[patch] MdeModulePkg:Fix bug in function AsciiStrToIp4.

[Zhang Lubo <lubo.zhang@intel.com>]

If a FQDN contains 3 dots '.' like "a.b.c.com", the AsciiStrToIp4
will return success as the HostName has a valid IP address. So we
need to check if it is a decimal character before using AsciiStrDecimalToUintn.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Zhang Lubo <lubo.zhang@intel.com>
Cc: Fu Siyuan <siyuan.fu@intel.com>
Cc: Ye Ting <ting.ye@intel.com>
Cc: Wu Jiaxin <jiaxin.wu@intel.com>
Cc: Hegde Nagaraj P <nagaraj-p.hegde@hpe.com>
---
 MdeModulePkg/Library/DxeNetLib/DxeNetLib.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/MdeModulePkg/Library/DxeNetLib/DxeNetLib.c b/MdeModulePkg/Library/DxeNetLib/DxeNetLib.c
index ef19439..f4376e9 100644
--- a/MdeModulePkg/Library/DxeNetLib/DxeNetLib.c
+++ b/MdeModulePkg/Library/DxeNetLib/DxeNetLib.c
@@ -2724,10 +2724,13 @@ NetLibAsciiStrToIp4 (
 
   for (Index = 0; Index < 4; Index++) {
     TempStr = Ip4Str;
 
     while ((*Ip4Str != '\0') && (*Ip4Str != '.')) {
+      if (!NET_IS_DIGIT(*Ip4Str)) {
+        return EFI_INVALID_PARAMETER;
+      }
       Ip4Str++;
     }
 
     //
     // The IPv4 address is X.X.X.X
-- 
1.9.5.msysgit.1