CVE-2022-49559 (GCVE-0-2022-49559)
Vulnerability from cvelistv5
Published
2025-02-26 02:14
Modified
2025-05-04 08:40
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
KVM: x86: Drop WARNs that assert a triple fault never "escapes" from L2
Remove WARNs that sanity check that KVM never lets a triple fault for L2
escape and incorrectly end up in L1. In normal operation, the sanity
check is perfectly valid, but it incorrectly assumes that it's impossible
for userspace to induce KVM_REQ_TRIPLE_FAULT without bouncing through
KVM_RUN (which guarantees kvm_check_nested_state() will see and handle
the triple fault).
The WARN can currently be triggered if userspace injects a machine check
while L2 is active and CR4.MCE=0. And a future fix to allow save/restore
of KVM_REQ_TRIPLE_FAULT, e.g. so that a synthesized triple fault isn't
lost on migration, will make it trivially easy for userspace to trigger
the WARN.
Clearing KVM_REQ_TRIPLE_FAULT when forcibly leaving guest mode is
tempting, but wrong, especially if/when the request is saved/restored,
e.g. if userspace restores events (including a triple fault) and then
restores nested state (which may forcibly leave guest mode). Ignoring
the fact that KVM doesn't currently provide the necessary APIs, it's
userspace's responsibility to manage pending events during save/restore.
------------[ cut here ]------------
WARNING: CPU: 7 PID: 1399 at arch/x86/kvm/vmx/nested.c:4522 nested_vmx_vmexit+0x7fe/0xd90 [kvm_intel]
Modules linked in: kvm_intel kvm irqbypass
CPU: 7 PID: 1399 Comm: state_test Not tainted 5.17.0-rc3+ #808
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
RIP: 0010:nested_vmx_vmexit+0x7fe/0xd90 [kvm_intel]
Call Trace:
<TASK>
vmx_leave_nested+0x30/0x40 [kvm_intel]
vmx_set_nested_state+0xca/0x3e0 [kvm_intel]
kvm_arch_vcpu_ioctl+0xf49/0x13e0 [kvm]
kvm_vcpu_ioctl+0x4b9/0x660 [kvm]
__x64_sys_ioctl+0x83/0xb0
do_syscall_64+0x3b/0xc0
entry_SYSCALL_64_after_hwframe+0x44/0xae
</TASK>
---[ end trace 0000000000000000 ]---
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"arch/x86/kvm/svm/nested.c",
"arch/x86/kvm/vmx/nested.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "8d3a2aa0976f57320ba89baf9d57fb158dd0cd0d",
"status": "affected",
"version": "cb6a32c2b8777ad31a02e585584d869251a790e3",
"versionType": "git"
},
{
"lessThan": "f476a59d5c86c02a79eef893c6da86735f2977ac",
"status": "affected",
"version": "cb6a32c2b8777ad31a02e585584d869251a790e3",
"versionType": "git"
},
{
"lessThan": "7de373c9b48229e428ecdb8fbde269c5a8617fd2",
"status": "affected",
"version": "cb6a32c2b8777ad31a02e585584d869251a790e3",
"versionType": "git"
},
{
"lessThan": "45846661d10422ce9e22da21f8277540b29eca22",
"status": "affected",
"version": "cb6a32c2b8777ad31a02e585584d869251a790e3",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"arch/x86/kvm/svm/nested.c",
"arch/x86/kvm/vmx/nested.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.13"
},
{
"lessThan": "5.13",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.45",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.17.*",
"status": "unaffected",
"version": "5.17.13",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.18.*",
"status": "unaffected",
"version": "5.18.2",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "5.19",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.15.45",
"versionStartIncluding": "5.13",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.17.13",
"versionStartIncluding": "5.13",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.18.2",
"versionStartIncluding": "5.13",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.19",
"versionStartIncluding": "5.13",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86: Drop WARNs that assert a triple fault never \"escapes\" from L2\n\nRemove WARNs that sanity check that KVM never lets a triple fault for L2\nescape and incorrectly end up in L1. In normal operation, the sanity\ncheck is perfectly valid, but it incorrectly assumes that it\u0027s impossible\nfor userspace to induce KVM_REQ_TRIPLE_FAULT without bouncing through\nKVM_RUN (which guarantees kvm_check_nested_state() will see and handle\nthe triple fault).\n\nThe WARN can currently be triggered if userspace injects a machine check\nwhile L2 is active and CR4.MCE=0. And a future fix to allow save/restore\nof KVM_REQ_TRIPLE_FAULT, e.g. so that a synthesized triple fault isn\u0027t\nlost on migration, will make it trivially easy for userspace to trigger\nthe WARN.\n\nClearing KVM_REQ_TRIPLE_FAULT when forcibly leaving guest mode is\ntempting, but wrong, especially if/when the request is saved/restored,\ne.g. if userspace restores events (including a triple fault) and then\nrestores nested state (which may forcibly leave guest mode). Ignoring\nthe fact that KVM doesn\u0027t currently provide the necessary APIs, it\u0027s\nuserspace\u0027s responsibility to manage pending events during save/restore.\n\n ------------[ cut here ]------------\n WARNING: CPU: 7 PID: 1399 at arch/x86/kvm/vmx/nested.c:4522 nested_vmx_vmexit+0x7fe/0xd90 [kvm_intel]\n Modules linked in: kvm_intel kvm irqbypass\n CPU: 7 PID: 1399 Comm: state_test Not tainted 5.17.0-rc3+ #808\n Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015\n RIP: 0010:nested_vmx_vmexit+0x7fe/0xd90 [kvm_intel]\n Call Trace:\n \u003cTASK\u003e\n vmx_leave_nested+0x30/0x40 [kvm_intel]\n vmx_set_nested_state+0xca/0x3e0 [kvm_intel]\n kvm_arch_vcpu_ioctl+0xf49/0x13e0 [kvm]\n kvm_vcpu_ioctl+0x4b9/0x660 [kvm]\n __x64_sys_ioctl+0x83/0xb0\n do_syscall_64+0x3b/0xc0\n entry_SYSCALL_64_after_hwframe+0x44/0xae\n \u003c/TASK\u003e\n ---[ end trace 0000000000000000 ]---"
}
],
"providerMetadata": {
"dateUpdated": "2025-05-04T08:40:32.768Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/8d3a2aa0976f57320ba89baf9d57fb158dd0cd0d"
},
{
"url": "https://git.kernel.org/stable/c/f476a59d5c86c02a79eef893c6da86735f2977ac"
},
{
"url": "https://git.kernel.org/stable/c/7de373c9b48229e428ecdb8fbde269c5a8617fd2"
},
{
"url": "https://git.kernel.org/stable/c/45846661d10422ce9e22da21f8277540b29eca22"
}
],
"title": "KVM: x86: Drop WARNs that assert a triple fault never \"escapes\" from L2",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2022-49559",
"datePublished": "2025-02-26T02:14:05.059Z",
"dateReserved": "2025-02-26T02:08:31.591Z",
"dateUpdated": "2025-05-04T08:40:32.768Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.1"
}