Fix StreamView.Read overflow

Visionaid-International-Ltd · Oct 8, 2024 · b7cf828 · b7cf828
1 parent 560ca59
commit b7cf828
Show file tree

Hide file tree

Showing 2 changed files with 17 additions and 2 deletions.
diff --git a/sources/OpenMcdf/MathEx.cs b/sources/OpenMcdf/MathEx.cs
@@ -0,0 +1,12 @@
+using System;
+
+namespace OpenMcdf
+{
+ internal static class MathEx
+ {
+ public static int Clamp(int value, int min, int max)
+ {
+ return Math.Max(min, Math.Min(max, value));
+ }
+ }
+}
diff --git a/sources/OpenMcdf/StreamView.cs b/sources/OpenMcdf/StreamView.cs
@@ -91,8 +91,11 @@ public override int Read(byte[] buffer, int offset, int count)
  int nRead = 0;
 
  // Don't try to read more bytes than this stream contains.
- long intMax = Math.Min(int.MaxValue, length);
- count = Math.Min((int)intMax, count);
+ long maxReadable = Math.Min(int.MaxValue, length - position);
+ count = MathEx.Clamp(count, 0, (int)maxReadable);
+
+ if (count == 0)
+ return 0;
 
  if (BaseSectorChain != null && BaseSectorChain.Count > 0)
  {