In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
af_unix: Unlink scc_entry in unix_del_edge().<\/p>\n
Kyle Zeng reported that GC could free a dead SCC partially.<\/p>\n
The scenario is as follows:<\/p>\n
1) Create two SCCs:<\/p>\n
X -. A B
\n ^–‘<\/p>\n
2) Run the following concurrently:<\/p>\n
2-1) send() sk-B to sk-B from sk-X
\n 2-2) close() both A and B<\/p>\n
At 2-1), there is a small window where unix_add_edges()
\npublishes a new edge (B B) to GC but its skb is not queued
\nby skb_queue_tail().<\/p>\n
If 2-2) completes before skb_queue_tail() and GC is triggered,
\nit judges A B as dead, but B is not freed because GC cannot
\ncollect the not-yet-queued skb holding the B B edge.<\/p>\n
X -. A B -. This edge is visible
\n ^–‘ ^..’ but skb is not<\/p>\n
This itself is not a problem since the next GC run will judge
\nB as dead as well and free it finally.<\/p>\n
X -. A B -.
\n ^–‘ ^–‘<\/p>\n
However, X’s SCC forces the next GC to call unix_walk_scc_fast(),
\nand it iterates over A through B’s scc_entry.<\/p>\n
Let’s unlink scc_entry before freeing the vertex in unix_del_edge().<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
af_unix: Unlink scc_entry in unix_del_edge().<\/p>\n
Kyle Zeng reported that GC could free a dead SCC partially.<\/p>\n
The scenario is as foll<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-11936","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/11936","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=11936"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=11936"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=11936"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}