Send request body to authorization server for forward auth

docs/content/middlewares/http/forwardauth.md

@@ -334,6 +334,98 @@ http:
     addAuthCookiesToResponse = ["Session-Cookie", "State-Cookie"]
 ```
 
+### `forwardBody`
+
+_Optional, Default=false_
+
+Set the `forwardBody` option to `true` to send Body.
+
+!!! info
+
+    As body is read inside Traefik before forwarding, this breaks streaming.
+
+```yaml tab="Docker & Swarm"
+labels:
+  - "traefik.http.middlewares.test-auth.forwardauth.forwardBody=true"
+```
+
+```yaml tab="Kubernetes"
+apiVersion: traefik.io/v1alpha1
+kind: Middleware
+metadata:
+  name: test-auth
+spec:
+  forwardAuth:
+    address: https://example.com/auth
+    forwardBody: true
+```
+
+```yaml tab="Consul Catalog"
+- "traefik.http.middlewares.test-auth.forwardauth.forwardBody=true"
+```
+
+```yaml tab="File (YAML)"
+http:
+  middlewares:
+    test-auth:
+      forwardAuth:
+        address: "https://example.com/auth"
+        forwardBody: true
+```
+
+```toml tab="File (TOML)"
+[http.middlewares]
+  [http.middlewares.test-auth.forwardAuth]
+    address = "https://example.com/auth"
+    forwardBody = true
+```
+
+### `maxBodySize`
+
+_Optional, Default=-1_
+
+Set the `maxBodySize` to limit the body size in bytes.
+If body is bigger than this, it returns a 401 (unauthorized).
+Default is `-1`, which means no limit.
+
+```yaml tab="Docker & Swarm"
+labels:
+  - "traefik.http.middlewares.test-auth.forwardauth.maxBodySize=1000"
+```
+
+```yaml tab="Kubernetes"
+apiVersion: traefik.io/v1alpha1
+kind: Middleware
+metadata:
+  name: test-auth
+spec:
+  forwardAuth:
+    address: https://example.com/auth
+    forwardBody: true
+    maxBodySize: 1000
+```
+
+```yaml tab="Consul Catalog"
+- "traefik.http.middlewares.test-auth.forwardauth.maxBodySize=1000"
+```
+
+```yaml tab="File (YAML)"
+http:
+  middlewares:
+    test-auth:
+      forwardAuth:
+        address: "https://example.com/auth"
+        maxBodySize: 1000
+```
+
+```toml tab="File (TOML)"
+[http.middlewares]
+  [http.middlewares.test-auth.forwardAuth]
+    address = "https://example.com/auth"
+    forwardBody = true
+    maxBodySize = 1000
+```
+
 ### `tls`
 
 _Optional_

docs/content/reference/dynamic-configuration/docker-labels.yml

@@ -38,7 +38,9 @@
 - "traefik.http.middlewares.middleware10.forwardauth.authrequestheaders=foobar, foobar"
 - "traefik.http.middlewares.middleware10.forwardauth.authresponseheaders=foobar, foobar"
 - "traefik.http.middlewares.middleware10.forwardauth.authresponseheadersregex=foobar"
+- "traefik.http.middlewares.middleware10.forwardauth.forwardbody=true"
 - "traefik.http.middlewares.middleware10.forwardauth.headerfield=foobar"
+- "traefik.http.middlewares.middleware10.forwardauth.maxbodysize=42"
 - "traefik.http.middlewares.middleware10.forwardauth.tls.ca=foobar"
 - "traefik.http.middlewares.middleware10.forwardauth.tls.caoptional=true"
 - "traefik.http.middlewares.middleware10.forwardauth.tls.cert=foobar"

docs/content/reference/dynamic-configuration/file.toml

@@ -182,6 +182,8 @@
         authRequestHeaders = ["foobar", "foobar"]
         addAuthCookiesToResponse = ["foobar", "foobar"]
         headerField = "foobar"
+        forwardBody = true
+        maxBodySize = 42
         [http.middlewares.Middleware10.forwardAuth.tls]
           ca = "foobar"
           cert = "foobar"

docs/content/reference/dynamic-configuration/file.yaml

@@ -209,6 +209,8 @@ http:
           - foobar
           - foobar
         headerField: foobar
+        forwardBody: true
+        maxBodySize: 42
     Middleware11:
       grpcWeb:
         allowOrigins:

docs/content/reference/dynamic-configuration/kubernetes-crd-definition-v1.yml

@@ -1234,6 +1234,15 @@ spec:
                       AuthResponseHeadersRegex defines the regex to match headers to copy from the authentication server response and set on forwarded request, after stripping all headers that match the regex.
