REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1521
We scan the SMM code with ROPgadget.
http://shell-storm.org/project/ROPgadget/https://github.com/JonathanSalwan/ROPgadget/tree/master
This tool reports the gadget in SMM driver.
This patch enabled CET ShadowStack for X86 SMM.
If CET is supported, SMM will enable CET ShadowStack.
SMM CET will save the OS CET context at SmmEntry and
restore OS CET context at SmmExit.
Test:
1) test Intel internal platform (x64 only, CET enabled/disabled)
Boot test:
CET supported or not supported CPU
on CET supported platform
CET enabled/disabled
PcdCpuSmmCetEnable enabled/disabled
Single core/Multiple core
PcdCpuSmmStackGuard enabled/disabled
PcdCpuSmmProfileEnable enabled/disabled
PcdCpuSmmStaticPageTable enabled/disabled
CET exception test:
#CF generated with PcdCpuSmmStackGuard enabled/disabled.
Other exception test:
#PF for normal stack overflow
#PF for NX protection
#PF for RO protection
CET env test:
Launch SMM in CET enabled/disabled environment (DXE) - no impact to DXE
The test case can be found at
https://github.com/jyao1/SecurityEx/tree/master/ControlFlowPkg
2) test ovmf (both IA32 and X64 SMM, CET disabled only)
test OvmfIa32/Ovmf3264, with -D SMM_REQUIRE.
qemu-system-x86_64.exe -machine q35,smm=on -smp 4
-serial file:serial.log
-drive if=pflash,format=raw,unit=0,file=OVMF_CODE.fd,readonly=on
-drive if=pflash,format=raw,unit=1,file=OVMF_VARS.fd
QEMU emulator version 3.1.0 (v3.1.0-11736-g7a30e7adb0-dirty)
3) not tested
IA32 CET enabled platform
Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Yao Jiewen <jiewen.yao@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
REF:https://bugzilla.tianocore.org/show_bug.cgi?id=1091
Previously, when compiling NASM source files, BaseTools did not support
including files outside of the NASM source file directory. As a result, we
duplicated multiple copies of "StuffRsb.inc" files in UefiCpuPkg. Those
INC files contain the common logic to stuff the Return Stack Buffer and
are identical.
After the fix of BZ 1085:
https://bugzilla.tianocore.org/show_bug.cgi?id=1085
The above support was introduced.
Thus, this commit will merge all the StuffRsb.inc files in UefiCpuPkg into
one file. The merged file will be named 'StuffRsbNasm.inc' and be placed
under folder UefiCpuPkg/Include/.
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
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>
"mXdSupported" is a global BOOLEAN variable, initialized to TRUE. The
CheckFeatureSupported() function is executed on all processors (not
concurrently though), called from SmmInitHandler(). If XD support is found
to be missing on any CPU, then "mXdSupported" is set to FALSE, and further
processors omit the check. Afterwards, "mXdSupported" is read by several
assembly and C code locations.
The tricky part is *where* "mXdSupported" is allocated (defined):
- Before commit 717fb60443 ("UefiCpuPkg/PiSmmCpuDxeSmm: Add paging
protection.", 2016-11-17), it used to be a normal global variable,
defined (allocated) in "SmmProfile.c".
- With said commit, we moved the definition (allocation) of "mXdSupported"
into "SmiEntry.nasm". The variable was defined over the last byte of a
"mov al, 1" instruction, so that setting it to FALSE in
CheckFeatureSupported() would patch the instruction to "mov al, 0". The
subsequent conditional jump would change behavior, plus all further read
references to "mXdSupported" (in C and assembly code) would read back
the source (imm8) operand of the patched MOV instruction as data.
This trick required that the MOV instruction be encoded with DB.
In order to get rid of the DB, we have to split both roles: we need a
label for the code patching, and "mXdSupported" has to be defined
(allocated) independently of the code patching. Of course, their values
must always remain in sync.
(1) Reinstate the "mXdSupported" definition and initialization in
"SmmProfile.c" from before commit 717fb60443. Change the assembly
language definition ("global") to a declaration ("extern").
