No description
  • C 98.2%
  • Assembly 1%
  • Makefile 0.3%
  • Shell 0.2%
  • Python 0.1%
Find a file
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Luke Nelson 50c5d91461 bpf, x86_32: Fix incorrect encoding in BPF_LDX zero-extension
commit 5fa9a98fb10380e48a398998cd36a85e4ef711d6 upstream.

The current JIT uses the following sequence to zero-extend into the
upper 32 bits of the destination register for BPF_LDX BPF_{B,H,W},
when the destination register is not on the stack:

  EMIT3(0xC7, add_1reg(0xC0, dst_hi), 0);

The problem is that C7 /0 encodes a MOV instruction that requires a 4-byte
immediate; the current code emits only 1 byte of the immediate. This
means that the first 3 bytes of the next instruction will be treated as
the rest of the immediate, breaking the stream of instructions.

This patch fixes the problem by instead emitting "xor dst_hi,dst_hi"
to clear the upper 32 bits. This fixes the problem and is more efficient
than using MOV to load a zero immediate.

This bug may not be currently triggerable as BPF_REG_AX is the only
register not stored on the stack and the verifier uses it in a limited
way, and the verifier implements a zero-extension optimization. But the
JIT should avoid emitting incorrect encodings regardless.

Fixes: 03f5781be2 ("bpf, x86_32: add eBPF JIT compiler for ia32")
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Luke Nelson <luke.r.nels@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Acked-by: Wang YanQing <udknight@gmail.com>
Link: https://lore.kernel.org/bpf/20200422173630.8351-1-luke.r.nels@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-02 08:48:53 +02:00
arch bpf, x86_32: Fix incorrect encoding in BPF_LDX zero-extension 2020-05-02 08:48:53 +02:00
block blk-iocost: Fix error on iocost_ioc_vrate_adj 2020-05-02 08:48:53 +02:00
certs
crypto crypto: rng - Fix a refcounting bug in crypto_rng_reset() 2020-04-17 10:50:16 +02:00
Documentation USB: hub: Revert commit bd0e6c9614 ("usb: hub: try old enumeration scheme first for high speed devices") 2020-04-29 16:33:14 +02:00
drivers PM: sleep: core: Switch back to async_schedule_dev() 2020-05-02 08:48:53 +02:00
fs xfs: acquire superblock freeze protection on eofblocks scans 2020-05-02 08:48:48 +02:00
include blk-iocost: Fix error on iocost_ioc_vrate_adj 2020-05-02 08:48:53 +02:00
init printk: queue wake_up_klogd irq_work only if per-CPU areas are ready 2020-05-02 08:48:42 +02:00
ipc ipc/util.c: sysvipc_find_ipc() should increase position index 2020-04-29 16:33:00 +02:00
kernel perf/core: fix parent pid/tid in task exit events 2020-05-02 08:48:52 +02:00
lib lib/raid6/test: fix build on distros whose /bin/sh is not bash 2020-04-29 16:33:00 +02:00
LICENSES
mm mm/ksm: fix NULL pointer dereference when KSM zero page is enabled 2020-04-29 16:33:15 +02:00
net netfilter: nat: fix error handling upon registering inet hook 2020-05-02 08:48:52 +02:00
samples vmalloc: fix remap_vmalloc_range() bounds checks 2020-04-29 16:33:14 +02:00
scripts kbuild: fix DT binding schema rule again to avoid needless rebuilds 2020-05-02 08:48:42 +02:00
security KEYS: Avoid false positive ENOMEM error on key read 2020-04-29 16:33:11 +02:00
sound ASoC: wm8960: Fix wrong clock after suspend & resume 2020-05-02 08:48:45 +02:00
tools bpf: Forbid XADD on spilled pointers for unprivileged users 2020-05-02 08:48:46 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: Check for a bad hva before dropping into the ghc slow path 2020-03-05 16:43:48 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: Update drm/i915 bug filing URL 2020-02-28 17:22:19 +01:00
Makefile Linux 5.4.36 2020-04-29 16:33:25 +02:00
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.