Re: [PATCH] UefiPayloadPkg: Fix bug that Elf loader doesn't relocate in some case


Guo Dong
 

Reviewed-by: Guo Dong <guo.dong@...>

-----Original Message-----
From: Liu, Zhiguang <zhiguang.liu@...>
Sent: Wednesday, April 6, 2022 6:52 AM
To: devel@edk2.groups.io
Cc: Dong, Guo <guo.dong@...>; Ni, Ray <ray.ni@...>; Ma, Maurice <maurice.ma@...>; You, Benjamin <benjamin.you@...>; Rhodes, Sean <sean@...>
Subject: [PATCH] UefiPayloadPkg: Fix bug that Elf loader doesn't relocate in some case

Current implementation of the Elf loader reuses the same memory range if the desired memory range is covered by [file base, file base + file size].
However, there is a potentil bug, for example:
If the first segment is located at 0x1000, and the desired address is 0x2000. While the second segment is located at 0x2000, and the desired address is 0x2000. When we parse and try to load the elf file, current implementation may load the first segment at 0x2000, and override second segment.

Cc: Guo Dong <guo.dong@...>
Cc: Ray Ni <ray.ni@...>
Cc: Maurice Ma <maurice.ma@...>
Cc: Benjamin You <benjamin.you@...>
Cc: Sean Rhodes <sean@...>

Signed-off-by: Zhiguang Liu <zhiguang.liu@...>
---
UefiPayloadPkg/PayloadLoaderPeim/ElfLib/ElfLib.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/UefiPayloadPkg/PayloadLoaderPeim/ElfLib/ElfLib.c b/UefiPayloadPkg/PayloadLoaderPeim/ElfLib/ElfLib.c
index 2a6305c67b..c7dfae14af 100644
--- a/UefiPayloadPkg/PayloadLoaderPeim/ElfLib/ElfLib.c
+++ b/UefiPayloadPkg/PayloadLoaderPeim/ElfLib/ElfLib.c
@@ -312,6 +312,13 @@ ParseElfImage (
ElfCt->ReloadRequired = TRUE; } + if (SegInfo.MemAddr != ((UINTN)ElfCt->FileBase + SegInfo.Offset)) {+ //+ // Need to relocate if the desired address is not the current address+ //+ ElfCt->ReloadRequired = TRUE;+ }+ if (Base > (SegInfo.MemAddr & ~(EFI_PAGE_SIZE - 1))) { Base = SegInfo.MemAddr & ~(EFI_PAGE_SIZE - 1); }--
2.32.0.windows.2

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