lkml.org 
[lkml]   [2018]   [Jan]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Subject[PATCH v6 00/10] Retpoline: Avoid speculative indirect calls in kernel
Date
This is a mitigation for the 'variant 2' attack described in
https://googleprojectzero.blogspot.com/2018/01/reading-privileged-memory-with-side.html

Using GCC patches available from the hjl/indirect/gcc-7-branch/master
branch of https://github.com/hjl-tools/gcc/commits/hjl and by manually
patching assembler code, all vulnerable indirect branches (that occur
after userspace first runs) are eliminated from the kernel.

They are replaced with a 'retpoline' call sequence which deliberately
prevents speculation.

Fedora 27 packages of the updated compiler are available at
https://koji.fedoraproject.org/koji/taskinfo?taskID=24065739


v1: Initial post.
v2: Add CONFIG_RETPOLINE to build kernel without it.
Change warning messages.
Hide modpost warning message
v3: Update to the latest CET-capable retpoline version
Reinstate ALTERNATIVE support
v4: Finish reconciling Andi's and my patch sets, bug fixes.
Exclude objtool support for now
Add 'noretpoline' boot option
Add AMD retpoline alternative
v5: Silence MODVERSIONS warnings
Use pause;jmp loop instead of lfence;jmp
Switch to X86_FEATURE_RETPOLINE positive feature logic
Emit thunks inline from assembler macros
Merge AMD support into initial patch
v6: Update to latest GCC patches with no dots in symbols
Fix MODVERSIONS properly(ish)
Fix typo breaking 32-bit, introduced in V5
Never set X86_FEATURE_RETPOLINE_AMD yet, pending confirmation

Andi Kleen (3):
x86/retpoline/irq32: Convert assembler indirect jumps
x86/retpoline: Add boot time option to disable retpoline
x86/retpoline: Exclude objtool with retpoline

David Woodhouse (7):
x86/retpoline: Add initial retpoline support
x86/retpoline/crypto: Convert crypto assembler indirect jumps
x86/retpoline/entry: Convert entry assembler indirect jumps
x86/retpoline/ftrace: Convert ftrace assembler indirect jumps
x86/retpoline/hyperv: Convert assembler indirect jumps
x86/retpoline/xen: Convert Xen hypercall indirect jumps
x86/retpoline/checksum32: Convert assembler indirect jumps

Documentation/admin-guide/kernel-parameters.txt | 3 +
arch/x86/Kconfig | 17 ++++-
arch/x86/Kconfig.debug | 6 +-
arch/x86/Makefile | 10 +++
arch/x86/crypto/aesni-intel_asm.S | 5 +-
arch/x86/crypto/camellia-aesni-avx-asm_64.S | 3 +-
arch/x86/crypto/camellia-aesni-avx2-asm_64.S | 3 +-
arch/x86/crypto/crc32c-pcl-intel-asm_64.S | 3 +-
arch/x86/entry/entry_32.S | 5 +-
arch/x86/entry/entry_64.S | 12 +++-
arch/x86/include/asm/asm-prototypes.h | 25 +++++++
arch/x86/include/asm/cpufeatures.h | 2 +
arch/x86/include/asm/mshyperv.h | 18 ++---
arch/x86/include/asm/nospec-branch.h | 92 +++++++++++++++++++++++++
arch/x86/include/asm/xen/hypercall.h | 5 +-
arch/x86/kernel/cpu/common.c | 3 +
arch/x86/kernel/cpu/intel.c | 11 +++
arch/x86/kernel/ftrace_32.S | 6 +-
arch/x86/kernel/ftrace_64.S | 8 +--
arch/x86/kernel/irq_32.c | 9 +--
arch/x86/lib/Makefile | 1 +
arch/x86/lib/checksum_32.S | 7 +-
arch/x86/lib/retpoline.S | 48 +++++++++++++
23 files changed, 264 insertions(+), 38 deletions(-)
create mode 100644 arch/x86/include/asm/nospec-branch.h
create mode 100644 arch/x86/lib/retpoline.S

--
2.7.4

\
 
 \ /
  Last update: 2018-01-14 23:16    [W:0.213 / U:22.540 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site