                       More info: https://doc.traefik.io/traefik/v3.2/middlewares/http/forwardauth/#authresponseheadersregex
                     type: string
+                  forwardBody:
+                    description: ForwardBody defines whether to send the request body
+                      to the authentication server.
+                    type: boolean
+                  maxBodySize:
+                    description: MaxBodySize defines the maximum body size in bytes
+                      allowed to be forwarded to the authentication server.
+                    format: int64
+                    type: integer
                   tls:
                     description: TLS defines the configuration used to secure the
                       connection to the authentication server.

docs/content/reference/dynamic-configuration/kv-ref.md

@@ -48,7 +48,9 @@ THIS FILE MUST NOT BE EDITED BY HAND
 | `traefik/http/middlewares/Middleware10/forwardAuth/authResponseHeaders/0` | `foobar` |
 | `traefik/http/middlewares/Middleware10/forwardAuth/authResponseHeaders/1` | `foobar` |
 | `traefik/http/middlewares/Middleware10/forwardAuth/authResponseHeadersRegex` | `foobar` |
+| `traefik/http/middlewares/Middleware10/forwardAuth/forwardBody` | `true` |
 | `traefik/http/middlewares/Middleware10/forwardAuth/headerField` | `foobar` |
+| `traefik/http/middlewares/Middleware10/forwardAuth/maxBodySize` | `42` |
 | `traefik/http/middlewares/Middleware10/forwardAuth/tls/ca` | `foobar` |
 | `traefik/http/middlewares/Middleware10/forwardAuth/tls/caOptional` | `true` |
 | `traefik/http/middlewares/Middleware10/forwardAuth/tls/cert` | `foobar` |

docs/content/reference/dynamic-configuration/traefik.io_middlewares.yaml

@@ -492,6 +492,15 @@ spec:
                       AuthResponseHeadersRegex defines the regex to match headers to copy from the authentication server response and set on forwarded request, after stripping all headers that match the regex.
                       More info: https://doc.traefik.io/traefik/v3.2/middlewares/http/forwardauth/#authresponseheadersregex
                     type: string
+                  forwardBody:
+                    description: ForwardBody defines whether to send the request body
+                      to the authentication server.
+                    type: boolean
+                  maxBodySize:
+                    description: MaxBodySize defines the maximum body size in bytes
+                      allowed to be forwarded to the authentication server.
+                    format: int64
+                    type: integer
                   tls:
                     description: TLS defines the configuration used to secure the
                       connection to the authentication server.

integration/fixtures/k8s/01-traefik-crd.yml

@@ -1234,6 +1234,15 @@ spec:
                       AuthResponseHeadersRegex defines the regex to match headers to copy from the authentication server response and set on forwarded request, after stripping all headers that match the regex.
                       More info: https://doc.traefik.io/traefik/v3.2/middlewares/http/forwardauth/#authresponseheadersregex
                     type: string
+                  forwardBody:
+                    description: ForwardBody defines whether to send the request body
+                      to the authentication server.
+                    type: boolean
+                  maxBodySize:
+                    description: MaxBodySize defines the maximum body size in bytes
+                      allowed to be forwarded to the authentication server.
+                    format: int64
+                    type: integer
                   tls:
                     description: TLS defines the configuration used to secure the
                       connection to the authentication server.

pkg/config/dynamic/http_config.go

@@ -21,6 +21,11 @@ const (
 
 	// DefaultFlushInterval is the default value for the ResponseForwarding flush interval.
