{
    "data_version": "4.0",
    "data_type": "CVE",
    "data_format": "MITRE",
    "CVE_data_meta": {
        "ID": "CVE-2021-47391",
        "ASSIGNER": "cve@kernel.org",
        "STATE": "PUBLIC"
    },
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/cma: Ensure rdma_addr_cancel() happens before issuing more requests\n\nThe FSM can run in a circle allowing rdma_resolve_ip() to be called twice\non the same id_priv. While this cannot happen without going through the\nwork, it violates the invariant that the same address resolution\nbackground request cannot be active twice.\n\n       CPU 1                                  CPU 2\n\nrdma_resolve_addr():\n  RDMA_CM_IDLE -> RDMA_CM_ADDR_QUERY\n  rdma_resolve_ip(addr_handler)  #1\n\n\t\t\t process_one_req(): for #1\n                          addr_handler():\n                            RDMA_CM_ADDR_QUERY -> RDMA_CM_ADDR_BOUND\n                            mutex_unlock(&id_priv->handler_mutex);\n                            [.. handler still running ..]\n\nrdma_resolve_addr():\n  RDMA_CM_ADDR_BOUND -> RDMA_CM_ADDR_QUERY\n  rdma_resolve_ip(addr_handler)\n    !! two requests are now on the req_list\n\nrdma_destroy_id():\n destroy_id_handler_unlock():\n  _destroy_id():\n   cma_cancel_operation():\n    rdma_addr_cancel()\n\n                          // process_one_req() self removes it\n\t\t          spin_lock_bh(&lock);\n                           cancel_delayed_work(&req->work);\n\t                   if (!list_empty(&req->list)) == true\n\n      ! rdma_addr_cancel() returns after process_on_req #1 is done\n\n   kfree(id_priv)\n\n\t\t\t process_one_req(): for #2\n                          addr_handler():\n\t                    mutex_lock(&id_priv->handler_mutex);\n                            !! Use after free on id_priv\n\nrdma_addr_cancel() expects there to be one req on the list and only\ncancels the first one. The self-removal behavior of the work only happens\nafter the handler has returned. This yields a situations where the\nreq_list can have two reqs for the same \"handle\" but rdma_addr_cancel()\nonly cancels the first one.\n\nThe second req remains active beyond rdma_destroy_id() and will\nuse-after-free id_priv once it inevitably triggers.\n\nFix this by remembering if the id_priv has called rdma_resolve_ip() and\nalways cancel before calling it again. This ensures the req_list never\ngets more than one item in it and doesn't cost anything in the normal flow\nthat never uses this strange error path."
            }
        ]
    },
    "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": "e51060f08a61",
                                            "version_value": "9a085fa9b7d6"
                                        },
                                        {
                                            "version_value": "not down converted",
                                            "x_cve_json_5_version_data": {
                                                "versions": [
                                                    {
                                                        "version": "2.6.18",
                                                        "status": "affected"
                                                    },
                                                    {
                                                        "version": "0",
                                                        "lessThan": "2.6.18",
                                                        "status": "unaffected",
                                                        "versionType": "custom"
                                                    },
                                                    {
                                                        "version": "5.10.188",
                                                        "lessThanOrEqual": "5.10.*",
                                                        "status": "unaffected",
                                                        "versionType": "custom"
                                                    },
                                                    {
                                                        "version": "5.14.10",
                                                        "lessThanOrEqual": "5.14.*",
                                                        "status": "unaffected",
                                                        "versionType": "custom"
                                                    },
                                                    {
                                                        "version": "5.15",
                                                        "lessThanOrEqual": "*",
                                                        "status": "unaffected",
                                                        "versionType": "original_commit_for_fix"
                                                    }
                                                ],
                                                "defaultStatus": "affected"
                                            }
                                        }
                                    ]
                                }
                            }
                        ]
                    }
                }
            ]
        }
    },
    "references": {
        "reference_data": [
            {
                "url": "https://git.kernel.org/stable/c/9a085fa9b7d644a234465091e038c1911e1a4f2a",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/9a085fa9b7d644a234465091e038c1911e1a4f2a"
            },
            {
                "url": "https://git.kernel.org/stable/c/03d884671572af8bcfbc9e63944c1021efce7589",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/03d884671572af8bcfbc9e63944c1021efce7589"
            },
            {
                "url": "https://git.kernel.org/stable/c/305d568b72f17f674155a2a8275f865f207b3808",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/305d568b72f17f674155a2a8275f865f207b3808"
            }
        ]
    },
    "generator": {
        "engine": "bippy-a5840b7849dd"
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}