Valid signature

sign/helpers.go

@@ -1,6 +1,8 @@
 package sign
 
 import (
+	"bitbucket.org/digitorus/pdf"
+	"errors"
 	"fmt"
 	"io"
 	"math"
@@ -9,6 +11,20 @@ import (
 	"time"
 )
 
+func findFirstPage(parent pdf.Value) (pdf.Value, error) {
+	value_type := parent.Key("Type").String()
+	if value_type == "/Pages" {
+		recurse_parent, recurse_err := findFirstPage(parent.Key("Kids").Index(0))
+		return recurse_parent, recurse_err
+	}
+
+	if value_type == "/Page" {
+		return parent, nil
+	}
+
+	return parent, errors.New("Could not find first page.")
+}
+
 func pdfString(text string) string {
 	text = strings.Replace(text, "\\", "\\\\", -1)
 	text = strings.Replace(text, ")", "\\)", -1)

sign/pdfcatalog.go

@@ -46,9 +46,9 @@ func (context *SignContext) createCatalog() (catalog string, err error) {
 
 	if !context.SignData.Signature.Approval {
 		if context.SignData.Signature.CertType > 0 {
-			catalog += " /Perms << /DocMDP " + strconv.Itoa(int(context.SignData.ObjectId)) + " 0 R >>";
+			catalog += " /Perms << /DocMDP " + strconv.Itoa(int(context.SignData.ObjectId)) + " 0 R >>"
 		} else {
-			catalog += " /Perms << /UR3 " + strconv.Itoa(int(context.SignData.ObjectId)) + " 0 R >>";
+			catalog += " /Perms << /UR3 " + strconv.Itoa(int(context.SignData.ObjectId)) + " 0 R >>"
 		}
 	}
 

sign/pdfinfo.go

@@ -0,0 +1,25 @@
+package sign
+
+import (
+	"strconv"
+)
+
+func (context *SignContext) createInfo() (info string, err error) {
+	original_info := context.PDFReader.Trailer().Key("Info")
+	info = strconv.Itoa(int(context.InfoData.ObjectId)) + " 0 obj\n"
+	info += "<<"
+
+	info_keys := original_info.Keys()
+	for _, key := range info_keys {
+		info += "/" + key
+		if key == "ModDate" {
+			info += pdfDateTime(context.SignData.Signature.Info.Date)
+		} else {
+			info += pdfString(original_info.Key(key).RawString())
+		}
+	}
+
+	info += ">>"
+	info += "\nendobj\n"
+	return info, nil
+}

sign/pdfsignature.go

@@ -108,7 +108,7 @@ func (context *SignContext) replaceSignature() error {
 	dst := make([]byte, hex.EncodedLen(len(signature)))
 	hex.Encode(dst, signature)
 
-	context.OutputFile.WriteAt(dst, context.ByteRangeValues[0] + context.ByteRangeValues[1] + 1)
+	context.OutputFile.WriteAt(dst, context.ByteRangeValues[0]+context.ByteRangeValues[1]+1)
 
 	return nil
 }

sign/pdftrailer.go

@@ -19,11 +19,18 @@ func (context *SignContext) writeTrailer() error {
 	new_root := "Root " + strconv.FormatInt(int64(context.CatalogData.ObjectId), 10) + " 0 R"
 
 	size_string := "Size " + strconv.FormatInt(context.PDFReader.XrefInformation.ItemCount, 10)
-	new_size := "Size " + strconv.FormatInt(context.PDFReader.XrefInformation.ItemCount+3, 10)
+	new_size := "Size " + strconv.FormatInt(context.PDFReader.XrefInformation.ItemCount+4, 10)
+
+	info := context.PDFReader.Trailer().Key("Info")
+	infoPtr := info.GetPtr()
+
+	info_string := "Info " + strconv.Itoa(int(infoPtr.GetID())) + " " + strconv.Itoa(int(infoPtr.GetGen())) + " R"
+	new_info := "Info " + strconv.FormatInt(int64(context.InfoData.ObjectId), 10) + " 0 R"
 
 	trailer_string := string(trailer_buf)
 	trailer_string = strings.Replace(trailer_string, root_string, new_root, -1)
 	trailer_string = strings.Replace(trailer_string, size_string, new_size, -1)
+	trailer_string = strings.Replace(trailer_string, info_string, new_info, -1)
 
