Append instead of replace

sign.go

@@ -98,6 +98,8 @@ func main() {
 					ContactInfo: "Geen",
 					Date:        time.Now().Local(),
 				},
+				CertType: 2,
+				Approval: false,
 			},
 			Signer:      pkey,
 			Certificate: cert,

sign/pdfbyterange.go

@@ -10,8 +10,7 @@ func (context *SignContext) updateByteRange() error {
 	// @todo: find out of this is safe.
 	output_file_stat, _ := context.OutputFile.Stat()
 
-	// Don't count last newline as file length.
+	output_file_size := output_file_stat.Size()
-	output_file_size := output_file_stat.Size() - 1
 
 	// Calculate ByteRange values to replace them.
 	context.ByteRangeValues = make([]int64, 4)
@@ -20,10 +19,10 @@ func (context *SignContext) updateByteRange() error {
 	context.ByteRangeValues[0] = int64(0)
 
 	// Signature ByteRange part 1 length always stops at the actual signature start byte.
-	context.ByteRangeValues[1] = context.SignatureContentsStartByte
+	context.ByteRangeValues[1] = context.SignatureContentsStartByte - 1
 
 	// Signature ByteRange part 2 start byte directly starts after the actual signature.
-	context.ByteRangeValues[2] = context.ByteRangeValues[1] + int64(signatureMaxLength)
+	context.ByteRangeValues[2] = context.ByteRangeValues[1] + 1 + int64(signatureMaxLength) + 1
 
 	// Signature ByteRange part 2 length is everything else of the file.
 	context.ByteRangeValues[3] = output_file_size - context.ByteRangeValues[2]

sign/pdfcatalog.go

@@ -30,7 +30,7 @@ func (context *SignContext) createCatalog() (catalog string, err error) {
 	pages := root.Key("Pages").GetPtr()
 	catalog += " /Pages " + strconv.Itoa(int(pages.GetID())) + " " + strconv.Itoa(int(pages.GetGen())) + " R"
 	catalog += " /AcroForm <<"
-	catalog += " /Fields [" + strconv.Itoa(int(context.SignData.ObjectId)) + " 0 R]"
+	catalog += " /Fields [" + strconv.Itoa(int(context.VisualSignData.ObjectId)) + " 0 R]"
 
 	if !context.SignData.Signature.Approval {
 		catalog += " /NeedAppearances false"
@@ -44,12 +44,11 @@ func (context *SignContext) createCatalog() (catalog string, err error) {
 
 	catalog += " >>"
 
-	// @todo: what do these do?
 	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/pdfsignature.go

@@ -29,7 +29,7 @@ func (context *SignContext) createSignaturePlaceholder() (signature string, byte
 	// Create a placeholder for the actual signature content, we wil replace it later.
 	signature += " /Contents<" + strings.Repeat("0", int(signatureMaxLength)) + ">"
 
-	if context.SignData.Signature.Approval {
+	if !context.SignData.Signature.Approval {
 		signature += " /Reference [" // array of signature reference dictionaries
 		signature += " << /Type /SigRef"
 		if context.SignData.Signature.CertType > 0 {
@@ -77,9 +77,6 @@ func (context *SignContext) createSignature() ([]byte, error) {
 	io.Copy(sign_buf, context.OutputFile)
 	file_content := sign_buf.Bytes()
 
-	// Remove trailing newline.
-	file_content = file_content[:len(file_content)-1]
-
 	// Collect the parts to sign.
 	sign_content := make([]byte, 0)
 	sign_content = append(sign_content, file_content[context.ByteRangeValues[0]:(context.ByteRangeValues[0]+context.ByteRangeValues[1])]...)
@@ -111,7 +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])
+	context.OutputFile.WriteAt(dst, context.ByteRangeValues[0] + context.ByteRangeValues[1] + 1)
 
 	return nil
 }

sign/pdftrailer.go

@@ -19,7 +19,7 @@ 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+2, 10)
+	new_size := "Size " + strconv.FormatInt(context.PDFReader.XrefInformation.ItemCount+3, 10)
 
 	trailer_string := string(trailer_buf)
 	trailer_string = strings.Replace(trailer_string, root_string, new_root, -1)
@@ -36,7 +36,7 @@ func (context *SignContext) writeTrailer() error {
 	}
 
