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Filename Latest commit message Latest commit date
Josh Poimboeuf 6c1599fd1b x86/speculation: Warn about eIBRS + LFENCE + Unprivileged eBPF + SMT
commit 0de05d056afdb00eca8c7bbb0c79a3438daf700c upstream.

The commit

   44a3918c8245 ("x86/speculation: Include unprivileged eBPF status in Spectre v2 mitigation reporting")

added a warning for the "eIBRS + unprivileged eBPF" combination, which
has been shown to be vulnerable against Spectre v2 BHB-based attacks.

However, there's no warning about the "eIBRS + LFENCE retpoline +
unprivileged eBPF" combo. The LFENCE adds more protection by shortening
the speculation window after a mispredicted branch. That makes an attack
significantly more difficult, even with unprivileged eBPF. So at least
for now the logic doesn't warn about that combination.

But if you then add SMT into the mix, the SMT attack angle weakens the
effectiveness of the LFENCE considerably.

So extend the "eIBRS + unprivileged eBPF" warning to also include the
"eIBRS + LFENCE + unprivileged eBPF + SMT" case.

  [ bp: Massage commit message. ]

Suggested-by: Alyssa Milburn <alyssa.milburn@linux.intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-11 11:22:37 +01:00
arch x86/speculation: Warn about eIBRS + LFENCE + Unprivileged eBPF + SMT 2022-03-11 11:22:37 +01:00
block block: Fix fsync always failed if once failed 2022-03-08 19:07:47 +01:00
certs
crypto
Documentation x86/speculation: Update link to AMD speculation whitepaper 2022-03-11 11:22:37 +01:00
drivers hamradio: fix macro redefine warning 2022-03-08 19:07:51 +01:00
fs btrfs: add missing run of delayed items after unlink during log replay 2022-03-08 19:07:50 +01:00
include x86/speculation: Include unprivileged eBPF status in Spectre v2 mitigation reporting 2022-03-11 11:22:37 +01:00
init bpf: Add kconfig knob for disabling unpriv bpf by default 2022-02-16 12:52:49 +01:00
ipc
kernel x86/speculation: Include unprivileged eBPF status in Spectre v2 mitigation reporting 2022-03-11 11:22:37 +01:00
lib lib/iov_iter: initialize "flags" in new pipe_buffer 2022-02-23 11:59:59 +01:00
LICENSES
mm memfd: fix F_SEAL_WRITE after shmem huge page allocated 2022-03-08 19:07:49 +01:00
net net: dcb: disable softirqs in dcbnl_flush_dev() 2022-03-08 19:07:51 +01:00
samples
scripts kconfig: fix failing to generate auto.conf 2022-02-23 12:00:01 +01:00
security ima: Do not print policy rule with inactive LSM labels 2022-02-16 12:52:47 +01:00
sound ASoC: cs4265: Fix the duplicated control name 2022-03-08 19:07:49 +01:00
tools x86/speculation: Rename RETPOLINE_AMD to RETPOLINE_LFENCE 2022-03-11 11:22:37 +01:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.183 2022-03-08 19:07:51 +01:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.