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iv/linux

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Lin Ma bd05a8f1b7 ax25: NPD bug when detaching AX25 device

commit 1ade48d0c27d5da1ccf4b583d8c5fc8b534a3ac8 upstream.

The existing cleanup routine implementation is not well synchronized
with the syscall routine. When a device is detaching, below race could
occur.

static int ax25_sendmsg(...) {
  ...
  lock_sock()
  ax25 = sk_to_ax25(sk);
  if (ax25->ax25_dev == NULL) // CHECK
  ...
  ax25_queue_xmit(skb, ax25->ax25_dev->dev); // USE
  ...
}

static void ax25_kill_by_device(...) {
  ...
  if (s->ax25_dev == ax25_dev) {
    s->ax25_dev = NULL;
    ...
}

Other syscall functions like ax25_getsockopt, ax25_getname,
ax25_info_show also suffer from similar races. To fix them, this patch
introduce lock_sock() into ax25_kill_by_device in order to guarantee
that the nullify action in cleanup routine cannot proceed when another
socket request is pending.

Signed-off-by: Hanjie Wu <nagi@zju.edu.cn>
Signed-off-by: Lin Ma <linma@zju.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2021-12-29 12:20:48 +01:00

af_ax25.c

ax25: NPD bug when detaching AX25 device

2021-12-29 12:20:48 +01:00

ax25_addr.c

ax25: remove blank line at EOF

2018-07-24 14:10:42 -07:00

ax25_dev.c

ax25: fix a use-after-free in ax25_fillin_cb()

2019-01-09 17:38:30 +01:00

ax25_ds_in.c

ax25: remove blank line at EOF