CVE-2022-49347
Estado: AnalizadaMedia (5.5)—
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix bug_on in ext4_writepages
The root cause of this issue is we destory inline data until call ext4_writepages under delay allocation mode. But there maybe already convert from inline to extent. To solve this issue, we call filemap_flush first..
Detalles técnicos trazas, registros y código del informe original
we got issue as follows:
EXT4-fs error (device loop0): ext4_mb_generate_buddy:1141: group 0, block bitmap and bg descriptor inconsistent: 25 vs 31513 free cls
------------[ cut here ]------------
kernel BUG at fs/ext4/inode.c:2708!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 2 PID: 2147 Comm: rep Not tainted 5.18.0-rc2-next-20220413+ #155
RIP: 0010:ext4_writepages+0x1977/0x1c10
RSP: 0018:ffff88811d3e7880 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff88811c098000
RDX: 0000000000000000 RSI: ffff88811c098000 RDI: 0000000000000002
RBP: ffff888128140f50 R08: ffffffffb1ff6387 R09: 0000000000000000
R10: 0000000000000007 R11: ffffed10250281ea R12: 0000000000000001
R13: 00000000000000a4 R14: ffff88811d3e7bb8 R15: ffff888128141028
FS: 00007f443aed9740(0000) GS:ffff8883aef00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020007200 CR3: 000000011c2a4000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
do_writepages+0x130/0x3a0
filemap_fdatawrite_wbc+0x83/0xa0
filemap_flush+0xab/0xe0
ext4_alloc_da_blocks+0x51/0x120
__ext4_ioctl+0x1534/0x3210
__x64_sys_ioctl+0x12c/0x170
do_syscall_64+0x3b/0x90
It may happen as follows:
1. write inline_data inode
vfs_write
new_sync_write
ext4_file_write_iter
ext4_buffered_write_iter
generic_perform_write
ext4_da_write_begin
ext4_da_write_inline_data_begin -> If inline data size too
small will allocate block to write, then mapping will has
dirty page
ext4_da_convert_inline_data_to_extent ->clear EXT4_STATE_MAY_INLINE_DATA
2. fallocate
do_vfs_ioctl
ioctl_preallocate
vfs_fallocate
ext4_fallocate
ext4_convert_inline_data
ext4_convert_inline_data_nolock
ext4_map_blocks -> fail will goto restore data
ext4_restore_inline_data
ext4_create_inline_data
ext4_write_inline_data
ext4_set_inode_state -> set inode EXT4_STATE_MAY_INLINE_DATA
3. writepages
__ext4_ioctl
ext4_alloc_da_blocks
filemap_flush
filemap_fdatawrite_wbc
do_writepages
ext4_writepages
if (ext4_has_inline_data(inode))
BUG_ON(ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA))CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Puntuación base: 5.5
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.29%
- Percentil entre todas las CVEs puntuadas: 20
- Fecha de la puntuación: 5/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
CWE
- CWE-617
Referencias
- https://git.kernel.org/stable/c/013f12bdedb96816aaa27ee04349f4433d361f52
- https://git.kernel.org/stable/c/18a759f7f99f0b65a08ff5b7e745fc405a42bde4
- https://git.kernel.org/stable/c/19918ec7717d87d5ab825884a46b26b21375d7ce
- https://git.kernel.org/stable/c/1b061af037646c9cdb0afd8a8d2f1e1c06285866
- https://git.kernel.org/stable/c/1cde35417edc0370fb0179a4e38b78a15350a8d0
- https://git.kernel.org/stable/c/73fd5b19285197078ee8a2e651d75d5b094a4de9
- https://git.kernel.org/stable/c/b2b78f5bf2d453dda3903955efee059260787a42
- https://git.kernel.org/stable/c/de1732b5c1693ad489c5d254f124f67cb775f37d
- https://git.kernel.org/stable/c/ef09ed5d37b84d18562b30cf7253e57062d0db05
JSON original (NVD)
Mostrar
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"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"integrityImpact": "NONE",
"userInteraction": "NONE",
"attackComplexity": "LOW",
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"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix bug_on in ext4_writepages\n\nwe got issue as follows:\nEXT4-fs error (device loop0): ext4_mb_generate_buddy:1141: group 0, block bitmap and bg descriptor inconsistent: 25 vs 31513 free cls\n------------[ cut here ]------------\nkernel BUG at fs/ext4/inode.c:2708!\ninvalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI\nCPU: 2 PID: 2147 Comm: rep Not tainted 5.18.0-rc2-next-20220413+ #155\nRIP: 0010:ext4_writepages+0x1977/0x1c10\nRSP: 0018:ffff88811d3e7880 EFLAGS: 00010246\nRAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff88811c098000\nRDX: 0000000000000000 RSI: ffff88811c098000 RDI: 0000000000000002\nRBP: ffff888128140f50 R08: ffffffffb1ff6387 R09: 0000000000000000\nR10: 0000000000000007 R11: ffffed10250281ea R12: 0000000000000001\nR13: 00000000000000a4 R14: ffff88811d3e7bb8 R15: ffff888128141028\nFS: 00007f443aed9740(0000) GS:ffff8883aef00000(0000) knlGS:0000000000000000\nCS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 0000000020007200 CR3: 000000011c2a4000 CR4: 00000000000006e0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\nCall Trace:\n <TASK>\n do_writepages+0x130/0x3a0\n filemap_fdatawrite_wbc+0x83/0xa0\n filemap_flush+0xab/0xe0\n ext4_alloc_da_blocks+0x51/0x120\n __ext4_ioctl+0x1534/0x3210\n __x64_sys_ioctl+0x12c/0x170\n do_syscall_64+0x3b/0x90\n\nIt may happen as follows:\n1. write inline_data inode\nvfs_write\n new_sync_write\n ext4_file_write_iter\n ext4_buffered_write_iter\n generic_perform_write\n ext4_da_write_begin\n ext4_da_write_inline_data_begin -> If inline data size too\n small will allocate block to write, then mapping will has\n dirty page\n ext4_da_convert_inline_data_to_extent ->clear EXT4_STATE_MAY_INLINE_DATA\n2. fallocate\ndo_vfs_ioctl\n ioctl_preallocate\n vfs_fallocate\n ext4_fallocate\n ext4_convert_inline_data\n ext4_convert_inline_data_nolock\n ext4_map_blocks -> fail will goto restore data\n ext4_restore_inline_data\n ext4_create_inline_data\n ext4_write_inline_data\n ext4_set_inode_state -> set inode EXT4_STATE_MAY_INLINE_DATA\n3. writepages\n__ext4_ioctl\n ext4_alloc_da_blocks\n filemap_flush\n filemap_fdatawrite_wbc\n do_writepages\n ext4_writepages\n if (ext4_has_inline_data(inode))\n BUG_ON(ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA))\n\nThe root cause of this issue is we destory inline data until call\next4_writepages under delay allocation mode. But there maybe already\nconvert from inline to extent. To solve this issue, we call\nfilemap_flush first.."
},
{
"lang": "es",
"value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ext4: corrección de bug_on en ext4_writepages. Tenemos el siguiente problema: Error EXT4-fs (dispositivo loop0): ext4_mb_generate_buddy:1141: grupo 0, mapa de bits de bloque y descriptor de fondo inconsistentes: 25 frente a 31513 cls libres ------------[ corte aquí ]------------ ¡ERROR del kernel en fs/ext4/inode.c:2708! código de operación no válido: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 2 PID: 2147 Comm: rep No contaminado 5.18.0-rc2-next-20220413+ #155 RIP: 0010:ext4_writepages+0x1977/0x1c10 RSP: 0018:ffff88811d3e7880 EFLAGS: 00010246 RAX: 000000000000000 RBX: 0000000000000001 RCX: ffff88811c098000 RDX: 0000000000000000 RSI: ffff88811c098000 RDI: 00000000000000002 RBP: ffff888128140f50 R08: ffffffffb1ff6387 R09: 0000000000000000 R10: 0000000000000007 R11: ffffed10250281ea R12: 000000000000001 R13: 00000000000000a4 R14: ffff88811d3e7bb8 R15: ffff888128141028 FS: 00007f443aed9740(0000) GS:ffff8883aef00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020007200 CR3: 000000011c2a4000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Seguimiento de llamadas: do_writepages+0x130/0x3a0 filemap_fdatawrite_wbc+0x83/0xa0 filemap_flush+0xab/0xe0 ext4_alloc_da_blocks+0x51/0x120 __ext4_ioctl+0x1534/0x3210 __x64_sys_ioctl+0x12c/0x170 do_syscall_64+0x3b/0x90 Puede suceder de la siguiente manera: 1. escribir inline_data inodo vfs_write new_sync_write ext4_file_write_iter ext4_buffered_write_iter generic_perform_write ext4_da_write_begin ext4_da_write_inline_data_begin -> Si el tamaño de los datos en línea es demasiado pequeño, se asignará un bloque para escribir, luego la asignación tendrá una página sucia ext4_da_convert_inline_data_to_extent -> borrar EXT4_STATE_MAY_INLINE_DATA 2. fallocate do_vfs_ioctl ioctl_preallocate vfs_fallocate ext4_fallocate ext4_convert_inline_data ext4_convert_inline_data_nolock ext4_map_blocks -> falla irá a restaurar datos ext4_restore_inline_data ext4_crear_inline_data ext4_write_inline_data ext4_set_inode_state -> establecer inodo EXT4_STATE_MAY_INLINE_DATA 3. writepages __ext4_ioctl ext4_alloc_da_blocks filemap_flush filemap_fdatawrite_wbc do_writepages ext4_writepages si (ext4_has_inline_data(inodo)) BUG_ON(ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) La causa principal de este problema es que destruimos los datos en línea hasta que llamamos a ext4_writepages en el modo de asignación de demora. Pero es posible que ya hayamos convertido de en línea a extendido. Para resolver este problema, primero llamamos a filemap_flush."
}
],
"lastModified": "2026-06-17T05:17:47.110",
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