mirror of https://github.com/acidanthera/audk.git
UefiCpuPkg/PiSmmCpuDxeSmm: [CVE-2017-5715] Stuff RSB before RSM
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1093 Return Stack Buffer (RSB) is used to predict the target of RET instructions. When the RSB underflows, some processors may fall back to using branch predictors. This might impact software using the retpoline mitigation strategy on those processors. This commit will add RSB stuffing logic before returning from SMM (the RSM instruction) to avoid interfering with non-SMM usage of the retpoline technique. After the stuffing, RSB entries will contain a trap like: @SpecTrap: pause lfence jmp @SpecTrap A more detailed explanation of the purpose of commit is under the 'Branch target injection mitigation' section of the below link: https://software.intel.com/security-software-guidance/insights/host-firmware-speculative-execution-side-channel-mitigation Please note that this commit requires further actions (BZ 1091) to remove the duplicated 'StuffRsb.inc' files and merge them into one under a UefiCpuPkg package-level directory (such as UefiCpuPkg/Include/). REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1091 Cc: Jiewen Yao <jiewen.yao@intel.com> Cc: Michael D Kinney <michael.d.kinney@intel.com> Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Hao Wu <hao.a.wu@intel.com> Acked-by: Laszlo Ersek <lersek@redhat.com> Regression-tested-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Eric Dong <eric.dong@intel.com>
This commit is contained in:
Hao Wu
parent
6cf6fed024
commit
02f7fd158e
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@ -18,6 +18,8 @@
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;
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;-------------------------------------------------------------------------------
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%include "StuffRsb.inc"
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%define MSR_IA32_MISC_ENABLE 0x1A0
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%define MSR_EFER 0xc0000080
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%define MSR_EFER_XD 0x800
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@ -204,6 +206,7 @@ ASM_PFX(SmiHandler):
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wrmsr
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.7:
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StuffRsb32
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rsm
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ASM_PFX(gcSmiHandlerSize): DW $ - _SmiEntryPoint
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@ -18,6 +18,8 @@
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;
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;-------------------------------------------------------------------------------
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%include "StuffRsb.inc"
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extern ASM_PFX(SmmInitHandler)
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extern ASM_PFX(mRebasedFlag)
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extern ASM_PFX(mSmmRelocationOriginalAddress)
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@ -75,6 +77,7 @@ BITS 32
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mov esp, strict dword 0 ; source operand will be patched
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ASM_PFX(gPatchSmmInitStack):
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call ASM_PFX(SmmInitHandler)
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StuffRsb32
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rsm
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BITS 16
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@ -0,0 +1,55 @@
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;------------------------------------------------------------------------------
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;
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; Copyright (c) 2018, Intel Corporation. All rights reserved.<BR>
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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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; Abstract:
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;
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; This file provides macro definitions for stuffing the Return Stack Buffer (RSB).
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;
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;------------------------------------------------------------------------------
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%define RSB_STUFF_ENTRIES 0x20
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;
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; parameters:
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; @param 1: register to use as counter (e.g. IA32:eax, X64:rax)
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; @param 2: stack pointer to restore (IA32:esp, X64:rsp)
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; @param 3: the size of a stack frame (IA32:4, X64:8)
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;
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%macro StuffRsb 3
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mov %1, RSB_STUFF_ENTRIES / 2
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%%Unroll1:
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call %%Unroll2
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%%SpecTrap1:
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pause
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lfence
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jmp %%SpecTrap1
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%%Unroll2:
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call %%StuffLoop
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%%SpecTrap2:
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pause
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lfence
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jmp %%SpecTrap2
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%%StuffLoop:
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dec %1
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jnz %%Unroll1
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add %2, RSB_STUFF_ENTRIES * %3 ; Restore the stack pointer
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%endmacro
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;
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; RSB stuffing macros for IA32 and X64
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;
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%macro StuffRsb32 0
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StuffRsb eax, esp, 4
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%endmacro
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%macro StuffRsb64 0
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StuffRsb rax, rsp, 8
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%endmacro
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@ -18,6 +18,8 @@
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;
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;-------------------------------------------------------------------------------
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%include "StuffRsb.inc"
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;
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; Variables referrenced by C code
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;
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@ -217,6 +219,7 @@ _SmiHandler:
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wrmsr
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.1:
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StuffRsb64
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rsm
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ASM_PFX(gcSmiHandlerSize) DW $ - _SmiEntryPoint
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@ -18,6 +18,8 @@
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;
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;-------------------------------------------------------------------------------
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%include "StuffRsb.inc"
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extern ASM_PFX(SmmInitHandler)
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extern ASM_PFX(mRebasedFlag)
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extern ASM_PFX(mSmmRelocationOriginalAddress)
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@ -101,6 +103,7 @@ ASM_PFX(gPatchSmmInitStack):
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movdqa xmm4, [rsp + 0x40]
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movdqa xmm5, [rsp + 0x50]
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StuffRsb64
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rsm
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BITS 16
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@ -0,0 +1,55 @@
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;------------------------------------------------------------------------------
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;
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; Copyright (c) 2018, Intel Corporation. All rights reserved.<BR>
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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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; Abstract:
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;
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; This file provides macro definitions for stuffing the Return Stack Buffer (RSB).
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;
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;------------------------------------------------------------------------------
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%define RSB_STUFF_ENTRIES 0x20
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;
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; parameters:
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; @param 1: register to use as counter (e.g. IA32:eax, X64:rax)
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; @param 2: stack pointer to restore (IA32:esp, X64:rsp)
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; @param 3: the size of a stack frame (IA32:4, X64:8)
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;
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%macro StuffRsb 3
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mov %1, RSB_STUFF_ENTRIES / 2
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%%Unroll1:
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call %%Unroll2
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%%SpecTrap1:
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pause
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lfence
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jmp %%SpecTrap1
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%%Unroll2:
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call %%StuffLoop
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%%SpecTrap2:
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pause
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lfence
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jmp %%SpecTrap2
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%%StuffLoop:
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dec %1
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jnz %%Unroll1
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add %2, RSB_STUFF_ENTRIES * %3 ; Restore the stack pointer
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%endmacro
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;
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; RSB stuffing macros for IA32 and X64
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;
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%macro StuffRsb32 0
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StuffRsb eax, esp, 4
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%endmacro
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%macro StuffRsb64 0
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StuffRsb rax, rsp, 8
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%endmacro
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