CyberRota Analysis
AI-GeneratedThe vulnerability affects the Linux kernel's IGMP (Internet Group Management Protocol) implementation, specifically in the functions igmp_mod_timer() and igmp_stop_timer(), which can lead to memory leaks when timers are improperly managed. This occurs when a multicast group is removed while a timer is active, causing the reference count of the multicast list entry to be decremented incorrectly, resulting in leaked memory. System administrators and developers managing Linux kernel environments should prioritize addressing this issue to prevent potential resource exhaustion and maintain system stability.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: ipv4: igmp: Fix potential memory leaks in igmp_mod_timer() and igmp_stop_timer() When a timer is deleted and not re-armed in igmp_mod_timer(), or stopped in igmp_stop_timer(), the code currently decrements the reference counter of the multicast list entry @im using refcount_dec(&im->refcnt). However, both functions can be called from the RCU reader path: - igmp_mod_timer() via igmp_heard_query() -> for_each_pmc_rcu() - igmp_stop_timer() via igmp_rcv() -> igmp_heard_report() If the group im was concurrently removed from the list by ip_mc_dec_group(), its reference count might have already been decremented to 1. In this case, timer_delete() succeeds, and refcount_dec() decrements the refcount from 1 to 0. Since refcount_dec() does not free the object when it hits 0 (unlike ip_ma_put()), the im structure is leaked. Fix this by using ip_ma_put(im) instead of refcount_dec(&im->refcnt), and deferring the put until after the spinlock is released.