 	DefaultFlushInterval = ptypes.Duration(100 * time.Millisecond)
+
+	// MirroringDefaultMirrorBody is the Mirroring.MirrorBody option default value.
+	MirroringDefaultMirrorBody = true
+	// MirroringDefaultMaxBodySize is the Mirroring.MaxBodySize option default value.
+	MirroringDefaultMaxBodySize int64 = -1
 )
 
 // +k8s:deepcopy-gen=true
@@ -100,9 +105,9 @@ type Mirroring struct {
 
 // SetDefaults Default values for a WRRService.
 func (m *Mirroring) SetDefaults() {
-	defaultMirrorBody := true
+	defaultMirrorBody := MirroringDefaultMirrorBody
 	m.MirrorBody = &defaultMirrorBody
-	var defaultMaxBodySize int64 = -1
+	defaultMaxBodySize := MirroringDefaultMaxBodySize
 	m.MaxBodySize = &defaultMaxBodySize
 }
 

pkg/config/dynamic/middlewares.go

@@ -9,6 +9,9 @@ import (
 	"github.com/traefik/traefik/v3/pkg/ip"
 )
 
+// ForwardAuthDefaultMaxBodySize is the ForwardAuth.MaxBodySize option default value.
+const ForwardAuthDefaultMaxBodySize int64 = -1
+
 // +k8s:deepcopy-gen=true
 
 // Middleware holds the Middleware configuration.
@@ -251,6 +254,15 @@ type ForwardAuth struct {
 	// HeaderField defines a header field to store the authenticated user.
 	// More info: https://doc.traefik.io/traefik/v3.0/middlewares/http/forwardauth/#headerfield
 	HeaderField string `json:"headerField,omitempty" toml:"headerField,omitempty" yaml:"headerField,omitempty" export:"true"`
+	// ForwardBody defines whether to send the request body to the authentication server.
+	ForwardBody bool `json:"forwardBody,omitempty" toml:"forwardBody,omitempty" yaml:"forwardBody,omitempty" export:"true"`
+	// MaxBodySize defines the maximum body size in bytes allowed to be forwarded to the authentication server.
+	MaxBodySize *int64 `json:"maxBodySize,omitempty" toml:"maxBodySize,omitempty" yaml:"maxBodySize,omitempty" export:"true"`
+}
+
+func (f *ForwardAuth) SetDefaults() {
+	defaultMaxBodySize := ForwardAuthDefaultMaxBodySize
+	f.MaxBodySize = &defaultMaxBodySize
 }
 
 // +k8s:deepcopy-gen=true

pkg/config/dynamic/zz_generated.deepcopy.go

@@ -370,6 +370,11 @@ func (in *ForwardAuth) DeepCopyInto(out *ForwardAuth) {
 		*out = make([]string, len(*in))
 		copy(*out, *in)
 	}
+	if in.MaxBodySize != nil {
+		in, out := &in.MaxBodySize, &out.MaxBodySize
+		*out = new(int64)
+		**out = **in
+	}
 	return
 }
 

pkg/config/label/label_test.go

@@ -51,6 +51,8 @@ func TestDecodeConfiguration(t *testing.T) {
 		"traefik.http.middlewares.Middleware7.forwardauth.tls.insecureskipverify":                  "true",
 		"traefik.http.middlewares.Middleware7.forwardauth.tls.key":                                 "foobar",
 		"traefik.http.middlewares.Middleware7.forwardauth.trustforwardheader":                      "true",
+		"traefik.http.middlewares.Middleware7.forwardauth.forwardbody":                             "true",
+		"traefik.http.middlewares.Middleware7.forwardauth.maxbodysize":                             "42",
 		"traefik.http.middlewares.Middleware8.headers.accesscontrolallowcredentials":               "true",
 		"traefik.http.middlewares.Middleware8.headers.allowedhosts":                                "foobar, fiibar",
 		"traefik.http.middlewares.Middleware8.headers.accesscontrolallowheaders":                   "X-foobar, X-fiibar",
@@ -572,6 +574,8 @@ func TestDecodeConfiguration(t *testing.T) {
 							"foobar",
 							"fiibar",
 						},
+						ForwardBody: true,
+						MaxBodySize: pointer(int64(42)),
 					},
 				},
 				"Middleware8": {
@@ -1114,6 +1118,8 @@ func TestEncodeConfiguration(t *testing.T) {
 							"foobar",
 							"fiibar",
 						},
+						ForwardBody: true,
