CVE-2021-46952 NFS: fs_context: validate UDP retrans to prevent shift out-of-bounds

2024-02-2718:40:35

Linux

github.com

linux kernel

nfs

vulnerability

AI Score

6.7

Confidence

Low

SSVC

Exploitation

none

Automatable

Technical Impact

partial

JSON

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

NFS: fs_context: validate UDP retrans to prevent shift out-of-bounds

Fix shift out-of-bounds in xprt_calc_majortimeo(). This is caused
by a garbage timeout (retrans) mount option being passed to nfs mount,
in this case from syzkaller.

If the protocol is XPRT_TRANSPORT_UDP, then ‘retrans’ is a shift
value for a 64-bit long integer, so ‘retrans’ cannot be >= 64.
If it is >= 64, fail the mount and return an error.

CNA Affected

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "9954bf92c0cd",
        "lessThan": "96fa26b74cdc",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9954bf92c0cd",
        "lessThan": "2f3380121d49",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9954bf92c0cd",
        "lessThan": "3d0163821c03",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9954bf92c0cd",
        "lessThan": "c09f11ef3595",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "fs/nfs/fs_context.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.6"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.6",
        "versionType": "custom"
      },
      {
        "status": "unaffected",
        "version": "5.10.36",
        "versionType": "custom",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.11.20",
        "versionType": "custom",
        "lessThanOrEqual": "5.11.*"
      },
      {
        "status": "unaffected",
        "version": "5.12.3",
        "versionType": "custom",
        "lessThanOrEqual": "5.12.*"
      },
      {
        "status": "unaffected",
        "version": "5.13",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "fs/nfs/fs_context.c"
    ],
    "defaultStatus": "affected"
  }
]