CVE-2022-49170

f2fs: fix to do sanity check on curseg->alloc_type

Published Feb 26, 2025 CVSS 3.1 · 7.8 High EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

f2fs: fix to do sanity check on curseg->alloc_type

As Wenqing Liu reported in bugzilla:

https://bugzilla.kernel.org/show_bug.cgi?id=215657

- Overview
UBSAN: array-index-out-of-bounds in fs/f2fs/segment.c:3460:2 when mount and operate a corrupted image

- Reproduce
tested on kernel 5.17-rc4, 5.17-rc6

1. mkdir test_crash
2. cd test_crash
3. unzip tmp2.zip
4. mkdir mnt
5. ./single_test.sh f2fs 2

- Kernel dump
[ 46.434454] loop0: detected capacity change from 0 to 131072
[ 46.529839] F2FS-fs (loop0): Mounted with checkpoint version = 7548c2d9
[ 46.738319] ================================================================================
[ 46.738412] UBSAN: array-index-out-of-bounds in fs/f2fs/segment.c:3460:2
[ 46.738475] index 231 is out of range for type 'unsigned int [2]'
[ 46.738539] CPU: 2 PID: 939 Comm: umount Not tainted 5.17.0-rc6 #1
[ 46.738547] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014
[ 46.738551] Call Trace:
[ 46.738556] <TASK>
[ 46.738563] dump_stack_lvl+0x47/0x5c
[ 46.738581] ubsan_epilogue+0x5/0x50
[ 46.738592] __ubsan_handle_out_of_bounds+0x68/0x80
[ 46.738604] f2fs_allocate_data_block+0xdff/0xe60 [f2fs]
[ 46.738819] do_write_page+0xef/0x210 [f2fs]
[ 46.738934] f2fs_do_write_node_page+0x3f/0x80 [f2fs]
[ 46.739038] __write_node_page+0x2b7/0x920 [f2fs]
[ 46.739162] f2fs_sync_node_pages+0x943/0xb00 [f2fs]
[ 46.739293] f2fs_write_checkpoint+0x7bb/0x1030 [f2fs]
[ 46.739405] kill_f2fs_super+0x125/0x150 [f2fs]
[ 46.739507] deactivate_locked_super+0x60/0xc0
[ 46.739517] deactivate_super+0x70/0xb0
[ 46.739524] cleanup_mnt+0x11a/0x200
[ 46.739532] __cleanup_mnt+0x16/0x20
[ 46.739538] task_work_run+0x67/0xa0
[ 46.739547] exit_to_user_mode_prepare+0x18c/0x1a0
[ 46.739559] syscall_exit_to_user_mode+0x26/0x40
[ 46.739568] do_syscall_64+0x46/0xb0
[ 46.739584] entry_SYSCALL_64_after_hwframe+0x44/0xae