+						MaxBodySize: pointer(int64(42)),
 					},
 				},
 				"Middleware8": {
@@ -1315,6 +1321,8 @@ func TestEncodeConfiguration(t *testing.T) {
 		"traefik.HTTP.Middlewares.Middleware7.ForwardAuth.Address":                                 "foobar",
 		"traefik.HTTP.Middlewares.Middleware7.ForwardAuth.AuthResponseHeaders":                     "foobar, fiibar",
 		"traefik.HTTP.Middlewares.Middleware7.ForwardAuth.AuthRequestHeaders":                      "foobar, fiibar",
+		"traefik.HTTP.Middlewares.Middleware7.ForwardAuth.ForwardBody":                             "true",
+		"traefik.HTTP.Middlewares.Middleware7.ForwardAuth.MaxBodySize":                             "42",
 		"traefik.HTTP.Middlewares.Middleware7.ForwardAuth.TLS.CA":                                  "foobar",
 		"traefik.HTTP.Middlewares.Middleware7.ForwardAuth.TLS.CAOptional":                          "true",
 		"traefik.HTTP.Middlewares.Middleware7.ForwardAuth.TLS.Cert":                                "foobar",

pkg/middlewares/auth/forward.go

@@ -1,6 +1,7 @@
 package auth
 
 import (
+	"bytes"
 	"context"
 	"errors"
 	"fmt"
@@ -22,13 +23,13 @@ import (
 	"go.opentelemetry.io/otel/trace"
 )
 
+const typeNameForward = "ForwardAuth"
+
 const (
 	xForwardedURI    = "X-Forwarded-Uri"
 	xForwardedMethod = "X-Forwarded-Method"
 )
 
-const typeNameForward = "ForwardAuth"
-
 // hopHeaders Hop-by-hop headers to be removed in the authentication request.
 // http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html
 // Proxy-Authorization header is forwarded to the authentication server (see https://tools.ietf.org/html/rfc7235#section-4.4).
@@ -52,6 +53,8 @@ type forwardAuth struct {
 	authRequestHeaders       []string
 	addAuthCookiesToResponse map[string]struct{}
 	headerField              string
+	forwardBody              bool
+	maxBodySize              int64
 }
 
 // NewForward creates a forward auth middleware.
@@ -73,6 +76,12 @@ func NewForward(ctx context.Context, next http.Handler, config dynamic.ForwardAu
 		authRequestHeaders:       config.AuthRequestHeaders,
 		addAuthCookiesToResponse: addAuthCookiesToResponse,
 		headerField:              config.HeaderField,
+		forwardBody:              config.ForwardBody,
+		maxBodySize:              dynamic.ForwardAuthDefaultMaxBodySize,
+	}
+
+	if config.MaxBodySize != nil {
+		fa.maxBodySize = *config.MaxBodySize
 	}
 
 	// Ensure our request client does not follow redirects
@@ -125,13 +134,37 @@ func (fa *forwardAuth) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
 
 	forwardReq, err := http.NewRequestWithContext(req.Context(), http.MethodGet, fa.address, nil)
 	if err != nil {
-		logger.Debug().Msgf("Error calling %s. Cause %s", fa.address, err)
+		logger.Debug().Err(err).Msgf("Error calling %s", fa.address)
 		observability.SetStatusErrorf(req.Context(), "Error calling %s. Cause %s", fa.address, err)
 
 		rw.WriteHeader(http.StatusInternalServerError)
 		return
 	}
 
+	if fa.forwardBody {
+		bodyBytes, err := fa.readBodyBytes(req)
+		if errors.Is(err, errBodyTooLarge) {
+			logger.Debug().Msgf("Request body is too large, maxBodySize: %d", fa.maxBodySize)
+
+			observability.SetStatusErrorf(req.Context(), "Request body is too large, maxBodySize: %d", fa.maxBodySize)
+			rw.WriteHeader(http.StatusUnauthorized)
+			return
+		}
+		if err != nil {
+			logger.Debug().Err(err).Msg("Error while reading body")
+
+			observability.SetStatusErrorf(req.Context(), "Error while reading Body: %s", err)
+			rw.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+
+		// bodyBytes is nil when the request has no body.
