In the Linux kernel, the following vulnerability has been resolved: ext4: avoid infinite loops caused by residual data On the mkdir/mknod path, when mapping logical blocks to physical blocks, if inserting a new extent into the extent tree fails (in this example, because the file system disabled the huge file feature when marking the inode as dirty), ext4_ext_map_blocks() only calls ext4_free_blocks() to reclaim the physical block without deleting the corresponding data in the extent tree. This causes subsequent mkdir operations to reference the previously reclaimed physical block number again, even though this physical block is already being used by the xattr block. Therefore, a situation arises where both the directory and xattr are using the same buffer head block in memory simultaneously. The above causes ext4_xattr_block_set() to enter an infinite loop about "inserted" and cannot release the inode lock, ultimately leading to the 143s blocking problem mentioned in [1]. If the metadata is corrupted, then trying to remove some extent space can do even more harm. Also in case EXT4_GET_BLOCKS_DELALLOC_RESERVE was passed, remove space wrongly update quota information. Jan Kara suggests distinguishing between two cases: 1) The error is ENOSPC or EDQUOT - in this case the filesystem is fully consistent and we must maintain its consistency including all the accounting. However these errors can happen only early before we've inserted the extent into the extent tree. So current code works correctly for this case. 2) Some other error - this means metadata is corrupted. We should strive to do as few modifications as possible to limit damage. So I'd just skip freeing of allocated blocks. [1] INFO: task syz.0.17:5995 blocked for more than 143 seconds. Call Trace: inode_lock_nested include/linux/fs.h:1073 [inline] __start_dirop fs/namei.c:2923 [inline] start_dirop fs/namei.c:2934 [inline]
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H
| Attack Vector | NETWORK |
|---|---|
| Attack Complexity | LOW |
| Privileges Required | NONE |
| User Interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality Impact | LOW |
| Integrity Impact | HIGH |
| Availability Impact | HIGH |
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Type: Secondary
Exploitability Score: 3.9
Impact Score: 5.5
| Source | Type | Description |
|---|---|---|
| [email protected] | Primary |
en
CWE-835
|
| Vendor | Product | Version | Update | Type |
|---|---|---|---|---|
| linux | linux_kernel | * | <built-in method update of dict object at 0x7d23a52f4640> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x7d2424651b40> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x7d236440c7c0> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x7d23be9e2900> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x7d23beb852c0> | Operating System |
| linux | linux_kernel | 2.6.22 | <built-in method update of dict object at 0x7d23beb87640> | Operating System |
| linux | linux_kernel | 2.6.22 | <built-in method update of dict object at 0x7d24246526c0> | Operating System |
| linux | linux_kernel | 2.6.22 | <built-in method update of dict object at 0x7d236440f140> | Operating System |
| linux | linux_kernel | 2.6.22 | <built-in method update of dict object at 0x7d2424652fc0> | Operating System |
| linux | linux_kernel | 2.6.22 | <built-in method update of dict object at 0x7d23beb86840> | Operating System |
| linux | linux_kernel | 7.0 | <built-in method update of dict object at 0x7d2424650440> | Operating System |
| linux | linux_kernel | 7.0 | <built-in method update of dict object at 0x7d23beb87a80> | Operating System |
| linux | linux_kernel | 7.0 | <built-in method update of dict object at 0x7d2424651400> | Operating System |
| linux | linux_kernel | 7.0 | <built-in method update of dict object at 0x7d23a52f7a00> | Operating System |
| linux | linux_kernel | 7.0 | <built-in method update of dict object at 0x7d2424652880> | Operating System |
| Vulnerable | CPE |
|---|---|
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:2.6.22:-:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:2.6.22:rc4:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:2.6.22:rc5:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:2.6.22:rc6:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:2.6.22:rc7:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:* |