In the Linux kernel, the following vulnerability has been resolved: mm: avoid leaving partial pfn mappings around in error case As Jann points out, PFN mappings are special, because unlike normal memory mappings, there is no lifetime information associated with the mapping - it is just a raw mapping of PFNs with no reference counting of a 'struct page'. That's all very much intentional, but it does mean that it's easy to mess up the cleanup in case of errors. Yes, a failed mmap() will always eventually clean up any partial mappings, but without any explicit lifetime in the page table mapping itself, it's very easy to do the error handling in the wrong order. In particular, it's easy to mistakenly free the physical backing store before the page tables are actually cleaned up and (temporarily) have stale dangling PTE entries. To make this situation less error-prone, just make sure that any partial pfn mapping is torn down early, before any other error handling.
History

Fri, 08 Nov 2024 16:00:00 +0000


Wed, 23 Oct 2024 15:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-20

Mon, 21 Oct 2024 17:45:00 +0000

Type Values Removed Values Added
References

Fri, 18 Oct 2024 15:15:00 +0000

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Weaknesses CWE-459
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.11:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.11:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.11:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.11:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.11:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.11:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.11:rc7:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel

Thu, 17 Oct 2024 14:00:00 +0000


Wed, 16 Oct 2024 01:30:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Low


Tue, 15 Oct 2024 13:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 15 Oct 2024 11:00:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: mm: avoid leaving partial pfn mappings around in error case As Jann points out, PFN mappings are special, because unlike normal memory mappings, there is no lifetime information associated with the mapping - it is just a raw mapping of PFNs with no reference counting of a 'struct page'. That's all very much intentional, but it does mean that it's easy to mess up the cleanup in case of errors. Yes, a failed mmap() will always eventually clean up any partial mappings, but without any explicit lifetime in the page table mapping itself, it's very easy to do the error handling in the wrong order. In particular, it's easy to mistakenly free the physical backing store before the page tables are actually cleaned up and (temporarily) have stale dangling PTE entries. To make this situation less error-prone, just make sure that any partial pfn mapping is torn down early, before any other error handling.
Title mm: avoid leaving partial pfn mappings around in error case
References

cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2024-10-15T10:48:33.481Z

Updated: 2024-11-08T15:56:08.957Z

Reserved: 2024-09-30T16:00:12.937Z

Link: CVE-2024-47674

cve-icon Vulnrichment

Updated: 2024-10-15T12:44:18.597Z

cve-icon NVD

Status : Modified

Published: 2024-10-15T11:15:13.073

Modified: 2024-11-08T16:15:24.737

Link: CVE-2024-47674

cve-icon Redhat

Severity : Low

Publid Date: 2024-10-15T00:00:00Z

Links: CVE-2024-47674 - Bugzilla