https://git.ruby-lang.org/ruby.git/commit/?id=684353fc03

From 684353fc03afd6e7c887b65bd18f0b3aeb98101c Mon Sep 17 00:00:00 2001
From: Jeremy Bopp <jeremy@b...>
Date: Sun, 11 Sep 2022 09:08:14 -0500
Subject: [Win32] Negative length `IO#sysread`

Raise `ArgumentError` in `IO#sysread` on Windows when given a negative
length.

Fixes [Bug #18880]
---
 io.c                 | 3 ++-
 test/ruby/test_io.rb | 8 ++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/io.c b/io.c
index 30165e1616..675c0ad3c2 100644
--- a/io.c
+++ b/io.c
@@ -3053,7 +3053,8 @@ static int https://github.com/ruby/ruby/blob/trunk/io.c#L3053
 io_setstrbuf(VALUE *str, long len)
 {
 #ifdef _WIN32
-    len = (len + 1) & ~1L;	/* round up for wide char */
+    if (len > 0)
+        len = (len + 1) & ~1L;	/* round up for wide char */
 #endif
     if (NIL_P(*str)) {
         *str = rb_str_new(0, len);
diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index d6fcf16ddd..f791b4415d 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -2213,6 +2213,14 @@ class TestIO < Test::Unit::TestCase https://github.com/ruby/ruby/blob/trunk/test/ruby/test_io.rb#L2213
     end)
   end
 
+  def test_sysread_with_negative_length
+    make_tempfile {|t|
+      open(t.path) do |f|
+        assert_raise(ArgumentError) { f.sysread(-1) }
+      end
+    }
+  end
+
   def test_flag
     make_tempfile {|t|
       assert_raise(ArgumentError) do
-- 
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