CVE-2021-47559 net/smc: Fix NULL pointer dereferencing in smc_vlan_by_tcpsk()

2024-05-2415:12:48

Linux

github.com

linux kernel

vulnerability

net/smc

null pointer

dereferencing

coverity

netdev_lower_get_next

dereference

is_vlan_dev

netdev_walk_all_lower_dev

AI Score

6.9

Confidence

Low

EPSS

Percentile

5.1%

SSVC

Exploitation

none

Automatable

Technical Impact

partial

JSON

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

net/smc: Fix NULL pointer dereferencing in smc_vlan_by_tcpsk()

Coverity reports a possible NULL dereferencing problem:

in smc_vlan_by_tcpsk():
6. returned_null: netdev_lower_get_next returns NULL (checked 29 out of 30 times).
7. var_assigned: Assigning: ndev = NULL return value from netdev_lower_get_next.
1623 ndev = (struct net_device *)netdev_lower_get_next(ndev, &lower);
CID 1468509 (#1 of 1): Dereference null return value (NULL_RETURNS)
8. dereference: Dereferencing a pointer that might be NULL ndev when calling is_vlan_dev.
1624 if (is_vlan_dev(ndev)) {

Remove the manual implementation and use netdev_walk_all_lower_dev() to
iterate over the lower devices. While on it remove an obsolete function
parameter comment.

CNA Affected

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "cb9d43f67754",
        "lessThan": "c94cbd262b6a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "cb9d43f67754",
        "lessThan": "bb851d0fb025",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "cb9d43f67754",
        "lessThan": "587acad41f1b",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/smc/smc_core.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "4.18"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "4.18",
        "versionType": "custom"
      },
      {
        "status": "unaffected",
        "version": "5.10.83",
        "versionType": "custom",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.6",
        "versionType": "custom",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "5.16",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/smc/smc_core.c"
    ],
    "defaultStatus": "affected"
  }
]