Re: [Patch] NetworkPkg: Correct the DNS token return status by RCODE

["Hegde, Nagaraj P" <nagaraj-p.hegde@hpe.com>]

Tested-by: Hegde Nagaraj P <nagaraj-p.hegde@hpe.com>

-----Original Message-----
From: Jiaxin Wu [mailto:jiaxin.wu@intel.com] 
Sent: Wednesday, September 14, 2016 12:16 PM
To: edk2-devel@lists.01.org
Cc: Hegde, Nagaraj P <nagaraj-p.hegde@hpe.com>; Fu Siyuan <siyuan.fu@intel.com>; Ye Ting <ting.ye@intel.com>
Subject: [Patch] NetworkPkg: Correct the DNS token return status by RCODE

When HostNameToIp() and GeneralLookUp() are called with a invalid
host name, RCODE (4 bit field is set as part of responses) error
will returned in packet to identify the domain name referenced in
the query does not exist. So, EFI_NOT_FOUND should be returned
directly.

Current implementation only check the RCODE in successful condition.
Need update the code for more error check according to RFC 1035 4.1.1
section.

Cc: Hegde Nagaraj P <nagaraj-p.hegde@hpe.com>
Cc: Fu Siyuan <siyuan.fu@intel.com>
Cc: Ye Ting <ting.ye@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jiaxin Wu <jiaxin.wu@intel.com>
---
 NetworkPkg/DnsDxe/DnsImpl.c | 104 +++++++++++++++++---------------------------
 1 file changed, 40 insertions(+), 64 deletions(-)

diff --git a/NetworkPkg/DnsDxe/DnsImpl.c b/NetworkPkg/DnsDxe/DnsImpl.c
index cfaa4c7..3f3b756 100644
--- a/NetworkPkg/DnsDxe/DnsImpl.c
+++ b/NetworkPkg/DnsDxe/DnsImpl.c
@@ -1230,12 +1230,20 @@ ParseDnsResponse (
   //
   // Continue Check Some Errors.
   //
   if (DnsHeader->Flags.Bits.RCode != DNS_FLAGS_RCODE_NO_ERROR || DnsHeader->AnswersNum < 1 || \
       DnsHeader->Flags.Bits.QR != DNS_FLAGS_QR_RESPONSE) {
-      Status = EFI_ABORTED;
-      goto ON_EXIT;
+    //
+    // The domain name referenced in the query does not exist.
+    //
+    if (DnsHeader->Flags.Bits.RCode == DNS_FLAGS_RCODE_NAME_ERROR) {
+      Status = EFI_NOT_FOUND; 
+    } else {
+      Status = EFI_DEVICE_ERROR;
+    }
+    
+    goto ON_COMPLETE;
   }
   
   //
   // Do some buffer allocations.
   //
@@ -1404,27 +1412,12 @@ ParseDnsResponse (
         
         HostAddr4 = Dns4TokenEntry->Token->RspData.H2AData->IpList;
         AnswerData = (UINT8 *) AnswerSection + sizeof (*AnswerSection);
         CopyMem (&HostAddr4[IpCount], AnswerData, sizeof (EFI_IPv4_ADDRESS));
 
-        //
-        // Update DNS cache dynamically.
-        //
-        if (Dns4CacheEntry != NULL) {
-          if (Dns4CacheEntry->HostName != NULL) {
-            FreePool (Dns4CacheEntry->HostName);
-          }
-
-          if (Dns4CacheEntry->IpAddress != NULL) {
-            FreePool (Dns4CacheEntry->IpAddress);
-          }
-          
-          FreePool (Dns4CacheEntry);
-        }
-
         // 
-        // Allocate new CacheEntry pool.
+        // Allocate new CacheEntry pool to update DNS cache dynamically.
         //
         Dns4CacheEntry = AllocateZeroPool (sizeof (EFI_DNS4_CACHE_ENTRY));
         if (Dns4CacheEntry == NULL) {
           Status = EFI_OUT_OF_RESOURCES;
           goto ON_EXIT;
@@ -1446,11 +1439,23 @@ ParseDnsResponse (
           Dns4CacheEntry->Timeout = MIN (CNameTtl, AnswerSection->Ttl);
         } else {
           Dns4CacheEntry->Timeout = MAX (CNameTtl, AnswerSection->Ttl);
         }
         
