CVE-2021-47483 regmap: Fix possible double-free in regcache_rbtree_exit()

2024-05-2208:19:34

Linux

www.cve.org

regmap

vulnerability

resolved

regcache_rbtree_insert_to_block

realloc

error handling

kasan

double-free

regcache_init

regmap_init

devm_regmap_init

madera_spi_probe

spi_probe

data structure

6.4 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

13.1%

JSON

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

regmap: Fix possible double-free in regcache_rbtree_exit()

In regcache_rbtree_insert_to_block(), when ‘present’ realloc failed,
the ‘blk’ which is supposed to assign to ‘rbnode->block’ will be freed,
so ‘rbnode->block’ points a freed memory, in the error handling path of
regcache_rbtree_init(), ‘rbnode->block’ will be freed again in
regcache_rbtree_exit(), KASAN will report double-free as follows:

BUG: KASAN: double-free or invalid-free in kfree+0xce/0x390
Call Trace:
slab_free_freelist_hook+0x10d/0x240
kfree+0xce/0x390
regcache_rbtree_exit+0x15d/0x1a0
regcache_rbtree_init+0x224/0x2c0
regcache_init+0x88d/0x1310
__regmap_init+0x3151/0x4a80
__devm_regmap_init+0x7d/0x100
madera_spi_probe+0x10f/0x333 [madera_spi]
spi_probe+0x183/0x210
really_probe+0x285/0xc30

To fix this, moving up the assignment of rbnode->block to immediately after
the reallocation has succeeded so that the data structure stays valid even
if the second reallocation fails.

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "drivers/base/regmap/regcache-rbtree.c"
    ],
    "versions": [
      {
        "version": "3f4ff561bc88",
        "lessThan": "e72dce9afbdb",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "3f4ff561bc88",
        "lessThan": "fc081477b47d",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "3f4ff561bc88",
        "lessThan": "758ced2c3878",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "3f4ff561bc88",
        "lessThan": "3dae1a4eced3",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "3f4ff561bc88",
        "lessThan": "1cead23c1c0b",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "3f4ff561bc88",
        "lessThan": "36e911a16b37",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "3f4ff561bc88",
        "lessThan": "50cc1462a668",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "3f4ff561bc88",
        "lessThan": "55e6d8037805",
        "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/base/regmap/regcache-rbtree.c"
    ],
    "versions": [
      {
        "version": "3.12",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "3.12",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.4.291",
        "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"
      }
    ]
  }
]