The root cause is we missed to do sanity check on curseg->alloc_type,
result in out-of-bound accessing on sbi->block_count[] array, fix it.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2022-55055 In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to do sanity check on curseg->alloc_type As Wenqing Liu reported in bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215657 - Overview UBSAN: array-index-out-of-bounds in fs/f2fs/segment.c:3460:2 when mount and operate a corrupted image - Reproduce tested on kernel 5.17-rc4, 5.17-rc6 1. mkdir test_crash 2. cd test_crash 3. unzip tmp2.zip 4. mkdir mnt 5. ./single_test.sh f2fs 2 - Kernel dump [ 46.434454] loop0: detected capacity change from 0 to 131072 [ 46.529839] F2FS-fs (loop0): Mounted with checkpoint version = 7548c2d9 [ 46.738319] ================================================================================ [ 46.738412] UBSAN: array-index-out-of-bounds in fs/f2fs/segment.c:3460:2 [ 46.738475] index 231 is out of range for type 'unsigned int [2]' [ 46.738539] CPU: 2 PID: 939 Comm: umount Not tainted 5.17.0-rc6 #1 [ 46.738547] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014 [ 46.738551] Call Trace: [ 46.738556] <TASK> [ 46.738563] dump_stack_lvl+0x47/0x5c [ 46.738581] ubsan_epilogue+0x5/0x50 [ 46.738592] __ubsan_handle_out_of_bounds+0x68/0x80 [ 46.738604] f2fs_allocate_data_block+0xdff/0xe60 [f2fs] [ 46.738819] do_write_page+0xef/0x210 [f2fs] [ 46.738934] f2fs_do_write_node_page+0x3f/0x80 [f2fs] [ 46.739038] __write_node_page+0x2b7/0x920 [f2fs] [ 46.739162] f2fs_sync_node_pages+0x943/0xb00 [f2fs] [ 46.739293] f2fs_write_checkpoint+0x7bb/0x1030 [f2fs] [ 46.739405] kill_f2fs_super+0x125/0x150 [f2fs] [ 46.739507] deactivate_locked_super+0x60/0xc0 [ 46.739517] deactivate_super+0x70/0xb0 [ 46.739524] cleanup_mnt+0x11a/0x200 [ 46.739532] __cleanup_mnt+0x16/0x20 [ 46.739538] task_work_run+0x67/0xa0 [ 46.739547] exit_to_user_mode_prepare+0x18c/0x1a0 [ 46.739559] syscall_exit_to_user_mode+0x26/0x40 [ 46.739568] do_syscall_64+0x46/0xb0 [ 46.739584] entry_SYSCALL_64_after_hwframe+0x44/0xae The root cause is we missed to do sanity check on curseg->alloc_type, result in out-of-bound accessing on sbi->block_count[] array, fix it.
Ubuntu USN Ubuntu USN USN-8919-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8920-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9032-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9033-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9034-1 Linux kernel (AWS) vulnerabilities
History
Type Values Removed Values Added
Weaknesses CWE-129
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Metrics cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to do sanity check on curseg->alloc_type As Wenqing Liu reported in bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215657 - Overview UBSAN: array-index-out-of-bounds in fs/f2fs/segment.c:3460:2 when mount and operate a corrupted image - Reproduce tested on kernel 5.17-rc4, 5.17-rc6 1. mkdir test_crash 2. cd test_crash 3. unzip tmp2.zip 4. mkdir mnt 5. ./single_test.sh f2fs 2 - Kernel dump [ 46.434454] loop0: detected capacity change from 0 to 131072 [ 46.529839] F2FS-fs (loop0): Mounted with checkpoint version = 7548c2d9 [ 46.738319] ================================================================================ [ 46.738412] UBSAN: array-index-out-of-bounds in fs/f2fs/segment.c:3460:2 [ 46.738475] index 231 is out of range for type 'unsigned int [2]' [ 46.738539] CPU: 2 PID: 939 Comm: umount Not tainted 5.17.0-rc6 #1 [ 46.738547] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014 [ 46.738551] Call Trace: [ 46.738556] <TASK> [ 46.738563] dump_stack_lvl+0x47/0x5c [ 46.738581] ubsan_epilogue+0x5/0x50 [ 46.738592] __ubsan_handle_out_of_bounds+0x68/0x80 [ 46.738604] f2fs_allocate_data_block+0xdff/0xe60 [f2fs] [ 46.738819] do_write_page+0xef/0x210 [f2fs] [ 46.738934] f2fs_do_write_node_page+0x3f/0x80 [f2fs] [ 46.739038] __write_node_page+0x2b7/0x920 [f2fs] [ 46.739162] f2fs_sync_node_pages+0x943/0xb00 [f2fs] [ 46.739293] f2fs_write_checkpoint+0x7bb/0x1030 [f2fs] [ 46.739405] kill_f2fs_super+0x125/0x150 [f2fs] [ 46.739507] deactivate_locked_super+0x60/0xc0 [ 46.739517] deactivate_super+0x70/0xb0 [ 46.739524] cleanup_mnt+0x11a/0x200 [ 46.739532] __cleanup_mnt+0x16/0x20 [ 46.739538] task_work_run+0x67/0xa0 [ 46.739547] exit_to_user_mode_prepare+0x18c/0x1a0 [ 46.739559] syscall_exit_to_user_mode+0x26/0x40 [ 46.739568] do_syscall_64+0x46/0xb0 [ 46.739584] entry_SYSCALL_64_after_hwframe+0x44/0xae The root cause is we missed to do sanity check on curseg->alloc_type, result in out-of-bound accessing on sbi->block_count[] array, fix it.
Title f2fs: fix to do sanity check on curseg->alloc_type
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Aug 12, 2026, 11:58 PM
Reserved
Feb 26, 2025, 1:49 AM
Status
Modified
Published
Feb 26, 2025, 7:00 AM
Modified
Aug 13, 2026, 12:17 AM
Severity
Moderate
Public date
Feb 26, 2025, 12:00 AM