{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2024-43837","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2024-08-17T09:11:59.274Z","datePublished":"2024-08-17T09:21:53.763Z","dateUpdated":"2025-11-03T22:05:28.863Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2025-05-04T09:27:21.949Z"},"descriptions":[{"lang":"en","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()."}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/bpf_verifier.h"],"versions":[{"version":"4a9c7bbe2ed4d2b240674b1fb606c41d3940c412","lessThan":"fcac5feb06f31ee4c88bca9bf98d8bc3ca7d2615","status":"affected","versionType":"git"},{"version":"4a9c7bbe2ed4d2b240674b1fb606c41d3940c412","lessThan":"9d40fd516aeae6779e3c84c6b96700ca76285847","status":"affected","versionType":"git"},{"version":"4a9c7bbe2ed4d2b240674b1fb606c41d3940c412","lessThan":"b29a880bb145e1f1c1df5ab88ed26b1495ff9f09","status":"affected","versionType":"git"},{"version":"4a9c7bbe2ed4d2b240674b1fb606c41d3940c412","lessThan":"f7866c35873377313ff94398f17d425b28b71de1","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/bpf_verifier.h"],"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"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.1.103"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.6.44"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.10.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.11"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/fcac5feb06f31ee4c88bca9bf98d8bc3ca7d2615"},{"url":"https://git.kernel.org/stable/c/9d40fd516aeae6779e3c84c6b96700ca76285847"},{"url":"https://git.kernel.org/stable/c/b29a880bb145e1f1c1df5ab88ed26b1495ff9f09"},{"url":"https://git.kernel.org/stable/c/f7866c35873377313ff94398f17d425b28b71de1"}],"title":"bpf: Fix null pointer dereference in resolve_prog_type() for BPF_PROG_TYPE_EXT","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2024-43837","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2024-09-10T16:08:08.802166Z"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2024-09-12T17:33:23.037Z"}},{"title":"CVE Program Container","references":[{"url":"https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"}],"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2025-11-03T22:05:28.863Z"}}]}}