CVE-2022-49728

Published Feb 26, 2025

Last updated a year ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: ipv6: Fix signed integer overflow in __ip6_append_data Resurrect ubsan overflow checks and ubsan report this warning, fix it by change the variable [length] type to size_t. UBSAN: signed-integer-overflow in net/ipv6/ip6_output.c:1489:19 2147479552 + 8567 cannot be represented in type 'int' CPU: 0 PID: 253 Comm: err Not tainted 5.16.0+ #1 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0x214/0x230 show_stack+0x30/0x78 dump_stack_lvl+0xf8/0x118 dump_stack+0x18/0x30 ubsan_epilogue+0x18/0x60 handle_overflow+0xd0/0xf0 __ubsan_handle_add_overflow+0x34/0x44 __ip6_append_data.isra.48+0x1598/0x1688 ip6_append_data+0x128/0x260 udpv6_sendmsg+0x680/0xdd0 inet6_sendmsg+0x54/0x90 sock_sendmsg+0x70/0x88 ____sys_sendmsg+0xe8/0x368 ___sys_sendmsg+0x98/0xe0 __sys_sendmmsg+0xf4/0x3b8 __arm64_sys_sendmmsg+0x34/0x48 invoke_syscall+0x64/0x160 el0_svc_common.constprop.4+0x124/0x300 do_el0_svc+0x44/0xc8 el0_svc+0x3c/0x1e8 el0t_64_sync_handler+0x88/0xb0 el0t_64_sync+0x16c/0x170 Changes since v1: -Change the variable [length] type to unsigned, as Eric Dumazet suggested. Changes since v2: -Don't change exthdrlen type in ip6_make_skb, as Paolo Abeni suggested. Changes since v3: -Don't change ulen type in udpv6_sendmsg and l2tp_ip6_sendmsg, as Jakub Kicinski suggested.
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Modified
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

nvd@nist.gov
CWE-190

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