320b4f084a
BaseExtractGuidedSectionLib uses a table at the static physical address
PcdGuidedExtractHandlerTableAddress, and modules that are linked against
BaseExtractGuidedSectionLib are expected to work together on that table.
Namely, some modules can register handlers for GUIDed sections, some other
modules can decode such sections with the pre-registered handlers. The
table carries persistent information between these modules.
BaseExtractGuidedSectionLib checks a table signature whenever it is used
(by whichever module that is linked against it), and at the first use
(identified by a signature mismatch) it initializes the table.
One of the module types that BaseExtractGuidedSectionLib can be used with
is SEC, if the SEC module in question runs with the platform's RAM already
available.
In such cases the question emerges whether the initial contents of the RAM
(ie. contents that predate the very first signature check) can be trusted.
Normally RAM starts out with all zeroes (leading to a signature mismatch
on the first check); however a malicious runtime OS can populate the area
with some payload, then force a warm platform reset or an S3
suspend-and-resume. In such cases the signature check in the SEC module
might not fire, and ExtractGuidedSectionDecode() might run code injected
by the runtime OS, as part of SEC (ie. with high privileges).
Therefore we clear the handler table in SEC.
See also git commit ad43bc6b2e (SVN rev 15433) -- this patch secures the
(d) and (e) code paths examined in that commit. Furthermore, a
non-malicious runtime OS will observe no change in behavior; see case (c)
in said commit.
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
[michael.d.kinney@intel.com: prevent VS20xx loop intrinsic with volatile]
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Michael Kinney <michael.d.kinney@intel.com>
Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19035 6f19259b-4bc3-4df7-8a09-765794883524
73 lines
2.0 KiB
INI
73 lines
2.0 KiB
INI
## @file
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# SEC Driver
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#
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# Copyright (c) 2008 - 2015, Intel Corporation. All rights reserved.<BR>
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#
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# This program and the accompanying materials
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# are licensed and made available under the terms and conditions of the BSD License
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# which accompanies this distribution. The full text of the license may be found at
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# http://opensource.org/licenses/bsd-license.php
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#
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# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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#
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##
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[Defines]
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INF_VERSION = 0x00010005
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BASE_NAME = SecMain
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FILE_GUID = df1ccef6-f301-4a63-9661-fc6030dcc880
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MODULE_TYPE = SEC
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VERSION_STRING = 1.0
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ENTRY_POINT = SecMain
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#
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# The following information is for reference only and not required by the build tools.
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#
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# VALID_ARCHITECTURES = IA32 X64 IPF EBC
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#
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[Sources]
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SecMain.c
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[Sources.IA32]
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Ia32/SecEntry.nasm
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[Sources.X64]
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X64/SecEntry.nasm
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[Packages]
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MdePkg/MdePkg.dec
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MdeModulePkg/MdeModulePkg.dec
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UefiCpuPkg/UefiCpuPkg.dec
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OvmfPkg/OvmfPkg.dec
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[LibraryClasses]
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BaseLib
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DebugLib
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BaseMemoryLib
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PeiServicesLib
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PcdLib
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UefiCpuLib
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DebugAgentLib
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IoLib
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PeCoffLib
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PeCoffGetEntryPointLib
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PeCoffExtraActionLib
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ExtractGuidedSectionLib
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LocalApicLib
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[Ppis]
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gEfiTemporaryRamSupportPpiGuid # PPI ALWAYS_PRODUCED
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[Pcd]
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gUefiOvmfPkgTokenSpaceGuid.PcdOvmfPeiMemFvBase
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gUefiOvmfPkgTokenSpaceGuid.PcdOvmfPeiMemFvSize
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gUefiOvmfPkgTokenSpaceGuid.PcdOvmfDxeMemFvBase
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gUefiOvmfPkgTokenSpaceGuid.PcdOvmfDxeMemFvSize
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gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPageTablesBase
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gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPeiTempRamBase
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gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPeiTempRamSize
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gEfiMdePkgTokenSpaceGuid.PcdGuidedExtractHandlerTableAddress
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gUefiOvmfPkgTokenSpaceGuid.PcdGuidedExtractHandlerTableSize
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