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Filename Latest commit message Latest commit date
Jann Horn 4ce87674c3 f2fs: Require FMODE_WRITE for atomic write ioctls
commit 4f5a100f87f32cb65d4bb1ad282a08c92f6f591e upstream.

The F2FS ioctls for starting and committing atomic writes check for
inode_owner_or_capable(), but this does not give LSMs like SELinux or
Landlock an opportunity to deny the write access - if the caller's FSUID
matches the inode's UID, inode_owner_or_capable() immediately returns true.

There are scenarios where LSMs want to deny a process the ability to write
particular files, even files that the FSUID of the process owns; but this
can currently partially be bypassed using atomic write ioctls in two ways:

 - F2FS_IOC_START_ATOMIC_REPLACE + F2FS_IOC_COMMIT_ATOMIC_WRITE can
   truncate an inode to size 0
 - F2FS_IOC_START_ATOMIC_WRITE + F2FS_IOC_ABORT_ATOMIC_WRITE can revert
   changes another process concurrently made to a file

Fix it by requiring FMODE_WRITE for these operations, just like for
F2FS_IOC_MOVE_RANGE. Since any legitimate caller should only be using these
ioctls when intending to write into the file, that seems unlikely to break
anything.

Fixes: 88b88a6679 ("f2fs: support atomic writes")
Cc: stable@vger.kernel.org
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-08 16:20:36 +01:00
arch riscv: Fix fp alignment bug in perf_callchain_user() 2024-11-08 16:20:32 +01:00
block block, bfq: don't break merge chain in bfq_split_bfqq() 2024-11-08 16:20:28 +01:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:11:22 +02:00
crypto crypto: aead,cipher - zeroize key buffer after use 2024-11-08 16:20:33 +01:00
Documentation ipmi: docs: don't advertise deprecated sysfs entries 2024-11-08 16:20:29 +01:00
drivers net: ethernet: lantiq_etop: fix memory disclosure 2024-11-08 16:20:36 +01:00
fs f2fs: Require FMODE_WRITE for atomic write ioctls 2024-11-08 16:20:36 +01:00
include netfilter: uapi: NFTA_FLOWTABLE_HOOK is NLA_NESTED 2024-11-08 16:20:35 +01:00
init init: open /initrd.image with O_LARGEFILE 2024-04-13 12:51:36 +02:00
ipc ipc: replace costly bailout check in sysvipc_find_ipc() 2024-09-04 13:15:02 +02:00
kernel bpf: Fix bpf_strtol and bpf_strtoul helpers for 32bit 2024-11-08 16:20:31 +01:00
lib debugobjects: Fix conditions in fill_pool() 2024-11-08 16:20:34 +01:00
LICENSES
mm mm: only enforce minimum stack gap size if it's sensible 2024-11-08 16:20:35 +01:00
net sctp: set sk_state back to CLOSED if autobind fails in sctp_listen_start 2024-11-08 16:20:36 +01:00
samples media: rename VFL_TYPE_GRABBER to _VIDEO 2024-03-26 18:22:22 -04:00
scripts scripts: kconfig: merge_config: config files: add a trailing newline 2024-11-08 16:20:24 +01:00
security smackfs: Use rcu_assign_pointer() to ensure safe assignment in smk_set_cipso 2024-11-08 16:20:30 +01:00
sound ALSA: hda/conexant: Fix conflicting quirk for System76 Pangolin 2024-11-08 16:20:36 +01:00
tools perf time-utils: Fix 32-bit nsec parsing 2024-11-08 16:20:31 +01:00
usr
virt KVM: async_pf: Cleanup kvm_setup_async_pf() 2024-05-02 16:18:32 +02:00
.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 iio: stx104: Move to addac subdirectory 2023-08-30 16:27:12 +02:00
Makefile Linux 5.4.284 2024-09-12 11:03:57 +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.