> -----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...@intel.com>; Gao, Liming > <liming....@intel.com>; > > Wang, Jian J <jian.j.w...@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....@intel.com> > > Cc: Jian J Wang <jian.j.w...@intel.com> > > Signed-off-by: Hao A Wu <hao.a...@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 > > > > > > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#44958): https://edk2.groups.io/g/devel/message/44958 Mute This Topic: https://groups.io/mt/32740915/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