 	// Write the new trailer.
 	if _, err := context.OutputFile.Write([]byte(trailer_string)); err != nil {

sign/pdfvisualsignature.go

@@ -28,10 +28,16 @@ func (context *SignContext) createVisualSignature() (visual_signature string, er
 	rootPtr := root.GetPtr()
 	context.CatalogData.RootString = strconv.Itoa(int(rootPtr.GetID())) + " " + strconv.Itoa(int(rootPtr.GetGen())) + " R"
 
-	page := root.Key("Pages").Key("Kids").Index(0).GetPtr()
+	first_page, err := findFirstPage(root.Key("Pages"))
-	visual_signature += " /P " + strconv.Itoa(int(page.GetID())) + " " + strconv.Itoa(int(page.GetGen())) + " R"
+	if err != nil {
+		return "", err
+	}
 
-	visual_signature += " /F 4"
+	first_page_ptr := first_page.GetPtr()
+
+	visual_signature += " /P " + strconv.Itoa(int(first_page_ptr.GetID())) + " " + strconv.Itoa(int(first_page_ptr.GetGen())) + " R"
+
+	visual_signature += " /F 132"
 	visual_signature += " /FT /Sig"
 	visual_signature += " /T " + pdfString("Signature")
 	visual_signature += " /Ff 0"

sign/pdfxref.go

@@ -22,7 +22,7 @@ func (context *SignContext) writeXref() error {
 
 func (context *SignContext) writeXrefTable() error {
 	xref_size := "xref\n0 " + strconv.FormatInt(context.PDFReader.XrefInformation.ItemCount, 10)
-	new_xref_size := "xref\n0 " + strconv.FormatInt(context.PDFReader.XrefInformation.ItemCount+3, 10)
+	new_xref_size := "xref\n0 " + strconv.FormatInt(context.PDFReader.XrefInformation.ItemCount+4, 10)
 
 	if _, err := context.OutputFile.Write([]byte(new_xref_size)); err != nil {
 		return err
@@ -35,7 +35,7 @@ func (context *SignContext) writeXrefTable() error {
 
 	// Create the new catalog xref line.
 	visual_signature_object_start_position := strconv.FormatInt(context.Filesize, 10)
-	visual_signature_xref_line := leftPad(visual_signature_object_start_position, "0", 10-len(visual_signature_object_start_position)) + " 00000 n\n"
+	visual_signature_xref_line := leftPad(visual_signature_object_start_position, "0", 10-len(visual_signature_object_start_position)) + " 00000 n \n"
 
 	// Write the new catalog xref line.
 	if _, err := context.OutputFile.Write([]byte(visual_signature_xref_line)); err != nil {
@@ -44,7 +44,7 @@ func (context *SignContext) writeXrefTable() error {
 
 	// Create the new catalog xref line.
 	catalog_object_start_position := strconv.FormatInt(context.Filesize+context.VisualSignData.Length, 10)
-	catalog_xref_line := leftPad(catalog_object_start_position, "0", 10-len(catalog_object_start_position)) + " 00000 n\n"
+	catalog_xref_line := leftPad(catalog_object_start_position, "0", 10-len(catalog_object_start_position)) + " 00000 n \n"
 
 	// Write the new catalog xref line.
 	if _, err := context.OutputFile.Write([]byte(catalog_xref_line)); err != nil {
@@ -52,8 +52,17 @@ func (context *SignContext) writeXrefTable() error {
 	}
 
 	// Create the new signature xref line.
-	signature_object_start_position := strconv.FormatInt(context.Filesize+context.VisualSignData.Length+context.CatalogData.Length, 10)
+	info_object_start_position := strconv.FormatInt(context.Filesize+context.VisualSignData.Length+context.CatalogData.Length, 10)
-	signature_xref_line := leftPad(signature_object_start_position, "0", 10-len(signature_object_start_position)) + " 00000 n\n"
+	info_xref_line := leftPad(info_object_start_position, "0", 10-len(info_object_start_position)) + " 00000 n \n"
+
+	// Write the new signature xref line.
+	if _, err := context.OutputFile.Write([]byte(info_xref_line)); err != nil {
+		return err
+	}
+
+	// Create the new signature xref line.
+	signature_object_start_position := strconv.FormatInt(context.Filesize+context.VisualSignData.Length+context.CatalogData.Length+context.InfoData.Length, 10)
+	signature_xref_line := leftPad(signature_object_start_position, "0", 10-len(signature_object_start_position)) + " 00000 n \n"
 
