refact lib functions

update tests

add cmd/cercat/main.go

add pkg/model

add pkg/homoglyph and config pkg

add pkg/slack

update Dockerfile

use pointer to hymoglyph map

rename NewSlackPayload to NewPayload

fix missing file

use pointer to hymoglyph map

Dockerfile

@@ -9,15 +9,15 @@ WORKDIR /src
 ADD . .
 
 RUN go mod download
-RUN go build -ldflags="-s -w" -o cercat
+RUN go build -ldflags="-s -w" -o cercat ./cmd/cercat
 
 # Final Docker image
 FROM alpine AS final-stage
 LABEL MAINTAINER "Thomas Labarussias <[email protected]>"
 
 RUN apk add --no-cache ca-certificates
 
-# Create user falcosidekick
+# Create user cercat
 RUN addgroup -S cercat && adduser -u 1234 -S cercat -G cercat
 USER 1234
 

cmd/main.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"cercat/config"
+	"cercat/lib"
+	"fmt"
+	"net/http"
+	"os"
+	"path/filepath"
+
+	"github.com/pkg/errors"
+	"gopkg.in/alecthomas/kingpin.v2"
+)
+
+func main() {
+	a := kingpin.New(filepath.Base(os.Args[0]), "")
+	configFile := a.Flag("configfile", "config file").Short('c').ExistingFile()
+	a.HelpFlag.Short('h')
+
+	_, err := a.Parse(os.Args[1:])
+	if err != nil {
+		fmt.Fprintln(os.Stderr, errors.Wrapf(err, "Error parsing commandline arguments"))
+		a.Usage(os.Args[1:])
+		os.Exit(2)
+	}
+
+	cfg := config.GetConfig(configFile)
+	go http.ListenAndServe("localhost:6060", nil)
+	for i := 0; i < cfg.Workers; i++ {
+		go lib.CertCheckWorker(cfg.Regexp, &cfg.Homoglyph, cfg.Messages, cfg.Buffer)
+	}
+	go lib.Notifier(cfg)
+	lib.LoopCertStream(cfg.Messages)
+}

lib/config.go → config/config.go

@@ -1,14 +1,15 @@
-package lib
+package config
 
 import (
+	"cercat/pkg/homoglyph"
+	"cercat/pkg/model"
 	"container/ring"
 	"path"
 	"path/filepath"
 	"regexp"
 
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/viper"
-	kingpin "gopkg.in/alecthomas/kingpin.v2"
 )
 
 // Configuration represents a configuration element
@@ -21,23 +22,20 @@ type Configuration struct {
 	Regexp          string
 	PreviousCerts   *ring.Ring
 	Messages        chan []byte
-	Buffer          chan *Result
+	Buffer          chan *model.Result
 	Homoglyph       map[string]string
 }
 
 // GetConfig provides a Configuration
-func GetConfig() *Configuration {
+func GetConfig(configFile *string) *Configuration {
 	c := &Configuration{
 		Workers:       50,
-		Homoglyph:     GetHomoglyphMap(),
+		Homoglyph:     homoglyph.GetHomoglyphMap(),
 		PreviousCerts: ring.New(20),
 		Messages:      make(chan []byte, 50),
-		Buffer:        make(chan *Result, 50),
+		Buffer:        make(chan *model.Result, 50),
 	}
 
-	configFile := kingpin.Flag("configfile", "config file").Short('c').ExistingFile()
-	kingpin.Parse()
-
 	v := viper.New()
 	v.SetDefault("SlackWebhookURL", "")
 	v.SetDefault("SlackIconURL", "")

go.mod

@@ -8,8 +8,8 @@ require (
 	github.com/gobwas/ws v1.0.3
 	github.com/onsi/ginkgo v1.12.2
 	github.com/onsi/gomega v1.10.1
-	github.com/patrickmn/go-cache v2.1.0+incompatible
 	github.com/picatz/homoglyphr v0.0.0-20180114170158-6e9a0e190785
+	github.com/pkg/errors v0.8.0
 	github.com/sirupsen/logrus v1.2.0
 	github.com/spf13/viper v1.6.3
 	github.com/stretchr/testify v1.4.0 // indirect

