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datapath-windows: Use only non executable memory
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Use only non-executable memory when using MmGetSystemAddressForMdlSafe.

Introduce a new function called OvsGetMdlWithLowPriority for readability.

Found using WDK 10 static code analysis.

Signed-off-by: Alin Gabriel Serdean <aserdean@cloudbasesolutions.com>
Acked-by: Shashank Ram <shashank08@gmail.com>
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@aserdean
Alin Serdean authored and aserdean committed Nov 29, 2017
1 parent c8025ae commit cba5d14
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Showing 10 changed files with 35 additions and 28 deletions.
8 changes: 4 additions & 4 deletions datapath-windows/ovsext/BufferMgmt.c
View file
Expand Up @@ -1157,7 +1157,7 @@ FixFragmentHeader(PNET_BUFFER nb, UINT16 fragmentSize,

mdl = NET_BUFFER_FIRST_MDL(nb);

bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(mdl, LowPagePriority);
bufferStart = (PUINT8)OvsGetMdlWithLowPriority(mdl);
if (!bufferStart) {
return NDIS_STATUS_RESOURCES;
}
Expand Down Expand Up @@ -1215,7 +1215,7 @@ FixSegmentHeader(PNET_BUFFER nb, UINT16 segmentSize, UINT32 seqNumber,

mdl = NET_BUFFER_FIRST_MDL(nb);

bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(mdl, LowPagePriority);
bufferStart = (PUINT8)OvsGetMdlWithLowPriority(mdl);
if (!bufferStart) {
return NDIS_STATUS_RESOURCES;
}
Expand Down Expand Up @@ -1521,8 +1521,8 @@ OvsAllocateNBLFromBuffer(PVOID context,

nb = NET_BUFFER_LIST_FIRST_NB(nbl);
mdl = NET_BUFFER_CURRENT_MDL(nb);
data = (PUINT8)MmGetSystemAddressForMdlSafe(mdl, LowPagePriority) +
NET_BUFFER_CURRENT_MDL_OFFSET(nb);
data = (PUINT8)OvsGetMdlWithLowPriority(mdl)
+ NET_BUFFER_CURRENT_MDL_OFFSET(nb);
if (!data) {
OvsCompleteNBL(switchContext, nbl, TRUE);
return NULL;
Expand Down
3 changes: 1 addition & 2 deletions datapath-windows/ovsext/Datapath.c
View file
Expand Up @@ -1593,8 +1593,7 @@ MapIrpOutputBuffer(PIRP irp,
if (irp->MdlAddress == NULL) {
return STATUS_INVALID_PARAMETER;
}
*buffer = MmGetSystemAddressForMdlSafe(irp->MdlAddress,
NormalPagePriority);
*buffer = OvsGetMdlWithLowPriority(irp->MdlAddress);
if (*buffer == NULL) {
return STATUS_INSUFFICIENT_RESOURCES;
}
Expand Down
2 changes: 1 addition & 1 deletion datapath-windows/ovsext/Flow.c
View file
Expand Up @@ -1933,7 +1933,7 @@ GetStartAddrNBL(const NET_BUFFER_LIST *_pNB)

// Ethernet Header is a guaranteed safe access.
curMdl = (NET_BUFFER_LIST_FIRST_NB(_pNB))->CurrentMdl;
curBuffer = MmGetSystemAddressForMdlSafe(curMdl, LowPagePriority);
curBuffer = OvsGetMdlWithLowPriority(curMdl);
if (!curBuffer) {
return NULL;
}
Expand Down
5 changes: 2 additions & 3 deletions datapath-windows/ovsext/Geneve.c
View file
Expand Up @@ -157,8 +157,7 @@ NDIS_STATUS OvsEncapGeneve(POVS_VPORT_ENTRY vport,
}

