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Ryusuke Konishi 8e63b1fd24 nilfs2: fix buffer corruption due to concurrent device reads
commit 679bd7ebdd315bf457a4740b306ae99f1d0a403d upstream.

As a result of analysis of a syzbot report, it turned out that in three
cases where nilfs2 allocates block device buffers directly via sb_getblk,
concurrent reads to the device can corrupt the allocated buffers.

Nilfs2 uses sb_getblk for segment summary blocks, that make up a log
header, and the super root block, that is the trailer, and when moving and
writing the second super block after fs resize.

In any of these, since the uptodate flag is not set when storing metadata
to be written in the allocated buffers, the stored metadata will be
overwritten if a device read of the same block occurs concurrently before
the write.  This causes metadata corruption and misbehavior in the log
write itself, causing warnings in nilfs_btree_assign() as reported.

Fix these issues by setting an uptodate flag on the buffer head on the
first or before modifying each buffer obtained with sb_getblk, and
clearing the flag on failure.

When setting the uptodate flag, the lock_buffer/unlock_buffer pair is used
to perform necessary exclusive control, and the buffer is filled to ensure
that uninitialized bytes are not mixed into the data read from others.  As
for buffers for segment summary blocks, they are filled incrementally, so
if the uptodate flag was unset on their allocation, set the flag and zero
fill the buffer once at that point.

Also, regarding the superblock move routine, the starting point of the
memset call to zerofill the block is incorrectly specified, which can
cause a buffer overflow on file systems with block sizes greater than
4KiB.  In addition, if the superblock is moved within a large block, it is
necessary to assume the possibility that the data in the superblock will
be destroyed by zero-filling before copying.  So fix these potential
issues as well.

Link: https://lkml.kernel.org/r/20230609035732.20426-1-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+31837fe952932efc8fb9@syzkaller.appspotmail.com
Closes: https://lkml.kernel.org/r/00000000000030000a05e981f475@google.com
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-06-28 11:12:22 +02:00
arch MIPS: Prefer cc-option for additions to cflags 2023-06-21 16:01:03 +02:00
block blk-mq: fix blk_mq_hw_ctx active request accounting 2023-06-14 11:15:31 +02:00
certs certs: Fix build error when PKCS#11 URI contains semicolon 2023-02-09 11:28:11 +01:00
crypto KEYS: asymmetric: Copy sig and digest in public_key_verify_signature() 2023-06-09 10:34:28 +02:00
Documentation mm: page_table_check: Make it dependent on EXCLUSIVE_SYSTEM_RAM 2023-06-14 11:15:29 +02:00
drivers tpm_crb: Add support for CRB devices based on Pluton 2023-06-28 11:12:17 +02:00
fs nilfs2: fix buffer corruption due to concurrent device reads 2023-06-28 11:12:22 +02:00
include writeback: fix dereferencing NULL mapping->host on writeback_page_template 2023-06-28 11:12:22 +02:00
init gcc: disable '-Warray-bounds' for gcc-13 too 2023-04-26 14:28:43 +02:00
io_uring io_uring/net: save msghdr->msg_control for retries 2023-06-21 16:00:55 +02:00
ipc ipc: fix memory leak in init_mqueue_fs() 2022-12-31 13:32:01 +01:00
kernel tick/common: Align tick period during sched_timer setup 2023-06-28 11:12:18 +02:00
lib test_firmware: prevent race conditions by a correct implementation of locking 2023-06-21 16:00:51 +02:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm: Fix copy_from_user_nofault(). 2023-06-28 11:12:17 +02:00
net neighbour: delete neigh_lookup_nodev as not used 2023-06-21 16:01:03 +02:00
rust rust: kernel: Mark rust_fmt_argument as extern "C" 2023-04-26 14:28:38 +02:00
samples samples/bpf: Fix fout leak in hbm's run_bpf_prog 2023-05-24 17:32:38 +01:00
scripts scripts: fix the gfp flags header path in gfp-translate 2023-06-28 11:12:22 +02:00
security selinux: don't use make's grouped targets feature yet 2023-06-09 10:34:24 +02:00
sound ALSA: hda/realtek: Add a quirk for Compaq N14JP6 2023-06-21 16:00:56 +02:00
tools selftests: mptcp: join: fix "userspace pm add & remove address" 2023-06-28 11:12:22 +02:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM: Fix vcpu_array[0] races 2023-05-24 17:32:50 +01:00
.clang-format inet: ping: use hlist_nulls rcu iterator during lookup 2022-12-01 12:42:46 +01:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes
.gitignore Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
.mailmap 9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address 2022-12-10 17:10:52 -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 Michal Marek from Kbuild maintainers 2022-11-16 14:53:00 +09:00
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 platform/x86: Move existing HP drivers to a new hp subdir 2023-05-24 17:32:42 +01:00
Makefile Linux 6.1.35 2023-06-21 16:01:03 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
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In order to build the documentation, use ``make htmldocs`` or
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    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.