From 3f0beb9fa3ba7436e1b0595096ffcb193f4220e1 Mon Sep 17 00:00:00 2001
From: Bruno Achauer <bruno.achauer@intel.com>
Date: Tue, 21 Feb 2023 17:40:13 +0100
Subject: [PATCH] Ensure that ELF images are loaded at their preferred address
 (#1833)

Currently, loading an ELF image will relocate the image (to its
preferred load address) only if there is at least one ELF segment
that is not completely contained in the file loaded (i.e. the memory
segment size is larger than the size inside the file. This behavior
is generally triggered by the segment that contains the .bss section).

Consequently, images that contain initialized data only (e.g. QNX IFS
files) don't get relocated, and will usually crash when jumping to the
image entry point.

This change checks whether the ELF image is already loaded at the
preferred address, and forces image relocation if not.

Signed-off-by: Bruno Achauer <bruno.achauer@intel.com>
---
 BootloaderCommonPkg/Library/ElfLib/ElfLib.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/BootloaderCommonPkg/Library/ElfLib/ElfLib.c b/BootloaderCommonPkg/Library/ElfLib/ElfLib.c
index 4e863363..f53a0d76 100644
--- a/BootloaderCommonPkg/Library/ElfLib/ElfLib.c
+++ b/BootloaderCommonPkg/Library/ElfLib/ElfLib.c
@@ -1,7 +1,7 @@
 /** @file
   ELF library
 
-  Copyright (c) 2019, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2019-2023, Intel Corporation. All rights reserved.<BR>
   SPDX-License-Identifier: BSD-2-Clause-Patent
 
 **/
@@ -242,6 +242,7 @@ ParseElfImage (
   UINTN          End;
   UINTN          Base;
   UINTN          FileOffset;
+  UINT8          *CurrentLoadAddress;
 
   if (ElfCt == NULL) {
     return EFI_INVALID_PARAMETER;
@@ -317,10 +318,14 @@ ParseElfImage (
   //
   ElfCt->ImageSize             = End - Base + 1;
   ElfCt->PreferredImageAddress = (VOID *) Base;
+  CurrentLoadAddress           = ElfCt->FileBase + FileOffset;
+  if (ElfCt->PreferredImageAddress != CurrentLoadAddress) {
+    ElfCt->ReloadRequired = TRUE;
+  }
   if (ElfCt->ReloadRequired) {
     ElfCt->ImageAddress = NULL;
   } else {
-    ElfCt->ImageAddress = ElfCt->FileBase + FileOffset;
+      ElfCt->ImageAddress = CurrentLoadAddress;
   }
 
   CalculateElfFileSize (ElfCt, &ElfCt->FileSize);