CVE-2022-50094

Published Jun 18, 2025

Last updated a year ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: spmi: trace: fix stack-out-of-bound access in SPMI tracing functions trace_spmi_write_begin() and trace_spmi_read_end() both call memcpy() with a length of "len + 1". This leads to one extra byte being read beyond the end of the specified buffer. Fix this out-of-bound memory access by using a length of "len" instead. Here is a KASAN log showing the issue: BUG: KASAN: stack-out-of-bounds in trace_event_raw_event_spmi_read_end+0x1d0/0x234 Read of size 2 at addr ffffffc0265b7540 by task thermal@2.0-ser/1314 ... Call trace: dump_backtrace+0x0/0x3e8 show_stack+0x2c/0x3c dump_stack_lvl+0xdc/0x11c print_address_description+0x74/0x384 kasan_report+0x188/0x268 kasan_check_range+0x270/0x2b0 memcpy+0x90/0xe8 trace_event_raw_event_spmi_read_end+0x1d0/0x234 spmi_read_cmd+0x294/0x3ac spmi_ext_register_readl+0x84/0x9c regmap_spmi_ext_read+0x144/0x1b0 [regmap_spmi] _regmap_raw_read+0x40c/0x754 regmap_raw_read+0x3a0/0x514 regmap_bulk_read+0x418/0x494 adc5_gen3_poll_wait_hs+0xe8/0x1e0 [qcom_spmi_adc5_gen3] ... __arm64_sys_read+0x4c/0x60 invoke_syscall+0x80/0x218 el0_svc_common+0xec/0x1c8 ... addr ffffffc0265b7540 is located in stack of task thermal@2.0-ser/1314 at offset 32 in frame: adc5_gen3_poll_wait_hs+0x0/0x1e0 [qcom_spmi_adc5_gen3] this frame has 1 object: [32, 33) 'status' Memory state around the buggy address: ffffffc0265b7400: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 ffffffc0265b7480: 04 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 >ffffffc0265b7500: 00 00 00 00 f1 f1 f1 f1 01 f3 f3 f3 00 00 00 00 ^ ffffffc0265b7580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffffffc0265b7600: f1 f1 f1 f1 01 f2 07 f2 f2 f2 01 f3 00 00 00 00 ==================================================================
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel

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