go.sum

@@ -100,12 +100,11 @@ github.com/onsi/ginkgo v1.12.2/go.mod h1:iSB4RoI2tjJc9BBv4NKIKWKya62Rps+oPG/Lv9k
 github.com/onsi/gomega v1.7.1/go.mod h1:XdKZgCCFLUoM/7CFJVPcG8C1xQ1AJ0vpAezJrB7JYyY=
 github.com/onsi/gomega v1.10.1 h1:o0+MgICZLuZ7xjH7Vx6zS/zcu93/BEp1VwkIW1mEXCE=
 github.com/onsi/gomega v1.10.1/go.mod h1:iN09h71vgCQne3DLsj+A5owkum+a2tYe+TOCB1ybHNo=
-github.com/patrickmn/go-cache v2.1.0+incompatible h1:HRMgzkcYKYpi3C8ajMPV8OFXaaRUnok+kx1WdO15EQc=
-github.com/patrickmn/go-cache v2.1.0+incompatible/go.mod h1:3Qf8kWWT7OJRJbdiICTKqZju1ZixQ/KpMGzzAfe6+WQ=
 github.com/pelletier/go-toml v1.2.0 h1:T5zMGML61Wp+FlcbWjRDT7yAxhJNAiPPLOFECq181zc=
 github.com/pelletier/go-toml v1.2.0/go.mod h1:5z9KED0ma1S8pY6P1sdut58dfprrGBbd/94hg7ilaic=
 github.com/picatz/homoglyphr v0.0.0-20180114170158-6e9a0e190785 h1:h1zv5J8K6Hi22jgCuXHJJF+sKG99kSfJO6aJEFJSLGM=
 github.com/picatz/homoglyphr v0.0.0-20180114170158-6e9a0e190785/go.mod h1:XC/aunjQY/D2krxYQwCI6ijxR75grw1/keXATRNWX+4=
+github.com/pkg/errors v0.8.0 h1:WdK/asTD0HN+q6hsWO3/vpuAkAr+tw6aNJNDFFf0+qw=
 github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
@@ -166,7 +165,6 @@ golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn
 golang.org/x/net v0.0.0-20190522155817-f3200d17e092/go.mod h1:HSz+uSET+XFnRR8LxR5pz3Of3rY3CfYBVs4xY44aLks=
 golang.org/x/net v0.0.0-20200520004742-59133d7f0dd7 h1:AeiKBIuRw3UomYXSbLy0Mc2dDLfdtbT/IVn4keq83P0=
 golang.org/x/net v0.0.0-20200520004742-59133d7f0dd7/go.mod h1:qpuaurCH72eLCgpAm/N6yyVIVM9cpaDIP3A8BGJEC5A=
-golang.org/x/net v0.0.0-20200528225125-3c3fba18258b h1:IYiJPiJfzktmDAO1HQiwjMjwjlYKHAL7KzeD544RJPs=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=

lib/lib.go

@@ -1,6 +1,10 @@
 package lib
 
 import (
+	"cercat/config"
+	"cercat/pkg/homoglyph"
+	"cercat/pkg/model"
+	"cercat/pkg/slack"
 	"context"
 	"encoding/json"
 	"net"
@@ -14,52 +18,15 @@ import (
 	"golang.org/x/net/idna"
 )
 
-// Result represents a catched certificate
-type Result struct {
-	Domain    string   `json:"domain"`
-	IDN       string   `json:"IDN,omitempty"`
-	SAN       []string `json:"SAN"`
-	Issuer    string   `json:"issuer"`
-	Addresses []string `json:"Addresses"`
-}
-
-// certificate represents a certificate from CertStream
-type certificate struct {
-	MessageType string `json:"message_type"`
-	Data        data   `json:"data"`
-}
-
-// data represents data field for a certificate from CertStream
-type data struct {
-	UpdateType string            `json:"update_type"`
-	LeafCert   leafCert          `json:"leaf_cert"`
-	Chain      []leafCert        `json:"chain"`
-	CertIndex  float32           `json:"cert_index"`
-	Seen       float32           `json:"seen"`
-	Source     map[string]string `json:"source"`
-}
-
-// leafCert represents leaf_cert field from CertStream
-type leafCert struct {
-	Subject      map[string]string      `json:"subject"`
-	Extensions   map[string]interface{} `json:"extensions"`
-	NotBefore    float32                `json:"not_before"`
-	NotAfter     float32                `json:"not_after"`
-	SerialNumber string                 `json:"serial_number"`
-	FingerPrint  string                 `json:"fingerprint"`
-	AsDer        string                 `json:"as_der"`
-	AllDomains   []string               `json:"all_domains"`
-}
-
 // the websocket stream from calidog
 const certInput = "wss://certstream.calidog.io"
 