+		if bodyBytes != nil {
+			req.Body = io.NopCloser(bytes.NewReader(bodyBytes))
+			forwardReq.Body = io.NopCloser(bytes.NewReader(bodyBytes))
+		}
+	}
+
 	writeHeader(req, forwardReq, fa.trustForwardHeader, fa.authRequestHeaders)
 
 	var forwardSpan trace.Span
@@ -149,7 +182,7 @@ func (fa *forwardAuth) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
 
 	forwardResponse, forwardErr := fa.client.Do(forwardReq)
 	if forwardErr != nil {
-		logger.Debug().Msgf("Error calling %s. Cause: %s", fa.address, forwardErr)
+		logger.Debug().Err(forwardErr).Msgf("Error calling %s", fa.address)
 		observability.SetStatusErrorf(req.Context(), "Error calling %s. Cause: %s", fa.address, forwardErr)
 
 		rw.WriteHeader(http.StatusInternalServerError)
@@ -159,7 +192,7 @@ func (fa *forwardAuth) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
 
 	body, readError := io.ReadAll(forwardResponse.Body)
 	if readError != nil {
-		logger.Debug().Msgf("Error reading body %s. Cause: %s", fa.address, readError)
+		logger.Debug().Err(readError).Msgf("Error reading body %s", fa.address)
 		observability.SetStatusErrorf(req.Context(), "Error reading body %s. Cause: %s", fa.address, readError)
 
 		rw.WriteHeader(http.StatusInternalServerError)
@@ -194,7 +227,7 @@ func (fa *forwardAuth) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
 
 		if err != nil {
 			if !errors.Is(err, http.ErrNoLocation) {
-				logger.Debug().Msgf("Error reading response location header %s. Cause: %s", fa.address, err)
+				logger.Debug().Err(err).Msgf("Error reading response location header %s", fa.address)
 				observability.SetStatusErrorf(req.Context(), "Error reading response location header %s. Cause: %s", fa.address, err)
 
 				rw.WriteHeader(http.StatusInternalServerError)
@@ -270,6 +303,27 @@ func (fa *forwardAuth) buildModifier(authCookies []*http.Cookie) func(res *http.
 	}
 }
 
+var errBodyTooLarge = errors.New("request body too large")
+
+func (fa *forwardAuth) readBodyBytes(req *http.Request) ([]byte, error) {
+	if fa.maxBodySize < 0 {
+		return io.ReadAll(req.Body)
+	}
+
+	body := make([]byte, fa.maxBodySize+1)
+	n, err := io.ReadFull(req.Body, body)
+	if errors.Is(err, io.EOF) {
+		return nil, nil
+	}
+	if err != nil && !errors.Is(err, io.ErrUnexpectedEOF) {
+		return nil, fmt.Errorf("reading body bytes: %w", err)
+	}
+	if errors.Is(err, io.ErrUnexpectedEOF) {
+		return body[:n], nil
+	}
+	return nil, errBodyTooLarge
+}
+
 func writeHeader(req, forwardReq *http.Request, trustForwardHeader bool, allowedHeaders []string) {
 	utils.CopyHeaders(forwardReq.Header, req.Header)
 

pkg/middlewares/auth/forward_test.go

@@ -1,6 +1,7 @@
 package auth
 
 import (
+	"bytes"
 	"context"
 	"fmt"
 	"io"
@@ -112,6 +113,154 @@ func TestForwardAuthSuccess(t *testing.T) {
 	assert.Equal(t, "traefik\n", string(body))
 }
 
+func TestForwardAuthForwardBody(t *testing.T) {
+	data := []byte("forwardBodyTest")
+
+	var serverCallCount int
+	server := httptest.NewServer(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
+		serverCallCount++
+
+		forwardedData, err := io.ReadAll(req.Body)
+		require.NoError(t, err)
+
+		assert.Equal(t, data, forwardedData)
+	}))
+	t.Cleanup(server.Close)
+
+	var nextCallCount int
+	next := http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
+		nextCallCount++
