[Patch] NetworkPkg: UefiPxeBcDxe: Add EXCLUSIVE attribute when opening SNP protocol installed by PXE.

[Wang Fan <fan.wang@intel.com>]

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1152

The PXE driver installs a SNP and open this SNP with attribute BY_DRIVER
to avoid it being opened by MNP driver, this SNP is also expected not to
be opened by other drivers with EXCLUSIVE attribute. In some cases, other
drivers may happen to do this by error, and thus cause a system crash.
This patch adds EXCLUSIVE attribute when opening SNP in PXE driver, and
will reject all OpenProtocol requests by EXCLUSIVE.

Cc: Ye Ting <ting.ye@intel.com>
Cc: Fu Siyuan <siyuan.fu@intel.com>
Cc: Wu Jiaxin <jiaxin.wu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Wang Fan <fan.wang@intel.com>
---
 NetworkPkg/UefiPxeBcDxe/PxeBcDriver.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/NetworkPkg/UefiPxeBcDxe/PxeBcDriver.c b/NetworkPkg/UefiPxeBcDxe/PxeBcDriver.c
index bc9dc914f3..1a9671d373 100644
--- a/NetworkPkg/UefiPxeBcDxe/PxeBcDriver.c
+++ b/NetworkPkg/UefiPxeBcDxe/PxeBcDriver.c
@@ -821,11 +821,11 @@ PxeBcCreateIp4Children (
                     Private->Ip4Nic->Controller,
                     &gEfiSimpleNetworkProtocolGuid,
                     (VOID **) &Snp,
                     This->DriverBindingHandle,
                     Private->Ip4Nic->Controller,
-                    EFI_OPEN_PROTOCOL_BY_DRIVER
+                    EFI_OPEN_PROTOCOL_BY_DRIVER|EFI_OPEN_PROTOCOL_EXCLUSIVE
                     );
     if (EFI_ERROR (Status)) {
       goto ON_ERROR;
     }
   }
-- 
2.16.2.windows.1