bpf: Free dynamically allocated bits in bpf_iter_bits_destroy()

{
  "id": "45addbfee5d38f1c8537e7d7e5a14334ac7701b5d4907774a72f443283cad451",
  "url": "https://osv.dev/vulnerability/CVE-2024-50254",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "bpf: Free dynamically allocated bits in bpf_iter_bits_destroy()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: bpf: Free dynamically allocated bits in bpf_iter_bits_destroy() bpf_iter_bits_destroy() uses \"kit->nr_bits <= 64\" to check whether the bits are dynamically allocated. However, the check is incorrect and may cause a kmemleak as shown below: unreferenced object 0xffff88812628c8c0 (size 32): comm \"swapper/0\", pid 1, jiffies 4294727320 hex dump (first 32 bytes): b0 c1 55 f5 81 88 ff ff f0 f0 f0 f0 f0 f0 f0 f0 ..U........... f0 f0 f0 f0 f0 f0 f0 f0 00 00 00 00 00 00 00 00 .............. backtrace (crc 781e32cc): [<00000000c452b4ab>] kmemleak_alloc+0x4b/0x80 [<0000000004e09f80>] __kmalloc_node_noprof+0x480/0x5c0 [<00000000597124d6>] __alloc.isra.0+0x89/0xb0 [<000000004ebfffcd>] alloc_bulk+0x2af/0x720 [<00000000d9c10145>] prefill_mem_cache+0x7f/0xb0 [<00000000ff9738ff>] bpf_mem_alloc_init+0x3e2/0x610 [<000000008b616eac>] bpf_global_ma_init+0x19/0x30 [<00000000fc473efc>] do_one_initcall+0xd3/0x3c0 [<00000000ec81498c>] kernel_init_freeable+0x66a/0x940 [<00000000b119f72f>] kernel_init+0x20/0x160 [<00000000f11ac9a7>] ret_from_fork+0x3c/0x70 [<0000000004671da4>] ret_from_fork_asm+0x1a/0x30 That is because nr_bits will be set as zero in bpf_iter_bits_next() after all bits have been iterated. Fix the issue by setting kit->bit to kit->nr_bits instead of setting kit->nr_bits to zero when the iteration completes in bpf_iter_bits_next(). In addition, use \"!nr_bits || bits >= nr_bits\" to check whether the iteration is complete ",
    "evidence": "osv:CVE-2024-50254",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.11.7",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2024-50254",
      "aliases": [
        "CVE-2024-50254"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "4665415975b0827e9646cab91c61d02a6b364d59"
                },
                {
                  "fixed": "9cee266fafaf79fd465314546f637f9a3c215830"
                },
                {
                  "fixed": "101ccfbabf4738041273ce64e2b116cf440dea13"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-50254.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.11.0"
                },
                {
                  "fixed": "6.11.7"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-50254.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:27.184188266Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/101ccfbabf4738041273ce64e2b116cf440dea13",
        "https://git.kernel.org/stable/c/9cee266fafaf79fd465314546f637f9a3c215830",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/50xxx/CVE-2024-50254.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2024-50254",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/50xxx/CVE-2024-50254.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2024-50254",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 493650,
  "published_at": "2024-11-09T10:15:07.805+00:00"
}