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.
[
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"arch/x86/kvm/svm/sev.c"
],
"versions": [
{
"version": "4f627ecde732",
"lessThan": "2d13b79640b1",
"status": "affected",
"versionType": "git"
},
{
"version": "19a23da53932",
"lessThan": "e126b508ed2e",
"status": "affected",
"versionType": "git"
},
{
"version": "19a23da53932",
"lessThan": "4868c0ecdb6c",
"status": "affected",
"versionType": "git"
},
{
"version": "19a23da53932",
"lessThan": "12f8e32a5a38",
"status": "affected",
"versionType": "git"
},
{
"version": "19a23da53932",
"lessThan": "f6d53d8a2617",
"status": "affected",
"versionType": "git"
},
{
"version": "19a23da53932",
"lessThan": "5ef1d8c1ddbf",
"status": "affected",
"versionType": "git"
}
]
},
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"arch/x86/kvm/svm/sev.c"
],
"versions": [
{
"version": "5.11",
"status": "affected"
},
{
"version": "0",
"lessThan": "5.11",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.10.215",
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.15.154",
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.1.84",
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.6.24",
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.7.12",
"lessThanOrEqual": "6.7.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.8",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
]
git.kernel.org/stable/c/12f8e32a5a389a5d58afc67728c76e61beee1ad4
git.kernel.org/stable/c/2d13b79640b147bd77c34a5998533b2021a4122d
git.kernel.org/stable/c/4868c0ecdb6cfde7c70cf478c46e06bb9c7e5865
git.kernel.org/stable/c/5ef1d8c1ddbf696e47b226e11888eaf8d9e8e807
git.kernel.org/stable/c/e126b508ed2e616d679d85fca2fbe77bb48bbdd7
git.kernel.org/stable/c/f6d53d8a2617dd58c89171a6b9610c470ebda38a
lists.debian.org/debian-lts-announce/2024/06/msg00017.html