 // CertCheckWorker parses certificates and raises alert if matches config
-func CertCheckWorker(config *Configuration) {
-	reg, _ := regexp.Compile(config.Regexp)
+func CertCheckWorker(r string, homoglyph *map[string]string, msgChan chan []byte, bufferChan chan *model.Result) {
+	reg, _ := regexp.Compile(r)
 
 	for {
-		msg := <-config.Messages
+		msg := <-msgChan
 		result, err := ParseResultCertificate(msg)
 		if err != nil {
 			log.Warnf("Error parsing message: %s", err)
@@ -68,24 +35,24 @@ func CertCheckWorker(config *Configuration) {
 		if result == nil {
 			continue
 		}
-		if !IsMatchingCert(config, result, reg) {
+		if !IsMatchingCert(homoglyph, result, reg) {
 			continue
 		}
-		config.Buffer <- result
+		bufferChan <- result
 	}
 }
 
 // ParseResultCertificate parses certificate details
-func ParseResultCertificate(msg []byte) (*Result, error) {
-	var c certificate
-	var r *Result
+func ParseResultCertificate(msg []byte) (*model.Result, error) {
+	var c model.Certificate
+	var r *model.Result
 
 	err := json.Unmarshal(msg, &c)
 	if err != nil || c.MessageType == "heartbeat" {
 		return nil, err
 	}
 
-	r = &Result{
+	r = &model.Result{
 		Domain:    c.Data.LeafCert.Subject["CN"],
 		Issuer:    c.Data.Chain[0].Subject["O"],
 		SAN:       c.Data.LeafCert.AllDomains,
@@ -129,12 +96,12 @@ func isIDN(domain string) bool {
 }
 
 // IsMatchingCert checks if certificate matches the regexp
-func IsMatchingCert(config *Configuration, result *Result, reg *regexp.Regexp) bool {
+func IsMatchingCert(homoglyphs *map[string]string, result *model.Result, reg *regexp.Regexp) bool {
 	domainList := append(result.SAN, result.Domain)
 	for _, domain := range domainList {
 		if isIDN(domain) {
 			result.IDN, _ = idna.ToUnicode(domain)
-			domain = replaceHomoglyph(result.IDN, config.Homoglyph)
+			domain = homoglyph.ReplaceHomoglyph(result.IDN, *homoglyphs)
 		}
 		if reg.MatchString(domain) {
 			return true
@@ -144,7 +111,7 @@ func IsMatchingCert(config *Configuration, result *Result, reg *regexp.Regexp) b
 }
 
 // LoopCertStream gathers messages from CertStream
-func LoopCertStream(config *Configuration) {
+func LoopCertStream(msgBuf chan []byte) {
 	dial := ws.Dialer{
 		ReadBufferSize:  8192,
 		WriteBufferSize: 512,
@@ -165,31 +132,31 @@ func LoopCertStream(config *Configuration) {
 				log.Warn("Error reading message from CertStream")
 				break
 			}
-			config.Messages <- msg
+			msgBuf <- msg
 		}
 		conn.Close()
 	}
 }
 
 // Notifier is a worker that receives cert, depduplicates and sends to Slack the event
-func Notifier(config *Configuration) {
+func Notifier(cfg *config.Configuration) {
 	for {
-		result := <-config.Buffer
+		result := <-cfg.Buffer
 		duplicate := false
-		config.PreviousCerts.Do(func(d interface{}) {
+		cfg.PreviousCerts.Do(func(d interface{}) {
 			if result.Domain == d {
 				duplicate = true
 			}
 		})
 		if !duplicate {
-			config.PreviousCerts = config.PreviousCerts.Prev()
-			config.PreviousCerts.Value = result.Domain
+			cfg.PreviousCerts = cfg.PreviousCerts.Prev()
+			cfg.PreviousCerts.Value = result.Domain
 			j, _ := json.Marshal(result)
 			log.Infof("A certificate for '%v' has been issued : %v\n", result.Domain, string(j))
-			if config.SlackWebHookURL != "" {
-				go func(c *Configuration, r *Result) {
-					NewSlackPayload(c, result).post(c)
-				}(config, result)
+			if cfg.SlackWebHookURL != "" {
+				go func(c *config.Configuration, r *model.Result) {
+					slack.NewPayload(c, result).Post(c)
+				}(cfg, result)
 			}
 		}
 	}

