Bluetooth: L2CAP: access chan->conn safely in get/setsockopt

Since commit b66774b48dd9 ("Bluetooth: L2CAP: Fix UAF in channel timeout by holding conn ref")
l2cap_chan::conn has held reference and remains non-NULL also after the
corresponding hci_conn is deleted.  In this state accessing various
fields eg. hci_conn::hdev is invalid, which leads to KASAN crash in
l2cap_sock_setsockopt() access of conn->hcon->hdev.

Check l2cap_chan::conn.hcon corresponds to an alive hci_conn before
trying to use it in l2cap_sock.c.  Hold l2cap_chan_lock() in
getsockopt/setsockopt to ensure it stays alive, and to avoid data races
in l2cap_chan fields.

Fixes: b66774b48dd9 ("Bluetooth: L2CAP: Fix UAF in channel timeout by holding conn ref")
Reported-by: syzbot+b106284c2a0b7bc80cf9@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=b106284c2a0b7bc80cf9
Signed-off-by: Pauli Virtanen <pav@iki.fi>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

0 files changed, 0 insertions, 0 deletions