Tryanks/pdfsign
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Retry with expected signature lenght

Browse Source
This commit is contained in:
Paul van Brouwershaven
2022-06-29 21:07:59 +02:00
parent 2ce268ea4d
commit 3caf640baa
2 changed files with 18 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
sign/pdfsignature.go
View File

@@ -225,7 +225,7 @@ func (context *SignContext) GetTSA(sign_content []byte) (timestamp_response []by
ts_request_reader := bytes.NewReader(ts_request)
req, err := http.NewRequest("POST", context.SignData.TSA.URL, ts_request_reader)
if err != nil {
return nil, err
return nil, fmt.Errorf("error requesting timestamp (%s): %w", context.SignData.TSA.URL, err)
}
req.Header.Add("Content-Type", "application/timestamp-query")
@@ -247,9 +247,9 @@ func (context *SignContext) GetTSA(sign_content []byte) (timestamp_response []by
if err == nil {
defer resp.Body.Close()
body, _ := ioutil.ReadAll(resp.Body)
err = errors.New("Non success response (" + strconv.Itoa(code) + "): " + string(body))
err = errors.New("non success response (" + strconv.Itoa(code) + "): " + string(body))
} else {
err = errors.New("Non success response (" + strconv.Itoa(code) + ")")
err = errors.New("non success response (" + strconv.Itoa(code) + ")")
}
return nil, err
@@ -274,7 +274,10 @@ func (context *SignContext) replaceSignature() error {
hex.Encode(dst, signature)
if uint32(len(dst)) > context.SignatureMaxLength {
return errors.New("Signature is too big to fit in reserved space.")
// TODO: Should we log this retry?
// set new base and try signing again
context.SignatureMaxLengthBase += (uint32(len(dst)) - context.SignatureMaxLength) + 1
return context.SignPDF()
}
context.OutputBuffer.Seek(0, 0)

15
sign/sign.go
View File

@@ -8,9 +8,10 @@ import (
"os"
"time"
"bitbucket.org/digitorus/pdf"
"bitbucket.org/digitorus/pdfsign/revocation"
"github.com/digitorus/pdf"
"github.com/digitorus/pdfsign/revocation"
"github.com/digitorus/pkcs7"
"github.com/mattetti/filebuffer"
)
@@ -90,6 +91,7 @@ type SignContext struct {
SignatureContentsStartByte int64
ByteRangeValues []int64
SignatureMaxLength uint32
SignatureMaxLengthBase uint32
}
func SignFile(input string, output string, sign_data SignData) error {
@@ -123,6 +125,7 @@ func Sign(input io.ReadSeeker, output io.Writer, rdr *pdf.Reader, size int64, si
sign_data.ObjectId = uint32(rdr.XrefInformation.ItemCount) + 3
// We do size+1 because we insert a newline.
context := SignContext{
Filesize: size + 1,
PDFReader: rdr,
@@ -138,6 +141,7 @@ func Sign(input io.ReadSeeker, output io.Writer, rdr *pdf.Reader, size int64, si
ObjectId: uint32(rdr.XrefInformation.ItemCount) + 2,
},
SignData: sign_data,
SignatureMaxLengthBase: uint32(hex.EncodedLen(512)),
}
err := context.SignPDF()
@@ -160,6 +164,7 @@ func (context *SignContext) SignPDF() error {
context.OutputBuffer = filebuffer.New([]byte{})
// Copy old file into new file.
context.InputFile.Seek(0, 0)
if _, err := io.Copy(context.OutputBuffer, context.InputFile); err != nil {
return err
}
@@ -170,9 +175,9 @@ func (context *SignContext) SignPDF() error {
}
// Base size for signature.
context.SignatureMaxLength = uint32(hex.EncodedLen(512))
context.SignatureMaxLength = context.SignatureMaxLengthBase
switch string(context.SignData.Certificate.SignatureAlgorithm) {
switch context.SignData.Certificate.SignatureAlgorithm.String() {
case "SHA1-RSA":
case "ECDSA-SHA1":
case "DSA-SHA1":
@@ -221,7 +226,7 @@ func (context *SignContext) SignPDF() error {
// Add estimated size for TSA.
// We can't kow actual size of TSA until after signing.
if context.SignData.TSA.URL != "" {
context.SignatureMaxLength += uint32(hex.EncodedLen(4000))
context.SignatureMaxLength += uint32(hex.EncodedLen(6000))
}
// Fetch revocation data before adding signature placeholder.