Obfuscated fonts

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "test/readium-test-files"]
+	path = test/readium-test-files
+	url = [email protected]:readium/readium-test-files.git

decoder/adobe_fonts.go

@@ -0,0 +1,67 @@
+package decoder
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"io/ioutil"
+	"strconv"
+	"strings"
+	"unicode"
+
+	"github.com/feedbooks/r2-streamer-go/models"
+)
+
+func init() {
+	decoderList = append(decoderList, List{decoderAlgorithm: "http://ns.adobe.com/pdf/enc#RC", decoder: DecodeAdobeFont})
+}
+
+// DecodeAdobeFont decode obfuscate fonts using idpf spec http://www.idpf.org/epub/20/spec/FontManglingSpec.html
+func DecodeAdobeFont(publication models.Publication, link models.Link, reader io.ReadSeeker) (io.ReadSeeker, error) {
+	var count int
+
+	key := getAdobeHashKey(publication)
+	if string(key) == "" {
+		return nil, errors.New("can't find hash key")
+	}
+
+	buff, _ := ioutil.ReadAll(reader)
+	if len(buff) > 1024 {
+		count = 1024
+	} else {
+		count = len(buff)
+	}
+
+	j := 0
+	for i := 0; i < count; i++ {
+		buff[i] = buff[i] ^ key[j]
+
+		j++
+		if j == 16 {
+			j = 0
+		}
+	}
+	readerSeeker := bytes.NewReader(buff)
+	return readerSeeker, nil
+}
+
+func getAdobeHashKey(publication models.Publication) []byte {
+	var stringKey []rune
+	var key []byte
+
+	id := strings.Replace(publication.Metadata.Identifier, "urn:uuid:", "", -1)
+	id = strings.Replace(id, "-", "", -1)
+	for _, c := range id {
+		if !unicode.IsSpace(c) {
+			stringKey = append(stringKey, c)
+		}
+	}
+
+	for i := 0; i < 16; i++ {
+		byteHex := stringKey[i*2 : i*2+2]
+		byteNumer, _ := strconv.ParseInt(string(byteHex), 16, 32)
+		key = append(key, byte(byteNumer))
+	}
+
+	return key
+}

decoder/decoder.go

@@ -0,0 +1,30 @@
+package decoder
+
+import (
+	"errors"
+	"fmt"
+	"io"
+
+	"github.com/feedbooks/r2-streamer-go/models"
+)
+
+// List TODO add doc
+type List struct {
+	decoderAlgorithm string
+	decoder          (func(models.Publication, models.Link, io.ReadSeeker) (io.ReadSeeker, error))
+}
+
+var decoderList []List
+
+// Decode decode the ressource
+func Decode(publication models.Publication, link models.Link, reader io.ReadSeeker) (io.ReadSeeker, error) {
+
+	fmt.Println(link.CryptAlgorithm)
+	for _, decoderFunc := range decoderList {
+		if link.CryptAlgorithm == decoderFunc.decoderAlgorithm {
+			return decoderFunc.decoder(publication, link, reader)
+		}
+	}
+
+	return nil, errors.New("can't find fetcher")
+}

decoder/fonts_test.go

@@ -0,0 +1,52 @@
+package decoder
+
+import (
+	"bytes"
+	"io/ioutil"
+	"os"
+	"testing"
+
+	"github.com/feedbooks/r2-streamer-go/models"
+	"github.com/feedbooks/r2-streamer-go/parser"
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+var testPublication models.Publication
+var testFonts []byte
+
+func init() {
+
+	testPublication, _ = parser.Parse("../test/readium-test-files/functional/smoke-tests/SmokeTestFXL")
+	ft, _ := os.Open("../test/readium-test-files/functional/smoke-tests/SmokeTestFXL/fonts/cut-cut.woff")
+	testFonts, _ = ioutil.ReadAll(ft)
+}
+
+func TestAdobeFonts(t *testing.T) {
+
+	f, _ := os.Open("../test/readium-test-files/functional/smoke-tests/SmokeTestFXL/fonts/cut-cut.adb.woff")
+
+	Convey("Given cut-cut.adb.woff fonts", t, func() {
+		fd, _ := DecodeAdobeFont(testPublication, models.Link{}, f)
+		buff, _ := ioutil.ReadAll(fd)
+		Convey("The adobe fonts is deobfuscated", func() {
+			So(bytes.Equal(buff, testFonts), ShouldBeTrue)
+		})
+
+	})
+
+}
+
+func TestIdpfFonts(t *testing.T) {
+
+	f, _ := os.Open("../test/readium-test-files/functional/smoke-tests/SmokeTestFXL/fonts/cut-cut.obf.woff")
+
+	Convey("Given cut-cut.obf.woff fonts", t, func() {
+		fd, _ := DecodeIdpfFont(testPublication, models.Link{}, f)
+		buff, _ := ioutil.ReadAll(fd)
+		Convey("The idpf fonts is deobfuscated", func() {
+			So(bytes.Equal(buff, testFonts), ShouldBeTrue)
+		})
+
+	})
+
+}

