cvelist/2024/43xxx/CVE-2024-43837.json

{
    "data_version": "4.0",
    "data_type": "CVE",
    "data_format": "MITRE",
    "CVE_data_meta": {
        "ID": "CVE-2024-43837",
        "ASSIGNER": "cve@kernel.org",
        "STATE": "PUBLIC"
    },
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix null pointer dereference in resolve_prog_type() for BPF_PROG_TYPE_EXT\n\nWhen loading a EXT program without specifying `attr->attach_prog_fd`,\nthe `prog->aux->dst_prog` will be null. At this time, calling\nresolve_prog_type() anywhere will result in a null pointer dereference.\n\nExample stack trace:\n\n[    8.107863] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004\n[    8.108262] Mem abort info:\n[    8.108384]   ESR = 0x0000000096000004\n[    8.108547]   EC = 0x25: DABT (current EL), IL = 32 bits\n[    8.108722]   SET = 0, FnV = 0\n[    8.108827]   EA = 0, S1PTW = 0\n[    8.108939]   FSC = 0x04: level 0 translation fault\n[    8.109102] Data abort info:\n[    8.109203]   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000\n[    8.109399]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0\n[    8.109614]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0\n[    8.109836] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000101354000\n[    8.110011] [0000000000000004] pgd=0000000000000000, p4d=0000000000000000\n[    8.112624] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP\n[    8.112783] Modules linked in:\n[    8.113120] CPU: 0 PID: 99 Comm: may_access_dire Not tainted 6.10.0-rc3-next-20240613-dirty #1\n[    8.113230] Hardware name: linux,dummy-virt (DT)\n[    8.113390] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)\n[    8.113429] pc : may_access_direct_pkt_data+0x24/0xa0\n[    8.113746] lr : add_subprog_and_kfunc+0x634/0x8e8\n[    8.113798] sp : ffff80008283b9f0\n[    8.113813] x29: ffff80008283b9f0 x28: ffff800082795048 x27: 0000000000000001\n[    8.113881] x26: ffff0000c0bb2600 x25: 0000000000000000 x24: 0000000000000000\n[    8.113897] x23: ffff0000c1134000 x22: 000000000001864f x21: ffff0000c1138000\n[    8.113912] x20: 0000000000000001 x19: ffff0000c12b8000 x18: ffffffffffffffff\n[    8.113929] x17: 0000000000000000 x16: 0000000000000000 x15: 0720072007200720\n[    8.113944] x14: 0720072007200720 x13: 0720072007200720 x12: 0720072007200720\n[    8.113958] x11: 0720072007200720 x10: 0000000000f9fca4 x9 : ffff80008021f4e4\n[    8.113991] x8 : 0101010101010101 x7 : 746f72705f6d656d x6 : 000000001e0e0f5f\n[    8.114006] x5 : 000000000001864f x4 : ffff0000c12b8000 x3 : 000000000000001c\n[    8.114020] x2 : 0000000000000002 x1 : 0000000000000000 x0 : 0000000000000000\n[    8.114126] Call trace:\n[    8.114159]  may_access_direct_pkt_data+0x24/0xa0\n[    8.114202]  bpf_check+0x3bc/0x28c0\n[    8.114214]  bpf_prog_load+0x658/0xa58\n[    8.114227]  __sys_bpf+0xc50/0x2250\n[    8.114240]  __arm64_sys_bpf+0x28/0x40\n[    8.114254]  invoke_syscall.constprop.0+0x54/0xf0\n[    8.114273]  do_el0_svc+0x4c/0xd8\n[    8.114289]  el0_svc+0x3c/0x140\n[    8.114305]  el0t_64_sync_handler+0x134/0x150\n[    8.114331]  el0t_64_sync+0x168/0x170\n[    8.114477] Code: 7100707f 54000081 f9401c00 f9403800 (b9400403)\n[    8.118672] ---[ end trace 0000000000000000 ]---\n\nOne way to fix it is by forcing `attach_prog_fd` non-empty when\nbpf_prog_load(). But this will lead to `libbpf_probe_bpf_prog_type`\nAPI broken which use verifier log to probe prog type and will log\nnothing if we reject invalid EXT prog before bpf_check().\n\nAnother way is by adding null check in resolve_prog_type().\n\nThe issue was introduced by commit 4a9c7bbe2ed4 (\"bpf: Resolve to\nprog->aux->dst_prog->type only for BPF_PROG_TYPE_EXT\") which wanted\nto correct type resolution for BPF_PROG_TYPE_TRACING programs. Before\nthat, the type resolution of BPF_PROG_TYPE_EXT prog actually follows\nthe logic below:\n\n  prog->aux->dst_prog ? prog->aux->dst_prog->type : prog->type;\n\nIt implies that when EXT program is not yet attached to `dst_prog`,\nthe prog type should be EXT itself. This code worked fine in the past.\nSo just keep using it.\n\nFix this by returning `prog->type` for BPF_PROG_TYPE_EXT if `dst_prog`\nis not present in resolve_prog_type()."
            }
        ]
    },
    "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": "4a9c7bbe2ed4",
                                            "version_value": "fcac5feb06f3"
                                        },
                                        {
                                            "version_value": "not down converted",
                                            "x_cve_json_5_version_data": {
                                                "versions": [
                                                    {
                                                        "version": "5.18",
                                                        "status": "affected"
                                                    },
                                                    {
                                                        "version": "0",
                                                        "lessThan": "5.18",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
                                                    },
                                                    {
                                                        "version": "6.1.103",
                                                        "lessThanOrEqual": "6.1.*",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
                                                    },
                                                    {
                                                        "version": "6.6.44",
                                                        "lessThanOrEqual": "6.6.*",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
                                                    },
                                                    {
                                                        "version": "6.10.3",
                                                        "lessThanOrEqual": "6.10.*",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
                                                    },
                                                    {
                                                        "version": "6.11",
                                                        "lessThanOrEqual": "*",
                                                        "status": "unaffected",
                                                        "versionType": "original_commit_for_fix"
                                                    }
                                                ],
                                                "defaultStatus": "affected"
                                            }
                                        }
                                    ]
                                }
                            }
                        ]
                    }
                }
            ]
        }
    },
    "references": {
        "reference_data": [
            {
                "url": "https://git.kernel.org/stable/c/fcac5feb06f31ee4c88bca9bf98d8bc3ca7d2615",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/fcac5feb06f31ee4c88bca9bf98d8bc3ca7d2615"
            },
            {
                "url": "https://git.kernel.org/stable/c/9d40fd516aeae6779e3c84c6b96700ca76285847",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/9d40fd516aeae6779e3c84c6b96700ca76285847"
            },
            {
                "url": "https://git.kernel.org/stable/c/b29a880bb145e1f1c1df5ab88ed26b1495ff9f09",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/b29a880bb145e1f1c1df5ab88ed26b1495ff9f09"
            },
            {
                "url": "https://git.kernel.org/stable/c/f7866c35873377313ff94398f17d425b28b71de1",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/f7866c35873377313ff94398f17d425b28b71de1"
            }
        ]
    },
    "generator": {
        "engine": "bippy-9e1c9544281a"
    }
}