Tryanks/pdfsign
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This commit is contained in:
Jeroen Bobbeldijk
2017-07-11 08:21:18 +02:00
parent db69b6a4c0
commit 7b19471330
9 changed files with 104 additions and 24 deletions
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16
sign/helpers.go
View File

@@ -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)

4
sign/pdfcatalog.go
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@@ -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 >>"
}
}

25
sign/pdfinfo.go Normal file
View File

@@ -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
}

2
sign/pdfsignature.go
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@@ -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
}

9
sign/pdftrailer.go
View File

@@ -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 {

12
sign/pdfvisualsignature.go
View File

@@ -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()
visual_signature += " /P " + strconv.Itoa(int(page.GetID())) + " " + strconv.Itoa(int(page.GetGen())) + " R"
first_page, err := findFirstPage(root.Key("Pages"))
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"

19
sign/pdfxref.go
View File

@@ -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)
signature_xref_line := leftPad(signature_object_start_position, "0", 10-len(signature_object_start_position)) + " 00000 n\n"
info_object_start_position := strconv.FormatInt(context.Filesize+context.VisualSignData.Length+context.CatalogData.Length, 10)
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 {

33
sign/sign.go
View File

@@ -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))
signature_contents_start_byte += context.Filesize + int64(len(catalog)) + int64(len(visual_signature))
byte_range_start_byte += appended_bytes
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

8
verify/verify.go
View File

@@ -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...)
}