CVE-2024-50250
- Source
- https://cve.org/CVERecord?id=CVE-2024-50250
- Import Source
- https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2024-50250.json
- JSON Data
- https://api.test.osv.dev/v1/vulns/CVE-2024-50250
- Downstream
- Related
- Published
- 2024-11-09T10:14:59Z
- Modified
- 2026-05-18T05:57:57Z
- Severity
-
- 7.1 (High) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N CVSS Calculator
- Summary
- fsdax: dax_unshare_iter needs to copy entire blocks
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
fsdax: dax_unshare_iter needs to copy entire blocks
The code that copies data from srcmap to iomap in dax_unshare_iter is very very broken, which bfoster's recent fsx changes have exposed.
If the pos and len passed to dax_file_unshare are not aligned to an fsblock boundary, the iter pos and length in the _iter function will reflect this unalignment.
dax_iomap_direct_access always returns a pointer to the start of the kmapped fsdax page, even if its pos argument is in the middle of that page. This is catastrophic for data integrity when iter->pos is not aligned to a page, because daddr/saddr do not point to the same byte in the file as iter->pos. Hence we corrupt user data by copying it to the wrong place.
If iter->pos + iomap_length() in the _iter function not aligned to a page, then we fail to copy a full block, and only partially populate the destination block. This is catastrophic for data confidentiality because we expose stale pmem contents.
Fix both of these issues by aligning copy_pos/copy_len to a page boundary (remember, this is fsdax so 1 fsblock == 1 base page) so that we always copy full blocks.
We're not done yet -- there's no call to invalidate_inode_pages2_range, so programs that have the file range mmap'd will continue accessing the old memory mapping after the file metadata updates have completed.
Be careful with the return value -- if the unshare succeeds, we still need to return the number of bytes that the iomap iter thinks we're operating on.
- Database specific
{ "cna_assigner": "Linux", "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/50xxx/CVE-2024-50250.json" }- References
-
- https://git.kernel.org/stable/c/50793801fc7f6d08def48754fb0f0706b0cfc394
- https://git.kernel.org/stable/c/8e9c0f500b42216ef930f5c0d1703989a451913d
- https://git.kernel.org/stable/c/9bc18bb476e50e32e5d08f2734d63d63e0fa528c
- https://git.kernel.org/stable/c/bdbc96c23197d773a7d1bf03e4f11de593b0ff28
- https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/50xxx/CVE-2024-50250.json
- https://nvd.nist.gov/vuln/detail/CVE-2024-50250
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected packages
Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected ranges
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced1bec6782a25c9b92c203ea7a1b3e3dc6a468cbc4Fixedbdbc96c23197d773a7d1bf03e4f11de593b0ff28
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introducedd984648e428bf88cbd94ebe346c73632cb92fffbFixed9bc18bb476e50e32e5d08f2734d63d63e0fa528cFixed8e9c0f500b42216ef930f5c0d1703989a451913dFixed50793801fc7f6d08def48754fb0f0706b0cfc394