CVE-2022-48809 net: fix a memleak when uncloning an skb dst and its metadata

2024-07-1611:43:59

Linux

www.cve.org

linux kernel

vulnerability

memleak

EPSS

Percentile

5.0%

JSON

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

net: fix a memleak when uncloning an skb dst and its metadata

When uncloning an skb dst and its associated metadata, a new
dst+metadata is allocated and later replaces the old one in the skb.
This is helpful to have a non-shared dst+metadata attached to a specific
skb.

The issue is the uncloned dst+metadata is initialized with a refcount of
1, which is increased to 2 before attaching it to the skb. When
tun_dst_unclone returns, the dst+metadata is only referenced from a
single place (the skb) while its refcount is 2. Its refcount will never
drop to 0 (when the skb is consumed), leading to a memory leak.

Fix this by removing the call to dst_hold in tun_dst_unclone, as the
dst+metadata refcount is already 1.

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "include/net/dst_metadata.h"
    ],
    "versions": [
      {
        "version": "fc4099f17240",
        "lessThan": "4ac84498fbe8",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "fc4099f17240",
        "lessThan": "c1ff27d100e2",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "fc4099f17240",
        "lessThan": "0be943916d78",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "fc4099f17240",
        "lessThan": "a80817adc2a4",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "fc4099f17240",
        "lessThan": "00e6d6c3bc14",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "fc4099f17240",
        "lessThan": "fdcb263fa5cd",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "fc4099f17240",
        "lessThan": "8b1087b998e2",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "fc4099f17240",
        "lessThan": "9eeabdf17fa0",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "include/net/dst_metadata.h"
    ],
    "versions": [
      {
        "version": "4.3",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "4.3",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.9.302",
        "lessThanOrEqual": "4.9.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.14.267",
        "lessThanOrEqual": "4.14.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.19.230",
        "lessThanOrEqual": "4.19.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.4.180",
        "lessThanOrEqual": "5.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.101",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.15.24",
        "lessThanOrEqual": "5.15.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.16.10",
        "lessThanOrEqual": "5.16.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.17",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]