Microarchitectural buffers on some Intel processors utilizing
speculative execution may allow a local process to obtain a memory
disclosure. An attacker may be able to read secret data from the
kernel or from a process when executing untrusted code (for example,
in a web browser).
Reference: https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00233.html
Security: CVE-2018-12126, CVE-2018-12127, CVE-2018-12130, CVE-2019-11091
Security: FreeBSD-SA-19:07.mds
Reviewed by: jhb
Tested by: emaste, lwhsu
Approved by: so (gtetlow)
loaded OS.
This should prevent at least some theoretical issues whith code
execution on HT sibling of the core where the update is loaded.
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D20201
The knob allows to select the flushing mode or turn it off/on. The
idea, as well as the list of the ignored syscall errors, were taken
from https://www.openwall.com/lists/kernel-hardening/2018/10/11/10 .
I was not able to measure statistically significant difference between
flush enabled vs disabled using syscall_timing getuid.
Reviewed by: bwidawsk
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D17536
Updates in the format described in section 9.11 of the Intel SDM can
now be applied as one of the first steps in booting the kernel. Updates
that are loaded this way are automatically re-applied upon exit from
ACPI sleep states, in contrast with the existing cpucontrol(8)-based
method. For the time being only Intel updates are supported.
Microcode update files are passed to the kernel via loader(8). The
file type must be "cpu_microcode" in order for the file to be recognized
as a candidate microcode update. Updates for multiple CPU types may be
concatenated together into a single file, in which case the kernel
will select and apply a matching update. Memory used to store the
update file will be freed back to the system once the update is applied,
so this approach will not consume more memory than required.
Reviewed by: kib
MFC after: 6 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D16370
This apparently works around issues with updates of certain Broadwell
CPUs.
Reviewed by: emaste, kib, sbruno
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D15520
Speculative Store Bypass (SSB) is a speculative execution side channel
vulnerability identified by Jann Horn of Google Project Zero (GPZ) and
Ken Johnson of the Microsoft Security Response Center (MSRC)
https://bugs.chromium.org/p/project-zero/issues/detail?id=1528.
Updated Intel microcode introduces a MSR bit to disable SSB as a
mitigation for the vulnerability.
Introduce a sysctl hw.spec_store_bypass_disable to provide global
control over the SSBD bit, akin to the existing sysctl that controls
IBRS. The sysctl can be set to one of three values:
0: off
1: on
2: auto
Future work will enable applications to control SSBD on a per-process
basis (when it is not enabled globally).
SSBD bit detection and control was verified with prerelease microcode.
Security: CVE-2018-3639
Tested by: emaste (previous version, without updated microcode)
Sponsored by: The FreeBSD Foundation
MFC after: 3 days
It is coded according to the Intel document 336996-001, reading of the
patches posted on lkml, and some additional consultations with Intel.
For existing processors, you need a microcode update which adds IBRS
CPU features, and to manually enable it by setting the tunable/sysctl
hw.ibrs_disable to 0. Current status can be checked in sysctl
hw.ibrs_active. The mitigation might be inactive if the CPU feature
is not patched in, or if CPU reports that IBRS use is not required, by
IA32_ARCH_CAP_IBRS_ALL bit.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D14029
Add cpuctl(4) ioctl CPUCTL_EVAL_CPU_FEATURES which forces re-read of
cpu_features, cpu_features2, cpu_stdext_features, and
std_stdext_features2.
The intent is to allow the kernel to see the changes in the CPU
features after micocode update. Of course, the update is not atomic
across variables and not synchronized with readers. See the man page
warning as well.
Reviewed by: imp (previous version), jilles
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D13770
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Newer CPUs (SkyLakes) have updates of 100K size, which is bigger than
current limit 32K. Increase it to 4M but leave the check around to
prevent kernel memory allocator abuse. Some time ago, the memory for
update was allocated by contigmalloc(9), and it was reasonable to be
conservative as much as possible. Since all uses of contigmalloc(9)
appear to be either misunderstanding or too cautious, and were
removed, provide more slack than strictly neccessary.
Submitted by: Oliver Pinter
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D8486
mp_maxid or CPU_FOREACH() as appropriate. This fixes a number of places in
the kernel that assumed CPU IDs are dense in [0, mp_ncpus) and would try,
for example, to run tasks on CPUs that did not exist or to allocate too
few buffers on systems with sparse CPU IDs in which there are holes in the
range and mp_maxid > mp_ncpus. Such circumstances generally occur on
systems with SMT, but on which SMT is disabled. This patch restores system
operation at least on POWER8 systems configured in this way.
