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authorspeck for Pawan Gupta <speck@linutronix.de>2019-05-06 19:23:50 (GMT)
committerThomas Gleixner <tglx@linutronix.de>2019-05-08 09:31:31 (GMT)
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x86/mds: Add MDSUM variant to the MDS documentation
Updated the documentation for a new CVE-2019-11091 Microarchitectural Data Sampling Uncacheable Memory (MDSUM) which is a variant of Microarchitectural Data Sampling (MDS). MDS is a family of side channel attacks on internal buffers in Intel CPUs. MDSUM is a special case of MSBDS, MFBDS and MLPDS. An uncacheable load from memory that takes a fault or assist can leave data in a microarchitectural structure that may later be observed using one of the same methods used by MSBDS, MFBDS or MLPDS. There are no new code changes expected for MDSUM. The existing mitigation for MDS applies to MDSUM as well. Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Tyler Hicks <tyhicks@canonical.com> Reviewed-by: Jon Masters <jcm@redhat.com>
Diffstat (limited to 'Documentation/x86')
-rw-r--r--Documentation/x86/mds.rst5
1 files changed, 5 insertions, 0 deletions
diff --git a/Documentation/x86/mds.rst b/Documentation/x86/mds.rst
index 3d6f943..979945b 100644
--- a/Documentation/x86/mds.rst
+++ b/Documentation/x86/mds.rst
@@ -12,6 +12,7 @@ on internal buffers in Intel CPUs. The variants are:
- Microarchitectural Store Buffer Data Sampling (MSBDS) (CVE-2018-12126)
- Microarchitectural Fill Buffer Data Sampling (MFBDS) (CVE-2018-12130)
- Microarchitectural Load Port Data Sampling (MLPDS) (CVE-2018-12127)
+ - Microarchitectural Data Sampling Uncacheable Memory (MDSUM) (CVE-2019-11091)
MSBDS leaks Store Buffer Entries which can be speculatively forwarded to a
dependent load (store-to-load forwarding) as an optimization. The forward
@@ -38,6 +39,10 @@ faulting or assisting loads under certain conditions, which again can be
exploited eventually. Load ports are shared between Hyper-Threads so cross
thread leakage is possible.
+MDSUM is a special case of MSBDS, MFBDS and MLPDS. An uncacheable load from
+memory that takes a fault or assist can leave data in a microarchitectural
+structure that may later be observed using one of the same methods used by
+MSBDS, MFBDS or MLPDS.
Exposure assumptions
--------------------