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Revert "Revert "fix: Existing catalog entries are being discarded""

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This commit is contained in:
Paul van Brouwershaven
2025-02-21 21:32:38 +01:00
committed by GitHub
parent be2806bdb6
commit 94e7fa22a9
2 changed files with 74 additions and 7 deletions
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69
sign/pdfcatalog.go
View File

@@ -2,15 +2,21 @@ package sign
import (
"bytes"
"fmt"
"github.com/digitorus/pdf"
"io"
"slices"
"strconv"
)
func (context *SignContext) createCatalog() ([]byte, error) {
var overwrittenCatalogKeys []string
var catalog_buffer bytes.Buffer
// Start the catalog object
catalog_buffer.WriteString("<<\n")
catalog_buffer.WriteString(" /Type /Catalog\n")
overwrittenCatalogKeys = append(overwrittenCatalogKeys, "Type")
// (Optional; PDF 1.4) The version of the PDF specification to which
// the document conforms (for example, 1.4) if later than the version
@@ -50,13 +56,16 @@ func (context *SignContext) createCatalog() ([]byte, error) {
if foundPages {
pages := root.Key("Pages").GetPtr()
catalog_buffer.WriteString(" /Pages " + strconv.Itoa(int(pages.GetID())) + " " + strconv.Itoa(int(pages.GetGen())) + " R\n")
overwrittenCatalogKeys = append(overwrittenCatalogKeys, "Pages")
}
if foundNames {
names := root.Key("Names").GetPtr()
catalog_buffer.WriteString(" /Names " + strconv.Itoa(int(names.GetID())) + " " + strconv.Itoa(int(names.GetGen())) + " R\n")
overwrittenCatalogKeys = append(overwrittenCatalogKeys, "Names")
}
// Start the AcroForm dictionary with /NeedAppearances
overwrittenCatalogKeys = append(overwrittenCatalogKeys, "AcroForm")
catalog_buffer.WriteString(" /AcroForm <<\n")
catalog_buffer.WriteString(" /Fields [")
@@ -119,7 +128,65 @@ func (context *SignContext) createCatalog() ([]byte, error) {
// Finalize the AcroForm and Catalog object
catalog_buffer.WriteString(" >>\n") // Close AcroForm
catalog_buffer.WriteString(">>\n") // Close Catalog
// Copy over existing catalog entries from the original document that we did not need to override.
for _, key := range root.Keys() {
if !slices.Contains(overwrittenCatalogKeys, key) {
_, _ = fmt.Fprintf(&catalog_buffer, "/%s ", key)
context.serializeCatalogEntry(&catalog_buffer, rootPtr.GetID(), root.Key(key))
}
}
catalog_buffer.WriteString(">>\n") // Close Catalog
return catalog_buffer.Bytes(), nil
}
// serializeCatalogEntry takes a pdf.Value and serializes it to the given writer.
func (context *SignContext) serializeCatalogEntry(w io.Writer, rootObjId uint32, value pdf.Value) {
if ptr := value.GetPtr(); ptr.GetID() != rootObjId {
// Indirect object
_, _ = fmt.Fprintf(w, "%d %d R", ptr.GetID(), ptr.GetGen())
return
}
// Direct object
switch value.Kind() {
case pdf.String:
_, _ = fmt.Fprintf(w, "(%s)", value.RawString())
case pdf.Null:
_, _ = fmt.Fprint(w, "null")
case pdf.Bool:
if value.Bool() {
_, _ = fmt.Fprint(w, "true")
} else {
_, _ = fmt.Fprint(w, "false")
}
case pdf.Integer:
_, _ = fmt.Fprintf(w, "%d", value.Int64())
case pdf.Real:
_, _ = fmt.Fprintf(w, "%f", value.Float64())
case pdf.Name:
_, _ = fmt.Fprintf(w, "/%s", value.Name())
case pdf.Dict:
_, _ = fmt.Fprint(w, "<<")
for idx, key := range value.Keys() {
if idx > 0 {
_, _ = fmt.Fprint(w, " ") // Space between items
}
_, _ = fmt.Fprintf(w, "/%s ", key)
context.serializeCatalogEntry(w, rootObjId, value.Key(key))
}
_, _ = fmt.Fprint(w, ">>")
case pdf.Array:
_, _ = fmt.Fprint(w, "[")
for idx := range value.Len() {
if idx > 0 {
_, _ = fmt.Fprint(w, " ") // Space between items
}
context.serializeCatalogEntry(w, rootObjId, value.Index(idx))
}
_, _ = fmt.Fprint(w, "]")
case pdf.Stream:
panic("stream cannot be a direct object")
}
}

12
sign/pdfcatalog_test.go
View File

@@ -15,17 +15,17 @@ var testFiles = []struct {
{
file: "../testfiles/testfile20.pdf",
expectedCatalogs: map[CertType]string{
CertificationSignature: "<<\n /Type /Catalog\n /Pages 3 0 R\n /AcroForm <<\n /Fields [10 0 R]\n /SigFlags 3\n >>\n>>\n",
UsageRightsSignature: "<<\n /Type /Catalog\n /Pages 3 0 R\n /AcroForm <<\n /Fields [10 0 R]\n /SigFlags 1\n >>\n>>\n",
ApprovalSignature: "<<\n /Type /Catalog\n /Pages 3 0 R\n /AcroForm <<\n /Fields [10 0 R]\n /SigFlags 3\n >>\n>>\n",
CertificationSignature: "<<\n /Type /Catalog\n /Pages 3 0 R\n /AcroForm <<\n /Fields [10 0 R]\n /SigFlags 3\n >>\n/Metadata 2 0 R>>\n",
UsageRightsSignature: "<<\n /Type /Catalog\n /Pages 3 0 R\n /AcroForm <<\n /Fields [10 0 R]\n /SigFlags 1\n >>\n/Metadata 2 0 R>>\n",
ApprovalSignature: "<<\n /Type /Catalog\n /Pages 3 0 R\n /AcroForm <<\n /Fields [10 0 R]\n /SigFlags 3\n >>\n/Metadata 2 0 R>>\n",
},
},
{
file: "../testfiles/testfile21.pdf",
expectedCatalogs: map[CertType]string{
CertificationSignature: "<<\n /Type /Catalog\n /Pages 9 0 R\n /Names 6 0 R\n /AcroForm <<\n /Fields [16 0 R]\n /SigFlags 3\n >>\n>>\n",
UsageRightsSignature: "<<\n /Type /Catalog\n /Pages 9 0 R\n /Names 6 0 R\n /AcroForm <<\n /Fields [16 0 R]\n /SigFlags 1\n >>\n>>\n",
ApprovalSignature: "<<\n /Type /Catalog\n /Pages 9 0 R\n /Names 6 0 R\n /AcroForm <<\n /Fields [16 0 R]\n /SigFlags 3\n >>\n>>\n",
CertificationSignature: "<<\n /Type /Catalog\n /Pages 9 0 R\n /Names 6 0 R\n /AcroForm <<\n /Fields [16 0 R]\n /SigFlags 3\n >>\n/Metadata 8 0 R>>\n",
UsageRightsSignature: "<<\n /Type /Catalog\n /Pages 9 0 R\n /Names 6 0 R\n /AcroForm <<\n /Fields [16 0 R]\n /SigFlags 1\n >>\n/Metadata 8 0 R>>\n",
ApprovalSignature: "<<\n /Type /Catalog\n /Pages 9 0 R\n /Names 6 0 R\n /AcroForm <<\n /Fields [16 0 R]\n /SigFlags 3\n >>\n/Metadata 8 0 R>>\n",
},
},
}