datapath-windows: Merge split dis-continuous net-buf.

NdisGetDataBuffer() is called without providing a buffer to copy packet data in case it is not contiguous. So, it fails in some scenarios where the packet is handled by the general network stack before OVS and headers become split in multiple buffers. In the fix it will supply the stack buffer to copy packet data when call NdisGetDataBuffer(). In the conntrack Action process, it will do OvsPartialCopyNBL firstly with the size of layers l7offsets. If the header is split the header will be merged to one continuous buffer. But IPV6 traffic is not handed in this case. Reported-at: openvswitch/ovs-issues#323 Signed-off-by: Wilson Peng <[email protected]> Signed-off-by: 0-day Robot <[email protected]>
ovsrobot · Jul 17, 2024 · 6941a76 · 6941a76
1 parent 903aa8f
commit 6941a76
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Showing 4 changed files with 29 additions and 6 deletions.
diff --git a/datapath-windows/ovsext/Actions.c b/datapath-windows/ovsext/Actions.c
@@ -2414,6 +2414,13 @@ OvsDoExecuteActions(POVS_SWITCH_CONTEXT switchContext,
             }
 
             PNET_BUFFER_LIST oldNbl = ovsFwdCtx.curNbl;
+            PUINT8 bufferStart = NULL;
+
+            bufferStart = OvsGetHeaderBySize(&ovsFwdCtx, layers->l7Offset);
+            if (!bufferStart) {
+                 dropReason = L"OVS-Netbuf reallocated failed";
+                 goto dropit;
+            }
             status = OvsExecuteConntrackAction(&ovsFwdCtx, key,
                                                (const PNL_ATTR)a);
             if (status != NDIS_STATUS_SUCCESS) {

diff --git a/datapath-windows/ovsext/BufferMgmt.c b/datapath-windows/ovsext/BufferMgmt.c
@@ -1110,12 +1110,22 @@ GetIpHeaderInfo(PNET_BUFFER_LIST curNbl,
     IPHdr *ipHdr;
     IPv6Hdr *ipv6Hdr;
     PNET_BUFFER curNb;
+    CHAR tempBuf[MAX_IPV4_HLEN];
 
     curNb = NET_BUFFER_LIST_FIRST_NB(curNbl);
     ASSERT(NET_BUFFER_NEXT_NB(curNb) == NULL);
-    eth = (EthHdr *)NdisGetDataBuffer(curNb,
-                                      hdrInfo->l4Offset,
-                                      NULL, 1, 0);
+
+    if (hdrInfo->isIPv6) {
+        eth = (EthHdr *)NdisGetDataBuffer(curNb,
+                                          hdrInfo->l4Offset,
+                                          NULL, 1, 0);
+    } else {
+        NdisZeroMemory(tempBuf, MAX_IPV4_HLEN);
+        eth = (EthHdr *)NdisGetDataBuffer(curNb,
+                                          hdrInfo->l4Offset,
+                                          (PVOID)tempBuf, 1, 0);
+    }
+
     if (eth == NULL) {
         return NDIS_STATUS_INVALID_PACKET;
     }

diff --git a/datapath-windows/ovsext/Conntrack.c b/datapath-windows/ovsext/Conntrack.c
@@ -683,6 +683,7 @@ OvsGetTcpHeader(PNET_BUFFER_LIST nbl,
     TCPHdr *tcp;
     VOID *dest = storage;
     uint16_t ipv6ExtLength = 0;
+    CHAR tempBuf[MAX_IPV4_HLEN];
 
     if (layers->isIPv6) {
         ipv6Hdr = NdisGetDataBuffer(NET_BUFFER_LIST_FIRST_NB(nbl),
@@ -701,9 +702,10 @@ OvsGetTcpHeader(PNET_BUFFER_LIST nbl,
             return storage;
         }
     } else {
+        NdisZeroMemory(tempBuf, MAX_IPV4_HLEN);
         ipHdr = NdisGetDataBuffer(NET_BUFFER_LIST_FIRST_NB(nbl),
                                   layers->l4Offset + sizeof(TCPHdr),
-                                  NULL, 1 /*no align*/, 0);
+                                  (PVOID)tempBuf, 1 /*no align*/, 0);
         if (ipHdr == NULL) {
             return NULL;
         }

diff --git a/datapath-windows/ovsext/IpFragment.c b/datapath-windows/ovsext/IpFragment.c
@@ -153,12 +153,14 @@ OvsIpv4Reassemble(POVS_SWITCH_CONTEXT switchContext,
     PNET_BUFFER_LIST newNbl = NULL;
     UINT16 ipHdrLen, packetHeader;
     UINT32 packetLen;
+    CHAR tempBuf[MAX_IPV4_HLEN];
 
     curNb = NET_BUFFER_LIST_FIRST_NB(*curNbl);
     ASSERT(NET_BUFFER_NEXT_NB(curNb) == NULL);
 
+    NdisZeroMemory(tempBuf, MAX_IPV4_HLEN);
     eth = (EthHdr*)NdisGetDataBuffer(curNb, layers->l4Offset,
-                                     NULL, 1, 0);
+                                     (PVOID)tempBuf, 1, 0);
     if (eth == NULL) {
         return NDIS_STATUS_INVALID_PACKET;
     }
@@ -253,12 +255,14 @@ OvsProcessIpv4Fragment(POVS_SWITCH_CONTEXT switchContext,
     POVS_IPFRAG_ENTRY entry;
     POVS_FRAGMENT_LIST fragStorage;
     LOCK_STATE_EX htLockState;
+    CHAR tempBuf[MAX_IPV4_HLEN];
 
     curNb = NET_BUFFER_LIST_FIRST_NB(*curNbl);
     ASSERT(NET_BUFFER_NEXT_NB(curNb) == NULL);
 
+    NdisZeroMemory(tempBuf, MAX_IPV4_HLEN);
     eth = (EthHdr*)NdisGetDataBuffer(curNb, layers->l4Offset,
-                                     NULL, 1, 0);
+                                     (PVOID)tempBuf, 1, 0);
     if (eth == NULL) {
         return NDIS_STATUS_INVALID_PACKET;
     }