GHSA-G43C-R7C6-FHRV

Vulnerability from github – Published: 2024-07-16 12:30 – Updated: 2025-09-25 21:30
VLAI?
Details

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

NFSD: Fix the behavior of READ near OFFSET_MAX

Dan Aloni reports:

Due to commit 8cfb9015280d ("NFS: Always provide aligned buffers to the RPC read layers") on the client, a read of 0xfff is aligned up to server rsize of 0x1000.

As a result, in a test where the server has a file of size 0x7fffffffffffffff, and the client tries to read from the offset 0x7ffffffffffff000, the read causes loff_t overflow in the server and it returns an NFS code of EINVAL to the client. The client as a result indefinitely retries the request.

The Linux NFS client does not handle NFS?ERR_INVAL, even though all NFS specifications permit servers to return that status code for a READ.

Instead of NFS?ERR_INVAL, have out-of-range READ requests succeed and return a short result. Set the EOF flag in the result to prevent the client from retrying the READ request. This behavior appears to be consistent with Solaris NFS servers.

Note that NFSv3 and NFSv4 use u64 offset values on the wire. These must be converted to loff_t internally before use -- an implicit type cast is not adequate for this purpose. Otherwise VFS checks against sb->s_maxbytes do not work properly.

Severity ?
7.1 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2022-48827"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-125"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-07-16T12:15:06Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Fix the behavior of READ near OFFSET_MAX\n\nDan Aloni reports:\n\u003e Due to commit 8cfb9015280d (\"NFS: Always provide aligned buffers to\n\u003e the RPC read layers\") on the client, a read of 0xfff is aligned up\n\u003e to server rsize of 0x1000.\n\u003e\n\u003e As a result, in a test where the server has a file of size\n\u003e 0x7fffffffffffffff, and the client tries to read from the offset\n\u003e 0x7ffffffffffff000, the read causes loff_t overflow in the server\n\u003e and it returns an NFS code of EINVAL to the client. The client as\n\u003e a result indefinitely retries the request.\n\nThe Linux NFS client does not handle NFS?ERR_INVAL, even though all\nNFS specifications permit servers to return that status code for a\nREAD.\n\nInstead of NFS?ERR_INVAL, have out-of-range READ requests succeed\nand return a short result. Set the EOF flag in the result to prevent\nthe client from retrying the READ request. This behavior appears to\nbe consistent with Solaris NFS servers.\n\nNote that NFSv3 and NFSv4 use u64 offset values on the wire. These\nmust be converted to loff_t internally before use -- an implicit\ntype cast is not adequate for this purpose. Otherwise VFS checks\nagainst sb-\u003es_maxbytes do not work properly.",
  "id": "GHSA-g43c-r7c6-fhrv",
  "modified": "2025-09-25T21:30:18Z",
  "published": "2024-07-16T12:30:41Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-48827"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0cb4d23ae08c48f6bf3c29a8e5c4a74b8388b960"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1726a39b0879acfb490b22dca643f26f4f907da9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/44502aca8e02ab32d6b0eb52e006a5ec9402719b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c6eff5c4277146a78b4fb8c9b668dd64542c41b0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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