github - ghsa-jr46-vc8c-pm2x

GHSA-JR46-VC8C-PM2X

Vulnerability from github – Published: 2025-12-08 03:31 – Updated: 2025-12-08 03:31

Details

In the Linux kernel, the following vulnerability has been resolved:

9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN

p9_read_work() doesn't set Rworksched and doesn't do schedule_work(m->rq) if list_empty(&m->req_list).

However, if the pipe is full, we need to read more data and this used to work prior to commit aaec5a95d59615 ("pipe_read: don't wake up the writer if the pipe is still full").

p9_read_work() does p9_fd_read() -> ... -> anon_pipe_read() which (before the commit above) triggered the unnecessary wakeup. This wakeup calls p9_pollwake() which kicks p9_poll_workfn() -> p9_poll_mux(), p9_poll_mux() will notice EPOLLIN and schedule_work(&m->rq).

This no longer happens after the optimization above, change p9_fd_request() to use p9_poll_mux() instead of only checking for EPOLLOUT.

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{
  "affected": [],
  "aliases": [
    "CVE-2025-40305"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-12-08T01:16:02Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\n9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN\n\np9_read_work() doesn\u0027t set Rworksched and doesn\u0027t do schedule_work(m-\u003erq)\nif list_empty(\u0026m-\u003ereq_list).\n\nHowever, if the pipe is full, we need to read more data and this used to\nwork prior to commit aaec5a95d59615 (\"pipe_read: don\u0027t wake up the writer\nif the pipe is still full\").\n\np9_read_work() does p9_fd_read() -\u003e ... -\u003e anon_pipe_read() which (before\nthe commit above) triggered the unnecessary wakeup. This wakeup calls\np9_pollwake() which kicks p9_poll_workfn() -\u003e p9_poll_mux(), p9_poll_mux()\nwill notice EPOLLIN and schedule_work(\u0026m-\u003erq).\n\nThis no longer happens after the optimization above, change p9_fd_request()\nto use p9_poll_mux() instead of only checking for EPOLLOUT.",
  "id": "GHSA-jr46-vc8c-pm2x",
  "modified": "2025-12-08T03:31:01Z",
  "published": "2025-12-08T03:31:01Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-40305"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/242531004d7de8c159f9bfadebe33fe8060b1046"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2e1461034aef99e905a1fe5589aaf00eaea73eee"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e8fe3f07a357c39d429e02ca34f740692d88967a"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2025-40305 (GCVE-0-2025-40305)

Vulnerability from cvelistv5 – Published: 2025-12-08 00:46 – Updated: 2025-12-08 00:46

Summary

In the Linux kernel, the following vulnerability has been resolved: 9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN p9_read_work() doesn't set Rworksched and doesn't do schedule_work(m->rq) if list_empty(&m->req_list). However, if the pipe is full, we need to read more data and this used to work prior to commit aaec5a95d59615 ("pipe_read: don't wake up the writer if the pipe is still full"). p9_read_work() does p9_fd_read() -> ... -> anon_pipe_read() which (before the commit above) triggered the unnecessary wakeup. This wakeup calls p9_pollwake() which kicks p9_poll_workfn() -> p9_poll_mux(), p9_poll_mux() will notice EPOLLIN and schedule_work(&m->rq). This no longer happens after the optimization above, change p9_fd_request() to use p9_poll_mux() instead of only checking for EPOLLOUT.

Severity ?

No CVSS data available.

Assigner

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/2e1461034aef99e90…
	https://git.kernel.org/stable/c/242531004d7de8c15…
	https://git.kernel.org/stable/c/e8fe3f07a357c39d4…

Impacted products

Vendor

Product

Version

Linux

Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 2e1461034aef99e905a1fe5589aaf00eaea73eee (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 242531004d7de8c159f9bfadebe33fe8060b1046 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < e8fe3f07a357c39d429e02ca34f740692d88967a (git)

Linux

Unaffected: 6.12.58 , ≤ 6.12.* (semver)
Unaffected: 6.17.8 , ≤ 6.17.* (semver)
Unaffected: 6.18 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/9p/trans_fd.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "2e1461034aef99e905a1fe5589aaf00eaea73eee",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "242531004d7de8c159f9bfadebe33fe8060b1046",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "e8fe3f07a357c39d429e02ca34f740692d88967a",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/9p/trans_fd.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.58",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.17.*",
              "status": "unaffected",
              "version": "6.17.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.18",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.58",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.17.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\n9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN\n\np9_read_work() doesn\u0027t set Rworksched and doesn\u0027t do schedule_work(m-\u003erq)\nif list_empty(\u0026m-\u003ereq_list).\n\nHowever, if the pipe is full, we need to read more data and this used to\nwork prior to commit aaec5a95d59615 (\"pipe_read: don\u0027t wake up the writer\nif the pipe is still full\").\n\np9_read_work() does p9_fd_read() -\u003e ... -\u003e anon_pipe_read() which (before\nthe commit above) triggered the unnecessary wakeup. This wakeup calls\np9_pollwake() which kicks p9_poll_workfn() -\u003e p9_poll_mux(), p9_poll_mux()\nwill notice EPOLLIN and schedule_work(\u0026m-\u003erq).\n\nThis no longer happens after the optimization above, change p9_fd_request()\nto use p9_poll_mux() instead of only checking for EPOLLOUT."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-12-08T00:46:30.327Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/2e1461034aef99e905a1fe5589aaf00eaea73eee"
        },
        {
          "url": "https://git.kernel.org/stable/c/242531004d7de8c159f9bfadebe33fe8060b1046"
        },
        {
          "url": "https://git.kernel.org/stable/c/e8fe3f07a357c39d429e02ca34f740692d88967a"
        }
      ],
      "title": "9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-40305",
    "datePublished": "2025-12-08T00:46:30.327Z",
    "dateReserved": "2025-04-16T07:20:57.185Z",
    "dateUpdated": "2025-12-08T00:46:30.327Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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-JR46-VC8C-PM2X

CVE-2025-40305 (GCVE-0-2025-40305)

Tags

Sightings

Nomenclature