CVE-2023-52699 sysv: don't call sb_bread() with pointers_lock held

2024-05-1910:10:30

Linux

www.cve.org

linux kernel

sysv

vulnerability

fixed

sysvfs

filesystem

deadlock

sb_bread()

pointers_lock

6.4 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

13.0%

JSON

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

sysv: don’t call sb_bread() with pointers_lock held

syzbot is reporting sleep in atomic context in SysV filesystem [1], for
sb_bread() is called with rw_spinlock held.

A “write_lock(&pointers_lock) => read_lock(&pointers_lock) deadlock” bug
and a “sb_bread() with write_lock(&pointers_lock)” bug were introduced by
“Replace BKL for chain locking with sysvfs-private rwlock” in Linux 2.5.12.

Then, “[PATCH] err1-40: sysvfs locking fix” in Linux 2.6.8 fixed the
former bug by moving pointers_lock lock to the callers, but instead
introduced a “sb_bread() with read_lock(&pointers_lock)” bug (which made
this problem easier to hit).

Al Viro suggested that why not to do like get_branch()/get_block()/
find_shared() in Minix filesystem does. And doing like that is almost a
revert of “[PATCH] err1-40: sysvfs locking fix” except that get_branch()
from with find_shared() is called without write_lock(&pointers_lock).

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "fs/sysv/itree.c"
    ],
    "versions": [
      {
        "version": "1da177e4c3f4",
        "lessThan": "13b33feb2ebd",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "1b4fe801b5be",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "674c1c4229e7",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "fd203d2c671b",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "53cb1e52c9db",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "89e8524135a3",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "a69224223746",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "f123dc86388c",
        "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/sysv/itree.c"
    ],
    "versions": [
      {
        "version": "4.19.312",
        "lessThanOrEqual": "4.19.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.4.274",
        "lessThanOrEqual": "5.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.215",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.15.155",
        "lessThanOrEqual": "5.15.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.1.86",
        "lessThanOrEqual": "6.1.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.6.27",
        "lessThanOrEqual": "6.6.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.8.6",
        "lessThanOrEqual": "6.8.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.9",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]