(2) Define the "gPatchXdSupported" label (type X86_ASSEMBLY_PATCH_LABEL)
in "SmiEntry.nasm", and add the C-language declaration to
"SmmProfileInternal.h". Replace the DB with the MOV mnemonic (keeping
the imm8 source operand with value 1).
(3) In CheckFeatureSupported(), whenever "mXdSupported" is set to FALSE,
patch the assembly code in sync, with PatchInstructionX86().
Cc: Eric Dong <eric.dong@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=866
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Rename the variable to "gPatchSmiCr3" so that its association with
PatchInstructionX86() is clear from the declaration, change its type to
X86_ASSEMBLY_PATCH_LABEL, and patch it with PatchInstructionX86(). This
lets us remove the binary (DB) encoding of some instructions in
"SmiEntry.nasm".
Cc: Eric Dong <eric.dong@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=866
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Rename the variable to "gPatchSmiStack" so that its association with
PatchInstructionX86() is clear from the declaration. Also change its type
to X86_ASSEMBLY_PATCH_LABEL.
Unlike "gSmbase" in the previous patch, "gSmiStack"'s patched value is
also de-referenced by C code (in other words, it is read back after
patching): the InstallSmiHandler() function stores "CpuIndex" to the given
CPU's SMI stack through "gSmiStack". Introduce the local variable
"CpuSmiStack" in InstallSmiHandler() for calculating the stack location
separately, then use this variable for both patching into the assembly
code, and for storing "CpuIndex" through it.
It's assumed that "volatile" stood in the declaration of "gSmiStack"
because we used to read "gSmiStack" back for de-referencing; with that use
gone, we can remove "volatile" too. (Note that the *target* of the pointer
was never volatile-qualified.)
Finally, replace the binary (DB) encoding of "mov esp, imm32" in
"SmiEntry.nasm".
Cc: Eric Dong <eric.dong@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=866
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Rename the variable to "gPatchSmbase" so that its association with
PatchInstructionX86() is clear from the declaration, change its type to
X86_ASSEMBLY_PATCH_LABEL, and patch it with PatchInstructionX86(). This
lets us remove the binary (DB) encoding of some instructions in
"SmiEntry.nasm".
Cc: Eric Dong <eric.dong@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=866
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
https://bugzilla.tianocore.org/show_bug.cgi?id=849
In V2, use "mov rax, strict qword 0" to replace the hard code db.
1. Use lea instruction to get the address instead of mov instruction.
2. Use the dummy address as jmp destination, and add the logic to fix up
the address to the absolute address at boot time.
3. On MpFuncs.nasm, use ExchangeInfo to record InitializeFloatingPointUnits.
This way is same to MpInitLib.
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Liming Gao <liming.gao@intel.com>
Cc: Andrew Fish <afish@apple.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
https://bugzilla.tianocore.org/show_bug.cgi?id=277
Remove dependency on layout of PROCESSOR_SMM_DESCRIPTOR
everywhere possible. The only exception is the standard
SMI entry handler template that is included with the
PiSmmCpuDxeSmm module. This allows an instance of the
SmmCpuFeaturesLib to provide alternate
PROCESSOR_SMM_DESCRIPTOR structure layouts.
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Jeff Fan <jeff.fan@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Michael Kinney <michael.d.kinney@intel.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
PiSmmCpuDxeSmm consumes SmmAttributesTable and setup page table:
1) Code region is marked as read-only and Data region is non-executable,
if the PE image is 4K aligned.
2) Important data structure is set to RO, such as GDT/IDT.
3) SmmSaveState is set to non-executable,
and SmmEntrypoint is set to read-only.
4) If static page is supported, page table is read-only.
We use page table to protect other components, and itself.
If we use dynamic paging, we can still provide *partial* protection.
And hope page table is not modified by other components.
The XD enabling code is moved to SmiEntry to let NX take effect.
Cc: Jeff Fan <jeff.fan@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jiewen Yao <jiewen.yao@intel.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com>
Michael D Kinney
Jiewen Yao
Hao Wu
Laszlo Ersek
Liming Gao