 	// Write the new signature xref line.
 	if _, err := context.OutputFile.Write([]byte(signature_xref_line)); err != nil {

sign/sign.go

@@ -3,11 +3,11 @@ package sign
 import (
 	"crypto"
 	"crypto/x509"
+	"io"
 	"os"
 	"time"
 
 	"bitbucket.org/digitorus/pdf"
-	"io"
 )
 
 type CatalogData struct {
@@ -29,6 +29,11 @@ type VisualSignData struct {
 	Length   int64
 }
 
+type InfoData struct {
+	ObjectId uint32
+	Length   int64
+}
+
 type SignDataSignature struct {
 	Approval bool
 	CertType uint32
@@ -50,6 +55,7 @@ type SignContext struct {
 	SignData                   SignData
 	CatalogData                CatalogData
 	VisualSignData             VisualSignData
+	InfoData                   InfoData
 	PDFReader                  *pdf.Reader
 	NewXrefStart               int64
 	ByteRangeStartByte         int64
@@ -81,7 +87,7 @@ func SignFile(input string, output string, sign_data SignData) error {
 		return err
 	}
 
-	sign_data.ObjectId = uint32(rdr.XrefInformation.ItemCount) + 2
+	sign_data.ObjectId = uint32(rdr.XrefInformation.ItemCount) + 3
 
 	// We do size+1 because we insert a newline.
 	context := SignContext{
@@ -95,6 +101,9 @@ func SignFile(input string, output string, sign_data SignData) error {
 		CatalogData: CatalogData{
 			ObjectId: uint32(rdr.XrefInformation.ItemCount) + 1,
 		},
+		InfoData: InfoData{
+			ObjectId: uint32(rdr.XrefInformation.ItemCount) + 2,
+		},
 		SignData: sign_data,
 	}
 
@@ -149,9 +158,23 @@ func (context *SignContext) SignPDF() error {
 	// Create the signature object
 	signature_object, byte_range_start_byte, signature_contents_start_byte := context.createSignaturePlaceholder()
 
+	info, err := context.createInfo()
+	if err != nil {
+		return err
+	}
+
+	context.InfoData.Length = int64(len(info))
+
+	// Write the new catalog object.
+	if _, err := context.OutputFile.Write([]byte(info)); err != nil {
+		return err
+	}
+
+	appended_bytes := context.Filesize + int64(len(catalog)) + int64(len(visual_signature)) + int64(len(info))
+
 	// Positions are relative to old start position of xref table.
-	byte_range_start_byte += context.Filesize + int64(len(catalog)) + int64(len(visual_signature))
+	byte_range_start_byte += appended_bytes
-	signature_contents_start_byte += context.Filesize + int64(len(catalog)) + int64(len(visual_signature))
+	signature_contents_start_byte += appended_bytes
 
 	context.ByteRangeStartByte = byte_range_start_byte
 	context.SignatureContentsStartByte = signature_contents_start_byte
@@ -162,7 +185,7 @@ func (context *SignContext) SignPDF() error {
 	}
 
 	// Calculate the new start position of the xref table.
-	context.NewXrefStart = context.Filesize + int64(len(signature_object)) + int64(len(catalog)) + int64(len(visual_signature))
+	context.NewXrefStart = appended_bytes + int64(len(signature_object))
 
 	if err := context.writeXref(); err != nil {
 		return err

verify/verify.go

@@ -13,8 +13,8 @@ import (
 	"bitbucket.org/digitorus/pdf"
 	"github.com/digitorus/pkcs7"
 	"github.com/digitorus/timestamp"
-	"golang.org/x/crypto/ocsp"
 	"go/src/log"
+	"golang.org/x/crypto/ocsp"
 )
 
 type RevocationInfoArchival struct {
@@ -132,12 +132,6 @@ func Verify(file *os.File) (apiResp *Response, err error) {
 				apiResp.Error = fmt.Sprintln("Failed to get ByteRange:", i, err)
 			}
 
-			log.Println(v.Key("ByteRange").Index(i-1).Int64())
-			log.Println(v.Key("ByteRange").Index(i).Int64())
-			log.Println(string(content[0:60]))
-			log.Println(string(content[len(content)-60:len(content)]))
-			log.Println(len(content))
-
 			p7.Content = append(p7.Content, content...)
 		}