UBUNTU-CVE-2024-35872
In the Linux kernel, the following vulnerability has been resolved: mm/secretmem: fix GUP-fast succeeding on secretmem folios folio_is_secretmem() currently relies on secretmem folios being LRU folios, to save some cycles. However, folios might reside in a folio batch without the LRU flag set, or temporarily have their LRU flag cleared. Consequently, the LRU flag is unreliable for this purpose. In particular, this is the case when secretmem_fault() allocates a fresh page and calls filemap_add_folio()->folio_add_lru(). The folio might be added to the per-cpu folio batch and won't get the LRU flag set until the batch was drained using e.g., lru_add_drain(). Consequently, folio_is_secretmem() might not detect secretmem folios and GUP-fast can succeed in grabbing a secretmem folio, crashing the kernel when we would later try reading/writing to the folio, because the folio has been unmapped from the directmap. Fix it by removing that unreliable check.
02 / AFFECTED SOFTWARE
Affected packages
12 explicit affected versions
27 explicit affected versions
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31 explicit affected versions
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40 explicit affected versions
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46 explicit affected versions
1 explicit affected versions
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34 explicit affected versions
6 explicit affected versions
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38 explicit affected versions
12 explicit affected versions
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2 explicit affected versions
37 explicit affected versions
13 explicit affected versions
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26 explicit affected versions
13 explicit affected versions
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13 explicit affected versions
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11 explicit affected versions
33 explicit affected versions
23 explicit affected versions
10 explicit affected versions
11 explicit affected versions
12 explicit affected versions
7 explicit affected versions
12 explicit affected versions
39 explicit affected versions
32 explicit affected versions
48 explicit affected versions
26 explicit affected versions
8 explicit affected versions
1 explicit affected versions
8 explicit affected versions
13 explicit affected versions
7 explicit affected versions
16 explicit affected versions
51 explicit affected versions
8 explicit affected versions
40 explicit affected versions
3 explicit affected versions
2 explicit affected versions
51 explicit affected versions
5 explicit affected versions
10 explicit affected versions
12 explicit affected versions
37 explicit affected versions
27 explicit affected versions
23 explicit affected versions
1 explicit affected versions
12 explicit affected versions
5 explicit affected versions
2 explicit affected versions
8 explicit affected versions
10 explicit affected versions
4 explicit affected versions
13 explicit affected versions
13 explicit affected versions
7 explicit affected versions
43 explicit affected versions
26 explicit affected versions
12 explicit affected versions
44 explicit affected versions
16 explicit affected versions
3 explicit affected versions
13 explicit affected versions
37 explicit affected versions
37 explicit affected versions
8 explicit affected versions
14 explicit affected versions
38 explicit affected versions
40 explicit affected versions
9 explicit affected versions
40 explicit affected versions
11 explicit affected versions
48 explicit affected versions
7 explicit affected versions
13 explicit affected versions
21 explicit affected versions
4 explicit affected versions
1 explicit affected versions
1 explicit affected versions
46 explicit affected versions
43 explicit affected versions
10 explicit affected versions
8 explicit affected versions
3 explicit affected versions
14 explicit affected versions
4 explicit affected versions
11 explicit affected versions
1 explicit affected versions
2 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: mm/secretmem: fix GUP-fast succeeding on secretmem folios folio_is_secretmem() currently relies on secretmem folios being LRU folios, to save some cycles. However, folios might reside in a folio batch without the LRU flag set, or temporarily have their LRU flag cleared. Consequently, the LRU flag is unreliable for this purpose. In particular, this is the case when secretmem_fault() allocates a fresh page and calls filemap_add_folio()->folio_add_lru(). The folio might be added to the per-cpu folio batch and won't get the LRU flag set until the batch was drained using e.g., lru_add_drain(). Consequently, folio_is_secretmem() might not detect secretmem folios and GUP-fast can succeed in grabbing a secretmem folio, crashing the kernel when we would later try reading/writing to the folio, because the folio has been unmapped from the directmap. Fix it by removing that unreliable check.
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/65291dcfcf8936e1b23cfd7718fdfde7cfaf7706
- https://git.kernel.org/stable/c/201e4aaf405dfd1308da54448654053004c579b5
- https://git.kernel.org/stable/c/43fad1d0284de30159661d0badfc3cbaf7e6f8f8
- https://git.kernel.org/stable/c/65291dcfcf8936e1b23cfd7718fdfde7cfaf7706
- https://git.kernel.org/stable/c/6564b014af92b677c1f07c44d7f5b595d589cf6e
- https://git.kernel.org/stable/c/9c2b4b657739ecda38e3b383354a29566955ac48
- https://ubuntu.com/security/CVE-2024-35872
- https://ubuntu.com/security/notices/USN-6893-1
- https://ubuntu.com/security/notices/USN-6893-2
- https://ubuntu.com/security/notices/USN-6893-3
- https://ubuntu.com/security/notices/USN-6898-1
- https://ubuntu.com/security/notices/USN-6898-2
- https://ubuntu.com/security/notices/USN-6898-3
- https://ubuntu.com/security/notices/USN-6898-4
- https://ubuntu.com/security/notices/USN-6917-1
- https://ubuntu.com/security/notices/USN-6918-1
- https://ubuntu.com/security/notices/USN-6919-1
- https://ubuntu.com/security/notices/USN-6927-1
- https://ubuntu.com/security/notices/USN-7019-1
- https://www.cve.org/CVERecord?id=CVE-2024-35872