CVE-2024-50250

Advisory lineage Upstream: 0 Downstream: 40
Modified
Published: 09 Nov 2024, 10:14
Last modified:23 May 2026, 15:54

Vulnerability Summary

Overall Risk (default)
medium
28/100
CVSS Score
7.1 HIGH
v3.1 (cve.org)
EPSS Score
0.02% LOW
0% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

09 Nov 2024, 10:14
Published
Vulnerability first disclosed
23 May 2026, 15:54
Last Modified
Vulnerability information updated

Description

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.

CVSS Metrics

  • v3.1•HIGH•Score: 7.1CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

EPSS Trends

Current EPSS score: 0.02%• Percentile: 6%

Affected Systems

  • linux•linux

    ≥ 1bec6782a25c9b92c203ea7a1b3e3dc6a468cbc4, < bdbc96c23197d773a7d1bf03e4f11de593b0ff28 | ≥ d984648e428bf88cbd94ebe346c73632cb92fffb, < 9bc18bb476e50e32e5d08f2734d63d63e0fa528c | ≥ d984648e428bf88cbd94ebe346c73632cb92fffb, < 8e9c0f500b42216ef930f5c0d1703989a451913d | ≥ d984648e428bf88cbd94ebe346c73632cb92fffb, < 50793801fc7f6d08def48754fb0f0706b0cfc394 | ≥ 6.1.113, < 6.1.116 | 6.2

  • linux•linux_kernel

    ≥ 6.1.113, < 6.1.116 | ≥ 6.2, < 6.6.60 | ≥ 6.7, < 6.11.7 | 6.12:rc1 | 6.12:rc2 | 6.12:rc3 | 6.12:rc4 | 6.12:rc5

References (5)