cvelist/2021/46xxx/CVE-2021-46978.json

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    "data_version": "4.0",
    "data_type": "CVE",
    "data_format": "MITRE",
    "CVE_data_meta": {
        "ID": "CVE-2021-46978",
        "ASSIGNER": "cve@kernel.org",
        "STATE": "PUBLIC"
    },
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: nVMX: Always make an attempt to map eVMCS after migration\n\nWhen enlightened VMCS is in use and nested state is migrated with\nvmx_get_nested_state()/vmx_set_nested_state() KVM can't map evmcs\npage right away: evmcs gpa is not 'struct kvm_vmx_nested_state_hdr'\nand we can't read it from VP assist page because userspace may decide\nto restore HV_X64_MSR_VP_ASSIST_PAGE after restoring nested state\n(and QEMU, for example, does exactly that). To make sure eVMCS is\nmapped /vmx_set_nested_state() raises KVM_REQ_GET_NESTED_STATE_PAGES\nrequest.\n\nCommit f2c7ef3ba955 (\"KVM: nSVM: cancel KVM_REQ_GET_NESTED_STATE_PAGES\non nested vmexit\") added KVM_REQ_GET_NESTED_STATE_PAGES clearing to\nnested_vmx_vmexit() to make sure MSR permission bitmap is not switched\nwhen an immediate exit from L2 to L1 happens right after migration (caused\nby a pending event, for example). Unfortunately, in the exact same\nsituation we still need to have eVMCS mapped so\nnested_sync_vmcs12_to_shadow() reflects changes in VMCS12 to eVMCS.\n\nAs a band-aid, restore nested_get_evmcs_page() when clearing\nKVM_REQ_GET_NESTED_STATE_PAGES in nested_vmx_vmexit(). The 'fix' is far\nfrom being ideal as we can't easily propagate possible failures and even if\nwe could, this is most likely already too late to do so. The whole\n'KVM_REQ_GET_NESTED_STATE_PAGES' idea for mapping eVMCS after migration\nseems to be fragile as we diverge too much from the 'native' path when\nvmptr loading happens on vmx_set_nested_state()."
            }
        ]
    },
    "problemtype": {
        "problemtype_data": [
            {
                "description": [
                    {
                        "lang": "eng",
                        "value": "n/a"
                    }
                ]
            }
        ]
    },
    "affects": {
        "vendor": {
            "vendor_data": [
                {
                    "vendor_name": "Linux",
                    "product": {
                        "product_data": [
                            {
                                "product_name": "Linux",
                                "version": {
                                    "version_data": [
                                        {
                                            "version_affected": "<",
                                            "version_name": "0faceb7d6dda",
                                            "version_value": "c8bf64e3fb77"
                                        },
                                        {
                                            "version_affected": "<",
                                            "version_name": "f2c7ef3ba955",
                                            "version_value": "200a45649ab7"
                                        },
                                        {
                                            "version_value": "not down converted",
                                            "x_cve_json_5_version_data": {
                                                "versions": [
                                                    {
                                                        "version": "5.11",
                                                        "status": "affected"
                                                    },
                                                    {
                                                        "version": "0",
                                                        "lessThan": "5.11",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
                                                    },
                                                    {
                                                        "version": "5.10.38",
                                                        "lessThanOrEqual": "5.10.*",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
                                                    },
                                                    {
                                                        "version": "5.11.22",
                                                        "lessThanOrEqual": "5.11.*",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
                                                    },
                                                    {
                                                        "version": "5.12.5",
                                                        "lessThanOrEqual": "5.12.*",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
                                                    },
                                                    {
                                                        "version": "5.13",
                                                        "lessThanOrEqual": "*",
                                                        "status": "unaffected",
                                                        "versionType": "original_commit_for_fix"
                                                    }
                                                ],
                                                "defaultStatus": "affected"
                                            }
                                        }
                                    ]
                                }
                            }
                        ]
                    }
                }
            ]
        }
    },
    "references": {
        "reference_data": [
            {
                "url": "https://git.kernel.org/stable/c/c8bf64e3fb77cc19bad146fbe26651985b117194",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/c8bf64e3fb77cc19bad146fbe26651985b117194"
            },
            {
                "url": "https://git.kernel.org/stable/c/200a45649ab7361bc80c70aebf7165b64f9a6c9f",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/200a45649ab7361bc80c70aebf7165b64f9a6c9f"
            },
            {
                "url": "https://git.kernel.org/stable/c/bd0e8455b85b651a4c77de9616e307129b15aaa7",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/bd0e8455b85b651a4c77de9616e307129b15aaa7"
            },
            {
                "url": "https://git.kernel.org/stable/c/f5c7e8425f18fdb9bdb7d13340651d7876890329",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/f5c7e8425f18fdb9bdb7d13340651d7876890329"
            }
        ]
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