decoder/idpf_fonts.go

@@ -0,0 +1,62 @@
+package decoder
+
+import (
+	"bytes"
+	"crypto/sha1"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"unicode"
+
+	"github.com/feedbooks/r2-streamer-go/models"
+)
+
+func init() {
+	decoderList = append(decoderList, List{decoderAlgorithm: "http://www.idpf.org/2008/embedding", decoder: DecodeIdpfFont})
+}
+
+// DecodeIdpfFont decode obfuscate fonts using idpf spec http://www.idpf.org/epub/20/spec/FontManglingSpec.html
+func DecodeIdpfFont(publication models.Publication, link models.Link, reader io.ReadSeeker) (io.ReadSeeker, error) {
+	var count int
+
+	key := getHashKey(publication)
+	fmt.Println(key)
+	if string(key) == "" {
+		return nil, errors.New("can't find hash key")
+	}
+
+	buff, _ := ioutil.ReadAll(reader)
+	if len(buff) > 1040 {
+		count = 1040
+	} else {
+		count = len(buff)
+	}
+
+	j := 0
+	for i := 0; i < count; i++ {
+		buff[i] = buff[i] ^ key[j]
+
+		j++
+		if j == 20 {
+			j = 0
+		}
+	}
+	readerSeeker := bytes.NewReader(buff)
+	return readerSeeker, nil
+}
+
+func getHashKey(publication models.Publication) []byte {
+	var stringKey []rune
+
+	for _, c := range publication.Metadata.Identifier {
+		if !unicode.IsSpace(c) {
+			stringKey = append(stringKey, c)
+		}
+	}
+
+	h := sha1.New()
+	io.WriteString(h, string(stringKey))
+
+	return h.Sum(nil)
+}

fetcher/epub.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"io/ioutil"
 
+	"github.com/feedbooks/r2-streamer-go/decoder"
 	"github.com/feedbooks/r2-streamer-go/models"
 )
 
@@ -18,6 +19,7 @@ func FetchEpub(publication models.Publication, publicationResource string) (io.R
 	var mediaType string
 	var reader *zip.ReadCloser
 	var assetFd io.ReadCloser
+	var link models.Link
 
 	for _, data := range publication.Internal {
 		if data.Name == "epub" {
@@ -32,9 +34,18 @@ func FetchEpub(publication models.Publication, publicationResource string) (io.R
 		}
 	}
 
+	for _, linkRes := range publication.Resources {
+		if publicationResource == linkRes.Href {
+			link = linkRes
+		}
+	}
 	buff, _ := ioutil.ReadAll(assetFd)
 	assetFd.Close()
 	readerSeeker := bytes.NewReader(buff)
+	readerSeekerDecode, err := decoder.Decode(publication, link, readerSeeker)
+	if err != nil {
+		return readerSeekerDecode, mediaType, nil
+	}
 
 	return readerSeeker, mediaType, nil
 }

fetcher/epub_dir.go

@@ -6,6 +6,7 @@ import (
 	"os"
 	"path"
 
+	"github.com/feedbooks/r2-streamer-go/decoder"
 	"github.com/feedbooks/r2-streamer-go/models"
 )
 
@@ -18,6 +19,7 @@ func FetchEpubDir(publication models.Publication, publicationResource string) (i
 	var mediaType string
 	var basePath string
 	var rootFile string
+	var link models.Link
 
 	for _, data := range publication.Internal {
 		if data.Name == "basepath" {
@@ -34,5 +36,15 @@ func FetchEpubDir(publication models.Publication, publicationResource string) (i
 		fmt.Println(err)
 	}
 
