From c61a56f208a6b3ca49b7542a81e75c141a198d6f Mon Sep 17 00:00:00 2001
From: jljusten <jljusten@6f19259b-4bc3-4df7-8a09-765794883524>
Date: Wed, 16 Jan 2013 06:49:45 +0000
Subject: OvmfPkg: LoadLinuxLib: Zero kernel parameters instead of passing
 garbage

We're supposed to zero everything in the kernel bootparams that we don't
explicitly initialise, other than the setup_header from 0x1f1 onwards
for a precisely defined length, which is copied from the bzImage.

We're *not* supposed to just pass the garbage that we happened to find
in the bzImage file surrounding the setup_header.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@14052 6f19259b-4bc3-4df7-8a09-765794883524
---
 OvmfPkg/Library/LoadLinuxLib/Linux.c        | 28 ++++++++++++++++++++++++++++
 OvmfPkg/Library/PlatformBdsLib/QemuKernel.c |  7 ++++++-
 2 files changed, 34 insertions(+), 1 deletion(-)

(limited to 'OvmfPkg/Library')

diff --git a/OvmfPkg/Library/LoadLinuxLib/Linux.c b/OvmfPkg/Library/LoadLinuxLib/Linux.c
index b06285c51a..1da5507ff1 100644
--- a/OvmfPkg/Library/LoadLinuxLib/Linux.c
+++ b/OvmfPkg/Library/LoadLinuxLib/Linux.c
@@ -119,6 +119,34 @@ LoadLinuxAllocateKernelSetupPages (
   }
 }
 
+EFI_STATUS
+EFIAPI
+LoadLinuxInitializeKernelSetup (
+  IN VOID        *KernelSetup
+  )
+{
+  EFI_STATUS                Status;
+  UINTN                     SetupEnd;
+  struct boot_params        *Bp;
+
+  Status = BasicKernelSetupCheck (KernelSetup);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  Bp = (struct boot_params*) KernelSetup;
+
+  SetupEnd = 0x202 + (Bp->hdr.jump & 0xff);
+
+  //
+  // Clear all but the setup_header
+  //
+  ZeroMem (KernelSetup, 0x1f1);
+  ZeroMem (((UINT8 *)KernelSetup) + SetupEnd, 4096 - SetupEnd);
+  DEBUG ((EFI_D_INFO, "Cleared kernel setup 0-0x1f1, 0x%x-0x1000\n", SetupEnd));
+
+  return EFI_SUCCESS;
+}
 
 VOID*
 EFIAPI
diff --git a/OvmfPkg/Library/PlatformBdsLib/QemuKernel.c b/OvmfPkg/Library/PlatformBdsLib/QemuKernel.c
index fa8bcbc9bf..47ebed9f6d 100644
--- a/OvmfPkg/Library/PlatformBdsLib/QemuKernel.c
+++ b/OvmfPkg/Library/PlatformBdsLib/QemuKernel.c
@@ -1,6 +1,6 @@
 /** @file
 
-  Copyright (c) 2006 - 2012, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>
   This program and the accompanying materials
   are licensed and made available under the terms and conditions of the BSD License
   which accompanies this distribution.  The full text of the license may be found at
@@ -78,6 +78,11 @@ TryRunningQemuKernel (
     goto FreeAndReturn;
   }
 
+  Status = LoadLinuxInitializeKernelSetup (SetupBuf);
+  if (EFI_ERROR (Status)) {
+    goto FreeAndReturn;
+  }
+
   KernelInitialSize = LoadLinuxGetKernelSize (SetupBuf, KernelSize);
   if (KernelInitialSize == 0) {
     Status = EFI_UNSUPPORTED;
-- 
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