 	// Write PDF ending.
-	if _, err := context.OutputFile.Write([]byte("%%EOF\n")); err != nil {
+	if _, err := context.OutputFile.Write([]byte("%%EOF")); err != nil {
 		return err
 	}
 

sign/pdfvisualsignature.go

@@ -0,0 +1,44 @@
+package sign
+
+import (
+	"errors"
+	"strconv"
+)
+
+func (context *SignContext) createVisualSignature() (visual_signature string, err error) {
+	visual_signature = strconv.Itoa(int(context.VisualSignData.ObjectId)) + " 0 obj\n"
+	visual_signature += "<< /Type /Annot"
+	visual_signature += " /Subtype /Widget"
+	visual_signature += " /Rect [0 0 0 0]"
+
+	root := context.PDFReader.Trailer().Key("Root")
+	root_keys := root.Keys()
+	found_pages := false
+	for _, key := range root_keys {
+		if key == "Pages" {
+			found_pages = true
+			break
+		}
+	}
+
+	if !found_pages {
+		return "", errors.New("Didn't find pages in PDF trailer Root.")
+	}
+
+	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()
+	visual_signature += " /P " + strconv.Itoa(int(page.GetID())) + " " + strconv.Itoa(int(page.GetGen())) + " R"
+
+	visual_signature += " /F 4"
+	visual_signature += " /FT /Sig"
+	visual_signature += " /T " + pdfString("Signature")
+	visual_signature += " /Ff 0"
+	visual_signature += " /V " + strconv.Itoa(int(context.SignData.ObjectId)) + " 0 R"
+
+	visual_signature += " >>"
+	visual_signature += "\nendobj\n"
+
+	return visual_signature, nil
+}

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+2, 10)
+	new_xref_size := "xref\n0 " + strconv.FormatInt(context.PDFReader.XrefInformation.ItemCount+3, 10)
 
 	if _, err := context.OutputFile.Write([]byte(new_xref_size)); err != nil {
 		return err
@@ -34,7 +34,16 @@ func (context *SignContext) writeXrefTable() error {
 	}
 
 	// Create the new catalog xref line.
-	catalog_object_start_position := strconv.FormatInt(context.PDFReader.XrefInformation.StartPos, 10)
+	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"
+
+	// Write the new catalog xref line.
+	if _, err := context.OutputFile.Write([]byte(visual_signature_xref_line)); err != nil {
+		return err
+	}
+
+	// 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"
 
 	// Write the new catalog xref line.
@@ -43,7 +52,7 @@ func (context *SignContext) writeXrefTable() error {
 	}
 
 	// Create the new signature xref line.
-	signature_object_start_position := strconv.FormatInt(context.PDFReader.XrefInformation.StartPos+context.CatalogData.Length, 10)
+	signature_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"
 
 	// Write the new signature xref line.

sign/sign.go

@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"bitbucket.org/digitorus/pdf"
+	"io"
 )
 
 type CatalogData struct {
@@ -23,6 +24,11 @@ type SignData struct {
 	CertificateChain []*x509.Certificate
 }
 
+type VisualSignData struct {
+	ObjectId uint32
+	Length   int64
+}
+
 type SignDataSignature struct {
 	Approval bool
 	CertType uint32
@@ -38,10 +44,12 @@ type SignDataSignatureInfo struct {
 }
 
 type SignContext struct {
+	Filesize                   int64
 	InputFile                  *os.File
 	OutputFile                 *os.File
 	SignData                   SignData
 	CatalogData                CatalogData
+	VisualSignData             VisualSignData
 	PDFReader                  *pdf.Reader
 	NewXrefStart               int64
 	ByteRangeStartByte         int64
@@ -73,15 +81,20 @@ func SignFile(input string, output string, sign_data SignData) error {
 		return err
 	}
 
-	sign_data.ObjectId = uint32(rdr.XrefInformation.ItemCount) + 1
+	sign_data.ObjectId = uint32(rdr.XrefInformation.ItemCount) + 2
 
