From 899c1020de7d1239891d61e15a034aa1b13a8381 Mon Sep 17 00:00:00 2001
From: Laszlo Ersek <lersek@redhat.com>
Date: Tue, 27 Jun 2017 01:34:25 +0200
Subject: [PATCH 3/3] MdeModulePkg/TerminalDxe: fix OpenProtocol() usage

The TerminalDriverBindingStart() function exploits the previous,
non-standard behavior of edk2 that OpenProtocol() outputs the valid
protocol Interface even when OpenProtocol() returns EFI_ALREADY_STARTED.

This behavior has been deleted with commit 45cfcd8dccf8
("MdeModulePkg/DxeCore: Fixed Interface returned by CoreOpenProtocol",
2017-06-23); Interface is no longer set on error (which conforms to the
UEFI spec). As a result, when the OpenProtocol() calls in
TerminalDriverBindingStart() fail with EFI_ALREADY_STARTED,
ParentDevicePath and SerialIo have uninitialized (indeterminate) values,
leading to a failed assertion later.

Restore the previous behavior of TerminalDriverBindingStart() by
explicitly getting the protocol interfaces with
EFI_OPEN_PROTOCOL_GET_PROTOCOL.

Cc: "Gabriel L. Somlo" <gsomlo@gmail.com>
Cc: Amit Kumar <amit.ak@samsung.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
---
 .../Universal/Console/TerminalDxe/Terminal.c       | 32 ++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/MdeModulePkg/Universal/Console/TerminalDxe/Terminal.c b/MdeModulePkg/Universal/Console/TerminalDxe/Terminal.c
index c90879b0dd87..16fe6de21f1e 100644
--- a/MdeModulePkg/Universal/Console/TerminalDxe/Terminal.c
+++ b/MdeModulePkg/Universal/Console/TerminalDxe/Terminal.c
@@ -508,36 +508,50 @@ TerminalDriverBindingStart (
   UINTN                               EntryCount;
   UINTN                               Index;
   EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL     *SimpleTextOutput;
   EFI_SIMPLE_TEXT_INPUT_PROTOCOL      *SimpleTextInput;
   EFI_UNICODE_STRING_TABLE            *ControllerNameTable;
 
   //
   // Get the Device Path Protocol to build the device path of the child device
   //
   Status = gBS->OpenProtocol (
                   Controller,
                   &gEfiDevicePathProtocolGuid,
                   (VOID **) &ParentDevicePath,
                   This->DriverBindingHandle,
                   Controller,
                   EFI_OPEN_PROTOCOL_BY_DRIVER
                   );
   ASSERT ((Status == EFI_SUCCESS) || (Status == EFI_ALREADY_STARTED));
+  if (Status == EFI_ALREADY_STARTED) {
+    //
+    // Repeat the above OpenProtocol() call with GET_PROTOCOL.
+    //
+    Status = gBS->OpenProtocol (
+                    Controller,
+                    &gEfiDevicePathProtocolGuid,
+                    (VOID **) &ParentDevicePath,
+                    This->DriverBindingHandle,
+                    Controller,
+                    EFI_OPEN_PROTOCOL_GET_PROTOCOL
+                    );
+    ASSERT_EFI_ERROR (Status);
+  }
 
   //
   // Open the Serial I/O Protocol BY_DRIVER.  It might already be started.
   //
   Status = gBS->OpenProtocol (
                   Controller,
                   &gEfiSerialIoProtocolGuid,
                   (VOID **) &SerialIo,
                   This->DriverBindingHandle,
                   Controller,
                   EFI_OPEN_PROTOCOL_BY_DRIVER
                   );
   ASSERT ((Status == EFI_SUCCESS) || (Status == EFI_ALREADY_STARTED));
 
   if (!IsHotPlugDevice (ParentDevicePath)) {
     //
     // if the serial device is a hot plug device, do not update the
     // ConInDev, ConOutDev, and StdErrDev variables.
@@ -549,36 +563,49 @@ TerminalDriverBindingStart (
 
   //
   // Do not create any child for END remaining device path.
   //
   if ((RemainingDevicePath != NULL) && IsDevicePathEnd (RemainingDevicePath)) {
     return EFI_SUCCESS;
   }
 
   if (Status == EFI_ALREADY_STARTED) {
 
     if (RemainingDevicePath == NULL) {
       //
       // If RemainingDevicePath is NULL or is the End of Device Path Node
       //
       return EFI_SUCCESS;
     }
 
     //
+    // Repeat the above OpenProtocol() call with GET_PROTOCOL.
+    //
+    Status = gBS->OpenProtocol (
+                    Controller,
+                    &gEfiSerialIoProtocolGuid,
+                    (VOID **) &SerialIo,
+                    This->DriverBindingHandle,
+                    Controller,
+                    EFI_OPEN_PROTOCOL_GET_PROTOCOL
+                    );
+    ASSERT_EFI_ERROR (Status);
+
+    //
     // This driver can only produce one child per serial port.
     // Change its terminal type as remaining device path requests.
     //
     Status = gBS->OpenProtocolInformation (
                     Controller,
                     &gEfiSerialIoProtocolGuid,
                     &OpenInfoBuffer,
                     &EntryCount
                     );
     if (!EFI_ERROR (Status)) {
       Status = EFI_NOT_FOUND;
       for (Index = 0; Index < EntryCount; Index++) {
         if ((OpenInfoBuffer[Index].Attributes & EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER) != 0) {
           Status = gBS->OpenProtocol (
                           OpenInfoBuffer[Index].ControllerHandle,
                           &gEfiSimpleTextInProtocolGuid,
                           (VOID **) &SimpleTextInput,
                           This->DriverBindingHandle,
@@ -850,36 +877,41 @@ FreeResources:
   }
 
   if (TerminalDevice->TerminalConsoleModeData != NULL) {
     FreePool (TerminalDevice->TerminalConsoleModeData);
   }
 
   FreePool (TerminalDevice);
 
 CloseProtocols:
 
   //
   // Remove Parent Device Path from
   // the Console Device Environment Variables
   //
   TerminalRemoveConsoleDevVariable (EFI_CON_IN_DEV_VARIABLE_NAME, ParentDevicePath);
   TerminalRemoveConsoleDevVariable (EFI_CON_OUT_DEV_VARIABLE_NAME, ParentDevicePath);
   TerminalRemoveConsoleDevVariable (EFI_ERR_OUT_DEV_VARIABLE_NAME, ParentDevicePath);
 
+  //
+  // Closing the protocol interfaces opened with BY_DRIVER is required. Closing
+  // the protocol interfaces opened with GET_PROTOCOL is not required but
+  // permitted.
+  //
   Status = gBS->CloseProtocol (
                   Controller,
                   &gEfiSerialIoProtocolGuid,
                   This->DriverBindingHandle,
                   Controller
                   );
   ASSERT_EFI_ERROR (Status);
 
   Status = gBS->CloseProtocol (
                   Controller,
                   &gEfiDevicePathProtocolGuid,
                   This->DriverBindingHandle,
                   Controller
                   );
   ASSERT_EFI_ERROR (Status);
   return Status;
 }
 
-- 
2.13.1.3.g8be5a757fa67