CVE-2024-35798 Affecting kernel-kdump package, versions *
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-CENTOS6-KERNELKDUMP-6887059
- published18 May 2024
- disclosed17 May 2024
Introduced: 17 May 2024
CVE-2024-35798 (opens in a new tab)How to fix?
There is no fixed version for Centos:6 kernel-kdump.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-kdump package and not the kernel-kdump package as distributed by Centos.
See How to fix? for Centos:6 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix race in read_extent_buffer_pages()
There are reports from tree-checker that detects corrupted nodes, without any obvious pattern so possibly an overwrite in memory. After some debugging it turns out there's a race when reading an extent buffer the uptodate status can be missed.
To prevent concurrent reads for the same extent buffer, read_extent_buffer_pages() performs these checks:
/* (1) */ if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags)) return 0;
/* (2) */ if (test_and_set_bit(EXTENT_BUFFER_READING, &eb->bflags)) goto done;
At this point, it seems safe to start the actual read operation. Once that completes, end_bbio_meta_read() does
/* (3) */ set_extent_buffer_uptodate(eb);
/* (4) */ clear_bit(EXTENT_BUFFER_READING, &eb->bflags);
Normally, this is enough to ensure only one read happens, and all other callers wait for it to finish before returning. Unfortunately, there is a racey interleaving:
Thread A | Thread B | Thread C
---------+----------+---------
(1) | |
| (1) |
(2) | |
(3) | |
(4) | |
| (2) |
| | (1)
When this happens, thread B kicks of an unnecessary read. Worse, thread C will see UPTODATE set and return immediately, while the read from thread B is still in progress. This race could result in tree-checker errors like this as the extent buffer is concurrently modified:
BTRFS critical (device dm-0): corrupted node, root=256
block=8550954455682405139 owner mismatch, have 11858205567642294356
expect [256, 18446744073709551360]
Fix it by testing UPTODATE again after setting the READING bit, and if it's been set, skip the unnecessary read.
[ minor update of changelog ]
References
- https://access.redhat.com/security/cve/CVE-2024-35798
- https://git.kernel.org/stable/c/0427c8ef8bbb7f304de42ef51d69c960e165e052
- https://git.kernel.org/stable/c/2885d54af2c2e1d910e20d5c8045bae40e02fbc1
- https://git.kernel.org/stable/c/3a25878a3378adce5d846300c9570f15aa7f7a80
- https://git.kernel.org/stable/c/ef1e68236b9153c27cb7cf29ead0c532870d4215