In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
net\/tcp-ao: fix use-after-free of current_key on reconnect to another peer<\/p>\n
tcp_inbound_ao_hash() is called before bh_lock_sock_nested() is taken,
\nwith only rcu_read_lock() held. On the fast path for established
\nsockets, if the rnext_keyid sent by the peer differs from
\ncurrent_key->sndid, the key the peer asked for is looked up and stored
\nin current_key. The lookup is inside the RCU read side, but current_key
\noutlives it.<\/p>\n
When the socket is disconnected and connect() is called again for
\nanother peer, tcp_ao_connect_init() unlinks every key that does not
\nmatch the new peer and frees it with call_rcu(). If current_key points
\nat such a key, it is cleared to NULL.<\/p>\n
The fast path reads sk_state only once on entry, so a softirq that got
\ninto it while the socket was still established can update current_key
\nafter that loop has already run. The update is inside the RCU read side,
\nso it comes before the call_rcu() callback, and once the callback frees
\nthe key, current_key is left pointing at freed memory.<\/p>\n
The next transmission picks that pointer up in tcp_get_current_key().
\ntcp_ao_transmit_skb() then reads the traffic key from the freed object,
\nwhich is the use-after-free.<\/p>\n
Wait for one grace period before unlinking, and only if a key is going
\nto be removed. By the time tcp_connect() runs the socket is already in
\nTCP_SYN_SENT, and TCP_AO_ESTABLISHED does not contain TCPF_SYN_SENT, so
\na softirq entering after the wait cannot reach the fast path, and the
\nones already in it have finished. The existing NULL handling in the loop
\nis then enough.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
net\/tcp-ao: fix use-after-free of current_key on reconnect to another peer<\/p>\n
tcp_inbound_ao_hash() is called before bh_lock_sock_nes<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-17353","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/17353","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=17353"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=17353"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=17353"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}