+	})
+
+	maxBodySize := int64(len(data))
+	auth := dynamic.ForwardAuth{Address: server.URL, ForwardBody: true, MaxBodySize: &maxBodySize}
+
+	middleware, err := NewForward(context.Background(), next, auth, "authTest")
+	require.NoError(t, err)
+
+	ts := httptest.NewServer(middleware)
+	t.Cleanup(ts.Close)
+
+	req := testhelpers.MustNewRequest(http.MethodGet, ts.URL, bytes.NewReader(data))
+
+	res, err := http.DefaultClient.Do(req)
+	require.NoError(t, err)
+
+	assert.Equal(t, http.StatusOK, res.StatusCode)
+	assert.Equal(t, 1, serverCallCount)
+	assert.Equal(t, 1, nextCallCount)
+}
+
+func TestForwardAuthForwardBodyEmptyBody(t *testing.T) {
+	var serverCallCount int
+	server := httptest.NewServer(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
+		serverCallCount++
+
+		forwardedData, err := io.ReadAll(req.Body)
+		require.NoError(t, err)
+
+		assert.Empty(t, forwardedData)
+	}))
+	t.Cleanup(server.Close)
+
+	var nextCallCount int
+	next := http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
+		nextCallCount++
+	})
+
+	auth := dynamic.ForwardAuth{Address: server.URL, ForwardBody: true}
+
+	middleware, err := NewForward(context.Background(), next, auth, "authTest")
+	require.NoError(t, err)
+
+	ts := httptest.NewServer(middleware)
+	t.Cleanup(ts.Close)
+
+	req := testhelpers.MustNewRequest(http.MethodGet, ts.URL, http.NoBody)
+
+	res, err := http.DefaultClient.Do(req)
+	require.NoError(t, err)
+
+	assert.Equal(t, http.StatusOK, res.StatusCode)
+	assert.Equal(t, 1, serverCallCount)
+	assert.Equal(t, 1, nextCallCount)
+}
+
+func TestForwardAuthForwardBodySizeLimit(t *testing.T) {
+	data := []byte("forwardBodyTest")
+
+	var serverCallCount int
+	server := httptest.NewServer(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
+		serverCallCount++
+
+		forwardedData, err := io.ReadAll(req.Body)
+		require.NoError(t, err)
+
+		assert.Equal(t, data, forwardedData)
+	}))
+	t.Cleanup(server.Close)
+
+	var nextCallCount int
+	next := http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
+		nextCallCount++
+	})
+
+	maxBodySize := int64(len(data)) - 1
+	auth := dynamic.ForwardAuth{Address: server.URL, ForwardBody: true, MaxBodySize: &maxBodySize}
+
+	middleware, err := NewForward(context.Background(), next, auth, "authTest")
+	require.NoError(t, err)
+
+	ts := httptest.NewServer(middleware)
+	t.Cleanup(ts.Close)
+
+	req := testhelpers.MustNewRequest(http.MethodGet, ts.URL, bytes.NewReader(data))
+
+	res, err := http.DefaultClient.Do(req)
+	require.NoError(t, err)
+
+	assert.Equal(t, http.StatusUnauthorized, res.StatusCode)
+	assert.Equal(t, 0, serverCallCount)
+	assert.Equal(t, 0, nextCallCount)
+}
+
+func TestForwardAuthNotForwardBody(t *testing.T) {
+	data := []byte("forwardBodyTest")
+
+	var serverCallCount int
+	server := httptest.NewServer(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
+		serverCallCount++
+
+		forwardedData, err := io.ReadAll(req.Body)
+		require.NoError(t, err)
+
+		assert.Empty(t, forwardedData)
+	}))
+	t.Cleanup(server.Close)
+
+	var nextCallCount int
+	next := http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
+		nextCallCount++
+	})
+
+	auth := dynamic.ForwardAuth{Address: server.URL}
+
+	middleware, err := NewForward(context.Background(), next, auth, "authTest")
+	require.NoError(t, err)
+
