CVE-2024-46786

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> fscache: delete fscache_cookie_lru_timer when fscache exits to avoid UAF<br /> <br /> The fscache_cookie_lru_timer is initialized when the fscache module<br /> is inserted, but is not deleted when the fscache module is removed.<br /> If timer_reduce() is called before removing the fscache module,<br /> the fscache_cookie_lru_timer will be added to the timer list of<br /> the current cpu. Afterwards, a use-after-free will be triggered<br /> in the softIRQ after removing the fscache module, as follows:<br /> <br /> ==================================================================<br /> BUG: unable to handle page fault for address: fffffbfff803c9e9<br /> PF: supervisor read access in kernel mode<br /> PF: error_code(0x0000) - not-present page<br /> PGD 21ffea067 P4D 21ffea067 PUD 21ffe6067 PMD 110a7c067 PTE 0<br /> Oops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI<br /> CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G W 6.11.0-rc3 #855<br /> Tainted: [W]=WARN<br /> RIP: 0010:__run_timer_base.part.0+0x254/0x8a0<br /> Call Trace:<br /> <br /> tmigr_handle_remote_up+0x627/0x810<br /> __walk_groups.isra.0+0x47/0x140<br /> tmigr_handle_remote+0x1fa/0x2f0<br /> handle_softirqs+0x180/0x590<br /> irq_exit_rcu+0x84/0xb0<br /> sysvec_apic_timer_interrupt+0x6e/0x90<br /> <br /> <br /> asm_sysvec_apic_timer_interrupt+0x1a/0x20<br /> RIP: 0010:default_idle+0xf/0x20<br /> default_idle_call+0x38/0x60<br /> do_idle+0x2b5/0x300<br /> cpu_startup_entry+0x54/0x60<br /> start_secondary+0x20d/0x280<br /> common_startup_64+0x13e/0x148<br /> <br /> Modules linked in: [last unloaded: netfs]<br /> ==================================================================<br /> <br /> Therefore delete fscache_cookie_lru_timer when removing the fscahe module.