Reviewed-by: Liming Gao <gaolim...@byosoft.com.cn> > -----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3月16日 12:00 > 收件人: devel@edk2.groups.io > 抄送: Jiewen Yao <jiewen....@intel.com>; Eric Dong <eric.d...@intel.com>; > Ray Ni <ray...@intel.com>; Jian J Wang <jian.j.w...@intel.com>; Liming Gao > <gaolim...@byosoft.com.cn> > 主题: [edk2-devel] [PATCH v1 1/1] MdeModulePkg: PiSmmCore: Inspect > memory guarded with pool headers > > 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....@intel.com> > Cc: Eric Dong <eric.d...@intel.com> > Cc: Ray Ni <ray...@intel.com> > Cc: Jian J Wang <jian.j.w...@intel.com> > Cc: Liming Gao <gaolim...@byosoft.com.cn> > > Signed-off-by: Kun Qin <kuqi...@gmail.com> > --- > 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); > -- > 2.35.1.windows.2 > > > > >
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