Re: [Patch] NetworkPkg/DnsDxe: Fixed the assert issue in DnsDxe

["Ye, Ting" <ting.ye@intel.com>]

Reviewed-by: Ye Ting <ting.ye@intel.com> 

-----Original Message-----
From: Wu, Jiaxin 
Sent: Thursday, December 08, 2016 8:55 AM
To: edk2-devel@lists.01.org
Cc: Ye, Ting <ting.ye@intel.com>; Fu, Siyuan <siyuan.fu@intel.com>; Zhang, Lubo <lubo.zhang@intel.com>; Wu, Jiaxin <jiaxin.wu@intel.com>
Subject: [Patch] NetworkPkg/DnsDxe: Fixed the assert issue in DnsDxe

Fix the DnsDxe assert issue when the incorrect answer message received.

Cc: Ye Ting <ting.ye@intel.com>
Cc: Fu Siyuan <siyuan.fu@intel.com>
Cc: Zhang Lubo <lubo.zhang@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Wu Jiaxin <jiaxin.wu@intel.com>
---
 NetworkPkg/DnsDxe/DnsImpl.c | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/NetworkPkg/DnsDxe/DnsImpl.c b/NetworkPkg/DnsDxe/DnsImpl.c index 74deaa4..794df1d 100644
--- a/NetworkPkg/DnsDxe/DnsImpl.c
+++ b/NetworkPkg/DnsDxe/DnsImpl.c
@@ -1328,13 +1328,16 @@ ParseDnsResponse (
   //
   // Processing AnswerSection.
   //
   while (AnswerSectionNum < DnsHeader->AnswersNum) {
     //
-    // Answer name should be PTR.
+    // Answer name should be PTR, else EFI_UNSUPPORTED returned.
     //
-    ASSERT ((*(UINT8 *) AnswerName & 0xC0) == 0xC0);
+    if ((*(UINT8 *) AnswerName & 0xC0) != 0xC0) {
+      Status = EFI_UNSUPPORTED;
+      goto ON_EXIT;
+    }
     
     //
     // Get Answer section.
     //
     AnswerSection = (DNS_ANSWER_SECTION *) (AnswerName + sizeof (UINT16)); @@ -1406,11 +1409,16 @@ ParseDnsResponse (
       switch (AnswerSection->Type) {
       case DNS_TYPE_A:
         //
         // This is address entry, get Data.
         //
-        ASSERT (Dns4TokenEntry != NULL && AnswerSection->DataLength == 4);
+        ASSERT (Dns4TokenEntry != NULL);
+
+        if (AnswerSection->DataLength != 4) {
+          Status = EFI_ABORTED;
+          goto ON_EXIT;
+        }
         
         HostAddr4 = Dns4TokenEntry->Token->RspData.H2AData->IpList;
         AnswerData = (UINT8 *) AnswerSection + sizeof (*AnswerSection);
         CopyMem (&HostAddr4[IpCount], AnswerData, sizeof (EFI_IPv4_ADDRESS));
 
@@ -1460,11 +1468,16 @@ ParseDnsResponse (
         break;
       case DNS_TYPE_AAAA:
         //
         // This is address entry, get Data.
         //
-        ASSERT (Dns6TokenEntry != NULL && AnswerSection->DataLength == 16);
+        ASSERT (Dns6TokenEntry != NULL);
+
+        if (AnswerSection->DataLength != 16) {
+          Status = EFI_ABORTED;
+          goto ON_EXIT;
+        }
         
         HostAddr6 = Dns6TokenEntry->Token->RspData.H2AData->IpList;
         AnswerData = (UINT8 *) AnswerSection + sizeof (*AnswerSection);
         CopyMem (&HostAddr6[IpCount], AnswerData, sizeof (EFI_IPv6_ADDRESS));
 
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