CVE-2021-47293 net/sched: act_skbmod: Skip non-Ethernet packets

2024-05-2114:35:17

Linux

github.com

linux kernel

vulnerability

resolved

net/sched

act_skbmod

skip

non-ethernet

packets

tcf_skbmod_act()

l2 protocol

can devices

skbmod actions

7 High

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

15.6%

JSON

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

net/sched: act_skbmod: Skip non-Ethernet packets

Currently tcf_skbmod_act() assumes that packets use Ethernet as their L2
protocol, which is not always the case. As an example, for CAN devices:

$ ip link add dev vcan0 type vcan
$ ip link set up vcan0
$ tc qdisc add dev vcan0 root handle 1: htb
$ tc filter add dev vcan0 parent 1: protocol ip prio 10 \
	matchall action skbmod swap mac

Doing the above silently corrupts all the packets. Do not perform skbmod
actions for non-Ethernet packets.

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "net/sched/act_skbmod.c"
    ],
    "versions": [
      {
        "version": "86da71b57383",
        "lessThan": "e4fdca366806",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "86da71b57383",
        "lessThan": "a88414fb1117",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "86da71b57383",
        "lessThan": "071729150be9",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "86da71b57383",
        "lessThan": "34f1e1f657fa",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "86da71b57383",
        "lessThan": "727d6a8b7ef3",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "net/sched/act_skbmod.c"
    ],
    "versions": [
      {
        "version": "4.9",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "4.9",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.19.199",
        "lessThanOrEqual": "4.19.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.4.136",
        "lessThanOrEqual": "5.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.54",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.13.6",
        "lessThanOrEqual": "5.13.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.14",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]