In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
nfc: llcp: Fix race condition in accept_queue lifecycle<\/p>\n
In nfc_llcp_socket_release(), sockets and listener accept queues are
\nwalked under the local sockets rwlock and bh_lock_sock(). However,
\nbh_lock_sock() does not synchronise against process-context lock_sock()
\nheld by nfc_llcp_accept_dequeue() during accept(). Because
\nsocket_release() does not check sock_owned_by_user(), both paths can
\nconcurrently unlink and release the same child socket, resulting in
\nuse-after-free or a NULL pointer dereference of child->parent in
\nnfc_llcp_accept_unlink().<\/p>\n
Fix this synchronisation race by having nfc_llcp_socket_release() use
\nprocess-context lock_sock() instead of bh_lock_sock():<\/p>\n
1. Pop sockets from the local sockets list under the write lock using
\n nfc_llcp_sock_list_pop() so lock_sock() can be acquired without
\n holding the rwlock.<\/p>\n
2. Because lock_sock() can sleep, defer the final release of the
\n nfc_llcp_local structure to a workqueue (release_work). This avoids
\n a sleeping-in-atomic bug when the last local reference is dropped
\n from softirq context. Additionally, hold a single device reference
\n on local from registration until final destruction.<\/p>\n
3. In nfc_llcp_local_get(), use kref_get_unless_zero() to prevent
\n resurrecting a local object whose teardown has been scheduled.<\/p>\n
4. In llcp_sock_accept(), verify that the listener socket state is still
\n LLCP_LISTEN after waking from schedule_timeout() to prevent hangs if
\n the listener is closed concurrently.<\/p>\n
5. When unlinking unaccepted child sockets during listener release,
\n unlink them from local->sockets, call sock_orphan(), and drop their
\n initial sk_alloc creation reference via sock_put().<\/p>\n
6. Make nfc_llcp_accept_unlink() idempotent by guarding parent access with
\n a NULL check.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
nfc: llcp: Fix race condition in accept_queue lifecycle<\/p>\n
In nfc_llcp_socket_release(), sockets and listener accept queues are
\nwalke<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-41052","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/41052","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=41052"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=41052"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=41052"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}