In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
igmp: convert struct ip_sf_list to RCU<\/p>\n
Commit 23d2b94043ca (“igmp: Add ip_mc_list lock in ip_check_mc_rcu”)
\nadded spin_lock_bh(&im->lock) to ip_check_mc_rcu() to prevent a
\nuse-after-free while iterating im->sources during concurrent deletions.<\/p>\n
However, ip_check_mc_rcu() is called from RCU read-side critical
\nsections in packet receive and route lookup fast paths (e.g.
\n__mkroute_output(), ip_route_input_rcu(), and __udp4_lib_rcv()).<\/p>\n
When igmpv3_send_cr() or igmpv3_send_report() holds &pmc->lock and
\ncalls add_grec() -> igmpv3_newpack() -> ip_route_output_ports(),
\nan XFRM policy matching a multicast destination triggers
\nxfrm_tmpl_resolve_one() -> xfrm4_get_saddr() -> __mkroute_output() ->
\nip_check_mc_rcu(). This attempts to acquire &im->lock while &pmc->lock
\nis already held on the same CPU, triggering a lockdep recursive locking
\nwarning \/ deadlock.<\/p>\n
Fix this by converting IPv4 struct ip_sf_list to RCU, mirroring the
\nIPv6 implementation in net\/ipv6\/mcast.c:<\/p>\n
1. Add struct rcu_head to struct ip_sf_list and annotate sf_next,
\n sources, and tomb as __rcu pointers.
\n2. Use rcu_assign_pointer() and kfree_rcu() for list updates and
\n deletions.
\n3. Remove spin_lock_bh(&im->lock) from ip_check_mc_rcu() and traverse
\n im->sources locklessly with for_each_psf_rcu(), reading and writing
\n counter fields with READ_ONCE() and WRITE_ONCE().<\/p>\n
Note: RCU conversion of \/proc\/net\/mcfilter will be done in a
\nseparate patch.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
igmp: convert struct ip_sf_list to RCU<\/p>\n
Commit 23d2b94043ca (“igmp: Add ip_mc_list lock in ip_check_mc_rcu”)
\nadded spin_lock_bh(&im<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-29257","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/29257","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=29257"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=29257"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=29257"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}