CVE-2022-49834 (GCVE-0-2022-49834)

Vulnerability from cvelistv5 – Published: 2025-05-01 14:09 – Updated: 2025-12-23 13:26
VLAI?
Title
nilfs2: fix use-after-free bug of ns_writer on remount
Summary
In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix use-after-free bug of ns_writer on remount If a nilfs2 filesystem is downgraded to read-only due to metadata corruption on disk and is remounted read/write, or if emergency read-only remount is performed, detaching a log writer and synchronizing the filesystem can be done at the same time. In these cases, use-after-free of the log writer (hereinafter nilfs->ns_writer) can happen as shown in the scenario below: Task1 Task2 -------------------------------- ------------------------------ nilfs_construct_segment nilfs_segctor_sync init_wait init_waitqueue_entry add_wait_queue schedule nilfs_remount (R/W remount case) nilfs_attach_log_writer nilfs_detach_log_writer nilfs_segctor_destroy kfree finish_wait _raw_spin_lock_irqsave __raw_spin_lock_irqsave do_raw_spin_lock debug_spin_lock_before <-- use-after-free While Task1 is sleeping, nilfs->ns_writer is freed by Task2. After Task1 waked up, Task1 accesses nilfs->ns_writer which is already freed. This scenario diagram is based on the Shigeru Yoshida's post [1]. This patch fixes the issue by not detaching nilfs->ns_writer on remount so that this UAF race doesn't happen. Along with this change, this patch also inserts a few necessary read-only checks with superblock instance where only the ns_writer pointer was used to check if the filesystem is read-only.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: fe5f171bb272946ce5fbf843ce2f8467d0d41b9a , < b2fbf10040216ef5ee270773755fc2f5da65b749 (git)
Affected: fe5f171bb272946ce5fbf843ce2f8467d0d41b9a , < 39a3ed68270b079c6b874d4e4727a512b9b4882c (git)
Affected: fe5f171bb272946ce5fbf843ce2f8467d0d41b9a , < b4736ab5542112fe0a40f140a0a0b072954f34da (git)
Affected: fe5f171bb272946ce5fbf843ce2f8467d0d41b9a , < 9b162e81045266a2d5b44df9dffdf05c54de9cca (git)
Affected: fe5f171bb272946ce5fbf843ce2f8467d0d41b9a , < 4feedde5486c07ea79787839153a71ca71329c7d (git)
Affected: fe5f171bb272946ce5fbf843ce2f8467d0d41b9a , < afbd1188382a75f6cfe22c0b68533f7f9664f182 (git)
Affected: fe5f171bb272946ce5fbf843ce2f8467d0d41b9a , < b152300d5a1ba4258dacf9916bff20e6a8c7603b (git)
Affected: fe5f171bb272946ce5fbf843ce2f8467d0d41b9a , < 8cccf05fe857a18ee26e20d11a8455a73ffd4efd (git)
Create a notification for this product.
    Linux Linux Affected: 2.6.34
Unaffected: 0 , < 2.6.34 (semver)
Unaffected: 4.9.334 , ≤ 4.9.* (semver)
Unaffected: 4.14.300 , ≤ 4.14.* (semver)
Unaffected: 4.19.267 , ≤ 4.19.* (semver)
Unaffected: 5.4.225 , ≤ 5.4.* (semver)
Unaffected: 5.10.155 , ≤ 5.10.* (semver)
Unaffected: 5.15.79 , ≤ 5.15.* (semver)
Unaffected: 6.0.9 , ≤ 6.0.* (semver)
Unaffected: 6.1 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nilfs2/segment.c",
            "fs/nilfs2/super.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "b2fbf10040216ef5ee270773755fc2f5da65b749",
              "status": "affected",
              "version": "fe5f171bb272946ce5fbf843ce2f8467d0d41b9a",
              "versionType": "git"
            },
            {
              "lessThan": "39a3ed68270b079c6b874d4e4727a512b9b4882c",
              "status": "affected",
              "version": "fe5f171bb272946ce5fbf843ce2f8467d0d41b9a",
              "versionType": "git"
            },
            {
              "lessThan": "b4736ab5542112fe0a40f140a0a0b072954f34da",
              "status": "affected",
              "version": "fe5f171bb272946ce5fbf843ce2f8467d0d41b9a",
              "versionType": "git"
            },
            {
              "lessThan": "9b162e81045266a2d5b44df9dffdf05c54de9cca",
              "status": "affected",
              "version": "fe5f171bb272946ce5fbf843ce2f8467d0d41b9a",
              "versionType": "git"
            },
            {
              "lessThan": "4feedde5486c07ea79787839153a71ca71329c7d",
              "status": "affected",
              "version": "fe5f171bb272946ce5fbf843ce2f8467d0d41b9a",
              "versionType": "git"
            },
            {
              "lessThan": "afbd1188382a75f6cfe22c0b68533f7f9664f182",
              "status": "affected",
              "version": "fe5f171bb272946ce5fbf843ce2f8467d0d41b9a",
              "versionType": "git"
            },
            {
              "lessThan": "b152300d5a1ba4258dacf9916bff20e6a8c7603b",
              "status": "affected",
              "version": "fe5f171bb272946ce5fbf843ce2f8467d0d41b9a",
              "versionType": "git"
            },
            {
              "lessThan": "8cccf05fe857a18ee26e20d11a8455a73ffd4efd",
              "status": "affected",
              "version": "fe5f171bb272946ce5fbf843ce2f8467d0d41b9a",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/nilfs2/segment.c",