+	ts := httptest.NewServer(middleware)
+	t.Cleanup(ts.Close)
+
+	req := testhelpers.MustNewRequest(http.MethodGet, ts.URL, bytes.NewReader(data))
+
+	res, err := http.DefaultClient.Do(req)
+	require.NoError(t, err)
+
+	assert.Equal(t, http.StatusOK, res.StatusCode)
+	assert.Equal(t, 1, serverCallCount)
+	assert.Equal(t, 1, nextCallCount)
+}
+
 func TestForwardAuthRedirect(t *testing.T) {
 	authTs := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		http.Redirect(w, r, "http://example.com/redirect-test", http.StatusFound)

pkg/provider/kubernetes/crd/kubernetes.go

@@ -789,34 +789,38 @@ func createForwardAuthMiddleware(k8sClient Client, namespace string, auth *traef
 		AuthResponseHeadersRegex: auth.AuthResponseHeadersRegex,
 		AuthRequestHeaders:       auth.AuthRequestHeaders,
 		AddAuthCookiesToResponse: auth.AddAuthCookiesToResponse,
+		ForwardBody:              auth.ForwardBody,
+	}
+	forwardAuth.SetDefaults()
+
+	if auth.MaxBodySize != nil {
+		forwardAuth.MaxBodySize = auth.MaxBodySize
 	}
 
-	if auth.TLS == nil {
+	if auth.TLS != nil {
-		return forwardAuth, nil
+		forwardAuth.TLS = &dynamic.ClientTLS{
-	}
+			InsecureSkipVerify: auth.TLS.InsecureSkipVerify,
-
-	forwardAuth.TLS = &dynamic.ClientTLS{
-		InsecureSkipVerify: auth.TLS.InsecureSkipVerify,
-	}
-
-	if len(auth.TLS.CASecret) > 0 {
-		caSecret, err := loadCASecret(namespace, auth.TLS.CASecret, k8sClient)
-		if err != nil {
-			return nil, fmt.Errorf("failed to load auth ca secret: %w", err)
 		}
-		forwardAuth.TLS.CA = caSecret
-	}
 
-	if len(auth.TLS.CertSecret) > 0 {
+		if len(auth.TLS.CASecret) > 0 {
-		authSecretCert, authSecretKey, err := loadAuthTLSSecret(namespace, auth.TLS.CertSecret, k8sClient)
+			caSecret, err := loadCASecret(namespace, auth.TLS.CASecret, k8sClient)
-		if err != nil {
+			if err != nil {
-			return nil, fmt.Errorf("failed to load auth secret: %w", err)
+				return nil, fmt.Errorf("failed to load auth ca secret: %w", err)
+			}
+			forwardAuth.TLS.CA = caSecret
 		}
-		forwardAuth.TLS.Cert = authSecretCert
-		forwardAuth.TLS.Key = authSecretKey
-	}
 
-	forwardAuth.TLS.CAOptional = auth.TLS.CAOptional
+		if len(auth.TLS.CertSecret) > 0 {
+			authSecretCert, authSecretKey, err := loadAuthTLSSecret(namespace, auth.TLS.CertSecret, k8sClient)
+			if err != nil {
+				return nil, fmt.Errorf("failed to load auth secret: %w", err)
+			}
+			forwardAuth.TLS.Cert = authSecretCert
+			forwardAuth.TLS.Key = authSecretKey
+		}
+
+		forwardAuth.TLS.CAOptional = auth.TLS.CAOptional
+	}
 
 	return forwardAuth, nil
 }

pkg/provider/kubernetes/crd/kubernetes_test.go

@@ -3915,7 +3915,8 @@ func TestLoadIngressRoutes(t *testing.T) {
 						},
 						"default-forwardauth": {
 							ForwardAuth: &dynamic.ForwardAuth{
-								Address: "test.com",
+								Address:     "test.com",
+								MaxBodySize: pointer(int64(-1)),
 								TLS: &dynamic.ClientTLS{
 									CA:   "-----BEGIN CERTIFICATE-----\n-----END CERTIFICATE-----",
 									Cert: "-----BEGIN CERTIFICATE-----\n-----END CERTIFICATE-----",

pkg/provider/kubernetes/crd/traefikio/v1alpha1/middleware.go

@@ -161,6 +161,10 @@ type ForwardAuth struct {
 	TLS *ClientTLS `json:"tls,omitempty"`
 	// AddAuthCookiesToResponse defines the list of cookies to copy from the authentication server response to the response.
