From 95099d4622f8cb224d94e314c7a8e0df60b13f87 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Sat, 09 Dec 2023 08:38:01 +0000
Subject: [PATCH] enable docker ppp
---
kernel/Documentation/admin-guide/hw-vuln/spectre.rst | 56 ++++++++++++++++++++++++++++++++++++++++----------------
1 files changed, 40 insertions(+), 16 deletions(-)
diff --git a/kernel/Documentation/admin-guide/hw-vuln/spectre.rst b/kernel/Documentation/admin-guide/hw-vuln/spectre.rst
index 985181d..7e061ed 100644
--- a/kernel/Documentation/admin-guide/hw-vuln/spectre.rst
+++ b/kernel/Documentation/admin-guide/hw-vuln/spectre.rst
@@ -60,8 +60,8 @@
Spectre variant 1 attacks take advantage of speculative execution of
conditional branches, while Spectre variant 2 attacks use speculative
execution of indirect branches to leak privileged memory.
-See :ref:`[1] <spec_ref1>` :ref:`[5] <spec_ref5>` :ref:`[7] <spec_ref7>`
-:ref:`[10] <spec_ref10>` :ref:`[11] <spec_ref11>`.
+See :ref:`[1] <spec_ref1>` :ref:`[5] <spec_ref5>` :ref:`[6] <spec_ref6>`
+:ref:`[7] <spec_ref7>` :ref:`[10] <spec_ref10>` :ref:`[11] <spec_ref11>`.
Spectre variant 1 (Bounds Check Bypass)
---------------------------------------
@@ -130,6 +130,19 @@
steer its indirect branch speculations to gadget code, and measure the
speculative execution's side effects left in level 1 cache to infer the
victim's data.
+
+Yet another variant 2 attack vector is for the attacker to poison the
+Branch History Buffer (BHB) to speculatively steer an indirect branch
+to a specific Branch Target Buffer (BTB) entry, even if the entry isn't
+associated with the source address of the indirect branch. Specifically,
+the BHB might be shared across privilege levels even in the presence of
+Enhanced IBRS.
+
+Currently the only known real-world BHB attack vector is via
+unprivileged eBPF. Therefore, it's highly recommended to not enable
+unprivileged eBPF, especially when eIBRS is used (without retpolines).
+For a full mitigation against BHB attacks, it's recommended to use
+retpolines (or eIBRS combined with retpolines).
Attack scenarios
----------------
@@ -364,13 +377,15 @@
- Kernel status:
- ==================================== =================================
- 'Not affected' The processor is not vulnerable
- 'Vulnerable' Vulnerable, no mitigation
- 'Mitigation: Full generic retpoline' Software-focused mitigation
- 'Mitigation: Full AMD retpoline' AMD-specific software mitigation
- 'Mitigation: Enhanced IBRS' Hardware-focused mitigation
- ==================================== =================================
+ ======================================== =================================
+ 'Not affected' The processor is not vulnerable
+ 'Mitigation: None' Vulnerable, no mitigation
+ 'Mitigation: Retpolines' Use Retpoline thunks
+ 'Mitigation: LFENCE' Use LFENCE instructions
+ 'Mitigation: Enhanced IBRS' Hardware-focused mitigation
+ 'Mitigation: Enhanced IBRS + Retpolines' Hardware-focused + Retpolines
+ 'Mitigation: Enhanced IBRS + LFENCE' Hardware-focused + LFENCE
+ ======================================== =================================
- Firmware status: Show if Indirect Branch Restricted Speculation (IBRS) is
used to protect against Spectre variant 2 attacks when calling firmware (x86 only).
@@ -406,6 +421,14 @@
============= ===========================================
'RSB filling' Protection of RSB on context switch enabled
============= ===========================================
+
+ - EIBRS Post-barrier Return Stack Buffer (PBRSB) protection status:
+
+ =========================== =======================================================
+ 'PBRSB-eIBRS: SW sequence' CPU is affected and protection of RSB on VMEXIT enabled
+ 'PBRSB-eIBRS: Vulnerable' CPU is vulnerable
+ 'PBRSB-eIBRS: Not affected' CPU is not affected by PBRSB
+ =========================== =======================================================
Full mitigation might require a microcode update from the CPU
vendor. When the necessary microcode is not available, the kernel will
@@ -584,12 +607,13 @@
Specific mitigations can also be selected manually:
- retpoline
- replace indirect branches
- retpoline,generic
- google's original retpoline
- retpoline,amd
- AMD-specific minimal thunk
+ retpoline auto pick between generic,lfence
+ retpoline,generic Retpolines
+ retpoline,lfence LFENCE; indirect branch
+ retpoline,amd alias for retpoline,lfence
+ eibrs enhanced IBRS
+ eibrs,retpoline enhanced IBRS + Retpolines
+ eibrs,lfence enhanced IBRS + LFENCE
Not specifying this option is equivalent to
spectre_v2=auto.
@@ -730,7 +754,7 @@
.. _spec_ref6:
-[6] `Software techniques for managing speculation on AMD processors <https://developer.amd.com/wp-content/resources/90343-B_SoftwareTechniquesforManagingSpeculation_WP_7-18Update_FNL.pdf>`_.
+[6] `Software techniques for managing speculation on AMD processors <https://developer.amd.com/wp-content/resources/Managing-Speculation-on-AMD-Processors.pdf>`_.
ARM white papers:
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