CVE-2021-47068 net/nfc: fix use-after-free llcp_sock_bind/connect

2024-02-2922:37:41

Linux

github.com

linux kernel

nfc

use-after-free

6.7 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

13.1%

JSON

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

net/nfc: fix use-after-free llcp_sock_bind/connect

Commits 8a4cd82d (“nfc: fix refcount leak in llcp_sock_connect()”)
and c33b1cc62 (“nfc: fix refcount leak in llcp_sock_bind()”)
fixed a refcount leak bug in bind/connect but introduced a
use-after-free if the same local is assigned to 2 different sockets.

This can be triggered by the following simple program:
int sock1 = socket( AF_NFC, SOCK_STREAM, NFC_SOCKPROTO_LLCP );
int sock2 = socket( AF_NFC, SOCK_STREAM, NFC_SOCKPROTO_LLCP );
memset( &addr, 0, sizeof(struct sockaddr_nfc_llcp) );
addr.sa_family = AF_NFC;
addr.nfc_protocol = NFC_PROTO_NFC_DEP;
bind( sock1, (struct sockaddr*) &addr, sizeof(struct sockaddr_nfc_llcp) )
bind( sock2, (struct sockaddr*) &addr, sizeof(struct sockaddr_nfc_llcp) )
close(sock1);
close(sock2);

Fix this by assigning NULL to llcp_sock->local after calling
nfc_llcp_local_put.

This addresses CVE-2021-23134.

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "net/nfc/llcp_sock.c"
    ],
    "versions": [
      {
        "version": "a1cdd18c49d2",
        "lessThan": "26157c82ba75",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "18013007b596",
        "lessThan": "ccddad6dd285",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "538a6ff11516",
        "lessThan": "18ae4a192a44",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "adbb1d218c5f",
        "lessThan": "48fba458fe54",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "c89903c9eff2",
        "lessThan": "e32352070bca",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "6fb003e5ae18",
        "lessThan": "6b7021ed36da",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "8c9e4971e142",
        "lessThan": "374cdde4dcc9",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "c33b1cc62ac0",
        "lessThan": "18175fe17ae0",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "c33b1cc62ac0",
        "lessThan": "c61760e6940d",
        "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/nfc/llcp_sock.c"
    ],
    "versions": [
      {
        "version": "5.12",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "5.12",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.4.269",
        "lessThanOrEqual": "4.4.*",
        "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"
      }
    ]
  }
]