CVE-2021-47013 net:emac/emac-mac: Fix a use after free in emac_mac_tx_buf_send

2024-02-2808:13:30

Linux

www.cve.org

linux kernel

vulnerability

resolved

use after free

emac_mac_tx_buf_send

emac_tx_fill_tpd

7.8 High

AI Score

Confidence

High

0.0004 Low

EPSS

Percentile

13.1%

JSON

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

net:emac/emac-mac: Fix a use after free in emac_mac_tx_buf_send

In emac_mac_tx_buf_send, it calls emac_tx_fill_tpd(…,skb,…).
If some error happens in emac_tx_fill_tpd(), the skb will be freed via
dev_kfree_skb(skb) in error branch of emac_tx_fill_tpd().
But the freed skb is still used via skb->len by netdev_sent_queue(,skb->len).

As i observed that emac_tx_fill_tpd() haven’t modified the value of skb->len,
thus my patch assigns skb->len to ‘len’ before the possible free and
use ‘len’ instead of skb->len later.

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "drivers/net/ethernet/qualcomm/emac/emac-mac.c"
    ],
    "versions": [
      {
        "version": "b9b17debc69d",
        "lessThan": "c7f75d11fe72",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "b9b17debc69d",
        "lessThan": "dc1b438a3577",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "b9b17debc69d",
        "lessThan": "16d8c44be52e",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "b9b17debc69d",
        "lessThan": "55fcdd1258fa",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "b9b17debc69d",
        "lessThan": "9dc373f74097",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "b9b17debc69d",
        "lessThan": "8c06f3478506",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "b9b17debc69d",
        "lessThan": "e407495ba678",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "b9b17debc69d",
        "lessThan": "6d72e7c767ac",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "drivers/net/ethernet/qualcomm/emac/emac-mac.c"
    ],
    "versions": [
      {
        "version": "4.9",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "4.9",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.9.269",
        "lessThanOrEqual": "4.9.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.14.233",
        "lessThanOrEqual": "4.14.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.19.191",
        "lessThanOrEqual": "4.19.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.4.119",
        "lessThanOrEqual": "5.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.37",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.11.21",
        "lessThanOrEqual": "5.11.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.12.4",
        "lessThanOrEqual": "5.12.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.13",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]