In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
net\/sched: cls_route: free emptied bucket on filter move<\/p>\n
route4_change can move an existing filter to a different top-level
\nbucket: route4_set_parms recomputes the handle from TCA_ROUTE4_TO\/
\nFROM\/IIF, and the handle-mismatch check is gated on the ‘new’ flag, so
\nfor an existing filter the new handle may differ from the old one and
\nland in a different bucket. When this happens, the filter is unlinked
\nfrom the old bucket, but the bucket itself is never freed once it goes
\nempty. The stale empty bucket remains in head->table[], causing
\nroute4_delete to report *last=false even after the last live filter is
\ngone. That pins the empty tcf_proto and causes a leak.<\/p>\n
Fix this by refcounting the filters linked to a bucket and freeing the
\nbucket when the count drops to zero. The existing scan in route4_delete
\ngoes away with it.<\/p>\n
The count is updated at all sites that link or unlink a filter during add,
\nchange and delete, and the bucket is dropped from head->table[] as soon as
\nit reaches zero.<\/p>\n
Conditions to recreate the bug:
\n CONFIG_NET_CLS_ROUTE4=y, CONFIG_NET_SCH_INGRESS=y, CONFIG_NET_CLS_ACT=y.<\/p>\n
tc qdisc replace dev lo clsact
\n tc filter add dev lo ingress protocol ip pref 100 route from 1 to 1
\n tc filter change dev lo ingress protocol ip pref 100 handle 0x10001
\n route from 1 to 2
\n tc filter del dev lo ingress protocol ip pref 100 handle 0x10002
\n route from 1 to 2
\n tc filter show dev lo ingress | grep -c ‘pref 100 route chain 0 ‘<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
net\/sched: cls_route: free emptied bucket on filter move<\/p>\n
route4_change can move an existing filter to a different top-level
\nbucket<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-29115","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/29115","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=29115"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=29115"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=29115"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}