+	// We do size+1 because we insert a newline.
 	context := SignContext{
+		Filesize:   size + 1,
 		PDFReader:  rdr,
 		InputFile:  input_file,
 		OutputFile: output_file,
-		CatalogData: CatalogData{
+		VisualSignData: VisualSignData{
 			ObjectId: uint32(rdr.XrefInformation.ItemCount),
 		},
+		CatalogData: CatalogData{
+			ObjectId: uint32(rdr.XrefInformation.ItemCount) + 1,
+		},
 		SignData: sign_data,
 	}
 
@@ -94,8 +107,30 @@ func SignFile(input string, output string, sign_data SignData) error {
 }
 
 func (context *SignContext) SignPDF() error {
-	// Write the PDF file to the output up til the xref.
+	// Copy old file into new file.
-	if err := writePartFromSourceFileToTargetFile(context.InputFile, context.OutputFile, 0, context.PDFReader.XrefInformation.StartPos); err != nil {
+	if _, err := io.Copy(context.OutputFile, context.InputFile); err != nil {
+		return err
+	}
+
+	err := context.OutputFile.Sync()
+	if err != nil {
+		return err
+	}
+
+	// File always needs an empty line after %%EOF.
+	if _, err := context.OutputFile.Write([]byte("\n")); err != nil {
+		return err
+	}
+
+	visual_signature, err := context.createVisualSignature()
+	if err != nil {
+		return err
+	}
+
+	context.VisualSignData.Length = int64(len(visual_signature))
+
+	// Write the new catalog object.
+	if _, err := context.OutputFile.Write([]byte(visual_signature)); err != nil {
 		return err
 	}
 
@@ -115,8 +150,8 @@ func (context *SignContext) SignPDF() error {
 	signature_object, byte_range_start_byte, signature_contents_start_byte := context.createSignaturePlaceholder()
 
 	// Positions are relative to old start position of xref table.
-	byte_range_start_byte += context.PDFReader.XrefInformation.StartPos + int64(len(catalog))
+	byte_range_start_byte += context.Filesize + int64(len(catalog)) + int64(len(visual_signature))
-	signature_contents_start_byte += context.PDFReader.XrefInformation.StartPos + int64(len(catalog))
+	signature_contents_start_byte += context.Filesize + int64(len(catalog)) + int64(len(visual_signature))
 
 	context.ByteRangeStartByte = byte_range_start_byte
 	context.SignatureContentsStartByte = signature_contents_start_byte
@@ -127,7 +162,7 @@ func (context *SignContext) SignPDF() error {
 	}
 
 	// Calculate the new start position of the xref table.
-	context.NewXrefStart = context.PDFReader.XrefInformation.StartPos + int64(len(signature_object)) + int64(len(catalog))
+	context.NewXrefStart = context.Filesize + int64(len(signature_object)) + int64(len(catalog)) + int64(len(visual_signature))
 
 	if err := context.writeXref(); err != nil {
 		return err
@@ -145,5 +180,10 @@ func (context *SignContext) SignPDF() error {
 		return err
 	}
 
+	err = context.OutputFile.Sync()
+	if err != nil {
+		return err
+	}
+
 	return nil
 }

verify/verify.go

@@ -14,6 +14,7 @@ import (
 	"github.com/digitorus/pkcs7"
 	"github.com/digitorus/timestamp"
 	"golang.org/x/crypto/ocsp"
+	"go/src/log"
 )
 
 type RevocationInfoArchival struct {
@@ -70,9 +71,11 @@ func Verify(file *os.File) (apiResp *Response, err error) {
 	finfo, _ := file.Stat()
 	size := finfo.Size()
 
+	file.Seek(0, 0)
+
 	rdr, err := pdf.NewReader(file, size)
 	if err != nil {
-		return nil, fmt.Errorf("Failed to open file")
+		return nil, fmt.Errorf("Failed to open file: %v", err)
 	}
 
 	// AcroForm will contain a SigFlags value if the form contains a digital signature
@@ -129,6 +132,12 @@ 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...)
 		}
 
@@ -180,8 +189,10 @@ func Verify(file *os.File) (apiResp *Response, err error) {
 				signer.ValidSignature = true
 				signer.TrustedIssuer = false
 			}
+			log.Println("Invalid sig")
 			apiResp.Error = fmt.Sprintln("Failed to verify signature:", err)
 		} else {
+			log.Println("Valid sig")
 			signer.ValidSignature = true
 			signer.TrustedIssuer = true
 		}