In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
drop_monitor: use timer_shutdown_sync() to prevent timer rearming during teardown<\/p>\n
In drop_monitor teardown paths (net_dm_trace_off_set(),
\nnet_dm_hw_monitor_stop(), and error unwind paths in net_dm_trace_on_set()
\nand net_dm_hw_monitor_start()), per-CPU timers are stopped using
\ntimer_delete_sync() followed by cancel_work_sync().<\/p>\n
However, there is a circular dependency between send_timer and
\ndm_alert_work:
\n1) sched_send_work() (timer callback) schedules dm_alert_work.
\n2) send_dm_alert() \/ net_dm_hw_summary_work() calls reset_per_cpu_data()
\n or net_dm_hw_reset_per_cpu_data().
\n3) If memory allocation fails under memory pressure in the reset
\n function, it re-arms the timer via mod_timer(&data->send_timer, …).<\/p>\n
If dm_alert_work is running concurrently while timer_delete_sync()
\nexecutes on another CPU, an allocation failure in the worker will
\nre-arm the timer after timer_delete_sync() has already returned.
\nOnce cancel_work_sync() completes and module_put() is called, the timer
\nremains active in the timer wheel. If the module is then unloaded, the
\ntimer will fire and execute sched_send_work() in freed memory,
\ntriggering a kernel panic \/ use-after-free.<\/p>\n
Switch from timer_delete_sync() to timer_shutdown_sync(). This guarantees
\nthat any in-flight timer handler has finished and prevents subsequent
\nre-arming attempts from running workers from succeeding. When monitoring
\nis restarted later, timer_setup() is invoked, which cleanly
\nre-initializes the timer.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
drop_monitor: use timer_shutdown_sync() to prevent timer rearming during teardown<\/p>\n
In drop_monitor teardown paths (net_dm_trace_off<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-33355","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/33355","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=33355"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=33355"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=33355"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}