+	for _, linkRes := range publication.Resources {
+		if publicationResource == linkRes.Href {
+			link = linkRes
+		}
+	}
+
+	readerSeekerDecode, err := decoder.Decode(publication, link, fd)
+	if err == nil {
+		return readerSeekerDecode, mediaType, nil
+	}
 	return fd, mediaType, nil
 }

models/publication.go

@@ -31,16 +31,17 @@ type Internal struct {
 
 // Link object used in collections and links
 type Link struct {
-	Href       string      `json:"href"`
-	TypeLink   string      `json:"type,omitempty"`
-	Rel        []string    `json:"rel,omitempty"`
-	Height     int         `json:"height,omitempty"`
-	Width      int         `json:"width,omitempty"`
-	Title      string      `json:"title,omitempty"`
-	Properties *Properties `json:"properties,omitempty"`
-	Duration   string      `json:"duration,omitempty"`
-	Templated  bool        `json:"templated,omitempty"`
-	Children   []Link      `json:"children,omitempty"`
+	Href           string      `json:"href"`
+	TypeLink       string      `json:"type,omitempty"`
+	Rel            []string    `json:"rel,omitempty"`
+	Height         int         `json:"height,omitempty"`
+	Width          int         `json:"width,omitempty"`
+	Title          string      `json:"title,omitempty"`
+	Properties     *Properties `json:"properties,omitempty"`
+	Duration       string      `json:"duration,omitempty"`
+	Templated      bool        `json:"templated,omitempty"`
+	Children       []Link      `json:"children,omitempty"`
+	CryptAlgorithm string      `json:"-"`
 }
 
 // PublicationCollection is used as an extension points for other collections in a Publication

parser/epub.go

@@ -2,6 +2,7 @@ package parser
 
 import (
 	"errors"
+	"path"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -34,16 +35,19 @@ func EpubParser(filePath string) (models.Publication, error) {
 	fileExt := filepath.Ext(filePath)
 	if fileExt == "" {
 		book, err = epub.OpenDir(filePath)
+		if err != nil {
+			return models.Publication{}, errors.New("can't open or parse epub file with err : " + err.Error())
+		}
 		publication.Internal = append(publication.Internal, models.Internal{Name: "type", Value: "epub_dir"})
 		publication.Internal = append(publication.Internal, models.Internal{Name: "basepath", Value: filePath})
 	} else {
 		book, err = epub.Open(filePath)
+		if err != nil {
+			return models.Publication{}, errors.New("can't open or parse epub file with err : " + err.Error())
+		}
 		publication.Internal = append(publication.Internal, models.Internal{Name: "type", Value: "epub"})
 		publication.Internal = append(publication.Internal, models.Internal{Name: "epub", Value: book.ZipReader()})
 	}
-	if err != nil {
-		return models.Publication{}, errors.New("can't open or parse epub file with err : " + err.Error())
-	}
 
 	if book.Container.Rootfile.Version != "" {
 		epubVersion = book.Container.Rootfile.Version
@@ -106,6 +110,8 @@ func EpubParser(filePath string) (models.Publication, error) {
 	}
 
 	fillCalibreSerieInfo(&publication, book)
+	fillEncryptionInfo(&publication, book)
+
 	return publication, nil
 }
 
@@ -558,3 +564,33 @@ func fillCalibreSerieInfo(publication *models.Publication, book *epub.Book) {
 	}
 
 }
+
+func fillEncryptionInfo(publication *models.Publication, book *epub.Book) {
+
+	for _, encInfo := range book.Encryption.EncryptedData {
+		resURI := encInfo.CipherData.CipherReference.URI
+		for i, l := range publication.Resources {
+			if resURI == FilePath(*publication, l.Href) {
+				publication.Resources[i].CryptAlgorithm = encInfo.EncryptionMethod.Algorithm
+			}
+		}
+		for i, l := range publication.Spine {
+			if resURI == FilePath(*publication, l.Href) {
+				publication.Spine[i].CryptAlgorithm = encInfo.EncryptionMethod.Algorithm
+			}
+		}
+	}
+}
+
+// FilePath return the complete path for the ressource
+func FilePath(publication models.Publication, publicationResource string) string {
+	var rootFile string
+
+	for _, data := range publication.Internal {
+		if data.Name == "rootfile" {
+			rootFile = data.Value.(string)
+		}
+	}
+
+	return path.Join(path.Dir(rootFile), publicationResource)
+}