smc: Fix use-after-free in __pnet_find_base_ndev().

{
  "id": "7115bfc8866244af08a4330c10257220f15337a685a4de13a15b1bf1fc49dcb3",
  "url": "https://osv.dev/vulnerability/CVE-2025-40064",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "smc: Fix use-after-free in __pnet_find_base_ndev().",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: smc: Fix use-after-free in __pnet_find_base_ndev(). syzbot reported use-after-free of net_device in __pnet_find_base_ndev(), which was called during connect(). [0] smc_pnet_find_ism_resource() fetches sk_dst_get(sk)->dev and passes down to pnet_find_base_ndev(), where RTNL is held. Then, UAF happened at __pnet_find_base_ndev() when the dev is first used. This means dev had already been freed before acquiring RTNL in pnet_find_base_ndev(). While dev is going away, dst->dev could be swapped with blackhole_netdev, and the dev's refcnt by dst will be released. We must hold dev's refcnt before calling smc_pnet_find_ism_resource(). Also, smc_pnet_find_roce_resource() has the same problem. Let's use __sk_dst_get() and dst_dev_rcu() in the two functions. [0]: BUG: KASAN: use-after-free in __pnet_find_base_ndev+0x1b1/0x1c0 net/smc/smc_pnet.c:926 Read of size 1 at addr ffff888036bac33a by task syz.0.3632/18609 CPU: 1 UID: 0 PID: 18609 Comm: syz.0.3632 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 __pnet_find_base_ndev+0x1b1/0x1c0 net/smc/smc_pnet.c:926 pnet_find_base_ndev net/smc/smc_pnet.c:946 [inline] smc_pnet_find_ism_by_pnetid ",
    "evidence": "osv:CVE-2025-40064",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.1.187",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.156",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.108",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.17.3",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2025-40064",
      "aliases": [
        "CVE-2025-40064"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0afff91c6f5ecef27715ea71e34dc2baacba1060"
                },
                {
                  "fixed": "005a7173d8e4710646043a681af36f79ce05a29b"
                },
                {
                  "fixed": "302dbed4760bcd19a661cc1c282d91bb7481307e"
                },
                {
                  "fixed": "08aca586482e88aab9616a3e81bc36cad22674a5"
                },
                {
                  "fixed": "233927b645cb7a14bb98d23ac72e4c7243a9f0d9"
                },
                {
                  "fixed": "3d3466878afd8d43ec0ca2facfbc7f03e40d0f79"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-40064.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "4.19.0"
                },
                {
                  "fixed": "6.1.187"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.156"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.108"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.17.3"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-40064.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:37.712563549Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/005a7173d8e4710646043a681af36f79ce05a29b",
        "https://git.kernel.org/stable/c/08aca586482e88aab9616a3e81bc36cad22674a5",
        "https://git.kernel.org/stable/c/233927b645cb7a14bb98d23ac72e4c7243a9f0d9",
        "https://git.kernel.org/stable/c/302dbed4760bcd19a661cc1c282d91bb7481307e",
        "https://git.kernel.org/stable/c/3d3466878afd8d43ec0ca2facfbc7f03e40d0f79",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40064.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-40064",
        "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/2025/40xxx/CVE-2025-40064.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-40064",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 505302,
  "published_at": "2025-10-28T11:48:35.155+00:00"
}