CVE-2024-42315 exfat: fix potential deadlock on __exfat_get_dentry_set

2024-08-1709:09:23

Linux

www.cve.org

linux kernel

vulnerability

exfat

potential deadlock

fix

gfp_nofs

bh-array

EPSS

Percentile

5.0%

JSON

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

exfat: fix potential deadlock on __exfat_get_dentry_set

When accessing a file with more entries than ES_MAX_ENTRY_NUM, the bh-array
is allocated in __exfat_get_entry_set. The problem is that the bh-array is
allocated with GFP_KERNEL. It does not make sense. In the following cases,
a deadlock for sbi->s_lock between the two processes may occur.

   CPU0                CPU1
   ----                ----

kswapd
balance_pgdat
lock(fs_reclaim)
exfat_iterate
lock(&sbi->s_lock)
exfat_readdir
exfat_get_uniname_from_ext_entry
exfat_get_dentry_set
__exfat_get_dentry_set
kmalloc_array
…
lock(fs_reclaim)
…
evict
exfat_evict_inode
lock(&sbi->s_lock)

To fix this, let’s allocate bh-array with GFP_NOFS.

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "fs/exfat/dir.c"
    ],
    "versions": [
      {
        "version": "a3ff29a95fde",
        "lessThan": "a7ac198f8dba",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "a3ff29a95fde",
        "lessThan": "1d1970493c28",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "a3ff29a95fde",
        "lessThan": "89fc548767a2",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "fs/exfat/dir.c"
    ],
    "versions": [
      {
        "version": "6.2",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "6.2",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.6.44",
        "lessThanOrEqual": "6.6.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.10.3",
        "lessThanOrEqual": "6.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.11",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]