curMdl = NET_BUFFER_CURRENT_MDL(curNb);
bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(curMdl,
LowPagePriority);
bufferStart = (PUINT8)OvsGetMdlWithLowPriority(curMdl);
if (!bufferStart) {
status = NDIS_STATUS_RESOURCES;
goto ret_error;
Expand Down Expand Up @@ -292,7 +291,7 @@ NDIS_STATUS OvsDecapGeneve(POVS_SWITCH_CONTEXT switchContext,
curNbl = *newNbl;
curNb = NET_BUFFER_LIST_FIRST_NB(curNbl);
curMdl = NET_BUFFER_CURRENT_MDL(curNb);
bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(curMdl, LowPagePriority)
bufferStart = (PUINT8)OvsGetMdlWithLowPriority(curMdl)
+ NET_BUFFER_CURRENT_MDL_OFFSET(curNb);
if (!bufferStart) {
status = NDIS_STATUS_RESOURCES;
Expand Down
3 changes: 1 addition & 2 deletions datapath-windows/ovsext/Gre.c
View file
Expand Up @@ -202,8 +202,7 @@ OvsDoEncapGre(POVS_VPORT_ENTRY vport,
}

curMdl = NET_BUFFER_CURRENT_MDL(curNb);
bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(curMdl,
LowPagePriority);
bufferStart = (PUINT8)OvsGetMdlWithLowPriority(curMdl);
if (!bufferStart) {
status = NDIS_STATUS_RESOURCES;
goto ret_error;
Expand Down
9 changes: 4 additions & 5 deletions datapath-windows/ovsext/Offload.c
View file
Expand Up @@ -460,7 +460,7 @@ CalculateChecksumNB(const PNET_BUFFER nb,

firstMdlLen = MIN(firstMdlLen, packetLen);
if (offset < firstMdlLen) {
src = (PUCHAR) MmGetSystemAddressForMdlSafe(currentMdl, LowPagePriority);
src = (PUCHAR)OvsGetMdlWithLowPriority(currentMdl);
if (!src) {
return 0;
}
Expand All @@ -485,7 +485,7 @@ CalculateChecksumNB(const PNET_BUFFER nb,
mdlLen = MIN(mdlLen, packetLen);
}

src = (PUCHAR)MmGetSystemAddressForMdlSafe(currentMdl, LowPagePriority);
src = (PUCHAR)OvsGetMdlWithLowPriority(currentMdl);
if (!src) {
return 0;
}
Expand All @@ -504,7 +504,7 @@ CalculateChecksumNB(const PNET_BUFFER nb,
csumDataLen -= csLen;
currentMdl = NDIS_MDL_LINKAGE(currentMdl);
if (csumDataLen && currentMdl) {
src = MmGetSystemAddressForMdlSafe(currentMdl, LowPagePriority);
src = OvsGetMdlWithLowPriority(currentMdl);
if (!src) {
return 0;
}
Expand Down Expand Up @@ -672,8 +672,7 @@ OvsApplySWChecksumOnNB(POVS_PACKET_HDR_INFO layers,
curNb = curNb->Next) {
packetLength = NET_BUFFER_DATA_LENGTH(curNb);
curMdl = NET_BUFFER_CURRENT_MDL(curNb);
bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(curMdl,
LowPagePriority);
bufferStart = (PUINT8)OvsGetMdlWithLowPriority(curMdl);
if (!bufferStart) {
return NDIS_STATUS_RESOURCES;
}
Expand Down
3 changes: 1 addition & 2 deletions datapath-windows/ovsext/PacketParser.c
View file
Expand Up @@ -38,8 +38,7 @@ OvsGetPacketBytes(const NET_BUFFER_LIST *nbl,

