CVE-2021-47482

2024-05-2209:15:10

416baaa9-dc9f-4396-8d5f-8c081fb06d67

web.nvd.nist.gov

linux kernel

vulnerability

error handling

batman-adv

memory allocation

performance improvement

bug fix

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: batman-adv: fix error handling

Syzbot reported ODEBUG warning in batadv_nc_mesh_free(). The problem was
in wrong error handling in batadv_mesh_init().

Before this patch batadv_mesh_init() was calling batadv_mesh_free() in case
of any batadv_*_init() calls failure. This approach may work well, when
there is some kind of indicator, which can tell which parts of batadv are
initialized; but there isn’t any.

All written above lead to cleaning up uninitialized fields. Even if we hide
ODEBUG warning by initializing bat_priv->nc.work, syzbot was able to hit
GPF in batadv_nc_purge_paths(), because hash pointer in still NULL. [1]

To fix these bugs we can unwind batadv_init() calls one by one.
It is good approach for 2 reasons: 1) It fixes bugs on error handling
path 2) It improves the performance, since we won’t call unneeded
batadv_free() functions.

So, this patch makes all batadv_init() clean up all allocated memory
before returning with an error to no call correspoing batadv_free()
and open-codes batadv_mesh_free() with proper order to avoid touching
uninitialized fields.

Affected configurations

Vulners

Node

linuxlinux_kernelRange2.6.38–4.4.293

linuxlinux_kernelRange4.5.0–4.9.289

linuxlinux_kernelRange4.10.0–4.14.254

linuxlinux_kernelRange4.15.0–4.19.215

linuxlinux_kernelRange4.20.0–5.4.157

linuxlinux_kernelRange5.5.0–5.10.77

linuxlinux_kernelRange5.11.0–5.14.16

linuxlinux_kernelRange5.15.0≥

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "net/batman-adv/bridge_loop_avoidance.c",
      "net/batman-adv/main.c",
      "net/batman-adv/network-coding.c",
      "net/batman-adv/translation-table.c"
    ],
    "versions": [
      {
        "version": "c6c8fea29769",
        "lessThan": "0c6b199f09be",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "c6c8fea29769",
        "lessThan": "07533f1a673c",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "c6c8fea29769",
        "lessThan": "e50f95765219",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "c6c8fea29769",
        "lessThan": "fbf150b16a36",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "c6c8fea29769",
        "lessThan": "6422e8471890",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "c6c8fea29769",
        "lessThan": "b0a2cd38553c",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "c6c8fea29769",
        "lessThan": "a8f7359259dd",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "c6c8fea29769",
        "lessThan": "6f68cd634856",
        "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/batman-adv/bridge_loop_avoidance.c",
      "net/batman-adv/main.c",
      "net/batman-adv/network-coding.c",
      "net/batman-adv/translation-table.c"
    ],
    "versions": [
      {
        "version": "2.6.38",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "2.6.38",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.4.293",
        "lessThanOrEqual": "4.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.9.289",
        "lessThanOrEqual": "4.9.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.14.254",
        "lessThanOrEqual": "4.14.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.19.215",
        "lessThanOrEqual": "4.19.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.4.157",
        "lessThanOrEqual": "5.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.77",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.14.16",
        "lessThanOrEqual": "5.14.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.15",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]