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Darrick J. Wong 678e1cc2f4 xfs: fix out of bounds memory read error in symlink repair
xfs/286 produced this report on my test fleet:

 ==================================================================
 BUG: KFENCE: out-of-bounds read in memcpy_orig+0x54/0x110

 Out-of-bounds read at 0xffff88843fe9e038 (184B right of kfence-#184):
  memcpy_orig+0x54/0x110
  xrep_symlink_salvage_inline+0xb3/0xf0 [xfs]
  xrep_symlink_salvage+0x100/0x110 [xfs]
  xrep_symlink+0x2e/0x80 [xfs]
  xrep_attempt+0x61/0x1f0 [xfs]
  xfs_scrub_metadata+0x34f/0x5c0 [xfs]
  xfs_ioc_scrubv_metadata+0x387/0x560 [xfs]
  xfs_file_ioctl+0xe23/0x10e0 [xfs]
  __x64_sys_ioctl+0x76/0xc0
  do_syscall_64+0x4e/0x1e0
  entry_SYSCALL_64_after_hwframe+0x4b/0x53

 kfence-#184: 0xffff88843fe9df80-0xffff88843fe9dfea, size=107, cache=kmalloc-128

 allocated by task 3470 on cpu 1 at 263329.131592s (192823.508886s ago):
  xfs_init_local_fork+0x79/0xe0 [xfs]
  xfs_iformat_local+0xa4/0x170 [xfs]
  xfs_iformat_data_fork+0x148/0x180 [xfs]
  xfs_inode_from_disk+0x2cd/0x480 [xfs]
  xfs_iget+0x450/0xd60 [xfs]
  xfs_bulkstat_one_int+0x6b/0x510 [xfs]
  xfs_bulkstat_iwalk+0x1e/0x30 [xfs]
  xfs_iwalk_ag_recs+0xdf/0x150 [xfs]
  xfs_iwalk_run_callbacks+0xb9/0x190 [xfs]
  xfs_iwalk_ag+0x1dc/0x2f0 [xfs]
  xfs_iwalk_args.constprop.0+0x6a/0x120 [xfs]
  xfs_iwalk+0xa4/0xd0 [xfs]
  xfs_bulkstat+0xfa/0x170 [xfs]
  xfs_ioc_fsbulkstat.isra.0+0x13a/0x230 [xfs]
  xfs_file_ioctl+0xbf2/0x10e0 [xfs]
  __x64_sys_ioctl+0x76/0xc0
  do_syscall_64+0x4e/0x1e0
  entry_SYSCALL_64_after_hwframe+0x4b/0x53

 CPU: 1 UID: 0 PID: 1300113 Comm: xfs_scrub Not tainted 6.18.0-rc4-djwx #rc4 PREEMPT(lazy)  3d744dd94e92690f00a04398d2bd8631dcef1954
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-4.module+el8.8.0+21164+ed375313 04/01/2014
 ==================================================================

On further analysis, I realized that the second parameter to min() is
not correct.  xfs_ifork::if_bytes is the size of the xfs_ifork::if_data
buffer.  if_bytes can be smaller than the data fork size because:

(a) the forkoff code tries to keep the data area as large as possible
(b) for symbolic links, if_bytes is the ondisk file size + 1
(c) forkoff is always a multiple of 8.

Case in point: for a single-byte symlink target, forkoff will be
8 but the buffer will only be 2 bytes long.

In other words, the logic here is wrong and we walk off the end of the
incore buffer.  Fix that.

Cc: stable@vger.kernel.org # v6.10
Fixes: 2651923d8d ("xfs: online repair of symbolic links")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
2025-11-20 11:06:24 +01:00
arch - Reset the why-the-system-rebooted register on AMD to avoid stale bits 2025-10-19 04:41:27 -10:00
block block-6.18-20251016 2025-10-17 08:31:26 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto This push contains the following changes: 2025-10-10 08:56:16 -07:00
Documentation Rust 'rustfmt' cleanup 2025-10-18 10:05:13 -10:00
drivers Hi, 2025-10-18 08:38:28 -10:00
fs xfs: fix out of bounds memory read error in symlink repair 2025-11-20 11:06:24 +01:00
include hid-for-linus-2025101701 2025-10-18 08:18:18 -10:00
init printk changes for 6.18 2025-10-04 11:13:11 -07:00
io_uring io_uring/rw: check for NULL io_br_sel when putting a buffer 2025-10-15 13:38:53 -06:00
ipc namespace-6.18-rc1 2025-09-29 11:20:29 -07:00
kernel - Make sure the check for lost pelt idle time is done unconditionally to 2025-10-19 04:59:43 -10:00
lib lib/test_kho: use kho_preserve_vmalloc instead of storing addresses in fdt 2025-10-07 13:48:56 -07:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm slab: reset slab->obj_ext when freeing and it is OBJEXTS_ALLOC_FAIL 2025-10-16 15:16:45 +02:00
net bpf-fixes 2025-10-18 08:00:43 -10:00
rust rust: bitmap: fix formatting 2025-10-17 13:02:22 +02:00
samples Char/Misc/IIO/Binder changes for 6.18-rc1 2025-10-04 16:26:32 -07:00
scripts Kbuild fixes for 6.18 #1 2025-10-11 15:47:12 -07:00
security integrity-v6.18 2025-10-05 10:48:33 -07:00
sound ALSA: hda/realtek: Fix mute led for HP Omen 17-cb0xxx 2025-10-17 16:37:21 +02:00
tools hid-for-linus-2025101701 2025-10-18 08:18:18 -10:00
usr gen_init_cpio: Ignore fsync() returning EINVAL on pipes 2025-10-07 09:53:05 -07:00
virt KVM x86 fixes for 6.18: 2025-10-18 10:25:43 +02:00
.clang-format memblock: drop for_each_free_mem_pfn_range_in_zone_from() 2025-09-14 08:49:03 +03:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore .gitignore: ignore compile_commands.json globally 2025-08-12 15:53:55 -07:00
.mailmap Including fixes from CAN 2025-10-16 09:41:21 -07:00
.pylintrc tools: docs: parse-headers.py: move it from sphinx dir 2025-08-29 15:54:42 -06:00
.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/Thunderbolt changes for 6.18-rc1 2025-10-04 16:07:08 -07:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS Including fixes from CAN 2025-10-16 09:41:21 -07:00
Makefile Linux 6.18-rc2 2025-10-19 15:19:16 -10:00
README README: Fix spelling 2024-03-18 03:36:32 -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 reStructuredText 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.