// Data on current MDL may be offset from start of MDL
while (destOffset < copyLen && currentMdl) {
PUCHAR srcMemory = MmGetSystemAddressForMdlSafe(currentMdl,
LowPagePriority);
PUCHAR srcMemory = OvsGetMdlWithLowPriority(currentMdl);
ULONG length = MmGetMdlByteCount(currentMdl);
if (!srcMemory) {
status = NDIS_STATUS_RESOURCES;
Expand Down
8 changes: 3 additions & 5 deletions datapath-windows/ovsext/Stt.c
View file
Expand Up @@ -215,8 +215,7 @@ OvsDoEncapStt(POVS_VPORT_ENTRY vport,
curNb = curNb->Next) {
curMdl = NET_BUFFER_CURRENT_MDL(curNb);
innerFrameLen = NET_BUFFER_DATA_LENGTH(curNb);
bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(curMdl,
LowPagePriority);
bufferStart = (PUINT8)OvsGetMdlWithLowPriority(curMdl);
if (bufferStart == NULL) {
status = NDIS_STATUS_RESOURCES;
goto ret_error;
Expand Down Expand Up @@ -266,7 +265,7 @@ OvsDoEncapStt(POVS_VPORT_ENTRY vport,
ASSERT((int) (MmGetMdlByteCount(curMdl) -
NET_BUFFER_CURRENT_MDL_OFFSET(curNb)) >= (int) headRoom);

buf = (PUINT8) MmGetSystemAddressForMdlSafe(curMdl, LowPagePriority);
buf = (PUINT8)OvsGetMdlWithLowPriority(curMdl);
if (!buf) {
ASSERT(!"MmGetSystemAddressForMdlSafe failed");
OVS_LOG_ERROR("MmGetSystemAddressForMdlSafe failed");
Expand Down Expand Up @@ -858,8 +857,7 @@ OvsDecapSetOffloads(PNET_BUFFER_LIST *curNbl,
curNb = NET_BUFFER_LIST_FIRST_NB(*curNbl);
curMdl = NET_BUFFER_CURRENT_MDL(curNb);

buf = (PUINT8)MmGetSystemAddressForMdlSafe(curMdl,
LowPagePriority);
buf = (PUINT8)OvsGetMdlWithLowPriority(curMdl);
if (buf == NULL) {
return NDIS_STATUS_RESOURCES;
}
Expand Down
15 changes: 15 additions & 0 deletions datapath-windows/ovsext/Util.h
View file
Expand Up @@ -152,4 +152,19 @@ UINT32 Rand()
return seed.LowPart *= 0x8088405 + 1;
}

/*
*----------------------------------------------------------------------------
* OvsGetMdlWithLowPriority --
* Return the nonpaged system-space virtual address for the given MDL
* `curMdl` using low page priority and no executable memory.
*----------------------------------------------------------------------------
*/

static __inline
PVOID OvsGetMdlWithLowPriority(PMDL curMdl)
{
return MmGetSystemAddressForMdlSafe(curMdl,
LowPagePriority | MdlMappingNoExecute);
}

#endif /* __UTIL_H_ */
7 changes: 3 additions & 4 deletions datapath-windows/ovsext/Vxlan.c
View file
Expand Up @@ -244,8 +244,7 @@ OvsDoEncapVxlan(POVS_VPORT_ENTRY vport,
}

curMdl = NET_BUFFER_CURRENT_MDL(curNb);
bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(curMdl,
LowPagePriority);
bufferStart = (PUINT8)OvsGetMdlWithLowPriority(curMdl);
if (!bufferStart) {
status = NDIS_STATUS_RESOURCES;
goto ret_error;
Expand Down Expand Up @@ -421,8 +420,8 @@ OvsDecapVxlan(POVS_SWITCH_CONTEXT switchContext,
curNbl = *newNbl;
curNb = NET_BUFFER_LIST_FIRST_NB(curNbl);
curMdl = NET_BUFFER_CURRENT_MDL(curNb);
bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(curMdl, LowPagePriority) +
NET_BUFFER_CURRENT_MDL_OFFSET(curNb);
bufferStart = (PUINT8)OvsGetMdlWithLowPriority(curMdl)
+ NET_BUFFER_CURRENT_MDL_OFFSET(curNb);
if (!bufferStart) {
status = NDIS_STATUS_RESOURCES;
goto dropNbl;
Expand Down

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