CVE-2025-40042

Description

In the Linux kernel, the following vulnerability has been resolved:tracing: Fix race condition in kprobe initialization causing null pointer dereferenceThere is a critical race condition in kprobe initialization that can lead tonull pointer dereference and kernel crash.[1135630.084782] Unable to handle kernel paging request at virtual address 0000710a04630000...[1135630.260314] pstate: 404003c9 (nZcv DAIF +PAN -UAO)[1135630.269239] pc : kprobe_perf_func+0x30/0x260[1135630.277643] lr : kprobe_dispatcher+0x44/0x60[1135630.286041] sp : ffffaeff4977fa40[1135630.293441] x29: ffffaeff4977fa40 x28: ffffaf015340e400[1135630.302837] x27: 0000000000000000 x26: 0000000000000000[1135630.312257] x25: ffffaf029ed108a8 x24: ffffaf015340e528[1135630.321705] x23: ffffaeff4977fc50 x22: ffffaeff4977fc50[1135630.331154] x21: 0000000000000000 x20: ffffaeff4977fc50[1135630.340586] x19: ffffaf015340e400 x18: 0000000000000000[1135630.349985] x17: 0000000000000000 x16: 0000000000000000[1135630.359285] x15: 0000000000000000 x14: 0000000000000000[1135630.368445] x13: 0000000000000000 x12: 0000000000000000[1135630.377473] x11: 0000000000000000 x10: 0000000000000000[1135630.386411] x9 : 0000000000000000 x8 : 0000000000000000[1135630.395252] x7 : 0000000000000000 x6 : 0000000000000000[1135630.403963] x5 : 0000000000000000 x4 : 0000000000000000[1135630.412545] x3 : 0000710a04630000 x2 : 0000000000000006[1135630.421021] x1 : ffffaeff4977fc50 x0 : 0000710a04630000[1135630.429410] Call trace:[1135630.434828] kprobe_perf_func+0x30/0x260[1135630.441661] kprobe_dispatcher+0x44/0x60[1135630.448396] aggr_pre_handler+0x70/0xc8[1135630.454959] kprobe_breakpoint_handler+0x140/0x1e0[1135630.462435] brk_handler+0xbc/0xd8[1135630.468437] do_debug_exception+0x84/0x138[1135630.475074] el1_dbg+0x18/0x8c[1135630.480582] security_file_permission+0x0/0xd0[1135630.487426] vfs_write+0x70/0x1c0[1135630.493059] ksys_write+0x5c/0xc8[1135630.498638] __arm64_sys_write+0x24/0x30[1135630.504821] el0_svc_common+0x78/0x130[1135630.510838] el0_svc_handler+0x38/0x78[1135630.516834] el0_svc+0x8/0x1b0kernel/trace/trace_kprobe.c: 13080xffff3df8995039ec : ldr x21, [x24,#120]include/linux/compiler.h: 2940xffff3df8995039f0 : ldr x1, [x21,x0]kernel/trace/trace_kprobe.c1308: head = this_cpu_ptr(call->perf_events);1309: if (hlist_empty(head))1310: return 0;crash> struct trace_event_call -ostruct trace_event_call { ... [120] struct hlist_head *perf_events; //(call->perf_event) ...}crash> struct trace_event_call ffffaf015340e528struct trace_event_call { ... perf_events = 0xffff0ad5fa89f088, //this value is correct, but x21 = 0 ...}Race Condition Analysis:The race occurs between kprobe activation and perf_events initialization: CPU0 CPU1 ==== ==== perf_kprobe_init perf_trace_event_init tp_event->perf_events = list;(1) tp_event->class->reg (2) KPROBE ACTIVE Debug exception triggers ... kprobe_dispatcher kprobe_perf_func (tk->tp.flags & TP_FLAG_PROFILE) head = this_cpu_ptr(call->perf_events)(3) (perf_events is still null)Problem:1. CPU0 executes (1) assigning tp_event->perf_events = list2. CPU0 executes (2) enabling kprobe functionality via class->reg()3. CPU1 triggers and reaches kprobe_dispatcher4. CPU1 checks TP_FLAG_PROFILE - condition passes (step 2 completed)5. CPU1 calls kprobe_perf_func() and crashes at (3) because call->perf_events is still nullCPU1 sees that kprobe functionality is enabled but does not see thatperf_events has been assigned.Add pairing read an---truncated---

Risk Information

Associated Vulnerability

Patch Details

References

https://nvd.nist.gov/vuln/detail/CVE-2023-1234
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-1234