            "fs/nilfs2/super.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.34"
            },
            {
              "lessThan": "2.6.34",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "4.9.*",
              "status": "unaffected",
              "version": "4.9.334",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "4.14.*",
              "status": "unaffected",
              "version": "4.14.300",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "4.19.*",
              "status": "unaffected",
              "version": "4.19.267",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.4.*",
              "status": "unaffected",
              "version": "5.4.225",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.155",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.79",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.0.*",
              "status": "unaffected",
              "version": "6.0.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "4.9.334",
                  "versionStartIncluding": "2.6.34",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "4.14.300",
                  "versionStartIncluding": "2.6.34",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "4.19.267",
                  "versionStartIncluding": "2.6.34",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.4.225",
                  "versionStartIncluding": "2.6.34",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.155",
                  "versionStartIncluding": "2.6.34",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.79",
                  "versionStartIncluding": "2.6.34",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.0.9",
                  "versionStartIncluding": "2.6.34",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1",
                  "versionStartIncluding": "2.6.34",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnilfs2: fix use-after-free bug of ns_writer on remount\n\nIf a nilfs2 filesystem is downgraded to read-only due to metadata\ncorruption on disk and is remounted read/write, or if emergency read-only\nremount is performed, detaching a log writer and synchronizing the\nfilesystem can be done at the same time.\n\nIn these cases, use-after-free of the log writer (hereinafter\nnilfs-\u003ens_writer) can happen as shown in the scenario below:\n\n Task1                               Task2\n --------------------------------    ------------------------------\n nilfs_construct_segment\n   nilfs_segctor_sync\n     init_wait\n     init_waitqueue_entry\n     add_wait_queue\n     schedule\n                                     nilfs_remount (R/W remount case)\n\t\t\t\t       nilfs_attach_log_writer\n                                         nilfs_detach_log_writer\n                                           nilfs_segctor_destroy\n                                             kfree\n     finish_wait\n       _raw_spin_lock_irqsave\n         __raw_spin_lock_irqsave\n           do_raw_spin_lock\n             debug_spin_lock_before  \u003c-- use-after-free\n\nWhile Task1 is sleeping, nilfs-\u003ens_writer is freed by Task2.  After Task1\nwaked up, Task1 accesses nilfs-\u003ens_writer which is already freed.  This\nscenario diagram is based on the Shigeru Yoshida\u0027s post [1].\n\nThis patch fixes the issue by not detaching nilfs-\u003ens_writer on remount so\nthat this UAF race doesn\u0027t happen.  Along with this change, this patch\nalso inserts a few necessary read-only checks with superblock instance\nwhere only the ns_writer pointer was used to check if the filesystem is\nread-only."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-12-23T13:26:00.337Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/b2fbf10040216ef5ee270773755fc2f5da65b749"
        },
        {
          "url": "https://git.kernel.org/stable/c/39a3ed68270b079c6b874d4e4727a512b9b4882c"
        },
        {
          "url": "https://git.kernel.org/stable/c/b4736ab5542112fe0a40f140a0a0b072954f34da"
        },
        {
          "url": "https://git.kernel.org/stable/c/9b162e81045266a2d5b44df9dffdf05c54de9cca"
        },
        {
          "url": "https://git.kernel.org/stable/c/4feedde5486c07ea79787839153a71ca71329c7d"
        },
        {
          "url": "https://git.kernel.org/stable/c/afbd1188382a75f6cfe22c0b68533f7f9664f182"
        },
        {
          "url": "https://git.kernel.org/stable/c/b152300d5a1ba4258dacf9916bff20e6a8c7603b"
        },
        {
          "url": "https://git.kernel.org/stable/c/8cccf05fe857a18ee26e20d11a8455a73ffd4efd"
        }
      ],
      "title": "nilfs2: fix use-after-free bug of ns_writer on remount",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2022-49834",
    "datePublished": "2025-05-01T14:09:52.076Z",
    "dateReserved": "2025-05-01T14:05:17.228Z",
    "dateUpdated": "2025-12-23T13:26:00.337Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.