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Filename Latest commit message Latest commit date
Duoming Zhou d2be5b563e ax25: fix NPD bug in ax25_disconnect
commit 7ec02f5ac8a5be5a3f20611731243dc5e1d9ba10 upstream.

The ax25_disconnect() in ax25_kill_by_device() is not
protected by any locks, thus there is a race condition
between ax25_disconnect() and ax25_destroy_socket().
when ax25->sk is assigned as NULL by ax25_destroy_socket(),
a NULL pointer dereference bug will occur if site (1) or (2)
dereferences ax25->sk.

ax25_kill_by_device()                | ax25_release()
  ax25_disconnect()                  |   ax25_destroy_socket()
    ...                              |
    if(ax25->sk != NULL)             |     ...
      ...                            |     ax25->sk = NULL;
      bh_lock_sock(ax25->sk); //(1)  |     ...
      ...                            |
      bh_unlock_sock(ax25->sk); //(2)|

This patch moves ax25_disconnect() into lock_sock(), which can
synchronize with ax25_destroy_socket() in ax25_release().

Fail log:
===============================================================
BUG: kernel NULL pointer dereference, address: 0000000000000088
...
RIP: 0010:_raw_spin_lock+0x7e/0xd0
...
Call Trace:
ax25_disconnect+0xf6/0x220
ax25_device_event+0x187/0x250
raw_notifier_call_chain+0x5e/0x70
dev_close_many+0x17d/0x230
rollback_registered_many+0x1f1/0x950
unregister_netdevice_queue+0x133/0x200
unregister_netdev+0x13/0x20
...

Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
[OP: backport to 5.4: adjust context]
Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-20 09:19:40 +02:00
arch ARM: davinci: da850-evm: Avoid NULL pointer dereference 2022-04-20 09:19:39 +02:00
block Revert "Revert "block, bfq: honor already-setup queue merges"" 2022-04-15 14:18:23 +02:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:47:29 +02:00
crypto crypto: authenc - Fix sleep in atomic context in decrypt_tail 2022-04-15 14:18:04 +02:00
Documentation dt-bindings: spi: mxic: The interrupt property is not mandatory 2022-04-15 14:18:30 +02:00
drivers i2c: pasemi: Wait for write xfers to finish 2022-04-20 09:19:39 +02:00
fs btrfs: mark resumed async balance as writing 2022-04-20 09:19:38 +02:00
include ax25: fix reference count leaks of ax25_dev 2022-04-20 09:19:39 +02:00
init init/main.c: return 1 from handled __setup() functions 2022-04-15 14:18:35 +02:00
ipc shm: extend forced shm destroy to support objects from several IPC nses 2021-12-01 09:23:35 +01:00
kernel dma-direct: avoid redundant memory sync for swiotlb 2022-04-20 09:19:39 +02:00
lib lz4: fix LZ4_decompress_safe_partial read out of bound 2022-04-15 14:18:39 +02:00
LICENSES
mm mm: kmemleak: take a full lowmem check in kmemleak_*_phys() 2022-04-20 09:19:38 +02:00
net ax25: fix NPD bug in ax25_disconnect 2022-04-20 09:19:40 +02:00
samples samples/kretprobes: Fix return value if register_kretprobe() failed 2021-11-17 09:48:39 +01:00
scripts gcc-plugins: latent_entropy: use /dev/urandom 2022-04-20 09:19:38 +02:00
security Fix incorrect type in assignment of ipv6 port for audit 2022-04-15 14:18:22 +02:00
sound ALSA: pcm: Test for "silence" field in struct "pcm_format_data" 2022-04-20 09:19:38 +02:00
tools testing/selftests/mqueue: Fix mq_perf_tests to free the allocated cpu set 2022-04-20 09:19:35 +02:00
usr
virt KVM: Prevent module exit until all VMs are freed 2022-04-15 14:18:27 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.189 2022-04-15 14:18:42 +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.