UBUNTU-CVE-2024-35791
In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Flush pages under kvm->lock to fix UAF in svm_register_enc_region() Do the cache flush of converted pages in svm_register_enc_region() before dropping kvm->lock to fix use-after-free issues where region and/or its array of pages could be freed by a different task, e.g. if userspace has __unregister_enc_region_locked() already queued up for the region. Note, the "obvious" alternative of using local variables doesn't fully resolve the bug, as region->pages is also dynamically allocated. I.e. the region structure itself would be fine, but region->pages could be freed. Flushing multiple pages under kvm->lock is unfortunate, but the entire flow is a rare slow path, and the manual flush is only needed on CPUs that lack coherency for encrypted memory.
02 / AFFECTED SOFTWARE
Affected packages
4 explicit affected versions
1 explicit affected versions
8 explicit affected versions
8 explicit affected versions
11 explicit affected versions
53 explicit affected versions
116 explicit affected versions
31 explicit affected versions
45 explicit affected versions
50 explicit affected versions
6 explicit affected versions
12 explicit affected versions
19 explicit affected versions
6 explicit affected versions
54 explicit affected versions
40 explicit affected versions
47 explicit affected versions
91 explicit affected versions
51 explicit affected versions
40 explicit affected versions
10 explicit affected versions
7 explicit affected versions
7 explicit affected versions
46 explicit affected versions
13 explicit affected versions
35 explicit affected versions
14 explicit affected versions
18 explicit affected versions
9 explicit affected versions
34 explicit affected versions
120 explicit affected versions
13 explicit affected versions
23 explicit affected versions
124 explicit affected versions
21 explicit affected versions
9 explicit affected versions
16 explicit affected versions
10 explicit affected versions
76 explicit affected versions
7 explicit affected versions
12 explicit affected versions
38 explicit affected versions
12 explicit affected versions
14 explicit affected versions
7 explicit affected versions
104 explicit affected versions
12 explicit affected versions
27 explicit affected versions
105 explicit affected versions
12 explicit affected versions
10 explicit affected versions
37 explicit affected versions
13 explicit affected versions
10 explicit affected versions
26 explicit affected versions
13 explicit affected versions
6 explicit affected versions
29 explicit affected versions
111 explicit affected versions
13 explicit affected versions
51 explicit affected versions
100 explicit affected versions
49 explicit affected versions
13 explicit affected versions
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
10 explicit affected versions
26 explicit affected versions
1 explicit affected versions
13 explicit affected versions
78 explicit affected versions
16 explicit affected versions
51 explicit affected versions
12 explicit affected versions
40 explicit affected versions
3 explicit affected versions
132 explicit affected versions
2 explicit affected versions
51 explicit affected versions
2 explicit affected versions
37 explicit affected versions
27 explicit affected versions
23 explicit affected versions
121 explicit affected versions
10 explicit affected versions
12 explicit affected versions
5 explicit affected versions
8 explicit affected versions
10 explicit affected versions
13 explicit affected versions
12 explicit affected versions
110 explicit affected versions
13 explicit affected versions
72 explicit affected versions
7 explicit affected versions
43 explicit affected versions
12 explicit affected versions
108 explicit affected versions
80 explicit affected versions
56 explicit affected versions
44 explicit affected versions
16 explicit affected versions
3 explicit affected versions
13 explicit affected versions
26 explicit affected versions
37 explicit affected versions
37 explicit affected versions
14 explicit affected versions
38 explicit affected versions
40 explicit affected versions
9 explicit affected versions
11 explicit affected versions
40 explicit affected versions
11 explicit affected versions
48 explicit affected versions
8 explicit affected versions
7 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
77 explicit affected versions
119 explicit affected versions
10 explicit affected versions
88 explicit affected versions
14 explicit affected versions
4 explicit affected versions
78 explicit affected versions
1 explicit affected versions
123 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Flush pages under kvm->lock to fix UAF in svm_register_enc_region() Do the cache flush of converted pages in svm_register_enc_region() before dropping kvm->lock to fix use-after-free issues where region and/or its array of pages could be freed by a different task, e.g. if userspace has __unregister_enc_region_locked() already queued up for the region. Note, the "obvious" alternative of using local variables doesn't fully resolve the bug, as region->pages is also dynamically allocated. I.e. the region structure itself would be fine, but region->pages could be freed. Flushing multiple pages under kvm->lock is unfortunate, but the entire flow is a rare slow path, and the manual flush is only needed on CPUs that lack coherency for encrypted memory.
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/5ef1d8c1ddbf696e47b226e11888eaf8d9e8e807
- https://git.kernel.org/stable/c/12f8e32a5a389a5d58afc67728c76e61beee1ad4
- https://git.kernel.org/stable/c/2d13b79640b147bd77c34a5998533b2021a4122d
- https://git.kernel.org/stable/c/4868c0ecdb6cfde7c70cf478c46e06bb9c7e5865
- https://git.kernel.org/stable/c/5ef1d8c1ddbf696e47b226e11888eaf8d9e8e807
- https://git.kernel.org/stable/c/e126b508ed2e616d679d85fca2fbe77bb48bbdd7
- https://git.kernel.org/stable/c/f6d53d8a2617dd58c89171a6b9610c470ebda38a
- https://ubuntu.com/security/CVE-2024-35791
- 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-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-2024-35791