KeyLocker is a new security feature available in new Intel CPUs that
protects data-encryption keys for the Advanced Encryption Standard (AES)
algorithm. These keys are more valuable than what they guard. If stolen
once, the key can be repeatedly used even on another system and even
after vulnerability closed.
It also introduces a CPU-internal wrapping key (IWKey), which is a key-
encryption key to wrap AES keys into handles. While the IWKey is
inaccessible to software, randomizing the value during the boot-time
helps its value unpredictable.
Keylocker usage:
- New “ENCODEKEY” instructions take original key input and returns HANDLE
crypted by an internal wrap key (IWKey, init by “LOADIWKEY” instruction)
- Software can then delete the original key from memory
- Early in boot/software, less likely to have vulnerability that allows
stealing original key
- Later encrypt/decrypt can use the HANDLE through new AES KeyLocker
instructions
- Note:
* Software can use original key without knowing it (use HANDLE)
* HANDLE cannot be used on other systems or after warm/cold reset
* IWKey cannot be read from CPU after it's loaded (this is the
nature of this feature) and only 1 copy of IWKey inside CPU.
The virtualization implementation of Key Locker on ACRN is:
- Each vCPU has a 'struct iwkey' to store its IWKey in struct
acrn_vcpu_arch.
- At initilization, every vCPU is created with a random IWKey.
- Hypervisor traps the execution of LOADIWKEY (by 'LOADIWKEY exiting'
VM-exectuion control) of vCPU to capture and save the IWKey if guest
set a new IWKey. Don't support randomization (emulate CPUID to
disable) of the LOADIWKEY as hypervisor cannot capture and save the
random IWKey. From keylocker spec:
"Note that a VMM may wish to enumerate no support for HW random IWKeys
to the guest (i.e. enumerate CPUID.19H:ECX[1] as 0) as such IWKeys
cannot be easily context switched. A guest ENCODEKEY will return the
type of IWKey used (IWKey.KeySource) and thus will notice if a VMM
virtualized a HW random IWKey with a SW specified IWKey."
- In context_switch_in() of each vCPU, hypervisor loads that vCPU's
IWKey into pCPU by LOADIWKEY instruction.
- There is an assumption that ACRN hypervisor will never use the
KeyLocker feature itself.
This patch implements the vCPU's IWKey management and the next patch
implements host context save/restore IWKey logic.
Tracked-On: #5695
Signed-off-by: Shuo A Liu <shuo.a.liu@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
Only apply the software workaround on the models that might be
affected by MCE on page size change. For these models that are
known immune to the issue, the mitigation is turned off.
Atom processors are not afftected by the issue.
Also check the CPUID & MSR to check whether the model is immune to the issue:
CPU is not vulnerable when both CPUID.(EAX=07H,ECX=0H).EDX[29] and
IA32_ARCH_CAPABILITIES[IF_PSCHANGE_MC_NO] are 1.
Other cases not listed above, CPU may be vulnerable.
This patch also changes MACROs for MSR IA32_ARCH_CAPABILITIES bits to UL instead of U
since the MSR is 64bit.
Tracked-On: #4101
Signed-off-by: Binbin Wu <binbin.wu@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
-- remove some unnecessary includes
-- fix a typo
-- remove unnecessary void before launch_vms
Tracked-On: #1842
Signed-off-by: Mingqiang Chi <mingqiang.chi@intel.com>
Microarchitectural Data Sampling (MDS) is a hardware vulnerability
which allows unprivileged speculative access to data which is available
in various CPU internal buffers.
1. Mitigation on ACRN:
1) Microcode update is required.
2) Clear CPU internal buffers (store buffer, load buffer and
load port) if current CPU is affected by MDS, when VM entry
to avoid any information leakage to guest thru above buffers.
3) Mitigation is not needed if ARCH_CAP_MDS_NO bit (bit5)
is set in IA32_ARCH_CAPABILITIES MSR (10AH), in this case,
current processor is no affected by MDS vulnerability, in other
cases mitigation for MDS is required.
2. Methods to clear CPU buffers (microcode update is required):
1) L1D cache flush
2) VERW instruction
Either of above operations will trigger clearing all
CPU internal buffers if this CPU is affected by MDS.
Above mechnism is enumerated by:
CPUID.(EAX=7H, ECX=0):EDX[MD_CLEAR=10].
3. Mitigation details on ACRN:
if (processor is affected by MDS)
if (processor is not affected by L1TF OR
L1D flush is not launched on VM Entry)
execute VERW instruction when VM entry.
endif
endif
4. Referrence:
Deep Dive: Intel Analysis of Microarchitectural Data Sampling
https://software.intel.com/security-software-guidance/insights/
deep-dive-intel-analysis-microarchitectural-data-sampling
Deep Dive: CPUID Enumeration and Architectural MSRs
https://software.intel.com/security-software-guidance/insights/
deep-dive-cpuid-enumeration-and-architectural-msrs
Tracked-On: #3317
Signed-off-by: Yonghua Huang <yonghua.huang@intel.com>
Reviewed-by: Anthony Xu <anthony.xu@intel.com>
Reviewed-by: Jason CJ Chen <jason.cj.chen@intel.com>
ACRN hypervisor always print CPU microcode update
warning message on KBL NUC platform, even after
BIOS was updated to the latest.
'check_cpu_security_cap()' returns false if
no ARCH_CAPABILITIES MSR support on current platform,
but this MSR may not be available on some platforms.
This patch is to remove this pre-condition.
Tracked-On: #3317
Signed-off-by: Yonghua Huang <yonghua.huang@intel.com>
Reviewed-by: Jason CJ Chen <jason.cj.chen@intel.com>
add get_ibrs_type API to get ibrs type.
this patch fix Misra C violation:
filename:/hypervisor/arch/x86/security.c function:None offset:19:
reason:Variable should be declared static. : ibrs_type
Tracked-On: #861
Signed-off-by: Jason Chen CJ <jason.cj.chen@intel.com>
there are still some security related funcs in cpu_caps.c & cpu.c,
move them out into security.c.
Changes to be committed:
modified: Makefile
modified: arch/x86/cpu.c
modified: arch/x86/cpu_caps.c
modified: arch/x86/guest/vcpu.c
new file: arch/x86/security.c
modified: arch/x86/trusty.c
modified: arch/x86/vmx_asm.S
modified: include/arch/x86/cpu.h
modified: include/arch/x86/cpu_caps.h
modified: include/arch/x86/per_cpu.h
new file: include/arch/x86/security.h
Tracked-On: #1842
Signed-off-by: Jason Chen CJ <jason.cj.chen@intel.com>
