{
    "data_version": "4.0",
    "data_type": "CVE",
    "data_format": "MITRE",
    "CVE_data_meta": {
        "ID": "CVE-2021-47226",
        "ASSIGNER": "cve@kernel.org",
        "STATE": "PUBLIC"
    },
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/fpu: Invalidate FPU state after a failed XRSTOR from a user buffer\n\nBoth Intel and AMD consider it to be architecturally valid for XRSTOR to\nfail with #PF but nonetheless change the register state.  The actual\nconditions under which this might occur are unclear [1], but it seems\nplausible that this might be triggered if one sibling thread unmaps a page\nand invalidates the shared TLB while another sibling thread is executing\nXRSTOR on the page in question.\n\n__fpu__restore_sig() can execute XRSTOR while the hardware registers\nare preserved on behalf of a different victim task (using the\nfpu_fpregs_owner_ctx mechanism), and, in theory, XRSTOR could fail but\nmodify the registers.\n\nIf this happens, then there is a window in which __fpu__restore_sig()\ncould schedule out and the victim task could schedule back in without\nreloading its own FPU registers. This would result in part of the FPU\nstate that __fpu__restore_sig() was attempting to load leaking into the\nvictim task's user-visible state.\n\nInvalidate preserved FPU registers on XRSTOR failure to prevent this\nsituation from corrupting any state.\n\n[1] Frequent readers of the errata lists might imagine \"complex\n    microarchitectural conditions\"."
            }
        ]
    },
    "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": "1d731e731c4c",
                                            "version_value": "a7748e021b9f"
                                        },
                                        {
                                            "version_value": "not down converted",
                                            "x_cve_json_5_version_data": {
                                                "versions": [
                                                    {
                                                        "version": "5.2",
                                                        "status": "affected"
                                                    },
                                                    {
                                                        "version": "0",
                                                        "lessThan": "5.2",
                                                        "status": "unaffected",
                                                        "versionType": "custom"
                                                    },
                                                    {
                                                        "version": "5.10.46",
                                                        "lessThanOrEqual": "5.10.*",
                                                        "status": "unaffected",
                                                        "versionType": "custom"
                                                    },
                                                    {
                                                        "version": "5.12.13",
                                                        "lessThanOrEqual": "5.12.*",
                                                        "status": "unaffected",
                                                        "versionType": "custom"
                                                    },
                                                    {
                                                        "version": "5.13",
                                                        "lessThanOrEqual": "*",
                                                        "status": "unaffected",
                                                        "versionType": "original_commit_for_fix"
                                                    }
                                                ],
                                                "defaultStatus": "affected"
                                            }
                                        }
                                    ]
                                }
                            }
                        ]
                    }
                }
            ]
        }
    },
    "references": {
        "reference_data": [
            {
                "url": "https://git.kernel.org/stable/c/a7748e021b9fb7739e3cb88449296539de0b6817",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/a7748e021b9fb7739e3cb88449296539de0b6817"
            },
            {
                "url": "https://git.kernel.org/stable/c/002665dcba4bbec8c82f0aeb4bd3f44334ed2c14",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/002665dcba4bbec8c82f0aeb4bd3f44334ed2c14"
            },
            {
                "url": "https://git.kernel.org/stable/c/d8778e393afa421f1f117471144f8ce6deb6953a",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/d8778e393afa421f1f117471144f8ce6deb6953a"
            }
        ]
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}