mm/secretmem: fix use-after-free race in fault handler
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 5.15.197, 6.1.159, 6.6.117, 6.12.59, 6.17.9
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: total
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/secretmem: fix use-after-free race in fault handler When a page fault occurs in a secret memory file created with `memfd_secret(2)`, the kernel will allocate a new folio for it, mark the underlying page as not-present in the direct map, and add it to the file mapping. If two tasks cause a fault in the same page concurrently, both could end up allocating a folio and removing the page from the direct map, but only one would succeed in adding the folio to the file mapping. The task that failed undoes the effects of its attempt by (a) freeing the folio again and (b) putting the page back into the direct map. However, by doing these two operations in this order, the page becomes available to the allocator again before it is placed back in the direct mapping. If another task attempts to allocate the page between (a) and (b), and the kernel tries to access it via the direct map, it would result in a supervisor not-present page fault. Fix the ordering to restore the direct map before the folio is freed.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: total
- Record last updated
Affected versions
- Linux Linux
From 1507f51255c9ff07d75909a84e7c0d7f3c4b2f49 · fixed in bb1c19636aedae39360e6fdbcaef4f2bcff25785; From 1507f51255c9ff07d75909a84e7c0d7f3c4b2f49 · fixed in 1e4643d6628edf9c0047b1f8f5bc574665025acb; From 1507f51255c9ff07d75909a84e7c0d7f3c4b2f49 · fixed in 42d486d35a4143cc37fc72ee66edc99d942dd367; From 1507f51255c9ff07d75909a84e7c0d7f3c4b2f49 · fixed in 52f2d5cf33de9a8f5e72bbb0ed38282ae0bc4649; From 1507f51255c9ff07d75909a84e7c0d7f3c4b2f49 · fixed in 4444767e625da46009fc94a453fd1967b80ba047; From 1507f51255c9ff07d75909a84e7c0d7f3c4b2f49 · fixed in 6f86d0534fddfbd08687fa0f01479d4226bc3c3d
- Linux Linux
5.14
- KernelLinux
From 5.14.0 · fixed in 5.15.197; From 5.16.0 · fixed in 6.1.159; From 6.2.0 · fixed in 6.6.117; From 6.7.0 · fixed in 6.12.59; From 6.13.0 · fixed in 6.17.9