FKIE_CVE-2025-68245

Vulnerability from fkie_nvd - Published: 2025-12-16 15:15 - Updated: 2025-12-18 15:08
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: net: netpoll: fix incorrect refcount handling causing incorrect cleanup commit efa95b01da18 ("netpoll: fix use after free") incorrectly ignored the refcount and prematurely set dev->npinfo to NULL during netpoll cleanup, leading to improper behavior and memory leaks. Scenario causing lack of proper cleanup: 1) A netpoll is associated with a NIC (e.g., eth0) and netdev->npinfo is allocated, and refcnt = 1 - Keep in mind that npinfo is shared among all netpoll instances. In this case, there is just one. 2) Another netpoll is also associated with the same NIC and npinfo->refcnt += 1. - Now dev->npinfo->refcnt = 2; - There is just one npinfo associated to the netdev. 3) When the first netpolls goes to clean up: - The first cleanup succeeds and clears np->dev->npinfo, ignoring refcnt. - It basically calls `RCU_INIT_POINTER(np->dev->npinfo, NULL);` - Set dev->npinfo = NULL, without proper cleanup - No ->ndo_netpoll_cleanup() is either called 4) Now the second target tries to clean up - The second cleanup fails because np->dev->npinfo is already NULL. * In this case, ops->ndo_netpoll_cleanup() was never called, and the skb pool is not cleaned as well (for the second netpoll instance) - This leaks npinfo and skbpool skbs, which is clearly reported by kmemleak. Revert commit efa95b01da18 ("netpoll: fix use after free") and adds clarifying comments emphasizing that npinfo cleanup should only happen once the refcount reaches zero, ensuring stable and correct netpoll behavior.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/49c8d2c1f94cc2f4d1a108530d7ba52614b874c2
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4afd4ebbad52aa146838ec23082ba393e426a2bb
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/890472d6fbf062e6de7fdd56642cb305ab79d669
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8e6a50edad11e3e1426e4c29e7aa6201f3468ac2
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9a51b5ccd1c79afec1c03a4e1e6688da52597556
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9b0bb18b4b9dc017c1825a2c5e763615e34a1593
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c645693180a98606c430825223d2029315d85e9d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c79a6d9da29219616b118a3adce9a14cd30f9bd0
Impacted products
Vendor Product Version
To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: netpoll: fix incorrect refcount handling causing incorrect cleanup\n\ncommit efa95b01da18 (\"netpoll: fix use after free\") incorrectly\nignored the refcount and prematurely set dev-\u003enpinfo to NULL during\nnetpoll cleanup, leading to improper behavior and memory leaks.\n\nScenario causing lack of proper cleanup:\n\n1) A netpoll is associated with a NIC (e.g., eth0) and netdev-\u003enpinfo is\n   allocated, and refcnt = 1\n   - Keep in mind that npinfo is shared among all netpoll instances. In\n     this case, there is just one.\n\n2) Another netpoll is also associated with the same NIC and\n   npinfo-\u003erefcnt += 1.\n   - Now dev-\u003enpinfo-\u003erefcnt = 2;\n   - There is just one npinfo associated to the netdev.\n\n3) When the first netpolls goes to clean up:\n   - The first cleanup succeeds and clears np-\u003edev-\u003enpinfo, ignoring\n     refcnt.\n     - It basically calls `RCU_INIT_POINTER(np-\u003edev-\u003enpinfo, NULL);`\n   - Set dev-\u003enpinfo = NULL, without proper cleanup\n   - No -\u003endo_netpoll_cleanup() is either called\n\n4) Now the second target tries to clean up\n   - The second cleanup fails because np-\u003edev-\u003enpinfo is already NULL.\n     * In this case, ops-\u003endo_netpoll_cleanup() was never called, and\n       the skb pool is not cleaned as well (for the second netpoll\n       instance)\n  - This leaks npinfo and skbpool skbs, which is clearly reported by\n    kmemleak.\n\nRevert commit efa95b01da18 (\"netpoll: fix use after free\") and adds\nclarifying comments emphasizing that npinfo cleanup should only happen\nonce the refcount reaches zero, ensuring stable and correct netpoll\nbehavior."
    }
  ],
  "id": "CVE-2025-68245",
  "lastModified": "2025-12-18T15:08:06.237",
  "metrics": {},
  "published": "2025-12-16T15:15:53.767",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/49c8d2c1f94cc2f4d1a108530d7ba52614b874c2"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4afd4ebbad52aa146838ec23082ba393e426a2bb"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/890472d6fbf062e6de7fdd56642cb305ab79d669"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8e6a50edad11e3e1426e4c29e7aa6201f3468ac2"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9a51b5ccd1c79afec1c03a4e1e6688da52597556"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9b0bb18b4b9dc017c1825a2c5e763615e34a1593"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c645693180a98606c430825223d2029315d85e9d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c79a6d9da29219616b118a3adce9a14cd30f9bd0"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.