In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
netfilter: nf_conntrack_expect: use conntrack GC to reap expectations<\/p>\n
This patch replaces the timer API by GC worker approach for
\nexpectations, as it already happened in many other subsystems.<\/p>\n
Use the existing conntrack GC worker to iterate over the local list of
\nexpectations in the master conntrack to reap expired expectations.
\nCheck IPS_HELPER_BIT to run GC for expectations, set it on for nft_ct
\nexpectation which nevers sets it. Hold the expectation spinlock while
\niterating over the master conntrack expectation list to synchronize with
\nnf_ct_remove_expectations(). This also performs runtime packet path
\ngarbage collection through the expectation insertion and lookup
\nfunctions while walking over one of the chains of the global expectation
\nhashtables. Unconfirmed conntrack entries are skipped since ct->ext can
\nbe reallocated and dying are skipped since those will be gone soon.
\nSet on IPS_HELPER_BIT if the helper ct extension is added, then the new
\nGC worker does not need to bump the ct refcount to check if the ct->ext
\nhelper is available.<\/p>\n
This removes the extra bump on the refcount for expectation timers, this
\nallows to remove several nf_ct_expect_put() calls after the unlink,
\nafter this update only refcount remains at 1 while on the expectation
\nhashes.<\/p>\n
This patch implicitly addresses a race with the existing timer API
\nallowing an expectation to access a stale exp->master pointer which has
\nbeen already released when expectation removal loses races with an
\nexpiring timer, ie. timer_del() reporting false.<\/p>\n
Add a new NF_CT_EXPECT_DEAD flag to reap this expectation via GC. This
\nis needed by nf_conntrack_unexpect_related() which is called in error
\npaths to invalidate newly created expectations that has been added into
\nthe hashes. These expectactions cannot be inmediately released as GC or
\nnf_ct_remove_expectations() could race to make it. On expectation
\ninsert, the runtime GC reaps stale expectations before checking the
\nexpectation limit set by policy.<\/p>\n
Set current timestamp in nf_ct_expect_alloc(), then add the expectation
\npolicy timeout (or custom timeout specified added on top of this) to
\nspecify the expectation lifetime.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
netfilter: nf_conntrack_expect: use conntrack GC to reap expectations<\/p>\n
This patch replaces the timer API by GC worker approach for<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-12328","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/12328","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=12328"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=12328"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=12328"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}