CVE-2022-50346

Published Sep 16, 2025

Last updated 9 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: ext4: init quota for 'old.inode' in 'ext4_rename' Syzbot found the following issue: ext4_parse_param: s_want_extra_isize=128 ext4_inode_info_init: s_want_extra_isize=32 ext4_rename: old.inode=ffff88823869a2c8 old.dir=ffff888238699828 new.inode=ffff88823869d7e8 new.dir=ffff888238699828 __ext4_mark_inode_dirty: inode=ffff888238699828 ea_isize=32 want_ea_size=128 __ext4_mark_inode_dirty: inode=ffff88823869a2c8 ea_isize=32 want_ea_size=128 ext4_xattr_block_set: inode=ffff88823869a2c8 ------------[ cut here ]------------ WARNING: CPU: 13 PID: 2234 at fs/ext4/xattr.c:2070 ext4_xattr_block_set.cold+0x22/0x980 Modules linked in: RIP: 0010:ext4_xattr_block_set.cold+0x22/0x980 RSP: 0018:ffff888227d3f3b0 EFLAGS: 00010202 RAX: 0000000000000001 RBX: ffff88823007a000 RCX: 0000000000000000 RDX: 0000000000000a03 RSI: 0000000000000040 RDI: ffff888230078178 RBP: 0000000000000000 R08: 000000000000002c R09: ffffed1075c7df8e R10: ffff8883ae3efc6b R11: ffffed1075c7df8d R12: 0000000000000000 R13: ffff88823869a2c8 R14: ffff8881012e0460 R15: dffffc0000000000 FS: 00007f350ac1f740(0000) GS:ffff8883ae200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f350a6ed6a0 CR3: 0000000237456000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ? ext4_xattr_set_entry+0x3b7/0x2320 ? ext4_xattr_block_set+0x0/0x2020 ? ext4_xattr_set_entry+0x0/0x2320 ? ext4_xattr_check_entries+0x77/0x310 ? ext4_xattr_ibody_set+0x23b/0x340 ext4_xattr_move_to_block+0x594/0x720 ext4_expand_extra_isize_ea+0x59a/0x10f0 __ext4_expand_extra_isize+0x278/0x3f0 __ext4_mark_inode_dirty.cold+0x347/0x410 ext4_rename+0xed3/0x174f vfs_rename+0x13a7/0x2510 do_renameat2+0x55d/0x920 __x64_sys_rename+0x7d/0xb0 do_syscall_64+0x3b/0xa0 entry_SYSCALL_64_after_hwframe+0x72/0xdc As 'ext4_rename' will modify 'old.inode' ctime and mark inode dirty, which may trigger expand 'extra_isize' and allocate block. If inode didn't init quota will lead to warning. To solve above issue, init 'old.inode' firstly in 'ext4_rename'.
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-908
134c704f-9b21-4f2e-91b3-4a467353bcc0
CWE-908

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