There are a number of other places in the kernel with potential problems
in these situations, but where sparse CPU IDs are not currently known
to occur, mostly in the ARM machine-dependent code. These will be fixed
in a follow-up commit after the stable/11 branch.
PR: kern/210106
Reviewed by: jhb
Approved by: re (glebius)
supported, e.g. CPUID or MSR, return ENODEV from the ioctl which needs
that feature.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Approved by: re (hrs)
separate argument structure with added level_type field for
CPUID_CPUID_COUNT request.
Reviewed by: attilio (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
performing cpuid calls.
Add also a new way to specify the level type to cpucontrol(8) as
reported in the manpage.
Sponsored by: EMC / Isilon storage division
Reviewed by: bdrewery, gcooper
Testerd by: bdrewery
unneeded checks for NULL, free(9) can handle NULL pointers on its own,
and the regions were allocated with M_WAITOK flag as well.
Reported and tested by: Larry Rosenman <ler@lerctr.org>
MFC after: 1 week
... instead of whatever random value may happen to be in the register.
ecx is important to some cpuid leaves.
To do: extend cpuctl interface to provide for ecx value parameter.
MFC after: 5 days
via cpuctl(4) driver. Two new CPUCTL_MSRSBIT and CPUCTL_MSRCBIT ioctl(2)
calls treat the data field of the argument struct passed as a mask
and set/clear bits of the MSR register according to the mask value.
- Allow user to perform atomic bitwise AND and OR operaions on MSR registers
via cpucontrol(8) utility. Two new operations ("&=" and "|=") have been
added. The first one applies bitwise AND operaion between the current
contents of the MSR register and the mask, and the second performs bitwise
OR. The argument can be optionally prefixed with "~" inversion operator.
This allows one to mimic the "clear bit" behavior by using the command
like this:
cpucontrol -m 0x10&=~0x02 # clear the second bit of TSC MSR
Inversion operator support in all modes (assignment, OR, AND).
Approved by: re (kib)
MFC after: 1 month
the value written to MSR register was always 0 regardless of value passed
by user.
- Use proper data pointer when performing AMD microcode update. Previously,
the pointer to user-space data has been provided instead, which is totally
incorrect.
Approved by: re (kib)
MFC after: 1 week
After I removed all the unit2minor()/minor2unit() calls from the kernel
yesterday, I realised calling minor() everywhere is quite confusing.
Character devices now only have the ability to store a unit number, not
a minor number. Remove the confusion by using dev2unit() everywhere.
This commit could also be considered as a bug fix. A lot of drivers call
minor(), while they should actually be calling dev2unit(). In -CURRENT
this isn't a problem, but it turns out we never had any problem reports
related to that issue in the past. I suspect not many people connect
more than 256 pieces of the same hardware.
Reviewed by: kib
The D_NEEDMINOR flag was introduced for drivers that do not actually
depend on storing a device unit/minor number, but require the ability to
address the cdevs by this number, which is used by clone_create().
The cpuctl(4) driver sets D_NEEDMINOR, even though it doesn't use the
clone_create() API. Remove the flag, because maybe we want to get rid of
it somewhere in the far future.
features of CPUs like reading/writing machine-specific registers,
retrieving cpuid data, and updating microcode.
- Add cpucontrol(8) utility, that provides userland access to
the features of cpuctl(4).
- Add subsequent manpages.
The cpuctl(4) device operates as follows. The pseudo-device node cpuctlX
is created for each cpu present in the systems. The pseudo-device minor
number corresponds to the cpu number in the system. The cpuctl(4) pseudo-
device allows a number of ioctl to be preformed, namely RDMSR/WRMSR/CPUID
and UPDATE. The first pair alows the caller to read/write machine-specific
registers from the correspondent CPU. cpuid data could be retrieved using
the CPUID call, and microcode updates are applied via UPDATE.
The permissions are inforced based on the pseudo-device file permissions.
RDMSR/CPUID will be allowed when the caller has read access to the device
node, while WRMSR/UPDATE will be granted only when the node is opened
for writing. There're also a number of priv(9) checks.
The cpucontrol(8) utility is intened to provide userland access to
the cpuctl(4) device features. The utility also allows one to apply
cpu microcode updates.
Currently only Intel and AMD cpus are supported and were tested.
Approved by: kib
Reviewed by: rpaulo, cokane, Peter Jeremy
MFC after: 1 month