-        UpdateDns4Cache (&mDriverData->Dns4CacheList, FALSE, TRUE, *Dns4CacheEntry);  
+        UpdateDns4Cache (&mDriverData->Dns4CacheList, FALSE, TRUE, *Dns4CacheEntry);
+
+        // 
+        // Free allocated CacheEntry pool.
+        //
+        FreePool (Dns4CacheEntry->HostName);
+        Dns4CacheEntry->HostName = NULL;
+        
+        FreePool (Dns4CacheEntry->IpAddress);
+        Dns4CacheEntry->IpAddress = NULL;
+
+        FreePool (Dns4CacheEntry);
+        Dns4CacheEntry = NULL;
 
         IpCount ++;
         Status = EFI_SUCCESS;
         break;
       case DNS_TYPE_AAAA:
@@ -1461,27 +1466,12 @@ ParseDnsResponse (
         
         HostAddr6 = Dns6TokenEntry->Token->RspData.H2AData->IpList;
         AnswerData = (UINT8 *) AnswerSection + sizeof (*AnswerSection);
         CopyMem (&HostAddr6[IpCount], AnswerData, sizeof (EFI_IPv6_ADDRESS));
 
-        //
-        // Update DNS cache dynamically.
-        //
-        if (Dns6CacheEntry != NULL) {
-          if (Dns6CacheEntry->HostName != NULL) {
-            FreePool (Dns6CacheEntry->HostName);
-          }
-
-          if (Dns6CacheEntry->IpAddress != NULL) {
-            FreePool (Dns6CacheEntry->IpAddress);
-          }
-          
-          FreePool (Dns6CacheEntry);
-        }
-
         // 
-        // Allocate new CacheEntry pool.
+        // Allocate new CacheEntry pool to update DNS cache dynamically.
         //
         Dns6CacheEntry = AllocateZeroPool (sizeof (EFI_DNS6_CACHE_ENTRY));
         if (Dns6CacheEntry == NULL) {
           Status = EFI_OUT_OF_RESOURCES;
           goto ON_EXIT;
@@ -1503,11 +1493,23 @@ ParseDnsResponse (
           Dns6CacheEntry->Timeout = MIN (CNameTtl, AnswerSection->Ttl);
         } else {
           Dns6CacheEntry->Timeout = MAX (CNameTtl, AnswerSection->Ttl);
         }
         
-        UpdateDns6Cache (&mDriverData->Dns6CacheList, FALSE, TRUE, *Dns6CacheEntry);  
+        UpdateDns6Cache (&mDriverData->Dns6CacheList, FALSE, TRUE, *Dns6CacheEntry);
+
+        // 
+        // Free allocated CacheEntry pool.
+        //
+        FreePool (Dns6CacheEntry->HostName);
+        Dns6CacheEntry->HostName = NULL;
+        
+        FreePool (Dns6CacheEntry->IpAddress);
+        Dns6CacheEntry->IpAddress = NULL;
+
+        FreePool (Dns6CacheEntry);
+        Dns6CacheEntry = NULL;
         
         IpCount ++;
         Status = EFI_SUCCESS;
         break;
       case DNS_TYPE_CNAME:
@@ -1556,11 +1558,12 @@ ParseDnsResponse (
         Status = EFI_UNSUPPORTED;
         goto ON_EXIT;
       }
     }
   }
-
+  
+ON_COMPLETE:
   //
   // Parsing is complete, free the sending packet and signal Event here.
   //
   if (Item != NULL && Item->Value != NULL) {
     NetbufFree ((NET_BUF *) (Item->Value));
@@ -1582,37 +1585,10 @@ ParseDnsResponse (
       gBS->SignalEvent (Dns6TokenEntry->Token->Event);
       DispatchDpc ();
     }
   }
 
-  // 
-  // Free allocated CacheEntry pool.
-  //
-  if (Dns4CacheEntry != NULL) {
-    if (Dns4CacheEntry->HostName != NULL) {
-      FreePool (Dns4CacheEntry->HostName);
-    }
-
-    if (Dns4CacheEntry->IpAddress != NULL) {
-      FreePool (Dns4CacheEntry->IpAddress);
-    }
-
-    FreePool (Dns4CacheEntry);
-  }
-  
-  if (Dns6CacheEntry != NULL) {
-    if (Dns6CacheEntry->HostName != NULL) {
-      FreePool (Dns6CacheEntry->HostName);
-    }
-
-    if (Dns6CacheEntry->IpAddress != NULL) {
-      FreePool (Dns6CacheEntry->IpAddress);
-    }
-  
-    FreePool (Dns6CacheEntry);
-  }
-
 ON_EXIT:
   gBS->RestoreTPL (OldTpl);
   return Status;
 }
 
-- 
1.9.5.msysgit.1