In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
Bluetooth: hci_sysfs: Fix NULL pointer dereference in device_del()<\/p>\n
A NULL pointer dereference in klist_put() occurs when a child device (such
\nas a BNEP network device in bnep_session) is concurrently being
\nunregistered while hci_conn_del_sysfs() reparents child devices.<\/p>\n
This is caused by a race condition between hci_conn_del_sysfs() and
\nconcurrent child device unregistration (e.g. bnep_session calling
\nunregister_netdev()). During device unregistration, device_del() snapshots
\na non-NULL parent pointer. Concurrently, hci_conn_del_sysfs() finds the
\nchild device using device_find_any_child() and calls device_move() to
\nreparent it to NULL, which removes the node from its parent’s klist and
\nclears knode_parent. Subsequently, device_del() calls
\nklist_del(&dev->p->knode_parent) using the stale parent snapshot, causing
\nklist_put() to dereference knode_klist(n)->put on an already removed node,
\nresulting in a NULL pointer dereference.<\/p>\n
This race was introduced by commit 27aabf27fd01 (“Bluetooth: fix
\nuse-after-free in device_for_each_child()”), which replaced
\ndevice_find_child(…, __match_tty) with device_find_any_child() in
\nhci_conn_del_sysfs(). That change was intended to avoid a use-after-free
\nwhere conn->dev outlived its parent hdev->dev when child devices held
\nreferences to conn->dev, because conn->dev only held a reference to
\nhdev->dev while registered in sysfs.<\/p>\n
Fix the issue properly by taking an explicit reference to the parent device
\nwith get_device(&hdev->dev) in hci_conn_init_sysfs() and dropping it with
\nput_device(parent) in bt_link_release() when the conn device is freed. This
\nensures that hdev->dev remains valid for the entire lifecycle of conn->dev,
\nresolving the underlying use-after-free. With the parent reference held
\nproperly, restore the __match_tty filter in hci_conn_del_sysfs() so that
\ndevice_move() is only invoked on persistent RFCOMM TTY devices as
\noriginally intended, eliminating the race condition with unregistering
\nnetwork devices.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
Bluetooth: hci_sysfs: Fix NULL pointer dereference in device_del()<\/p>\n
A NULL pointer dereference in klist_put() occurs when a child d<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-29131","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/29131","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=29131"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=29131"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=29131"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}