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| author | Lin Ma <linma@zju.edu.cn> | 2021-12-17 10:29:41 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-12-29 12:20:48 +0100 |
| commit | bd05a8f1b7368ef4f7845548312fc61ab4fa63ce (patch) | |
| tree | f94bb419cbe3d38c191a270142705018e5f2762e /net/ax25 | |
| parent | b3d4efca11d7bcc93b7f4243528d4b6beb886b0b (diff) | |
| download | linux-stable-bd05a8f1b7368ef4f7845548312fc61ab4fa63ce.tar.gz linux-stable-bd05a8f1b7368ef4f7845548312fc61ab4fa63ce.tar.bz2 linux-stable-bd05a8f1b7368ef4f7845548312fc61ab4fa63ce.zip | |
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>
Diffstat (limited to 'net/ax25')
| -rw-r--r-- | net/ax25/af_ax25.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c index a45db78eaf00..567fdfd9678d 100644 --- a/net/ax25/af_ax25.c +++ b/net/ax25/af_ax25.c @@ -88,8 +88,10 @@ static void ax25_kill_by_device(struct net_device *dev) again: ax25_for_each(s, &ax25_list) { if (s->ax25_dev == ax25_dev) { - s->ax25_dev = NULL; spin_unlock_bh(&ax25_list_lock); + lock_sock(s->sk); + s->ax25_dev = NULL; + release_sock(s->sk); ax25_disconnect(s, ENETUNREACH); spin_lock_bh(&ax25_list_lock); |