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[edk2-devel] [PATCH v1] MdeModulePkg/Variable/RuntimeDxe: Not copy SMM pointers in comm buffer

Wu, Hao A posted 1 patch 4 years, 8 months ago
Failed in applying to current master (apply log)
There is a newer version of this series
MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c | 33 ++++++++++++++++++--
1 file changed, 31 insertions(+), 2 deletions(-)
[edk2-devel] [PATCH v1] MdeModulePkg/Variable/RuntimeDxe: Not copy SMM pointers in comm buffer
Posted by Wu, Hao A 4 years, 8 months ago 
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


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Re: [edk2-devel] [PATCH v1] MdeModulePkg/Variable/RuntimeDxe: Not copy SMM pointers in comm buffer
Posted by Zeng, Star 4 years, 8 months ago 
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
> 
> 
> 


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Re: [edk2-devel] [PATCH v1] MdeModulePkg/Variable/RuntimeDxe: Not copy SMM pointers in comm buffer
Posted by Wu, Hao A 4 years, 8 months ago 
> -----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
> >
> >
> > 


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