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CVE-2022-50021

Updated on 18 Jun 2025

Severity

7.8 High severity

Details

CVSS score
7.8
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE ID
Links
NISTCIRCLRHELUbuntu

Overview

About vulnerability

In the Linux kernel, the following vulnerability has been resolved:

ext4: block range must be validated before use in ext4_mb_clear_bb()

Block range to free is validated in ext4_free_blocks() using ext4_inode_block_valid() and then it’s passed to ext4_mb_clear_bb(). However in some situations on bigalloc file system the range might be adjusted after the validation in ext4_free_blocks() which can lead to troubles on corrupted file systems such as one found by syzkaller that resulted in the following BUG

kernel BUG at fs/ext4/ext4.h:3319! PREEMPT SMP NOPTI CPU: 28 PID: 4243 Comm: repro Kdump: loaded Not tainted 5.19.0-rc6+ #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1.fc35 04/01/2014 RIP: 0010:ext4_free_blocks+0x95e/0xa90 Call Trace: <TASK> ? lock_timer_base+0x61/0x80 ? __es_remove_extent+0x5a/0x760 ? __mod_timer+0x256/0x380 ? ext4_ind_truncate_ensure_credits+0x90/0x220 ext4_clear_blocks+0x107/0x1b0 ext4_free_data+0x15b/0x170 ext4_ind_truncate+0x214/0x2c0 ? _raw_spin_unlock+0x15/0x30 ? ext4_discard_preallocations+0x15a/0x410 ? ext4_journal_check_start+0xe/0x90 ? __ext4_journal_start_sb+0x2f/0x110 ext4_truncate+0x1b5/0x460 ? __ext4_journal_start_sb+0x2f/0x110 ext4_evict_inode+0x2b4/0x6f0 evict+0xd0/0x1d0 ext4_enable_quotas+0x11f/0x1f0 ext4_orphan_cleanup+0x3de/0x430 ? proc_create_seq_private+0x43/0x50 ext4_fill_super+0x295f/0x3ae0 ? snprintf+0x39/0x40 ? sget_fc+0x19c/0x330 ? ext4_reconfigure+0x850/0x850 get_tree_bdev+0x16d/0x260 vfs_get_tree+0x25/0xb0 path_mount+0x431/0xa70 __x64_sys_mount+0xe2/0x120 do_syscall_64+0x5b/0x80 ? do_user_addr_fault+0x1e2/0x670 ? exc_page_fault+0x70/0x170 entry_SYSCALL_64_after_hwframe+0x46/0xb0 RIP: 0033:0x7fdf4e512ace

Fix it by making sure that the block range is properly validated before used every time it changes in ext4_free_blocks() or ext4_mb_clear_bb().

Details

Affected product:
AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , CentOS 6 ELS , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , CloudLinux 6 ELS , CloudLinux 7 ELS , Debian 10 ELS , Oracle Linux 6 ELS , Oracle Linux 7 ELS , RHEL 7 ELS , TuxCare 9.6 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
Affected packages:
kernel @ 5.10.0 (+18 more)

Fixes

KernelCare state

Live-patch status from KernelCare for each operating system.

Operating system Status Covered kernels
Amazon Linux 2 5.10 Will Not Fix —
CentOS 7 ELS Released
31 kernels
  • 3.10.0-1160.119.1.el7.tuxcare.els10
  • 3.10.0-1160.119.1.el7.tuxcare.els4
  • 3.10.0-1160.119.1.el7.tuxcare.els6
  • 3.10.0-1160.119.1.el7.tuxcare.els15
  • 3.10.0-1160.119.1.el7.tuxcare.els5
  • 3.10.0-1160.119.1.el7.tuxcare.els3
  • 3.10.0-1160.119.1.el7.tuxcare.els14
  • 3.10.0-1160.119.1.el7.tuxcare.els16
  • 3.10.0-1160.119.1.el7.tuxcare.els13
  • 3.10.0-1160.119.1.el7.tuxcare.els7
  • 3.10.0-1160.119.1.el7.tuxcare.els12
  • 3.10.0-1160.119.1.el7.tuxcare.els9
  • 3.10.0-1160.119.1.el7.tuxcare.els8
  • 3.10.0-1160.119.1.el7.tuxcare.els17
  • 3.10.0-1160.119.1.el7.tuxcare.els18
  • 3.10.0-1160.119.1.el7.tuxcare.els19
  • 3.10.0-1160.119.1.el7.tuxcare.els20
  • 3.10.0-1160.119.1.el7.tuxcare.els21
  • 3.10.0-1160.119.1.el7.tuxcare.els24
  • 3.10.0-1160.119.1.el7.tuxcare.els22
  • 3.10.0-1160.119.1.el7.tuxcare.els25
  • 3.10.0-1160.139.1.el7.tuxcare.els2
  • 3.10.0-1160.139.1.el7.tuxcare.els3
  • 3.10.0-1160.139.1.el7.tuxcare.els4
  • 3.10.0-1160.142.1.el7.tuxcare.els1
  • 3.10.0-1160.144.1.el7.tuxcare.els1
  • 3.10.0-1160.144.1.el7.tuxcare.els2
  • 3.10.0-1160.144.1.el7.tuxcare.els3
  • 3.10.0-1160.144.1.el7.tuxcare.els4
  • 3.10.0-1160.144.1.el7.tuxcare.els5
  • 3.10.0-1160.144.1.el7.tuxcare.els6
RHEL 9 Will Not Fix —
Ubuntu 22.04 Planned —