CVE-2022-50336

Published Sep 15, 2025

Last updated 2 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: Add null pointer check to attr_load_runs_vcn Some metadata files are handled before MFT. This adds a null pointer check for some corner cases that could lead to NPD while reading these metadata files for a malformed NTFS image. [ 240.190827] BUG: kernel NULL pointer dereference, address: 0000000000000158 [ 240.191583] #PF: supervisor read access in kernel mode [ 240.191956] #PF: error_code(0x0000) - not-present page [ 240.192391] PGD 0 P4D 0 [ 240.192897] Oops: 0000 [#1] PREEMPT SMP KASAN NOPTI [ 240.193805] CPU: 0 PID: 242 Comm: mount Tainted: G B 5.19.0+ #17 [ 240.194477] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 [ 240.195152] RIP: 0010:ni_find_attr+0xae/0x300 [ 240.195679] Code: c8 48 c7 45 88 c0 4e 5e 86 c7 00 f1 f1 f1 f1 c7 40 04 00 f3 f3 f3 65 48 8b 04 25 28 00 00 00 48 89 45 d0 31 c0 e8 e2 d9f [ 240.196642] RSP: 0018:ffff88800812f690 EFLAGS: 00000286 [ 240.197019] RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff85ef037a [ 240.197523] RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff88e95f60 [ 240.197877] RBP: ffff88800812f738 R08: 0000000000000001 R09: fffffbfff11d2bed [ 240.198292] R10: ffffffff88e95f67 R11: fffffbfff11d2bec R12: 0000000000000000 [ 240.198647] R13: 0000000000000080 R14: 0000000000000000 R15: 0000000000000000 [ 240.199410] FS: 00007f233c33be40(0000) GS:ffff888058200000(0000) knlGS:0000000000000000 [ 240.199895] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 240.200314] CR2: 0000000000000158 CR3: 0000000004d32000 CR4: 00000000000006f0 [ 240.200839] Call Trace: [ 240.201104] <TASK> [ 240.201502] ? ni_load_mi+0x80/0x80 [ 240.202297] ? ___slab_alloc+0x465/0x830 [ 240.202614] attr_load_runs_vcn+0x8c/0x1a0 [ 240.202886] ? __kasan_slab_alloc+0x32/0x90 [ 240.203157] ? attr_data_write_resident+0x250/0x250 [ 240.203543] mi_read+0x133/0x2c0 [ 240.203785] mi_get+0x70/0x140 [ 240.204012] ni_load_mi_ex+0xfa/0x190 [ 240.204346] ? ni_std5+0x90/0x90 [ 240.204588] ? __kasan_kmalloc+0x88/0xb0 [ 240.204859] ni_enum_attr_ex+0xf1/0x1c0 [ 240.205107] ? ni_fname_type.part.0+0xd0/0xd0 [ 240.205600] ? ntfs_load_attr_list+0xbe/0x300 [ 240.205864] ? ntfs_cmp_names_cpu+0x125/0x180 [ 240.206157] ntfs_iget5+0x56c/0x1870 [ 240.206510] ? ntfs_get_block_bmap+0x70/0x70 [ 240.206776] ? __kasan_kmalloc+0x88/0xb0 [ 240.207030] ? set_blocksize+0x95/0x150 [ 240.207545] ntfs_fill_super+0xb8f/0x1e20 [ 240.207839] ? put_ntfs+0x1d0/0x1d0 [ 240.208069] ? vsprintf+0x20/0x20 [ 240.208467] ? mutex_unlock+0x81/0xd0 [ 240.208846] ? set_blocksize+0x95/0x150 [ 240.209221] get_tree_bdev+0x232/0x370 [ 240.209804] ? put_ntfs+0x1d0/0x1d0 [ 240.210519] ntfs_fs_get_tree+0x15/0x20 [ 240.210991] vfs_get_tree+0x4c/0x130 [ 240.211455] path_mount+0x645/0xfd0 [ 240.211806] ? putname+0x80/0xa0 [ 240.212112] ? finish_automount+0x2e0/0x2e0 [ 240.212559] ? kmem_cache_free+0x110/0x390 [ 240.212906] ? putname+0x80/0xa0 [ 240.213329] do_mount+0xd6/0xf0 [ 240.213829] ? path_mount+0xfd0/0xfd0 [ 240.214246] ? __kasan_check_write+0x14/0x20 [ 240.214774] __x64_sys_mount+0xca/0x110 [ 240.215080] do_syscall_64+0x3b/0x90 [ 240.215442] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 240.215811] RIP: 0033:0x7f233b4e948a [ 240.216104] Code: 48 8b 0d 11 fa 2a 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 008 [ 240.217615] RSP: 002b:00007fff02211ec8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5 [ 240.218718] RAX: ffffffffffffffda RBX: 0000561cdc35b060 RCX: 00007f233b4e948a [ 240.219556] RDX: 0000561cdc35b260 RSI: 0000561cdc35b2e0 RDI: 0000561cdc363af0 [ 240.219975] RBP: 0000000000000000 R08: 0000561cdc35b280 R09: 0000000000000020 [ 240.220403] R10: 00000000c0ed0000 R11: 0000000000000202 R12: 0000561cdc363af0 [ 240.220803] R13: 000 ---truncated---
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
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-476

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