In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
ipv4: igmp: Fix potential UAF in igmp_gq_start_timer()<\/p>\n
A race condition exists between device teardown (inetdev_destroy) and
\nincoming IGMP query processing (igmp_rcv), leading to a Use-After-Free
\nin the IGMP timer callback.<\/p>\n
During device destruction, inetdev_destroy() drops the primary reference
\nto in_device, which can drop its refcount to 0. The actual freeing of
\nin_device memory is deferred via RCU (using call_rcu()).<\/p>\n
Concurrently, igmp_rcv() runs under RCU read lock and obtains the
\nin_device pointer. Because the memory is RCU-protected, CPU-0 can safely
\ndereference in_device even if its refcount has hit 0.<\/p>\n
However, if CPU-0 calls igmp_gq_start_timer() and re-arms the timer, it
\nattempts to acquire a reference using in_dev_hold(). This increments the
\nrefcount from 0 to 1, triggering a “refcount_t: addition on 0” warning.
\nSince the in_device memory is still scheduled to be freed after the RCU
\ngrace period (as the free callback does not check the refcount again),
\nthe device is freed while the timer is still armed. When the timer
\nexpires, it accesses the freed memory, causing a kernel panic.<\/p>\n
Fix this by using refcount_inc_not_zero() (via a new helper
\nin_dev_hold_safe()) to prevent acquiring a reference if the device is
\nalready being destroyed. If the refcount is 0, we do not arm the timer.<\/p>\n
A similar issue in IPv6 MLD is fixed in a subsequent patch.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
ipv4: igmp: Fix potential UAF in igmp_gq_start_timer()<\/p>\n
A race condition exists between device teardown (inetdev_destroy) and
\nincom<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-6951","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/6951","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=6951"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6951"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6951"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}