CVE-2023-53312

Published Sep 16, 2025

Last updated 9 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: net: fix net_dev_start_xmit trace event vs skb_transport_offset() After blamed commit, we must be more careful about using skb_transport_offset(), as reminded us by syzbot: WARNING: CPU: 0 PID: 10 at include/linux/skbuff.h:2868 skb_transport_offset include/linux/skbuff.h:2977 [inline] WARNING: CPU: 0 PID: 10 at include/linux/skbuff.h:2868 perf_trace_net_dev_start_xmit+0x89a/0xce0 include/trace/events/net.h:14 Modules linked in: CPU: 0 PID: 10 Comm: kworker/u4:1 Not tainted 6.1.30-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet RIP: 0010:skb_transport_header include/linux/skbuff.h:2868 [inline] RIP: 0010:skb_transport_offset include/linux/skbuff.h:2977 [inline] RIP: 0010:perf_trace_net_dev_start_xmit+0x89a/0xce0 include/trace/events/net.h:14 Code: 8b 04 25 28 00 00 00 48 3b 84 24 c0 00 00 00 0f 85 4e 04 00 00 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc e8 56 22 01 fd <0f> 0b e9 f6 fc ff ff 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c 86 f9 ff RSP: 0018:ffffc900002bf700 EFLAGS: 00010293 RAX: ffffffff8485d8ca RBX: 000000000000ffff RCX: ffff888100914280 RDX: 0000000000000000 RSI: 000000000000ffff RDI: 000000000000ffff RBP: ffffc900002bf818 R08: ffffffff8485d5b6 R09: fffffbfff0f8fb5e R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff110217d8f67 R13: ffff88810bec7b3a R14: dffffc0000000000 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8881f6a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f96cf6d52f0 CR3: 000000012224c000 CR4: 0000000000350ef0 Call Trace: <TASK> [<ffffffff84715e35>] trace_net_dev_start_xmit include/trace/events/net.h:14 [inline] [<ffffffff84715e35>] xmit_one net/core/dev.c:3643 [inline] [<ffffffff84715e35>] dev_hard_start_xmit+0x705/0x980 net/core/dev.c:3660 [<ffffffff8471a232>] __dev_queue_xmit+0x16b2/0x3370 net/core/dev.c:4324 [<ffffffff85416493>] dev_queue_xmit include/linux/netdevice.h:3030 [inline] [<ffffffff85416493>] batadv_send_skb_packet+0x3f3/0x680 net/batman-adv/send.c:108 [<ffffffff85416744>] batadv_send_broadcast_skb+0x24/0x30 net/batman-adv/send.c:127 [<ffffffff853bc52a>] batadv_iv_ogm_send_to_if net/batman-adv/bat_iv_ogm.c:393 [inline] [<ffffffff853bc52a>] batadv_iv_ogm_emit net/batman-adv/bat_iv_ogm.c:421 [inline] [<ffffffff853bc52a>] batadv_iv_send_outstanding_bat_ogm_packet+0x69a/0x840 net/batman-adv/bat_iv_ogm.c:1701 [<ffffffff8151023c>] process_one_work+0x8ac/0x1170 kernel/workqueue.c:2289 [<ffffffff81511938>] worker_thread+0xaa8/0x12d0 kernel/workqueue.c:2436
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-401
134c704f-9b21-4f2e-91b3-4a467353bcc0
CWE-401

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