From 34a5f0e3e3d2274aa25f0712402ceca86d330f8d Mon Sep 17 00:00:00 2001 From: Hao Wu Date: Thu, 16 Aug 2018 09:32:10 +0800 Subject: [PATCH] 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 Cc: Michael D Kinney Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Hao Wu Acked-by: Laszlo Ersek Regression-tested-by: Laszlo Ersek Reviewed-by: Eric Dong (cherry picked from commit 02f7fd158e977d0368705129c52a800217fe8887) --- UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm | 3 ++ UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm | 3 ++ UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/StuffRsb.inc | 55 ++++++++++++++++++++ UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm | 3 ++ UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmInit.nasm | 3 ++ UefiCpuPkg/PiSmmCpuDxeSmm/X64/StuffRsb.inc | 55 ++++++++++++++++++++ 6 files changed, 122 insertions(+) create mode 100644 UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/StuffRsb.inc create mode 100644 UefiCpuPkg/PiSmmCpuDxeSmm/X64/StuffRsb.inc diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm index a8324a7f4a..192af173cc 100644 --- a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm @@ -18,6 +18,8 @@ ; ;------------------------------------------------------------------------------- +%include "StuffRsb.inc" + %define MSR_IA32_MISC_ENABLE 0x1A0 %define MSR_EFER 0xc0000080 %define MSR_EFER_XD 0x800 @@ -203,6 +205,7 @@ ASM_PFX(SmiHandler): wrmsr .7: + StuffRsb32 rsm ASM_PFX(gcSmiHandlerSize): DW $ - _SmiEntryPoint diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm index a5c62e77ce..d95bd8bf11 100644 --- a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm @@ -18,6 +18,8 @@ ; ;------------------------------------------------------------------------------- +%include "StuffRsb.inc" + extern ASM_PFX(SmmInitHandler) extern ASM_PFX(mRebasedFlag) extern ASM_PFX(mSmmRelocationOriginalAddress) @@ -67,6 +69,7 @@ ASM_PFX(gSmmJmpAddr): DB 0xbc ; mov esp, imm32 ASM_PFX(gSmmInitStack): DD 0 call ASM_PFX(SmmInitHandler) + StuffRsb32 rsm BITS 16 diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/StuffRsb.inc b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/StuffRsb.inc new file mode 100644 index 0000000000..14267c3fde --- /dev/null +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/StuffRsb.inc @@ -0,0 +1,55 @@ +;------------------------------------------------------------------------------ +; +; Copyright (c) 2018, Intel Corporation. All rights reserved.
+; 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 +; http://opensource.org/licenses/bsd-license.php. +; +; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, +; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. +; +; Abstract: +; +; This file provides macro definitions for stuffing the Return Stack Buffer (RSB). +; +;------------------------------------------------------------------------------ + +%define RSB_STUFF_ENTRIES 0x20 + +; +; parameters: +; @param 1: register to use as counter (e.g. IA32:eax, X64:rax) +; @param 2: stack pointer to restore (IA32:esp, X64:rsp) +; @param 3: the size of a stack frame (IA32:4, X64:8) +; +%macro StuffRsb 3 + mov %1, RSB_STUFF_ENTRIES / 2 + %%Unroll1: + call %%Unroll2 + %%SpecTrap1: + pause + lfence + jmp %%SpecTrap1 + %%Unroll2: + call %%StuffLoop + %%SpecTrap2: + pause + lfence + jmp %%SpecTrap2 + %%StuffLoop: + dec %1 + jnz %%Unroll1 + add %2, RSB_STUFF_ENTRIES * %3 ; Restore the stack pointer +%endmacro + +; +; RSB stuffing macros for IA32 and X64 +; +%macro StuffRsb32 0 + StuffRsb eax, esp, 4 +%endmacro + +%macro StuffRsb64 0 + StuffRsb rax, rsp, 8 +%endmacro diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm index 697fd2bec7..ac223adf0f 100644 --- a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm @@ -18,6 +18,8 @@ ; ;------------------------------------------------------------------------------- +%include "StuffRsb.inc" + ; ; Variables referrenced by C code ; @@ -218,6 +220,7 @@ _SmiHandler: wrmsr .1: + StuffRsb64 rsm ASM_PFX(gcSmiHandlerSize) DW $ - _SmiEntryPoint diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmInit.nasm b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmInit.nasm index 2701689c3d..ff92ed764c 100644 --- a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmInit.nasm +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmInit.nasm @@ -18,6 +18,8 @@ ; ;------------------------------------------------------------------------------- +%include "StuffRsb.inc" + extern ASM_PFX(SmmInitHandler) extern ASM_PFX(mRebasedFlag) extern ASM_PFX(mSmmRelocationOriginalAddress) @@ -91,6 +93,7 @@ ASM_PFX(gSmmInitStack): DQ 0 movdqa xmm4, [rsp + 0x40] movdqa xmm5, [rsp + 0x50] + StuffRsb64 rsm BITS 16 diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/StuffRsb.inc b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/StuffRsb.inc new file mode 100644 index 0000000000..14267c3fde --- /dev/null +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/StuffRsb.inc @@ -0,0 +1,55 @@ +;------------------------------------------------------------------------------ +; +; Copyright (c) 2018, Intel Corporation. All rights reserved.
+; 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 +; http://opensource.org/licenses/bsd-license.php. +; +; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, +; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. +; +; Abstract: +; +; This file provides macro definitions for stuffing the Return Stack Buffer (RSB). +; +;------------------------------------------------------------------------------ + +%define RSB_STUFF_ENTRIES 0x20 + +; +; parameters: +; @param 1: register to use as counter (e.g. IA32:eax, X64:rax) +; @param 2: stack pointer to restore (IA32:esp, X64:rsp) +; @param 3: the size of a stack frame (IA32:4, X64:8) +; +%macro StuffRsb 3 + mov %1, RSB_STUFF_ENTRIES / 2 + %%Unroll1: + call %%Unroll2 + %%SpecTrap1: + pause + lfence + jmp %%SpecTrap1 + %%Unroll2: + call %%StuffLoop + %%SpecTrap2: + pause + lfence + jmp %%SpecTrap2 + %%StuffLoop: + dec %1 + jnz %%Unroll1 + add %2, RSB_STUFF_ENTRIES * %3 ; Restore the stack pointer +%endmacro + +; +; RSB stuffing macros for IA32 and X64 +; +%macro StuffRsb32 0 + StuffRsb eax, esp, 4 +%endmacro + +%macro StuffRsb64 0 + StuffRsb rax, rsp, 8 +%endmacro