FKIE_CVE-2025-68341

Vulnerability from fkie_nvd - Published: 2025-12-23 14:16 - Updated: 2025-12-23 14:51
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: veth: reduce XDP no_direct return section to fix race As explain in commit fa349e396e48 ("veth: Fix race with AF_XDP exposing old or uninitialized descriptors") for veth there is a chance after napi_complete_done() that another CPU can manage start another NAPI instance running veth_pool(). For NAPI this is correctly handled as the napi_schedule_prep() check will prevent multiple instances from getting scheduled, but for the remaining code in veth_pool() this can run concurrent with the newly started NAPI instance. The problem/race is that xdp_clear_return_frame_no_direct() isn't designed to be nested. Prior to commit 401cb7dae813 ("net: Reference bpf_redirect_info via task_struct on PREEMPT_RT.") the temporary BPF net context bpf_redirect_info was stored per CPU, where this wasn't an issue. Since this commit the BPF context is stored in 'current' task_struct. When running veth in threaded-NAPI mode, then the kthread becomes the storage area. Now a race exists between two concurrent veth_pool() function calls one exiting NAPI and one running new NAPI, both using the same BPF net context. Race is when another CPU gets within the xdp_set_return_frame_no_direct() section before exiting veth_pool() calls the clear-function xdp_clear_return_frame_no_direct().
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a14602fcae17a3f1cb8a8521bedf31728f9e7e39
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c1ceabcb347d1b0f7e70a7384ec7eff3847b7628
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d0bd018ad72a8a598ae709588934135017f8af52
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nveth: reduce XDP no_direct return section to fix race\n\nAs explain in commit fa349e396e48 (\"veth: Fix race with AF_XDP exposing\nold or uninitialized descriptors\") for veth there is a chance after\nnapi_complete_done() that another CPU can manage start another NAPI\ninstance running veth_pool(). For NAPI this is correctly handled as the\nnapi_schedule_prep() check will prevent multiple instances from getting\nscheduled, but for the remaining code in veth_pool() this can run\nconcurrent with the newly started NAPI instance.\n\nThe problem/race is that xdp_clear_return_frame_no_direct() isn\u0027t\ndesigned to be nested.\n\nPrior to commit 401cb7dae813 (\"net: Reference bpf_redirect_info via\ntask_struct on PREEMPT_RT.\") the temporary BPF net context\nbpf_redirect_info was stored per CPU, where this wasn\u0027t an issue. Since\nthis commit the BPF context is stored in \u0027current\u0027 task_struct. When\nrunning veth in threaded-NAPI mode, then the kthread becomes the storage\narea. Now a race exists between two concurrent veth_pool() function calls\none exiting NAPI and one running new NAPI, both using the same BPF net\ncontext.\n\nRace is when another CPU gets within the xdp_set_return_frame_no_direct()\nsection before exiting veth_pool() calls the clear-function\nxdp_clear_return_frame_no_direct()."
    }
  ],
  "id": "CVE-2025-68341",
  "lastModified": "2025-12-23T14:51:52.650",
  "metrics": {},
  "published": "2025-12-23T14:16:40.683",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a14602fcae17a3f1cb8a8521bedf31728f9e7e39"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c1ceabcb347d1b0f7e70a7384ec7eff3847b7628"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d0bd018ad72a8a598ae709588934135017f8af52"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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