CVE-2024-36888
Linux Kernel Workqueue CPU Online Mask Vulnerability
Description
In the Linux kernel, the following vulnerability has been resolved: workqueue: Fix selection of wake_cpu in kick_pool() With cpu_possible_mask=0-63 and cpu_online_mask=0-7 the following kernel oops was observed: smp: Bringing up secondary CPUs ... smp: Brought up 1 node, 8 CPUs Unable to handle kernel pointer dereference in virtual kernel address space Failing address: 0000000000000000 TEID: 0000000000000803 [..] Call Trace: arch_vcpu_is_preempted+0x12/0x80 select_idle_sibling+0x42/0x560 select_task_rq_fair+0x29a/0x3b0 try_to_wake_up+0x38e/0x6e0 kick_pool+0xa4/0x198 __queue_work.part.0+0x2bc/0x3a8 call_timer_fn+0x36/0x160 __run_timers+0x1e2/0x328 __run_timer_base+0x5a/0x88 run_timer_softirq+0x40/0x78 __do_softirq+0x118/0x388 irq_exit_rcu+0xc0/0xd8 do_ext_irq+0xae/0x168 ext_int_handler+0xbe/0xf0 psw_idle_exit+0x0/0xc default_idle_call+0x3c/0x110 do_idle+0xd4/0x158 cpu_startup_entry+0x40/0x48 rest_init+0xc6/0xc8 start_kernel+0x3c4/0x5e0 startup_continue+0x3c/0x50 The crash is caused by calling arch_vcpu_is_preempted() for an offline CPU. To avoid this, select the cpu with cpumask_any_and_distribute() to mask __pod_cpumask with cpu_online_mask. In case no cpu is left in the pool, skip the assignment. tj: This doesn't fully fix the bug as CPUs can still go down between picking the target CPU and the wake call. Fixing that likely requires adding cpu_online() test to either the sched or s390 arch code. However, regardless of how that is fixed, workqueue shouldn't be picking a CPU which isn't online as that would result in unpredictable and worse behavior.
INFO
Published Date :
May 30, 2024, 4:15 p.m.
Last Modified :
July 3, 2024, 2:03 a.m.
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Remotely Exploitable :
No
Impact Score :
3.6
Exploitability Score :
2.5
References to Advisories, Solutions, and Tools
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Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 03, 2024
Action Type Old Value New Value Added CWE CISA-ADP CWE-476 Added CVSS V3.1 CISA-ADP AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H -
CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 30, 2024
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: workqueue: Fix selection of wake_cpu in kick_pool() With cpu_possible_mask=0-63 and cpu_online_mask=0-7 the following kernel oops was observed: smp: Bringing up secondary CPUs ... smp: Brought up 1 node, 8 CPUs Unable to handle kernel pointer dereference in virtual kernel address space Failing address: 0000000000000000 TEID: 0000000000000803 [..] Call Trace: arch_vcpu_is_preempted+0x12/0x80 select_idle_sibling+0x42/0x560 select_task_rq_fair+0x29a/0x3b0 try_to_wake_up+0x38e/0x6e0 kick_pool+0xa4/0x198 __queue_work.part.0+0x2bc/0x3a8 call_timer_fn+0x36/0x160 __run_timers+0x1e2/0x328 __run_timer_base+0x5a/0x88 run_timer_softirq+0x40/0x78 __do_softirq+0x118/0x388 irq_exit_rcu+0xc0/0xd8 do_ext_irq+0xae/0x168 ext_int_handler+0xbe/0xf0 psw_idle_exit+0x0/0xc default_idle_call+0x3c/0x110 do_idle+0xd4/0x158 cpu_startup_entry+0x40/0x48 rest_init+0xc6/0xc8 start_kernel+0x3c4/0x5e0 startup_continue+0x3c/0x50 The crash is caused by calling arch_vcpu_is_preempted() for an offline CPU. To avoid this, select the cpu with cpumask_any_and_distribute() to mask __pod_cpumask with cpu_online_mask. In case no cpu is left in the pool, skip the assignment. tj: This doesn't fully fix the bug as CPUs can still go down between picking the target CPU and the wake call. Fixing that likely requires adding cpu_online() test to either the sched or s390 arch code. However, regardless of how that is fixed, workqueue shouldn't be picking a CPU which isn't online as that would result in unpredictable and worse behavior. Added Reference kernel.org https://git.kernel.org/stable/c/c57824d4fe07c2131f8c48687cbd5ee2be60c767 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/6d559e70b3eb6623935cbe7f94c1912c1099777b [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/57a01eafdcf78f6da34fad9ff075ed5dfdd9f420 [No types assigned]
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2024-36888 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2024-36888
weaknesses.