CVE-2025-38320

Published Jul 10, 2025

Last updated 10 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: arm64/ptrace: Fix stack-out-of-bounds read in regs_get_kernel_stack_nth() KASAN reports a stack-out-of-bounds read in regs_get_kernel_stack_nth(). Call Trace: [ 97.283505] BUG: KASAN: stack-out-of-bounds in regs_get_kernel_stack_nth+0xa8/0xc8 [ 97.284677] Read of size 8 at addr ffff800089277c10 by task 1.sh/2550 [ 97.285732] [ 97.286067] CPU: 7 PID: 2550 Comm: 1.sh Not tainted 6.6.0+ #11 [ 97.287032] Hardware name: linux,dummy-virt (DT) [ 97.287815] Call trace: [ 97.288279] dump_backtrace+0xa0/0x128 [ 97.288946] show_stack+0x20/0x38 [ 97.289551] dump_stack_lvl+0x78/0xc8 [ 97.290203] print_address_description.constprop.0+0x84/0x3c8 [ 97.291159] print_report+0xb0/0x280 [ 97.291792] kasan_report+0x84/0xd0 [ 97.292421] __asan_load8+0x9c/0xc0 [ 97.293042] regs_get_kernel_stack_nth+0xa8/0xc8 [ 97.293835] process_fetch_insn+0x770/0xa30 [ 97.294562] kprobe_trace_func+0x254/0x3b0 [ 97.295271] kprobe_dispatcher+0x98/0xe0 [ 97.295955] kprobe_breakpoint_handler+0x1b0/0x210 [ 97.296774] call_break_hook+0xc4/0x100 [ 97.297451] brk_handler+0x24/0x78 [ 97.298073] do_debug_exception+0xac/0x178 [ 97.298785] el1_dbg+0x70/0x90 [ 97.299344] el1h_64_sync_handler+0xcc/0xe8 [ 97.300066] el1h_64_sync+0x78/0x80 [ 97.300699] kernel_clone+0x0/0x500 [ 97.301331] __arm64_sys_clone+0x70/0x90 [ 97.302084] invoke_syscall+0x68/0x198 [ 97.302746] el0_svc_common.constprop.0+0x11c/0x150 [ 97.303569] do_el0_svc+0x38/0x50 [ 97.304164] el0_svc+0x44/0x1d8 [ 97.304749] el0t_64_sync_handler+0x100/0x130 [ 97.305500] el0t_64_sync+0x188/0x190 [ 97.306151] [ 97.306475] The buggy address belongs to stack of task 1.sh/2550 [ 97.307461] and is located at offset 0 in frame: [ 97.308257] __se_sys_clone+0x0/0x138 [ 97.308910] [ 97.309241] This frame has 1 object: [ 97.309873] [48, 184) 'args' [ 97.309876] [ 97.310749] The buggy address belongs to the virtual mapping at [ 97.310749] [ffff800089270000, ffff800089279000) created by: [ 97.310749] dup_task_struct+0xc0/0x2e8 [ 97.313347] [ 97.313674] The buggy address belongs to the physical page: [ 97.314604] page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x14f69a [ 97.315885] flags: 0x15ffffe00000000(node=1|zone=2|lastcpupid=0xfffff) [ 97.316957] raw: 015ffffe00000000 0000000000000000 dead000000000122 0000000000000000 [ 97.318207] raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000 [ 97.319445] page dumped because: kasan: bad access detected [ 97.320371] [ 97.320694] Memory state around the buggy address: [ 97.321511] ffff800089277b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 97.322681] ffff800089277b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 97.323846] >ffff800089277c00: 00 00 f1 f1 f1 f1 f1 f1 00 00 00 00 00 00 00 00 [ 97.325023] ^ [ 97.325683] ffff800089277c80: 00 00 00 00 00 00 00 00 00 f3 f3 f3 f3 f3 f3 f3 [ 97.326856] ffff800089277d00: f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 00 00 This issue seems to be related to the behavior of some gcc compilers and was also fixed on the s390 architecture before: commit d93a855c31b7 ("s390/ptrace: Avoid KASAN false positives in regs_get_kernel_stack_nth()") As described in that commit, regs_get_kernel_stack_nth() has confirmed that `addr` is on the stack, so reading the value at `*addr` should be allowed. Use READ_ONCE_NOCHECK() helper to silence the KASAN check for this case. [will: Use '*addr' as the argument to READ_ONCE_NOCHECK()]
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel, debian_linux

Risk scores

CVSS 3.1

Type
Primary
Base score
7.1
Impact score
5.2
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Severity
HIGH

Weaknesses

nvd@nist.gov
CWE-125

Social media

Hype score
Not currently trending

Configurations

  1. In the Linux kernel, the following vulnerability has been resolved: cgroup: Avoid iteration of dying tasks with zero refcount The commit 260fbcb92bbea ("cgroup: Move dying_tasks cleanup from cgroup_task_release() to cgroup_task_free()") extended the lifetime of tasks on the dying_tasks list. The iterators have provision to go through dying_tasks because of dying threadgroup leaders or explicit CSS_TASK_ITER_WITH_DEAD, however, it was expected that such tasks can obtain a new reference (that is possible before cgroup_task_release()/put_task_struct_rcu_user()). The tasks after cgroup_task_release() and before cgroup_task_free() are subject to race when they may or may not have ->usage count > 0. The race window is between css_task_iter_next() invocations when css_set_lock is released and we may arrive at a new ->task_pos. The iterator should not attempt to resurrect tasks whose ->usage count dropped to zero. (When that happens, __put_task_struct_rcu_cb() is already imminent and the returned task_struct would could be used after free.) As for the fix, we cannot simply check the signal->live count of a task on the dying list because that won't distinguish regular zombies waiting to be reaped from RCU remnant tasks that are going to be free'd. Therefore add an extra check to rule out ->usage==0 tasks from any iteration. The repeat: loop in css_task_iter_advance() doesn't consider ->usage count, so add a new loop to css_task_iter_next() to skip de-used tasks on the dying_list. Rough illustration of the possible race R (reader of cgroup.procs) T (thread) L (group leader) --------------------------------- -------------------------------- -------------------------------- L exits, signal->live > 0 cgroup_task_dead(L) css_set_skip_task_iters() // skips only cset->tasks list_add_tail(&L->cg_list, &cset->dying_tasks) css_task_iter_next() take css_set_lock css_task_iter_advance() leader && signal->live != 0 => it->task_pos = &L->cg_list release css_set_lock T exits --signal->live == 0 cgroup_task_dead(T) // css_set_lock release_task(T) cgroup_task_release(T) release_task(L) // zap_leader cgroup_task_release(L) put_task_struct_rcu_user(L) ...RCU... put_task_struct(L) L->usage = 0 /* L still on dying_tasks */ ...RCU... __put_task_struct(L) css_task_iter_next() // another iteration take css_set_lock it->task_pos = &L->cg_list get_task_struct(L) => addition on 0 drop css_set_lock cgroup_task_free(L) css_set_skip_task_iters() // dying skip comes too late free_task(L) cgroup_procs_show() task_pid_vnr(L)•CVE-2026-98163