Linux Kernel up to 6.12.3 drain_vmap_area_work allocation of resources

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.12.3. It has been declared as problematic. This affects the function drain_vmap_area_work. Such manipulation leads to allocation of resources. This vulnerability is traded as CVE-2024-56559. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.12.3. It has been rated as problematic. Affected by this issue is the function drain_vmap_area_work. The manipulation with an unknown input leads to a allocation of resources vulnerability. Using CWE to declare the problem leads to CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. The impact remains unknown. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: mm/vmalloc: combine all TLB flush operations of KASAN shadow virtual address into one operation When compiling kernel source 'make -j $(nproc)' with the up-and-running KASAN-enabled kernel on a 256-core machine, the following soft lockup is shown: watchdog: BUG: soft lockup - CPU#28 stuck for 22s! [kworker/28:1:1760] CPU: 28 PID: 1760 Comm: kworker/28:1 Kdump: loaded Not tainted 6.10.0-rc5 #95 Workqueue: events drain_vmap_area_work RIP: 0010:smp_call_function_many_cond+0x1d8/0xbb0 Code: 38 c8 7c 08 84 c9 0f 85 49 08 00 00 8b 45 08 a8 01 74 2e 48 89 f1 49 89 f7 48 c1 e9 03 41 83 e7 07 4c 01 e9 41 83 c7 03 f3 90 b6 01 41 38 c7 7c 08 84 c0 0f 85 d4 06 00 00 8b 45 08 a8 01 75 RSP: 0018:ffffc9000cb3fb60 EFLAGS: 00000202 RAX: 0000000000000011 RBX: ffff8883bc4469c0 RCX: ffffed10776e9949 RDX: 0000000000000002 RSI: ffff8883bb74ca48 RDI: ffffffff8434dc50 RBP: ffff8883bb74ca40 R08: ffff888103585dc0 R09: ffff8884533a1800 R10: 0000000000000004 R11: ffffffffffffffff R12: ffffed1077888d39 R13: dffffc0000000000 R14: ffffed1077888d38 R15: 0000000000000003 FS: 0000000000000000(0000) GS:ffff8883bc400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005577b5c8d158 CR3: 0000000004850000 CR4: 0000000000350ef0 Call Trace: ? watchdog_timer_fn+0x2cd/0x390 ? __pfx_watchdog_timer_fn+0x10/0x10 ? __hrtimer_run_queues+0x300/0x6d0 ? sched_clock_cpu+0x69/0x4e0 ? __pfx___hrtimer_run_queues+0x10/0x10 ? srso_return_thunk+0x5/0x5f ? ktime_get_update_offsets_now+0x7f/0x2a0 ? srso_return_thunk+0x5/0x5f ? srso_return_thunk+0x5/0x5f ? hrtimer_interrupt+0x2ca/0x760 ? __sysvec_apic_timer_interrupt+0x8c/0x2b0 ? sysvec_apic_timer_interrupt+0x6a/0x90 ? asm_sysvec_apic_timer_interrupt+0x16/0x20 ? smp_call_function_many_cond+0x1d8/0xbb0 ? __pfx_do_kernel_range_flush+0x10/0x10 on_each_cpu_cond_mask+0x20/0x40 flush_tlb_kernel_range+0x19b/0x250 ? srso_return_thunk+0x5/0x5f ? kasan_release_vmalloc+0xa7/0xc0 purge_vmap_node+0x357/0x820 ? __pfx_purge_vmap_node+0x10/0x10 __purge_vmap_area_lazy+0x5b8/0xa10 drain_vmap_area_work+0x21/0x30 process_one_work+0x661/0x10b0 worker_thread+0x844/0x10e0 ? srso_return_thunk+0x5/0x5f ? __kthread_parkme+0x82/0x140 ? __pfx_worker_thread+0x10/0x10 kthread+0x2a5/0x370 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x30/0x70 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 Debugging Analysis: 1. The following ftrace log shows that the lockup CPU spends too much time iterating vmap_nodes and flushing TLB when purging vm_area structures. (Some info is trimmed). kworker: funcgraph_entry: | drain_vmap_area_work() { kworker: funcgraph_entry: | mutex_lock() { kworker: funcgraph_entry: 1.092 us | __cond_resched(); kworker: funcgraph_exit: 3.306 us | } ... ... kworker: funcgraph_entry: | flush_tlb_kernel_range() { ... ... kworker: funcgraph_exit: # 7533.649 us | } ... ... kworker: funcgraph_entry: 2.344 us | mutex_unlock(); kworker: funcgraph_exit: $ 23871554 us | } The drain_vmap_area_work() spends over 23 seconds. There are 2805 flush_tlb_kernel_range() calls in the ftrace log. * One is called in __purge_vmap_area_lazy(). * Others are called by purge_vmap_node->kasan_release_vmalloc. purge_vmap_node() iteratively releases kasan vmalloc allocations and flushes TLB for each vmap_area. - [Rough calculation] Each flush_tlb_kernel_range() runs about 7.5ms. -- 2804 * 7.5ms = 21.03 seconds. -- That's why a soft lock is triggered. 2. Extending the soft lockup time can work around the issue (For example, # echo ---truncated---

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2024-56559 since 12/27/2024. The exploitation is known to be difficult. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 233479 (Ubuntu 24.10 : Linux kernel (Low Latency) vulnerabilities (USN-7380-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.12.4 eliminates this vulnerability. Applying the patch f9a18889aad9b4c19c6c4550c67ad4f9ed2a354f/9e9e085effe9b7e342138fde3cf8577d22509932 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (233479), EUVD (EUVD-2024-53207) and CERT Bund (WID-SEC-2024-3762). Once again VulDB remains the best source for vulnerability data.

Affected

• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• RESF Rocky Linux
• Dell NetWorker
• Dell Avamar
• Red Hat OpenShift
• IBM QRadar SIEM
• Dell PowerProtect Data Domain
• Open Source Linux Kernel
• IBM DataPower Gateway
• Dell Secure Connect Gateway

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3

License

• open-source

Website

• Vendor: https://www.kernel.org/

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