 	AddAuthCookiesToResponse []string `json:"addAuthCookiesToResponse,omitempty"`
+	// ForwardBody defines whether to send the request body to the authentication server.
+	ForwardBody bool `json:"forwardBody,omitempty"`
+	// MaxBodySize defines the maximum body size in bytes allowed to be forwarded to the authentication server.
+	MaxBodySize *int64 `json:"maxBodySize,omitempty"`
 }
 
 // ClientTLS holds the client TLS configuration.

pkg/provider/kubernetes/crd/traefikio/v1alpha1/zz_generated.deepcopy.go

@@ -266,6 +266,11 @@ func (in *ForwardAuth) DeepCopyInto(out *ForwardAuth) {
 		*out = make([]string, len(*in))
 		copy(*out, *in)
 	}
+	if in.MaxBodySize != nil {
+		in, out := &in.MaxBodySize, &out.MaxBodySize
+		*out = new(int64)
+		**out = **in
+	}
 	return
 }
 

pkg/provider/kv/kv_test.go

@@ -88,6 +88,8 @@ func Test_buildConfiguration(t *testing.T) {
 		"traefik/http/middlewares/Middleware08/forwardAuth/tls/cert":                                 "foobar",
 		"traefik/http/middlewares/Middleware08/forwardAuth/address":                                  "foobar",
 		"traefik/http/middlewares/Middleware08/forwardAuth/trustForwardHeader":                       "true",
+		"traefik/http/middlewares/Middleware08/forwardAuth/forwardBody":                              "true",
+		"traefik/http/middlewares/Middleware08/forwardAuth/maxBodySize":                              "42",
 		"traefik/http/middlewares/Middleware15/redirectScheme/scheme":                                "foobar",
 		"traefik/http/middlewares/Middleware15/redirectScheme/port":                                  "foobar",
 		"traefik/http/middlewares/Middleware15/redirectScheme/permanent":                             "true",
@@ -440,6 +442,8 @@ func Test_buildConfiguration(t *testing.T) {
 							"foobar",
 							"foobar",
 						},
+						ForwardBody: true,
+						MaxBodySize: pointer(int64(42)),
 					},
 				},
 				"Middleware06": {

pkg/server/service/service.go

@@ -35,11 +35,6 @@ import (
 	"google.golang.org/grpc/status"
 )
 
-const (
-	defaultMirrorBody        = true
-	defaultMaxBodySize int64 = -1
-)
-
 // ProxyBuilder builds reverse proxy handlers.
 type ProxyBuilder interface {
 	Build(cfgName string, targetURL *url.URL, shouldObserve, passHostHeader, preservePath bool, flushInterval time.Duration) (http.Handler, error)
@@ -221,12 +216,12 @@ func (m *Manager) getMirrorServiceHandler(ctx context.Context, config *dynamic.M
 		return nil, err
 	}
 
-	mirrorBody := defaultMirrorBody
+	mirrorBody := dynamic.MirroringDefaultMirrorBody
 	if config.MirrorBody != nil {
 		mirrorBody = *config.MirrorBody
 	}
 
-	maxBodySize := defaultMaxBodySize
+	maxBodySize := dynamic.MirroringDefaultMaxBodySize
 	if config.MaxBodySize != nil {
 		maxBodySize = *config.MaxBodySize
 	}