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Ryusuke Konishi a8ef5109f9 nilfs2: fix underflow in second superblock position calculations 
commit 99b9402a36 upstream.

Macro NILFS_SB2_OFFSET_BYTES, which computes the position of the second
superblock, underflows when the argument device size is less than 4096
bytes.  Therefore, when using this macro, it is necessary to check in
advance that the device size is not less than a lower limit, or at least
that underflow does not occur.

The current nilfs2 implementation lacks this check, causing out-of-bound
block access when mounting devices smaller than 4096 bytes:

 I/O error, dev loop0, sector 36028797018963960 op 0x0:(READ) flags 0x0
 phys_seg 1 prio class 2
 NILFS (loop0): unable to read secondary superblock (blocksize = 1024)

In addition, when trying to resize the filesystem to a size below 4096
bytes, this underflow occurs in nilfs_resize_fs(), passing a huge number
of segments to nilfs_sufile_resize(), corrupting parameters such as the
number of segments in superblocks.  This causes excessive loop iterations
in nilfs_sufile_resize() during a subsequent resize ioctl, causing
semaphore ns_segctor_sem to block for a long time and hang the writer
thread:

 INFO: task segctord:5067 blocked for more than 143 seconds.
      Not tainted 6.2.0-rc8-syzkaller-00015-gf6feea56f66d #0
 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
 task:segctord        state:D stack:23456 pid:5067  ppid:2
 flags:0x00004000
 Call Trace:
  <TASK>
  context_switch kernel/sched/core.c:5293 [inline]
  __schedule+0x1409/0x43f0 kernel/sched/core.c:6606
  schedule+0xc3/0x190 kernel/sched/core.c:6682
  rwsem_down_write_slowpath+0xfcf/0x14a0 kernel/locking/rwsem.c:1190
  nilfs_transaction_lock+0x25c/0x4f0 fs/nilfs2/segment.c:357
  nilfs_segctor_thread_construct fs/nilfs2/segment.c:2486 [inline]
  nilfs_segctor_thread+0x52f/0x1140 fs/nilfs2/segment.c:2570
  kthread+0x270/0x300 kernel/kthread.c:376
  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
  </TASK>
 ...
 Call Trace:
  <TASK>
  folio_mark_accessed+0x51c/0xf00 mm/swap.c:515
  __nilfs_get_page_block fs/nilfs2/page.c:42 [inline]
  nilfs_grab_buffer+0x3d3/0x540 fs/nilfs2/page.c:61
  nilfs_mdt_submit_block+0xd7/0x8f0 fs/nilfs2/mdt.c:121
  nilfs_mdt_read_block+0xeb/0x430 fs/nilfs2/mdt.c:176
  nilfs_mdt_get_block+0x12d/0xbb0 fs/nilfs2/mdt.c:251
  nilfs_sufile_get_segment_usage_block fs/nilfs2/sufile.c:92 [inline]
  nilfs_sufile_truncate_range fs/nilfs2/sufile.c:679 [inline]
  nilfs_sufile_resize+0x7a3/0x12b0 fs/nilfs2/sufile.c:777
  nilfs_resize_fs+0x20c/0xed0 fs/nilfs2/super.c:422
  nilfs_ioctl_resize fs/nilfs2/ioctl.c:1033 [inline]
  nilfs_ioctl+0x137c/0x2440 fs/nilfs2/ioctl.c:1301
  ...

This fixes these issues by inserting appropriate minimum device size
checks or anti-underflow checks, depending on where the macro is used.

Link: https://lkml.kernel.org/r/0000000000004e1dfa05f4a48e6b@google.com
Link: https://lkml.kernel.org/r/20230214224043.24141-1-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: <syzbot+f0c4082ce5ebebdac63b@syzkaller.appspotmail.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>
2023-02-22 12:59:49 +01:00
arch s390/decompressor: specify __decompress() buf len to avoid overflow 2023-02-22 12:59:43 +01:00
block block, bfq: fix uaf for bfqq in bic_set_bfqq() 2023-02-09 11:28:06 +01:00
certs certs: Fix build error when PKCS#11 URI contains semicolon 2023-02-09 11:28:11 +01:00
crypto use less confusing names for iov_iter direction initializers 2023-02-09 11:28:04 +01:00
Documentation Documentation/hw-vuln: Add documentation for Cross-Thread Return Predictions 2023-02-14 19:11:56 +01:00
drivers ata: libata-core: Disable READ LOG DMA EXT for Samsung MZ7LH 2023-02-22 12:59:49 +01:00
fs nilfs2: fix underflow in second superblock position calculations 2023-02-22 12:59:49 +01:00
include hugetlb: check for undefined shift on 32 bit architectures 2023-02-22 12:59:49 +01:00
init gcc: disable -Warray-bounds for gcc-11 too 2023-01-14 10:33:43 +01:00
io_uring use less confusing names for iov_iter direction initializers 2023-02-09 11:28:04 +01:00
ipc ipc: fix memory leak in init_mqueue_fs() 2022-12-31 13:32:01 +01:00
kernel sched/psi: Fix use-after-free in ep_remove_wait_queue() 2023-02-22 12:59:49 +01:00
lib maple_tree: fix mas_empty_area_rev() lower bound validation 2023-02-09 11:28:23 +01:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm: shrinkers: fix deadlock in shrinker debugfs 2023-02-22 12:59:46 +01:00
net net: sched: sch: Bounds check priority 2023-02-22 12:59:43 +01:00
rust rust: print: avoid evaluating arguments in pr_* macros in unsafe blocks 2023-02-06 08:06:34 +01:00
samples ftrace: Export ftrace_free_filter() to modules 2023-02-01 08:34:37 +01:00
scripts kbuild: modinst: Fix build error when CONFIG_MODULE_SIG_KEY is a PKCS#11 URI 2023-02-09 11:28:11 +01:00
security use less confusing names for iov_iter direction initializers 2023-02-09 11:28:04 +01:00
sound ALSA: hda/realtek: Enable mute/micmute LEDs and speaker support for HP Laptops 2023-02-22 12:59:48 +01:00
tools selftests: mptcp: userspace: fix v4-v6 test in v6.1 2023-02-22 12:59:45 +01:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt kvm/vfio: Fix potential deadlock on vfio group_lock 2023-02-01 08:34:36 +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 .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.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 panic: Expose "warn_count" to sysfs 2023-01-24 07:24:41 +01:00
Makefile Linux 6.1.12 2023-02-14 19:11:56 +01:00
README

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.