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Darrick J. Wong 7c2d68e091 xfs: fix out of bounds memory read error in symlink repair
[ Upstream commit 678e1cc2f4 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2025-12-01 11:43:39 +01:00
arch s390/mm: Fix __ptep_rdp() inline assembly 2025-12-01 11:43:37 +01:00
block blk-crypto: use BLK_STS_INVAL for alignment errors 2025-12-01 11:43:36 +01:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: essiv - Check ssize for decryption and in-place encryption 2025-10-19 16:33:42 +02:00
Documentation platform/x86: msi-wmi-platform: Fix typo in WMI GUID 2025-12-01 11:43:30 +01:00
drivers drm/i915/dp_mst: Disable Panel Replay 2025-12-01 11:43:39 +01:00
fs xfs: fix out of bounds memory read error in symlink repair 2025-12-01 11:43:39 +01:00
include net: tls: Cancel RX async resync request on rcd_delta overflow 2025-12-01 11:43:36 +01:00
init init: handle bootloader identifier in kernel parameters 2025-10-19 16:33:50 +02:00
io_uring io_uring/napi: fix io_napi_entry RCU accesses 2025-11-24 10:36:06 +01:00
ipc ipc: fix to protect IPCS lookups using RCU 2025-06-27 11:11:22 +01:00
kernel timers: Fix NULL function pointer race in timer_shutdown_sync() 2025-12-01 11:43:18 +01:00
lib maple_tree: fix tracepoint string pointers 2025-12-01 11:43:39 +01:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm/mempool: fix poisoning order>0 pages with HIGHMEM 2025-12-01 11:43:23 +01:00
net mptcp: fix a race in mptcp_pm_del_add_timer() 2025-12-01 11:43:39 +01:00
rust rust: kbuild: workaround rustdoc doctests modifier bug 2025-11-24 10:36:07 +01:00
samples ftrace/samples: Fix function size computation 2025-09-19 16:35:44 +02:00
scripts kconfig/nconf: Initialize the default locale at startup 2025-12-01 11:43:36 +01:00
security ima: don't clear IMA_DIGSIG flag when setting or removing non-IMA xattr 2025-11-13 15:34:32 -05:00
sound ALSA: usb-audio: fix uac2 clock source at terminal parser 2025-12-01 11:43:37 +01:00
tools tracing/tools: Fix incorrcet short option in usage text for --threads 2025-12-01 11:43:38 +01:00
usr kbuild: uapi: Strip comments before size type check 2025-11-13 15:34:35 -05:00
virt KVM: guest_memfd: Remove bindings on memslot deletion when gmem is dying 2025-11-24 10:36:06 +01:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: give Clippy the minimum supported Rust version 2025-08-01 09:48:44 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: introduce .clippy.toml 2025-03-13 13:01:42 +01:00
.mailmap mailmap: add entry for Thorsten Blum 2024-11-07 14:14:59 -08:00
.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 MAINTAINERS: Remove self from DSA entry 2024-11-03 12:52:38 -08:00
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 MAINTAINERS: Update Alexey Makhalov's email address 2025-05-22 14:29:46 +02:00
Makefile Linux 6.12.59 2025-11-24 10:36:08 +01:00
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.