From 45f52ca29cc178dda500f7136c359ea3707ce068 Mon Sep 17 00:00:00 2001
From: Mickael Jeanroy <1067361+mjeanroy@users.noreply.github.com>
Date: Thu, 16 Jul 2020 17:36:04 +0200
Subject: [PATCH] fix: access logs header names filtering is case insensitive

---
 integration/helloworld/helloworld.pb.go  |   3 +-
 pkg/middlewares/accesslog/logger.go      |  12 +++
 pkg/middlewares/accesslog/logger_test.go | 109 +++++++++++++++++++++--
 3 files changed, 115 insertions(+), 9 deletions(-)

diff --git a/integration/helloworld/helloworld.pb.go b/integration/helloworld/helloworld.pb.go
index 7b3335444..96320f02a 100644
--- a/integration/helloworld/helloworld.pb.go
+++ b/integration/helloworld/helloworld.pb.go
@@ -16,9 +16,10 @@ It has these top-level messages:
 package helloworld
 
 import (
-	proto "github.com/golang/protobuf/proto"
 	fmt "fmt"
 	math "math"
+
+	proto "github.com/golang/protobuf/proto"
 )
 
 import (
diff --git a/pkg/middlewares/accesslog/logger.go b/pkg/middlewares/accesslog/logger.go
index c876efcb3..13af24c9b 100644
--- a/pkg/middlewares/accesslog/logger.go
+++ b/pkg/middlewares/accesslog/logger.go
@@ -6,6 +6,7 @@ import (
 	"io"
 	"net"
 	"net/http"
+	"net/textproto"
 	"net/url"
 	"os"
 	"path/filepath"
@@ -100,6 +101,17 @@ func NewHandler(config *types.AccessLog) (*Handler, error) {
 		Level:     logrus.InfoLevel,
 	}
 
+	// Transform headers names in config to a canonical form, to be used as is without further transformations.
+	if config.Fields != nil && config.Fields.Headers != nil && len(config.Fields.Headers.Names) > 0 {
+		fields := map[string]string{}
+
+		for h, v := range config.Fields.Headers.Names {
+			fields[textproto.CanonicalMIMEHeaderKey(h)] = v
+		}
+
+		config.Fields.Headers.Names = fields
+	}
+
 	logHandler := &Handler{
 		config:         config,
 		logger:         logger,
diff --git a/pkg/middlewares/accesslog/logger_test.go b/pkg/middlewares/accesslog/logger_test.go
index 6d1567db0..eeeceba7b 100644
--- a/pkg/middlewares/accesslog/logger_test.go
+++ b/pkg/middlewares/accesslog/logger_test.go
@@ -41,11 +41,7 @@ var (
 )
 
 func TestLogRotation(t *testing.T) {
-	tempDir, err := ioutil.TempDir("", "traefik_")
-	if err != nil {
-		t.Fatalf("Error setting up temporary directory: %s", err)
-	}
-	defer os.RemoveAll(tempDir)
+	tempDir := createTempDir(t, "traefik_")
 
 	fileName := filepath.Join(tempDir, "traefik.log")
 	rotatedFileName := fileName + ".rotated"
@@ -119,9 +115,106 @@ func lineCount(t *testing.T, fileName string) int {
 	return count
 }
 
+func TestLoggerHeaderFields(t *testing.T) {
+	tmpDir := createTempDir(t, CommonFormat)
+
+	expectedValue := "expectedValue"
+
+	testCases := []struct {
+		desc            string
+		accessLogFields types.AccessLogFields
+		header          string
+		expected        string
+	}{
+		{
+			desc:     "with default mode",
+			header:   "User-Agent",
+			expected: types.AccessLogDrop,
+			accessLogFields: types.AccessLogFields{
+				DefaultMode: types.AccessLogDrop,
+				Headers: &types.FieldHeaders{
+					DefaultMode: types.AccessLogDrop,
+					Names:       map[string]string{},
+				},
+			},
+		},
+		{
+			desc:     "with exact header name",
+			header:   "User-Agent",
+			expected: types.AccessLogKeep,
+			accessLogFields: types.AccessLogFields{
+				DefaultMode: types.AccessLogDrop,
+				Headers: &types.FieldHeaders{
+					DefaultMode: types.AccessLogDrop,
+					Names: map[string]string{
+						"User-Agent": types.AccessLogKeep,
+					},
+				},
+			},
+		},
+		{
+			desc:     "with case insensitive match on header name",
+			header:   "User-Agent",
+			expected: types.AccessLogKeep,
+			accessLogFields: types.AccessLogFields{
+				DefaultMode: types.AccessLogDrop,
+				Headers: &types.FieldHeaders{
+					DefaultMode: types.AccessLogDrop,
+					Names: map[string]string{
+						"user-agent": types.AccessLogKeep,
+					},
+				},
+			},
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			logFile, err := ioutil.TempFile(tmpDir, "*.log")
+			require.NoError(t, err)
+
+			config := &types.AccessLog{
+				FilePath: logFile.Name(),
+				Format:   CommonFormat,
+				Fields:   &test.accessLogFields,
+			}
+
+			logger, err := NewHandler(config)
+			require.NoError(t, err)
+			defer logger.Close()
+
+			if config.FilePath != "" {
+				_, err = os.Stat(config.FilePath)
+				require.NoError(t, err, fmt.Sprintf("logger should create %s", config.FilePath))
+			}
+
+			req := &http.Request{
+				Header: map[string][]string{},
+				URL: &url.URL{
+					Path: testPath,
+				},
+			}
+			req.Header.Set(test.header, expectedValue)
+
+			logger.ServeHTTP(httptest.NewRecorder(), req, http.HandlerFunc(func(writer http.ResponseWriter, r *http.Request) {
+				writer.WriteHeader(http.StatusOK)
+			}))
+
+			logData, err := ioutil.ReadFile(logFile.Name())
+			require.NoError(t, err)
+
+			if test.expected == types.AccessLogDrop {
+				assert.NotContains(t, string(logData), expectedValue)
+			} else {
+				assert.Contains(t, string(logData), expectedValue)
+			}
+		})
+	}
+}
+
 func TestLoggerCLF(t *testing.T) {
 	tmpDir := createTempDir(t, CommonFormat)
-	defer os.RemoveAll(tmpDir)
 
 	logFilePath := filepath.Join(tmpDir, logFileNameSuffix)
 	config := &types.AccessLog{FilePath: logFilePath, Format: CommonFormat}
@@ -136,7 +229,6 @@ func TestLoggerCLF(t *testing.T) {
 
 func TestAsyncLoggerCLF(t *testing.T) {
 	tmpDir := createTempDir(t, CommonFormat)
-	defer os.RemoveAll(tmpDir)
 
 	logFilePath := filepath.Join(tmpDir, logFileNameSuffix)
 	config := &types.AccessLog{FilePath: logFilePath, Format: CommonFormat, BufferingSize: 1024}
@@ -358,7 +450,6 @@ func TestLoggerJSON(t *testing.T) {
 			t.Parallel()
 
 			tmpDir := createTempDir(t, JSONFormat)
-			defer os.RemoveAll(tmpDir)
 
 			logFilePath := filepath.Join(tmpDir, logFileNameSuffix)
 
@@ -642,6 +733,8 @@ func createTempDir(t *testing.T, prefix string) string {
 	tmpDir, err := ioutil.TempDir("", prefix)
 	require.NoError(t, err, "failed to create temp dir")
 
+	t.Cleanup(func() { _ = os.RemoveAll(tmpDir) })
+
 	return tmpDir
 }