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Eduard Zingerman bfe9446ea1 bpf: sync_linked_regs() must preserve subreg_def
commit e9bd9c498c upstream.

Range propagation must not affect subreg_def marks, otherwise the
following example is rewritten by verifier incorrectly when
BPF_F_TEST_RND_HI32 flag is set:

  0: call bpf_ktime_get_ns                   call bpf_ktime_get_ns
  1: r0 &= 0x7fffffff       after verifier   r0 &= 0x7fffffff
  2: w1 = w0                rewrites         w1 = w0
  3: if w0 < 10 goto +0     -------------->  r11 = 0x2f5674a6     (r)
  4: r1 >>= 32                               r11 <<= 32           (r)
  5: r0 = r1                                 r1 |= r11            (r)
  6: exit;                                   if w0 < 0xa goto pc+0
                                             r1 >>= 32
                                             r0 = r1
                                             exit

(or zero extension of w1 at (2) is missing for architectures that
 require zero extension for upper register half).

The following happens w/o this patch:
- r0 is marked as not a subreg at (0);
- w1 is marked as subreg at (2);
- w1 subreg_def is overridden at (3) by copy_register_state();
- w1 is read at (5) but mark_insn_zext() does not mark (2)
  for zero extension, because w1 subreg_def is not set;
- because of BPF_F_TEST_RND_HI32 flag verifier inserts random
  value for hi32 bits of (2) (marked (r));
- this random value is read at (5).

Fixes: 75748837b7 ("bpf: Propagate scalar ranges through register assignments.")
Reported-by: Lonial Con <kongln9170@gmail.com>
Signed-off-by: Lonial Con <kongln9170@gmail.com>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Closes: https://lore.kernel.org/bpf/7e2aa30a62d740db182c170fdd8f81c596df280d.camel@gmail.com
Link: https://lore.kernel.org/bpf/20240924210844.1758441-1-eddyz87@gmail.com
[ shung-hsi.yu: sync_linked_regs() was called find_equal_scalars() before commit
  4bf79f9be4 ("bpf: Track equal scalars history on per-instruction level"), and
  modification is done because there is only a single call to
  copy_register_state() before commit 98d7ca374b ("bpf: Track delta between
  "linked" registers."). ]
Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2024-12-19 18:11:35 +01:00
arch KVM: arm64: Disable MPAM visibility by default and ignore VMM writes 2024-12-19 18:11:34 +01:00
block blk-iocost: Avoid using clamp() on inuse in __propagate_weights() 2024-12-19 18:11:34 +01:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto crypto: pcrypt - Call crypto layer directly when padata_do_parallel() return -EBUSY 2024-12-09 10:31:48 +01:00
Documentation Documentation: PM: Clarify pm_runtime_resume_and_get() return value 2024-12-19 18:11:30 +01:00
drivers net: dsa: microchip: KSZ9896 register regmap alignment to 32 bit boundaries 2024-12-19 18:11:34 +01:00
fs xfs: only run precommits once per transaction object 2024-12-19 18:11:25 +01:00
include Bluetooth: SCO: Add support for 16 bits transparent voice setting 2024-12-19 18:11:34 +01:00
init Compiler Attributes: disable __counted_by for clang < 19.1.3 2024-12-09 10:32:46 +01:00
io_uring io_uring/tctx: work around xa_store() allocation error issue 2024-12-14 20:00:17 +01:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-09 10:32:54 +01:00
kernel bpf: sync_linked_regs() must preserve subreg_def 2024-12-19 18:11:35 +01:00
lib lib: stackinit: hide never-taken branch from compiler 2024-12-14 19:59:57 +01:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm/damon/vaddr: fix issue in damon_va_evenly_split_region() 2024-12-14 20:00:21 +01:00
net Bluetooth: SCO: Add support for 16 bits transparent voice setting 2024-12-19 18:11:34 +01:00
rust rust: macros: fix documentation of the paste! macro 2024-12-09 10:32:25 +01:00
samples samples/bpf: Fix a resource leak 2024-12-14 20:00:03 +01:00
scripts setlocalversion: work around "git describe" performance 2024-12-14 20:00:17 +01:00
security apparmor: test: Fix memory leak for aa_unpack_strdup() 2024-12-09 10:32:45 +01:00
sound ASoC: amd: yc: Fix the wrong return value 2024-12-19 18:11:30 +01:00
tools kselftest/arm64: abi: fix SVCR detection 2024-12-19 18:11:34 +01:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt KVM: Use dedicated mutex to protect kvm_usage_count to avoid deadlock 2024-10-04 16:29:47 +02:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Remove *.orig pattern from .gitignore 2024-10-04 16:29:44 +02:00
.mailmap 20 hotfixes. 12 are cc:stable and the remainder address post-6.5 issues 2023-10-24 09:52:16 -10:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS membarrier: riscv: Add full memory barrier in switch_mm() 2024-09-12 11:11:45 +02:00
Makefile Linux 6.6.66 2024-12-14 20:00:23 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.