Fix Signature#signed_data to work for invalid offsets

CHANGELOG.md

@@ -10,6 +10,10 @@
 * [HexaPDF::Type::AcroForm::Form] text-like field creation methods to always set
   a default appearance string
 
+### Fixed
+
+* [HexaPDF::DigitalSignature::Signature#signed_data] to work for invalid offsets
+
 
 ## 0.47.0 - 2024-09-07
 

lib/hexapdf/digital_signature/signature.rb

@@ -211,7 +211,7 @@ def signed_data
         data = ''.b
         self[:ByteRange]&.each_slice(2) do |offset, length|
           io.pos = offset
-          data << io.read(length)
+          data << io.read(length).to_s
         end
         data
       end

test/hexapdf/digital_signature/test_signature.rb

@@ -111,6 +111,13 @@
       assert_equal((MINIMAL_PDF[0, 400] << MINIMAL_PDF[500, 333]).b, @sig.signed_data)
     end
 
+    it "works for invalid offsets" do
+      doc = HexaPDF::Document.new(io: StringIO.new(MINIMAL_PDF))
+      @sig.document = doc
+      @sig[:ByteRange] = [0, 400, 9000, 333]
+      assert_equal(MINIMAL_PDF[0, 400], @sig.signed_data)
+    end
+
     it "fails if the document isn't associated with an existing PDF file" do
       assert_raises(HexaPDF::Error) { @sig.signed_data }
     end