* [PATCH v1] MdeModulePkg/Variable/RuntimeDxe: Not copy SMM pointers in comm buffer
@ 2019-08-06 7:18 Wu, Hao A
2019-08-06 14:55 ` [edk2-devel] " Zeng, Star
0 siblings, 1 reply; 3+ messages in thread
From: Wu, Hao A @ 2019-08-06 7:18 UTC (permalink / raw)
To: devel; +Cc: Hao A Wu, Liming Gao, Jian J Wang
REF:https://bugzilla.tianocore.org/show_bug.cgi?id=2002
This commit will update the logic in function SmmVariableGetStatistics()
so that the pointer fields ('Next' and 'Name') in structure
VARIABLE_INFO_ENTRY will not be copied into the SMM communication buffer.
Doing so will prevent SMM pointers address from being leaked into non-SMM
environment.
Please note that newly introduced internal function CopyVarInfoEntry()
will not use CopyMem() to copy the whole VARIABLE_INFO_ENTRY structure and
then zero out the 'Next' and 'Name' fields. This is for preventing race
conditions where the pointers value might still be read.
Cc: Liming Gao <liming.gao@intel.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Signed-off-by: Hao A Wu <hao.a.wu@intel.com>
---
MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c | 33 ++++++++++++++++++--
1 file changed, 31 insertions(+), 2 deletions(-)
diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
index ec463d063e..81a9c9e849 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
@@ -312,6 +312,35 @@ GetFvbCountAndBuffer (
/**
+ Copy only the meaningful fields of the variable statistics information from
+ source buffer to the destination buffer. Other fields are filled with zero.
+
+ @param[in] DstInfoEntry A pointer to the buffer of destination variable
+ information entry.
+ @param[in] SrcInfoEntry A pointer to the buffer of source variable
+ information entry.
+
+**/
+static
+VOID
+CopyVarInfoEntry (
+ IN VARIABLE_INFO_ENTRY *DstInfoEntry,
+ IN VARIABLE_INFO_ENTRY *SrcInfoEntry
+ )
+{
+ DstInfoEntry->Next = NULL;
+ DstInfoEntry->Name = NULL;
+
+ CopyGuid (&DstInfoEntry->VendorGuid, &SrcInfoEntry->VendorGuid);
+ DstInfoEntry->Attributes = SrcInfoEntry->Attributes;
+ DstInfoEntry->ReadCount = SrcInfoEntry->ReadCount;
+ DstInfoEntry->WriteCount = SrcInfoEntry->WriteCount;
+ DstInfoEntry->DeleteCount = SrcInfoEntry->DeleteCount;
+ DstInfoEntry->CacheCount = SrcInfoEntry->CacheCount;
+ DstInfoEntry->Volatile = SrcInfoEntry->Volatile;
+}
+
+/**
Get the variable statistics information from the information buffer pointed by gVariableInfo.
Caution: This function may be invoked at SMM runtime.
@@ -373,7 +402,7 @@ SmmVariableGetStatistics (
*InfoSize = StatisticsInfoSize;
return EFI_BUFFER_TOO_SMALL;
}
- CopyMem (InfoEntry, VariableInfo, sizeof (VARIABLE_INFO_ENTRY));
+ CopyVarInfoEntry (InfoEntry, VariableInfo);
CopyMem (InfoName, VariableInfo->Name, NameSize);
*InfoSize = StatisticsInfoSize;
return EFI_SUCCESS;
@@ -413,7 +442,7 @@ SmmVariableGetStatistics (
return EFI_BUFFER_TOO_SMALL;
}
- CopyMem (InfoEntry, VariableInfo, sizeof (VARIABLE_INFO_ENTRY));
+ CopyVarInfoEntry (InfoEntry, VariableInfo);
CopyMem (InfoName, VariableInfo->Name, NameSize);
*InfoSize = StatisticsInfoSize;
--
2.12.0.windows.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [edk2-devel] [PATCH v1] MdeModulePkg/Variable/RuntimeDxe: Not copy SMM pointers in comm buffer 2019-08-06 7:18 [PATCH v1] MdeModulePkg/Variable/RuntimeDxe: Not copy SMM pointers in comm buffer Wu, Hao A @ 2019-08-06 14:55 ` Zeng, Star 2019-08-07 0:07 ` Wu, Hao A 0 siblings, 1 reply; 3+ messages in thread From: Zeng, Star @ 2019-08-06 14:55 UTC (permalink / raw) To: devel@edk2.groups.io, Wu, Hao A; +Cc: Gao, Liming, Wang, Jian J, Zeng, Star The DstInfoEntry is better to have identifer [out] instead of [in]? Thanks, Star > -----Original Message----- > From: devel@edk2.groups.io [mailto:devel@edk2.groups.io] On Behalf Of Wu, > Hao A > Sent: Tuesday, August 6, 2019 3:19 PM > To: devel@edk2.groups.io > Cc: Wu, Hao A <hao.a.wu@intel.com>; Gao, Liming <liming.gao@intel.com>; > Wang, Jian J <jian.j.wang@intel.com> > Subject: [edk2-devel] [PATCH v1] MdeModulePkg/Variable/RuntimeDxe: