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...@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 (#44951): https://edk2.groups.io/g/devel/message/44951 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] -=-=-=-=-=-=-=-=-=-=-=-