lib/lib_test.go

@@ -1,7 +1,11 @@
 package lib_test
 
 import (
+	"cercat/config"
 	"cercat/lib"
+	"cercat/pkg/homoglyph"
+	"cercat/pkg/model"
+	"cercat/pkg/slack"
 	"io/ioutil"
 	"regexp"
 
@@ -10,31 +14,31 @@ import (
 )
 
 var _ = Describe("Handler", func() {
-	config := &lib.Configuration{
-		Homoglyph:     lib.GetHomoglyphMap(),
+	config := &config.Configuration{
+		Homoglyph:     homoglyph.GetHomoglyphMap(),
 		SlackUsername: "test",
 		SlackIconURL:  "http://test",
 	}
 	reg, _ := regexp.Compile(".*test.*")
 	Describe("isMatchingCert", func() {
 		Describe("If certificate matches", func() {
-			cert := &lib.Result{Domain: "www.test.com"}
+			cert := &model.Result{Domain: "www.test.com"}
 			It("should return true", func() {
-				result := lib.IsMatchingCert(config, cert, reg)
+				result := lib.IsMatchingCert(&config.Homoglyph, cert, reg)
 				Expect(result).To(BeTrue())
 			})
 		})
 		Describe("If alternative subject matches", func() {
-			cert := &lib.Result{Domain: "www.tset.net", SAN: []string{"www.test.com"}}
+			cert := &model.Result{Domain: "www.tset.net", SAN: []string{"www.test.com"}}
 			It("should return true", func() {
-				result := lib.IsMatchingCert(config, cert, reg)
+				result := lib.IsMatchingCert(&config.Homoglyph, cert, reg)
 				Expect(result).To(BeTrue())
 			})
 		})
 		Describe("If domain is IDN", func() {
-			cert := &lib.Result{Domain: "www.xn--tst-rdd.com"}
+			cert := &model.Result{Domain: "www.xn--tst-rdd.com"}
 			It("should return true", func() {
-				result := lib.IsMatchingCert(config, cert, reg)
+				result := lib.IsMatchingCert(&config.Homoglyph, cert, reg)
 				Expect(result).To(BeTrue())
 				Expect(cert.IDN).To(Equal("www.tеst.com")) // e is cyrillic
 			})
@@ -44,8 +48,8 @@ var _ = Describe("Handler", func() {
 		msg, _ := ioutil.ReadFile("../res/cert.json")
 		It("should return a valid payload", func() {
 			result, err := lib.ParseResultCertificate(msg)
-			slackPayload := lib.NewSlackPayload(config, result)
-			Expect(slackPayload.Text).Should(Equal("A certificate for *baden-mueller.de* has been issued"))
+			slackPayload := slack.NewPayload(config, result)
+			Expect(slackPayload.Text).Should(Equal("A certificate for baden-mueller.de has been issued"))
 			Expect(slackPayload.Username).Should(Equal("test"))
 			Expect(slackPayload.IconURL).Should(Equal("http://test"))
 			Expect(err).ToNot(HaveOccurred())
@@ -84,7 +88,7 @@ var _ = Describe("Handler", func() {
 			msg, _ := ioutil.ReadFile("../res/cert_idn.json")
 			It("should return valid infos", func() {
 				result, err := lib.ParseResultCertificate(msg)
-				lib.IsMatchingCert(config, result, reg)
+				lib.IsMatchingCert(&config.Homoglyph, result, reg)
 				Expect(result.Domain).Should(Equal("xn--badn-mullr-msiec.de"))
 				Expect(result.IDN).Should(Equal("badеn-muеllеr.de")) // e is cyrillic
 				Expect(result.SAN).Should(Equal([]string{"xn--badn-mullr-msiec.de", "www.baden-mueller.de"}))