Not > copy SMM pointers in comm buffer > > REF:https://bugzilla.tianocore.org/show_bug.cgi?id=2002 > > This commit will update the logic in function SmmVariableGetStatistics() so > that the pointer fields ('Next' and 'Name') in structure > VARIABLE_INFO_ENTRY will not be copied into the SMM communication > buffer. > > Doing so will prevent SMM pointers address from being leaked into non- > SMM environment. > > Please note that newly introduced internal function CopyVarInfoEntry() will > not use CopyMem() to copy the whole VARIABLE_INFO_ENTRY structure and > then zero out the 'Next' and 'Name' fields. This is for preventing race > conditions where the pointers value might still be read. > > Cc: Liming Gao <liming.gao@intel.com> > Cc: Jian J Wang <jian.j.wang@intel.com> > Signed-off-by: Hao A Wu <hao.a.wu@intel.com> > --- > MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c | 33 > ++++++++++++++++++-- > 1 file changed, 31 insertions(+), 2 deletions(-) > > diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c > index ec463d063e..81a9c9e849 100644 > --- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c > +++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c > @@ -312,6 +312,35 @@ GetFvbCountAndBuffer ( > > > /** > + Copy only the meaningful fields of the variable statistics > + information from source buffer to the destination buffer. Other fields are > filled with zero. > + > + @param[in] DstInfoEntry A pointer to the buffer of destination variable > + information entry. > + @param[in] SrcInfoEntry A pointer to the buffer of source variable > + information entry. > + > +**/ > +static > +VOID > +CopyVarInfoEntry ( > + IN VARIABLE_INFO_ENTRY *DstInfoEntry, > + IN VARIABLE_INFO_ENTRY *SrcInfoEntry > + ) > +{ > + DstInfoEntry->Next = NULL; > + DstInfoEntry->Name = NULL; > + > + CopyGuid (&DstInfoEntry->VendorGuid, &SrcInfoEntry->VendorGuid); > + DstInfoEntry->Attributes = SrcInfoEntry->Attributes; > + DstInfoEntry->ReadCount = SrcInfoEntry->ReadCount; > + DstInfoEntry->WriteCount = SrcInfoEntry->WriteCount; > + DstInfoEntry->DeleteCount = SrcInfoEntry->DeleteCount; > + DstInfoEntry->CacheCount = SrcInfoEntry->CacheCount; > + DstInfoEntry->Volatile = SrcInfoEntry->Volatile; > +} > + > +/** > Get the variable statistics information from the information buffer pointed > by gVariableInfo. > > Caution: This function may be invoked at SMM runtime. > @@ -373,7 +402,7 @@ SmmVariableGetStatistics ( > *InfoSize = StatisticsInfoSize; > return EFI_BUFFER_TOO_SMALL; > } > - CopyMem (InfoEntry, VariableInfo, sizeof (VARIABLE_INFO_ENTRY)); > + CopyVarInfoEntry (InfoEntry, VariableInfo); > CopyMem (InfoName, VariableInfo->Name, NameSize); > *InfoSize = StatisticsInfoSize; > return EFI_SUCCESS; > @@ -413,7 +442,7 @@ SmmVariableGetStatistics ( > return EFI_BUFFER_TOO_SMALL; > } > > - CopyMem (InfoEntry, VariableInfo, sizeof (VARIABLE_INFO_ENTRY)); > + CopyVarInfoEntry (InfoEntry, VariableInfo); > CopyMem (InfoName, VariableInfo->Name, NameSize); > *InfoSize = StatisticsInfoSize; > > -- > 2.12.0.windows.1 > > > ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [edk2-devel] [PATCH v1] MdeModulePkg/Variable/RuntimeDxe: Not copy SMM pointers in comm buffer 2019-08-06 14:55 ` [edk2-devel] " Zeng, Star @ 2019-08-07 0:07 ` Wu, Hao A 0 siblings, 0 replies; 3+ messages in thread From: Wu, Hao A @ 2019-08-07 0:07 UTC (permalink / raw) To: Zeng, Star, devel@edk2.groups.io; +Cc: Gao, Liming, Wang, Jian J > -----Original Message----- > From: Zeng, Star > Sent: Tuesday, August 06, 2019 10:56 PM > To: devel@edk2.groups.io; Wu, Hao A > Cc: Gao, Liming; Wang, Jian J; Zeng, Star > Subject: RE: [edk2-devel] [PATCH v1] MdeModulePkg/Variable/RuntimeDxe: > Not copy SMM pointers in comm buffer > > The DstInfoEntry is better to have identifer [out] instead of [in]? Yes, good point. I will update it and send out the V2 patch. Best Regards, Hao Wu > > Thanks, > Star > > > -----Original Message----- > > From: devel@edk2.groups.io [mailto:devel@edk2.groups.io] On