github - ghsa-68w5-72rc-pgrc

GHSA-68W5-72RC-PGRC

Vulnerability from github – Published: 2025-12-23 15:30 – Updated: 2025-12-23 15:30

Details

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().

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{
  "affected": [],
  "aliases": [
    "CVE-2025-68341"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-12-23T14:16:40Z",
    "severity": null
  },
  "details": "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": "GHSA-68w5-72rc-pgrc",
  "modified": "2025-12-23T15:30:40Z",
  "published": "2025-12-23T15:30:40Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-68341"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a14602fcae17a3f1cb8a8521bedf31728f9e7e39"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c1ceabcb347d1b0f7e70a7384ec7eff3847b7628"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d0bd018ad72a8a598ae709588934135017f8af52"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2025-68341 (GCVE-0-2025-68341)

Vulnerability from cvelistv5 – Published: 2025-12-23 13:58 – Updated: 2025-12-23 13:58

Title

veth: reduce XDP no_direct return section to fix race

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().

Severity ?

No CVSS data available.

Assigner

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/c1ceabcb347d1b0f7…
	https://git.kernel.org/stable/c/d0bd018ad72a8a598…
	https://git.kernel.org/stable/c/a14602fcae17a3f1c…

Impacted products

Vendor

Product

Version

Linux

Affected: 401cb7dae8130fd34eb84648e02ab4c506df7d5e , < c1ceabcb347d1b0f7e70a7384ec7eff3847b7628 (git)
Affected: 401cb7dae8130fd34eb84648e02ab4c506df7d5e , < d0bd018ad72a8a598ae709588934135017f8af52 (git)
Affected: 401cb7dae8130fd34eb84648e02ab4c506df7d5e , < a14602fcae17a3f1cb8a8521bedf31728f9e7e39 (git)

Linux

Affected: 6.11
Unaffected: 0 , < 6.11 (semver)
Unaffected: 6.12.61 , ≤ 6.12.* (semver)
Unaffected: 6.17.11 , ≤ 6.17.* (semver)
Unaffected: 6.18 , ≤ * (original_commit_for_fix)

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JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/veth.c"
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          "vendor": "Linux",
          "versions": [
            {
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              "status": "affected",
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              "versionType": "git"
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              "versionType": "git"
            },
            {
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            }
          ]
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          "vendor": "Linux",
          "versions": [
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              "version": "6.11"
            },
            {
              "lessThan": "6.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "6.12.61",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.17.*",
              "status": "unaffected",
              "version": "6.17.11",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "6.18",
              "versionType": "original_commit_for_fix"
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          ]
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      ],
      "cpeApplicability": [
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          "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()."
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        {
          "url": "https://git.kernel.org/stable/c/a14602fcae17a3f1cb8a8521bedf31728f9e7e39"
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      "title": "veth: reduce XDP no_direct return section to fix race",
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  "cveMetadata": {
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    "datePublished": "2025-12-23T13:58:26.749Z",
    "dateReserved": "2025-12-16T14:48:05.298Z",
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    "state": "PUBLISHED"
  },
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}

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.

Action not permitted

GHSA-68W5-72RC-PGRC

CVE-2025-68341 (GCVE-0-2025-68341)

Tags

Sightings

Nomenclature