CVE-2025-40178

In the Linux kernel, the following vulnerability has been resolved:

pid: Add a judgment for ns null in pid_nr_ns

__task_pid_nr_ns

ns = task_active_pid_ns(current);

pid_nr_ns(rcu_dereference(*task_pid_ptr(task, type)), ns);

if (pid && ns->level <= pid->level) {

Sometimes null is returned for task_active_pid_ns. Then it will trigger kernel panic in pid_nr_ns.

For example:

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000058

Mem abort info:

ESR = 0x0000000096000007

EC = 0x25: DABT (current EL), IL = 32 bits

SET = 0, FnV = 0

EA = 0, S1PTW = 0

FSC = 0x07: level 3 translation fault

Data abort info:

ISV = 0, ISS = 0x00000007, ISS2 = 0x00000000

CM = 0, WnR = 0, TnD = 0, TagAccess = 0

GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0

user pgtable: 4k pages, 39-bit VAs, pgdp=00000002175aa000

[0000000000000058] pgd=08000002175ab003, p4d=08000002175ab003, pud=08000002175ab003, pmd=08000002175be003, pte=0000000000000000

pstate: 834000c5 (Nzcv daIF +PAN -UAO +TCO +DIT -SSBS BTYPE=--)

pc : __task_pid_nr_ns+0x74/0xd0

lr : __task_pid_nr_ns+0x24/0xd0

sp : ffffffc08001bd10

x29: ffffffc08001bd10 x28: ffffffd4422b2000 x27: 0000000000000001

x26: ffffffd442821168 x25: ffffffd442821000 x24: 00000f89492eab31

x23: 00000000000000c0 x22: ffffff806f5693c0 x21: ffffff806f5693c0

x20: 0000000000000001 x19: 0000000000000000 x18: 0000000000000000

x17: 00000000529c6ef0 x16: 00000000529c6ef0 x15: 00000000023a1adc

x14: 0000000000000003 x13: 00000000007ef6d8 x12: 001167c391c78800

x11: 00ffffffffffffff x10: 0000000000000000 x9 : 0000000000000001

x8 : ffffff80816fa3c0 x7 : 0000000000000000 x6 : 49534d702d535449

x5 : ffffffc080c4c2c0 x4 : ffffffd43ee128c8 x3 : ffffffd43ee124dc

x2 : 0000000000000000 x1 : 0000000000000001 x0 : ffffff806f5693c0

Call trace:

__task_pid_nr_ns+0x74/0xd0

...

__handle_irq_event_percpu+0xd4/0x284

handle_irq_event+0x48/0xb0

handle_fasteoi_irq+0x160/0x2d8

generic_handle_domain_irq+0x44/0x60

gic_handle_irq+0x4c/0x114

call_on_irq_stack+0x3c/0x74

do_interrupt_handler+0x4c/0x84

el1_interrupt+0x34/0x58

el1h_64_irq_handler+0x18/0x24

el1h_64_irq+0x68/0x6c

account_kernel_stack+0x60/0x144

exit_task_stack_account+0x1c/0x80

do_exit+0x7e4/0xaf8

...

get_signal+0x7bc/0x8d8

do_notify_resume+0x128/0x828

el0_svc+0x6c/0x70

el0t_64_sync_handler+0x68/0xbc

el0t_64_sync+0x1a8/0x1ac

Code: 35fffe54 911a02a8 f9400108 b4000128 (b9405a69)

---[ end trace 0000000000000000 ]---

Kernel panic - not syncing: Oops: Fatal exception in interrupt