MdeModulePkg: Update IP4 driver to check for NULL pointer before using.

Cc: Ye Ting <ting.ye@intel.com>
Cc: Wu Jiaxin <jiaxin.wu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Fu Siyuan <siyuan.fu@intel.com>
Reviewed-by: Wu Jiaxin <jiaxin.wu@intel.com>

1 files changed, 17 insertions, 20 deletions

diff --git a/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Impl.c b/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Impl.c
index fa84a9b1ca..6a26143e30 100644
--- a/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Impl.c
+++ b/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Impl.c
@@ -682,7 +682,7 @@ Ip4ConfigProtocol (
     //

     if (IpSb->State == IP4_SERVICE_UNSTARTED) {

       //

-      // Trigger the EFI_IP4_CONFIG2_PROTOCOL to retrieve the

+      // Trigger the EFI_IP4_CONFIG2_PROTOCOL to retrieve the 

       // default IPv4 address if it is not available yet.

       //

       Policy = IpSb->Ip4Config2Instance.Policy;

@@ -1048,11 +1048,8 @@ Ip4Groups (
   // is decreamented each time an address is removed..

   //

   for (Index = IpInstance->GroupCount; Index > 0 ; Index--) {

-    Group = 0;

-    if(IpInstance->Groups != NULL) {

-      Group = IpInstance->Groups[Index - 1];

-    }

-

+    ASSERT (IpInstance->Groups != NULL);

+    Group = IpInstance->Groups[Index - 1];

     if ((GroupAddress == NULL) || EFI_IP4_EQUAL (&Group, GroupAddress)) {

       if (EFI_ERROR (Ip4LeaveGroup (IpInstance, NTOHL (Group)))) {

         return EFI_DEVICE_ERROR;

@@ -1663,7 +1660,7 @@ EfiIp4Transmit (
     }

 

     RawHdrLen = (UINT8) (RawHdrLen << 2);

-

+    

     CopyMem (&Head, FirstFragment, IP4_MIN_HEADLEN);

 

     Ip4NtohHead (&Head);

@@ -2253,8 +2250,8 @@ Ip4SentPacketTicking (
 }

 

 /**

-  This heart beat timer of IP4 service instance times out all of its IP4 children's

-  received-but-not-delivered and transmitted-but-not-recycle packets, and provides

+  This heart beat timer of IP4 service instance times out all of its IP4 children's 

+  received-but-not-delivered and transmitted-but-not-recycle packets, and provides 

   time input for its IGMP protocol.

 

   @param[in]  Event                  The IP4 service instance's heart beat timer.

@@ -2272,17 +2269,17 @@ Ip4TimerTicking (
 

   IpSb = (IP4_SERVICE *) Context;

   NET_CHECK_SIGNATURE (IpSb, IP4_SERVICE_SIGNATURE);

-

+  

   Ip4PacketTimerTicking (IpSb);

   Ip4IgmpTicking (IpSb);

 }

 

 /**

-  This dedicated timer is used to poll underlying network media status. In case

-  of cable swap or wireless network switch, a new round auto configuration will

-  be initiated. The timer will signal the IP4 to run DHCP configuration again.

-  IP4 driver will free old IP address related resource, such as route table and

-  Interface, then initiate a DHCP process to acquire new IP, eventually create

+  This dedicated timer is used to poll underlying network media status. In case 

+  of cable swap or wireless network switch, a new round auto configuration will 

+  be initiated. The timer will signal the IP4 to run DHCP configuration again. 

+  IP4 driver will free old IP address related resource, such as route table and 

+  Interface, then initiate a DHCP process to acquire new IP, eventually create 

   route table for new IP address.

 

   @param[in]  Event                  The IP4 service instance's heart beat timer.

@@ -2303,12 +2300,12 @@ Ip4TimerReconfigChecking (
 

   IpSb = (IP4_SERVICE *) Context;

   NET_CHECK_SIGNATURE (IpSb, IP4_SERVICE_SIGNATURE);

-

+  

   OldMediaPresent = IpSb->MediaPresent;

 

   //

-  // Get fresh mode data from MNP, since underlying media status may change.

-  // Here, it needs to mention that the MediaPresent can also be checked even if

+  // Get fresh mode data from MNP, since underlying media status may change. 

+  // Here, it needs to mention that the MediaPresent can also be checked even if 

   // EFI_NOT_STARTED returned while this MNP child driver instance isn't configured.

   //

   Status = IpSb->Mnp->GetModeData (IpSb->Mnp, NULL, &SnpModeData);

@@ -2323,8 +2320,8 @@ Ip4TimerReconfigChecking (
   if (!OldMediaPresent && IpSb->MediaPresent && (IpSb->Ip4Config2Instance.Policy == Ip4Config2PolicyDhcp)) {

     //

     // Signal the IP4 to run the dhcp configuration again. IP4 driver will free

-    // old IP address related resource, such as route table and Interface, then

-    // initiate a DHCP round to acquire new IP, eventually

+    // old IP address related resource, such as route table and Interface, then 

+    // initiate a DHCP round to acquire new IP, eventually 

     // create route table for new IP address.

     //

     if (IpSb->ReconfigEvent != NULL) {