It looks good to me. Thanks for fixing it. Reviewed-by: Jian J Wang <[email protected]>
Regards, Jian > -----Original Message----- > From: [email protected] <[email protected]> On Behalf Of Kun Qin > Sent: Wednesday, March 16, 2022 12:00 PM > To: [email protected] > Cc: Yao, Jiewen <[email protected]>; Dong, Eric <[email protected]>; Ni, > Ray <[email protected]>; Wang, Jian J <[email protected]>; Gao, Liming > <[email protected]> > Subject: [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 <[email protected]> > Cc: Eric Dong <[email protected]> > Cc: Ray Ni <[email protected]> > Cc: Jian J Wang <[email protected]> > Cc: Liming Gao <[email protected]> > > Signed-off-by: Kun Qin <[email protected]> > --- > 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 > > > > > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#89209): https://edk2.groups.io/g/devel/message/89209 Mute This Topic: https://groups.io/mt/89815350/21656 Group Owner: [email protected] Unsubscribe: https://edk2.groups.io/g/devel/unsub [[email protected]] -=-=-=-=-=-=-=-=-=-=-=-