Behalf Of > Wu, > > Hao A > > Sent: Tuesday, August 6, 2019 3:19 PM > > To: devel@edk2.groups.io > > Cc: Wu, Hao A <hao.a.wu@intel.com>; Gao, Liming > <liming.gao@intel.com>; > > Wang, Jian J <jian.j.wang@intel.com> > > Subject: [edk2-devel] [PATCH v1] MdeModulePkg/Variable/RuntimeDxe: > Not > > copy SMM pointers in comm buffer > > > > REF:https://bugzilla.tianocore.org/show_bug.cgi?id=2002 > > > > This commit will update the logic in function SmmVariableGetStatistics() so > > that the pointer fields ('Next' and 'Name') in structure > > VARIABLE_INFO_ENTRY will not be copied into the SMM communication > > buffer. > > > > Doing so will prevent SMM pointers address from being leaked into non- > > SMM environment. > > > > Please note that newly introduced internal function CopyVarInfoEntry() will > > not use CopyMem() to copy the whole VARIABLE_INFO_ENTRY structure > and > > then zero out the 'Next' and 'Name' fields. This is for preventing race > > conditions where the pointers value might still be read. > > > > Cc: Liming Gao <liming.gao@intel.com> > > Cc: Jian J Wang <jian.j.wang@intel.com> > > Signed-off-by: Hao A Wu <hao.a.wu@intel.com> > > --- > > MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c | 33 > > ++++++++++++++++++-- > > 1 file changed, 31 insertions(+), 2 deletions(-) > > > > diff --git > a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c > > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c > > index ec463d063e..81a9c9e849 100644 > > --- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c > > +++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c > > @@ -312,6 +312,35 @@ GetFvbCountAndBuffer ( > > > > > > /** > > + Copy only the meaningful fields of the variable statistics > > + information from source buffer to the destination buffer. Other fields > are > > filled with zero. > > + > > + @param[in] DstInfoEntry A pointer to the buffer of destination > variable > > + information entry. > > + @param[in] SrcInfoEntry A pointer to the buffer of source variable > > + information entry. > > + > > +**/ > > +static > > +VOID > > +CopyVarInfoEntry ( > > + IN VARIABLE_INFO_ENTRY *DstInfoEntry, > > + IN VARIABLE_INFO_ENTRY *SrcInfoEntry > > + ) > > +{ > > + DstInfoEntry->Next = NULL; > > + DstInfoEntry->Name = NULL; > > + > > + CopyGuid (&DstInfoEntry->VendorGuid, &SrcInfoEntry->VendorGuid); > > + DstInfoEntry->Attributes = SrcInfoEntry->Attributes; > > + DstInfoEntry->ReadCount = SrcInfoEntry->ReadCount; > > + DstInfoEntry->WriteCount = SrcInfoEntry->WriteCount; > > + DstInfoEntry->DeleteCount = SrcInfoEntry->DeleteCount; > > + DstInfoEntry->CacheCount = SrcInfoEntry->CacheCount; > > + DstInfoEntry->Volatile = SrcInfoEntry->Volatile; > > +} > > + > > +/** > > Get the variable statistics information from the information buffer > pointed > > by gVariableInfo. > > > > Caution: This function may be invoked at SMM runtime. > > @@ -373,7 +402,7 @@ SmmVariableGetStatistics ( > > *InfoSize = StatisticsInfoSize; > > return EFI_BUFFER_TOO_SMALL; > > } > > - CopyMem (InfoEntry, VariableInfo, sizeof (VARIABLE_INFO_ENTRY)); > > + CopyVarInfoEntry (InfoEntry, VariableInfo); > > CopyMem (InfoName, VariableInfo->Name, NameSize); > > *InfoSize = StatisticsInfoSize; > > return EFI_SUCCESS; > > @@ -413,7 +442,7 @@ SmmVariableGetStatistics ( > > return EFI_BUFFER_TOO_SMALL; > > } > > > > - CopyMem (InfoEntry, VariableInfo, sizeof (VARIABLE_INFO_ENTRY)); > > + CopyVarInfoEntry (InfoEntry, VariableInfo); > > CopyMem (InfoName, VariableInfo->Name, NameSize); > > *InfoSize = StatisticsInfoSize; > > > > -- > > 2.12.0.windows.1 > > > > > > ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2019-08-07 0:07 UTC | newest] Thread overview: 3+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2019-08-06 7:18 [PATCH v1] MdeModulePkg/Variable/RuntimeDxe: Not copy SMM pointers in comm buffer Wu, Hao A 2019-08-06 14:55 ` [edk2-devel] " Zeng, Star 2019-08-07 0:07 ` Wu, Hao A
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox