,7 @@ func (s *Service) handleQueryData(ctx context.Context, user *user.SignedInUser,
 	middlewares := []httpclient.Middleware{}
 	if parsedReq.httpRequest != nil {
 		middlewares = append(middlewares,
-			httpclientprovider.ForwardedCookiesMiddleware(parsedReq.httpRequest.Cookies(), ds.AllowedCookies()),
+			httpclientprovider.ForwardedCookiesMiddleware(parsedReq.httpRequest.Cookies(), ds.AllowedCookies(), []string{s.cfg.LoginCookieName}),
 		)
 	}
 
@@ -188,7 +188,7 @@ func (s *Service) handleQueryData(ctx context.Context, user *user.SignedInUser,
 	}
 
 	if parsedReq.httpRequest != nil {
-		proxyutil.ClearCookieHeader(parsedReq.httpRequest, ds.AllowedCookies())
+		proxyutil.ClearCookieHeader(parsedReq.httpRequest, ds.AllowedCookies(), []string{s.cfg.LoginCookieName})
 		if cookieStr := parsedReq.httpRequest.Header.Get("Cookie"); cookieStr != "" {
 			req.Headers["Cookie"] = cookieStr
 		}

pkg/services/query/query_test.go

@@ -26,6 +26,7 @@ import (
 	secretsmng "github.com/grafana/grafana/pkg/services/secrets/manager"
 	"github.com/grafana/grafana/pkg/services/sqlstore"
 	"github.com/grafana/grafana/pkg/services/user"
+	"github.com/grafana/grafana/pkg/setting"
 )
 
 func TestQueryDataMultipleSources(t *testing.T) {
@@ -197,7 +198,7 @@ func setup(t *testing.T) *testContext {
 		dataSourceCache:        dc,
 		oauthTokenService:      tc,
 		pluginRequestValidator: rv,
-		queryService:           query.ProvideService(nil, dc, exprService, rv, ds, pc, tc),
+		queryService:           query.ProvideService(setting.NewCfg(), dc, exprService, rv, ds, pc, tc),
 	}
 }
 

pkg/util/proxyutil/proxyutil.go

@@ -3,6 +3,7 @@ package proxyutil
 import (
 	"net"
 	"net/http"
+	"sort"
 )
 
 // PrepareProxyRequest prepares a request for being proxied.
@@ -26,19 +27,31 @@ func PrepareProxyRequest(req *http.Request) {
 	}
 }
 
-// ClearCookieHeader clear cookie header, except for cookies specified to be kept.
-func ClearCookieHeader(req *http.Request, keepCookiesNames []string) {
-	var keepCookies []*http.Cookie
+// ClearCookieHeader clear cookie header, except for cookies specified to be kept (keepCookiesNames) if not in skipCookiesNames.
+func ClearCookieHeader(req *http.Request, keepCookiesNames []string, skipCookiesNames []string) {
+	keepCookies := map[string]*http.Cookie{}
 	for _, c := range req.Cookies() {
 		for _, v := range keepCookiesNames {
 			if c.Name == v {
-				keepCookies = append(keepCookies, c)
+				keepCookies[c.Name] = c
 			}
 		}
 	}
 
+	for _, v := range skipCookiesNames {
+		delete(keepCookies, v)
+	}
+
 	req.Header.Del("Cookie")
-	for _, c := range keepCookies {
+
+	sortedCookies := []string{}
+	for name := range keepCookies {
+		sortedCookies = append(sortedCookies, name)
+	}
+	sort.Strings(sortedCookies)
+
+	for _, name := range sortedCookies {
+		c := keepCookies[name]
 		req.AddCookie(c)
 	}
 }

pkg/util/proxyutil/proxyutil_test.go

@@ -49,7 +49,7 @@ func TestClearCookieHeader(t *testing.T) {
 		require.NoError(t, err)
 		req.AddCookie(&http.Cookie{Name: "cookie"})
 
-		ClearCookieHeader(req, nil)
+		ClearCookieHeader(req, nil, nil)
 		require.NotContains(t, req.Header, "Cookie")
 	})
 
@@ -60,8 +60,20 @@ func TestClearCookieHeader(t *testing.T) {
 		req.AddCookie(&http.Cookie{Name: "cookie2"})
 		req.AddCookie(&http.Cookie{Name: "cookie3"})
 
-		ClearCookieHeader(req, []string{"cookie1", "cookie3"})
+		ClearCookieHeader(req, []string{"cookie1", "cookie3"}, nil)
 		require.Contains(t, req.Header, "Cookie")
 		require.Equal(t, "cookie1=; cookie3=", req.Header.Get("Cookie"))
 	})
+
+	t.Run("Clear cookie header with cookies to keep and skip should clear Cookie header and keep cookies", func(t *testing.T) {
+		req, err := http.NewRequest(http.MethodGet, "/", nil)
+		require.NoError(t, err)
+		req.AddCookie(&http.Cookie{Name: "cookie1"})
+		req.AddCookie(&http.Cookie{Name: "cookie2"})
+		req.AddCookie(&http.Cookie{Name: "cookie3"})
+
+		ClearCookieHeader(req, []string{"cookie1", "cookie3"}, []string{"cookie3"})
+		require.Contains(t, req.Header, "Cookie")
+		require.Equal(t, "cookie1=", req.Header.Get("Cookie"))
+	})
 }

pkg/util/proxyutil/reverse_proxy.go

@@ -10,6 +10,7 @@ import (
 	"time"
 
 	glog "github.com/grafana/grafana/pkg/infra/log"
+	"github.com/grafana/grafana/pkg/services/contexthandler"
 )
 
 // StatusClientClosedRequest A non-standard status code introduced by nginx
@@ -66,6 +67,13 @@ func NewReverseProxy(logger glog.Logger, director func(*http.Request), opts ...R
 // wrapDirector wraps a director and adds additional functionality.
 func wrapDirector(d func(*http.Request)) func(req *http.Request) {
 	return func(req *http.Request) {
+		list := contexthandler.AuthHTTPHeaderListFromContext(req.Context())
+		if list != nil {
+			for _, name := range list.Items {
+				req.Header.Del(name)
+			}
+		}
+
 		d(req)
 		PrepareProxyRequest(req)
 

pkg/util/proxyutil/reverse_proxy_test.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/grafana/grafana/pkg/infra/log"
+	"github.com/grafana/grafana/pkg/services/contexthandler"
 	"github.com/stretchr/testify/require"
 )
 
@@ -30,6 +31,11 @@ func TestReverseProxy(t *testing.T) {
 		req.Header.Set("Referer", "https://test.com/api")
 		req.RemoteAddr = "10.0.0.1"
 
+		const customHeader = "X-CUSTOM"
+		req.Header.Set(customHeader, "val")
+		ctx := contexthandler.WithAuthHTTPHeader(req.Context(), customHeader)
+		req = req.WithContext(ctx)
+
 		rp := NewReverseProxy(log.New("test"), func(req *http.Request) {
 			req.Header.Set("X-KEY", "value")
 		})
@@ -49,6 +55,7 @@ func TestReverseProxy(t *testing.T) {
 		require.Empty(t, resp.Cookies())
 		require.Equal(t, "sandbox", resp.Header.Get("Content-Security-Policy"))
 		require.NoError(t, resp.Body.Close())
+		require.Empty(t, actualReq.Header.Get(customHeader))
 	})
 
 	t.Run("When proxying a request using WithModifyResponse should call it before default ModifyResponse func", func(t *testing.T) {