From cb4bd3db8b3842215f66e04c2d274faa43b9f764 Mon Sep 17 00:00:00 2001
From: Rafal Kupiec <belliash@codingworkshop.eu.org>
Date: Tue, 9 Jan 2024 16:24:57 +0100
Subject: [PATCH] Return a copy of config value, so that it won't get altered

---
 xtldr/config.c | 26 +++++++++++++++++++++-----
 1 file changed, 21 insertions(+), 5 deletions(-)

diff --git a/xtldr/config.c b/xtldr/config.c
index 763a03d..c2e8569 100644
--- a/xtldr/config.c
+++ b/xtldr/config.c
@@ -25,10 +25,12 @@ BlGetConfigValue(IN CONST PWCHAR ConfigName)
 {
     PXTBL_CONFIG_ENTRY ConfigEntry;
     PLIST_ENTRY ConfigListEntry;
-    SIZE_T Length;
+    SIZE_T KeyLength, ValueLength;
+    EFI_STATUS Status;
+    PWCHAR Value;
 
     /* Get config entry name length */
-    Length = RtlWideStringLength(ConfigName, 0);
+    KeyLength = RtlWideStringLength(ConfigName, 0);
 
     /* Iterate through config entries */
     ConfigListEntry = BlpConfig.Flink;
@@ -38,10 +40,24 @@ BlGetConfigValue(IN CONST PWCHAR ConfigName)
         ConfigEntry = CONTAIN_RECORD(ConfigListEntry, XTBL_CONFIG_ENTRY, Flink);
 
         /* Check if requested configuration found */
-        if(RtlCompareWideStringInsensitive(ConfigEntry->Name, ConfigName, Length) == 0)
+        if(RtlCompareWideStringInsensitive(ConfigEntry->Name, ConfigName, KeyLength) == 0)
         {
-            /* Return config value */
-            return ConfigEntry->Value;
+            /* Get value length */
+            ValueLength = RtlWideStringLength(ConfigEntry->Value, 0);
+
+            /* Allocate memory for value */
+            Status = BlMemoryAllocatePool(ValueLength * sizeof(WCHAR), (PVOID *)&Value);
+            if(Status != STATUS_EFI_SUCCESS)
+            {
+                /* Memory allocation failure, return NULL */
+                BlDebugPrint(L"ERROR: Memory allocation failure (Status Code: 0x%lx)\n", Status);
+                return NULL;
+            }
+
+            /* Copy value and return it */
+            RtlCopyMemory(Value, ConfigEntry->Value, ValueLength * sizeof(WCHAR));
+            Value[ValueLength] = 0;
+            return Value;
         }
 
         /* Move to the next config entry */