{
    "data_version": "4.0",
    "data_type": "CVE",
    "data_format": "MITRE",
    "CVE_data_meta": {
        "ID": "CVE-2021-47615",
        "ASSIGNER": "cve@kernel.org",
        "STATE": "PUBLIC"
    },
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/mlx5: Fix releasing unallocated memory in dereg MR flow\n\nFor the case of IB_MR_TYPE_DM the mr does doesn't have a umem, even though\nit is a user MR. This causes function mlx5_free_priv_descs() to think that\nit is a kernel MR, leading to wrongly accessing mr->descs that will get\nwrong values in the union which leads to attempt to release resources that\nwere not allocated in the first place.\n\nFor example:\n DMA-API: mlx5_core 0000:08:00.1: device driver tries to free DMA memory it has not allocated [device address=0x0000000000000000] [size=0 bytes]\n WARNING: CPU: 8 PID: 1021 at kernel/dma/debug.c:961 check_unmap+0x54f/0x8b0\n RIP: 0010:check_unmap+0x54f/0x8b0\n Call Trace:\n  debug_dma_unmap_page+0x57/0x60\n  mlx5_free_priv_descs+0x57/0x70 [mlx5_ib]\n  mlx5_ib_dereg_mr+0x1fb/0x3d0 [mlx5_ib]\n  ib_dereg_mr_user+0x60/0x140 [ib_core]\n  uverbs_destroy_uobject+0x59/0x210 [ib_uverbs]\n  uobj_destroy+0x3f/0x80 [ib_uverbs]\n  ib_uverbs_cmd_verbs+0x435/0xd10 [ib_uverbs]\n  ? uverbs_finalize_object+0x50/0x50 [ib_uverbs]\n  ? lock_acquire+0xc4/0x2e0\n  ? lock_acquired+0x12/0x380\n  ? lock_acquire+0xc4/0x2e0\n  ? lock_acquire+0xc4/0x2e0\n  ? ib_uverbs_ioctl+0x7c/0x140 [ib_uverbs]\n  ? lock_release+0x28a/0x400\n  ib_uverbs_ioctl+0xc0/0x140 [ib_uverbs]\n  ? ib_uverbs_ioctl+0x7c/0x140 [ib_uverbs]\n  __x64_sys_ioctl+0x7f/0xb0\n  do_syscall_64+0x38/0x90\n\nFix it by reorganizing the dereg flow and mlx5_ib_mr structure:\n - Move the ib_umem field into the user MRs structure in the union as it's\n   applicable only there.\n - Function mlx5_ib_dereg_mr() will now call mlx5_free_priv_descs() only\n   in case there isn't udata, which indicates that this isn't a user MR."
            }
        ]
    },
    "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": "f18ec4223117",
                                            "version_value": "e3bc4d4b50ca"
                                        },
                                        {
                                            "version_value": "not down converted",
                                            "x_cve_json_5_version_data": {
                                                "versions": [
                                                    {
                                                        "version": "5.13",
                                                        "status": "affected"
                                                    },
                                                    {
                                                        "version": "0",
                                                        "lessThan": "5.13",
                                                        "status": "unaffected",
                                                        "versionType": "custom"
                                                    },
                                                    {
                                                        "version": "5.15.10",
                                                        "lessThanOrEqual": "5.15.*",
                                                        "status": "unaffected",
                                                        "versionType": "custom"
                                                    },
                                                    {
                                                        "version": "5.15.14",
                                                        "lessThanOrEqual": "5.15.*",
                                                        "status": "unaffected",
                                                        "versionType": "custom"
                                                    },
                                                    {
                                                        "version": "5.16",
                                                        "lessThanOrEqual": "*",
                                                        "status": "unaffected",
                                                        "versionType": "original_commit_for_fix"
                                                    }
                                                ],
                                                "defaultStatus": "affected"
                                            }
                                        }
                                    ]
                                }
                            }
                        ]
                    }
                }
            ]
        }
    },
    "references": {
        "reference_data": [
            {
                "url": "https://git.kernel.org/stable/c/e3bc4d4b50cae7db08e50dbe43f771c906e97701",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/e3bc4d4b50cae7db08e50dbe43f771c906e97701"
            },
            {
                "url": "https://git.kernel.org/stable/c/c44979ace49b4aede3cc7cb5542316e53a4005c9",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/c44979ace49b4aede3cc7cb5542316e53a4005c9"
            },
            {
                "url": "https://git.kernel.org/stable/c/f0ae4afe3d35e67db042c58a52909e06262b740f",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/f0ae4afe3d35e67db042c58a52909e06262b740f"
            }
        ]
    },
    "generator": {
        "engine": "bippy-a5840b7849dd"
    }
}