From 86b33bd3cefd85e18732cea6325daa8b33535ad0 Mon Sep 17 00:00:00 2001
From: CasualPokePlayer <50538166+CasualPokePlayer@users.noreply.github.com>
Date: Sun, 2 Apr 2023 02:19:52 -0700
Subject: [PATCH] fix DeltaSerializer validation checks and add one more

---
 src/BizHawk.Common/DeltaSerializer.cs | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/BizHawk.Common/DeltaSerializer.cs b/src/BizHawk.Common/DeltaSerializer.cs
index ddbeb6da7f..0851199f9e 100644
--- a/src/BizHawk.Common/DeltaSerializer.cs
+++ b/src/BizHawk.Common/DeltaSerializer.cs
@@ -126,7 +126,7 @@ namespace BizHawk.Common
 				{
 					header = -header;
 
-					if (header < dataEnd - dataPos || header < deltaEnd - deltaPos)
+					if (dataEnd - dataPos < header || deltaEnd - deltaPos < header)
 					{
 						throw new InvalidOperationException("Corrupt delta header!");
 					}
@@ -140,7 +140,7 @@ namespace BizHawk.Common
 				}
 				else // sameness block
 				{
-					if (header < dataEnd - dataPos)
+					if (dataEnd - dataPos < header)
 					{
 						throw new InvalidOperationException("Corrupt delta header!");
 					}
@@ -150,6 +150,11 @@ namespace BizHawk.Common
 
 				dataPos += header;
 			}
+
+			if (dataPos != dataEnd)
+			{
+				throw new InvalidOperationException("Did not reach end of data after applying delta!");
+			}
 		}
 	}
 }