vulnerability
Amazon Linux AMI 2: CVE-2021-47117: Security patch for kernel (Multiple Advisories)
| Severity | CVSS | Published | Added | Modified |
|---|---|---|---|---|
| 5 | (AV:L/AC:L/Au:S/C:N/I:N/A:C) | Mar 15, 2024 | Aug 2, 2024 | May 20, 2026 |
Description
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix bug on in ext4_es_cache_extent as ext4_split_extent_at failed
We got follow bug_on when run fsstress with injecting IO fault:
[130747.323114] kernel BUG at fs/ext4/extents_status.c:762!
[130747.323117] Internal error: Oops - BUG: 0 [#1] SMP
......
[130747.334329] Call trace:
[130747.334553] ext4_es_cache_extent+0x150/0x168 [ext4]
[130747.334975] ext4_cache_extents+0x64/0xe8 [ext4]
[130747.335368] ext4_find_extent+0x300/0x330 [ext4]
[130747.335759] ext4_ext_map_blocks+0x74/0x1178 [ext4]
[130747.336179] ext4_map_blocks+0x2f4/0x5f0 [ext4]
[130747.336567] ext4_mpage_readpages+0x4a8/0x7a8 [ext4]
[130747.336995] ext4_readpage+0x54/0x100 [ext4]
[130747.337359] generic_file_buffered_read+0x410/0xae8
[130747.337767] generic_file_read_iter+0x114/0x190
[130747.338152] ext4_file_read_iter+0x5c/0x140 [ext4]
[130747.338556] __vfs_read+0x11c/0x188
[130747.338851] vfs_read+0x94/0x150
[130747.339110] ksys_read+0x74/0xf0
This patch's modification is according to Jan Kara's suggestion in:
https://patchwork.ozlabs.org/project/linux-ext4/patch/[email protected]/
"I see. Now I understand your patch. Honestly, seeing how fragile is trying
to fix extent tree after split has failed in the middle, I would probably
go even further and make sure we fix the tree properly in case of ENOSPC
and EDQUOT (those are easily user triggerable). Anything else indicates a
HW problem or fs corruption so I'd rather leave the extent tree as is and
don't try to fix it (which also means we will not create overlapping
extents)."
Solutions
References
- AMAZON-AL2/ALAS-2021-1685
- AMAZON-AL2/ALAS2KERNEL-5.10-2022-002
- AMAZON-AL2/ALAS2KERNEL-5.4-2022-004
- AMAZON-AL2/ALASKERNEL-5.10-2022-002
- AMAZON-AL2/ALASKERNEL-5.4-2022-004
- CVE-2021-47117
- https://attackerkb.com/topics/CVE-2021-47117
- EUVD-EUVD-2021-33765
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-33765
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