Kun:
This patch is reviewed before soft feature freeze. I agree to merge it for this stable tag.

Here is PR https://github.com/tianocore/edk2/pull/2881

Thanks
Liming

-----邮件原件-----
发件人: devel@edk2.groups.io <devel@edk2.groups.io> 代表 Kun Qin
发送时间: 2022年5月13日 8:23
收件人: devel@edk2.groups.io
抄送: Jiewen Yao <jiewen.yao@...>; Eric Dong <eric.dong@...>;
Ray Ni <ray.ni@...>; Jian J Wang <jian.j.wang@...>; Liming Gao
<gaoliming@...>
主题: Re: [edk2-devel] [PATCH v2 1/1] MdeModulePkg: PiSmmCore: Inspect
memory guarded with pool headers

Hi maintainers,

This patch was reviewed and sent a while back, could you please help me
to merge in this change, if no further feedback?

Thanks in advance,
Kun

On 4/25/2022 5:47 PM, Kun Qin via groups.io wrote:

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3488

Current free pool routine from PiSmmCore will inspect memory guard status
for target buffer without considering pool headers. This could lead to
`IsMemoryGuarded` function to return incorrect results.

In that sense, allocating a 0 sized pool could cause an allocated buffer
directly points into a guard page, which is legal. However, trying to
free this pool will cause the routine changed in this commit to read XP
pages, which leads to page fault.

This change will inspect memory guarded with pool headers. This can avoid
errors when a pool content happens to be on a page boundary.

Cc: Jiewen Yao <jiewen.yao@...>
Cc: Eric Dong <eric.dong@...>
Cc: Ray Ni <ray.ni@...>
Cc: Jian J Wang <jian.j.wang@...>
Cc: Liming Gao <gaoliming@...>

Signed-off-by: Kun Qin <kuqin12@...>
Reviewed-by: Jian J Wang <jian.j.wang@...>
Reviewed-by: Liming Gao <gaoliming@...>
---

Notes:
v2:
- Added reviewed-by tag [Jian]
- Added reviewed-by tag [Liming]

MdeModulePkg/Core/PiSmmCore/Pool.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/MdeModulePkg/Core/PiSmmCore/Pool.c

b/MdeModulePkg/Core/PiSmmCore/Pool.c

index 96ebe811c669..e1ff40a8ea55 100644
--- a/MdeModulePkg/Core/PiSmmCore/Pool.c
+++ b/MdeModulePkg/Core/PiSmmCore/Pool.c
@@ -382,11 +382,6 @@ SmmInternalFreePool (
return EFI_INVALID_PARAMETER;
}

- MemoryGuarded = IsHeapGuardEnabled () &&
- IsMemoryGuarded

((EFI_PHYSICAL_ADDRESS)(UINTN)Buffer);

- HasPoolTail = !(MemoryGuarded &&
- ((PcdGet8 (PcdHeapGuardPropertyMask) & BIT7) ==

0));

-
FreePoolHdr = (FREE_POOL_HEADER *)((POOL_HEADER *)Buffer - 1);
ASSERT (FreePoolHdr->Header.Signature ==

POOL_HEAD_SIGNATURE);

ASSERT (!FreePoolHdr->Header.Available);
@@ -394,6 +389,11 @@ SmmInternalFreePool (
return EFI_INVALID_PARAMETER;
}

+ MemoryGuarded = IsHeapGuardEnabled () &&
+ IsMemoryGuarded

((EFI_PHYSICAL_ADDRESS)(UINTN)FreePoolHdr);

+ HasPoolTail = !(MemoryGuarded &&
+ ((PcdGet8 (PcdHeapGuardPropertyMask) & BIT7) ==

0));

+
if (HasPoolTail) {
PoolTail = HEAD_TO_TAIL (&FreePoolHdr->Header);
ASSERT (PoolTail->Signature == POOL_TAIL_SIGNATURE);