From a63f5bc4ea1081dfbb8c504103dbb735ab2d1994 Mon Sep 17 00:00:00 2001
From: Thomas Leitner <t_leitner@gmx.at>
Date: Sat, 14 Sep 2024 22:27:59 +0200
Subject: [PATCH] Fix Signature#signed_data to work for invalid offsets

---
 CHANGELOG.md                                     | 4 ++++
 lib/hexapdf/digital_signature/signature.rb       | 2 +-
 test/hexapdf/digital_signature/test_signature.rb | 7 +++++++
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c3963272..dbef86fe 100644
--- a/CHANGELOG.md
+++ b/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
 
diff --git a/lib/hexapdf/digital_signature/signature.rb b/lib/hexapdf/digital_signature/signature.rb
index 346a6ce4..8bbad086 100644
--- a/lib/hexapdf/digital_signature/signature.rb
+++ b/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
diff --git a/test/hexapdf/digital_signature/test_signature.rb b/test/hexapdf/digital_signature/test_signature.rb
index 869cfd96..dbe4b043 100644
--- a/test/hexapdf/digital_signature/test_signature.rb
+++ b/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