{ "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": "custom" }, { "version": "6.1.103", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "custom" }, { "version": "6.6.44", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "custom" }, { "version": "6.10.3", "lessThanOrEqual": "6.10.*", "status": "unaffected", "versionType": "custom" }, { "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-c9c4e1df01b2" } }