From c8a50907b02f69ac1af44559eb34fe3bd2916eaf Mon Sep 17 00:00:00 2001
From: vit9696 <vit9696@users.noreply.github.com>
Date: Tue, 14 Apr 2020 07:55:15 +0300
Subject: [PATCH] OcXmlLib: Fix parsing negative integers

Resolves issues with parsing MinVersion/MinDate in APFS section
---
 Library/OcXmlLib/OcXmlLib.c | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/Library/OcXmlLib/OcXmlLib.c b/Library/OcXmlLib/OcXmlLib.c
index 7b41558c..074f1261 100755
--- a/Library/OcXmlLib/OcXmlLib.c
+++ b/Library/OcXmlLib/OcXmlLib.c
@@ -1530,16 +1530,37 @@ PlistIntegerValue (
   BOOLEAN   Hex
   )
 {
-  UINT64  Temp;
+  UINT64       Temp;
+  CONST CHAR8  *TempStr;
+  BOOLEAN      Negate;
 
   if (PlistNodeCast (Node, PLIST_NODE_TYPE_INTEGER) == NULL) {
     return FALSE;
   }
 
+  TempStr = XmlNodeContent (Node);
+
+  while (*TempStr == ' ' || *TempStr == '\t') {
+    ++TempStr;
+  }
+
+  Negate = *TempStr == '-';
+
+  if (Negate) {
+    ++TempStr;
+  }
+
   if (Hex) {
-    Temp = AsciiStrHexToUint64 (XmlNodeContent (Node));
+    Temp = AsciiStrHexToUint64 (TempStr);
   } else {
-    Temp = AsciiStrDecimalToUint64 (XmlNodeContent (Node));
+    Temp = AsciiStrDecimalToUint64 (TempStr);
+  }
+
+  //
+  // May produce unexpected results when the value is too large, but just do not care.
+  //
+  if (Negate) {
+    Temp = 0ULL - Temp;
   }
 
   switch (Size) {