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Filename Latest commit message Latest commit date
Kees Cook 094353c10f ovl: Check for NULL d_inode() in ovl_dentry_upper()
[ Upstream commit 8a39f1c870e9d6fbac5638f3a42a6a6363829c49 ]

In ovl_path_type() and ovl_is_metacopy_dentry() GCC notices that it is
possible for OVL_E() to return NULL (which implies that d_inode(dentry)
may be NULL). This would result in out of bounds reads via container_of(),
seen with GCC 15's -Warray-bounds -fdiagnostics-details. For example:

In file included from arch/x86/include/generated/asm/rwonce.h:1,
                 from include/linux/compiler.h:339,
                 from include/linux/export.h:5,
                 from include/linux/linkage.h:7,
                 from include/linux/fs.h:5,
                 from fs/overlayfs/util.c:7:
In function 'ovl_upperdentry_dereference',
    inlined from 'ovl_dentry_upper' at ../fs/overlayfs/util.c:305:9,
    inlined from 'ovl_path_type' at ../fs/overlayfs/util.c:216:6:
include/asm-generic/rwonce.h:44:26: error: array subscript 0 is outside array bounds of 'struct inode[7486503276667837]' [-Werror=array-bounds=]
   44 | #define __READ_ONCE(x)  (*(const volatile __unqual_scalar_typeof(x) *)&(x))
      |                         ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/asm-generic/rwonce.h:50:9: note: in expansion of macro '__READ_ONCE'
   50 |         __READ_ONCE(x);                                                 \
      |         ^~~~~~~~~~~
fs/overlayfs/ovl_entry.h:195:16: note: in expansion of macro 'READ_ONCE'
  195 |         return READ_ONCE(oi->__upperdentry);
      |                ^~~~~~~~~
  'ovl_path_type': event 1
  185 |         return inode ? OVL_I(inode)->oe : NULL;
  'ovl_path_type': event 2

Avoid this by allowing ovl_dentry_upper() to return NULL if d_inode() is
NULL, as that means the problematic dereferencing can never be reached.
Note that this fixes the over-eager compiler warning in an effort to
being able to enable -Warray-bounds globally. There is no known
behavioral bug here.

Suggested-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Kees Cook <kees@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-17 18:24:51 +02:00
arch arm64/ptrace: Fix stack-out-of-bounds read in regs_get_kernel_stack_nth() 2025-06-27 11:02:58 +01:00
block block: fix 'kmem_cache of name 'bio-108' already exists' 2025-04-10 14:29:37 +02:00
certs
crypto crypto: algif_hash - fix double free in hash_accept 2025-06-04 14:32:35 +02:00
Documentation Revert "x86/bugs: Make spectre user default depend on MITIGATION_SPECTRE_V2" on v6.6 and older 2025-06-27 11:02:56 +01:00
drivers usb: typec: displayport: Receive DP Status Update NAK request exit dp altmode 2025-07-17 18:24:50 +02:00
fs ovl: Check for NULL d_inode() in ovl_dentry_upper() 2025-07-17 18:24:51 +02:00
include erofs: remove unused trace event erofs_destroy_inode 2025-06-27 11:02:57 +01:00
init sched/isolation: Make CONFIG_CPU_ISOLATION depend on CONFIG_SMP 2025-05-02 07:39:28 +02:00
ipc ipc: fix to protect IPCS lookups using RCU 2025-06-27 11:02:52 +01:00
kernel perf: Fix sample vs do_exit() 2025-06-27 11:02:58 +01:00
lib dql: Fix dql->limit value when reset. 2025-06-04 14:32:30 +02:00
LICENSES
mm mm/huge_memory: fix dereferencing invalid pmd migration entry 2025-06-27 11:02:58 +01:00
net xprtrdma: fix pointer derefs in error cases of rpcrdma_ep_create 2025-06-27 11:02:58 +01:00
samples samples/bpf: Fix a resource leak 2024-12-14 19:44:50 +01:00
scripts kbuild: fix argument parsing in scripts/config 2025-06-04 14:32:31 +02:00
security selinux: fix selinux_xfrm_alloc_user() to set correct ctx_len 2025-06-27 11:02:56 +01:00
sound ALSA: hda: Ignore unsol events for cards being shut down 2025-07-17 18:24:50 +02:00
tools perf record: Fix incorrect --user-regs comments 2025-06-27 11:02:48 +01:00
usr
virt KVM: arm64: Ignore PMCNTENSET_EL0 while checking for overflow status 2024-12-19 18:05:04 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Remove *.orig pattern from .gitignore 2024-11-08 16:20:33 +01:00
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS platform: Add Surface platform directory 2025-06-27 11:02:56 +01:00
Makefile Linux 5.4.295 2025-06-27 11:02:58 +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.