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erofs: handle overlapped pclusters out of crafted images properly

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: erofs: handle overlapped pclusters out of crafted images properly syzbot reported a task hang issue due to a deadlock case where it is waiting for the folio lock of a cached folio that will be used for cache I/Os. After looking into the crafted fuzzed image, I found it's formed with several overlapped big pclusters as below: Ext: logical offset | length : physical offset | length 0: 0.. 16384 | 16384 : 151552.. 167936 | 16384 1: 16384.. 32768 | 16384 : 155648.. 172032 | 16384 2: 32768.. 49152 | 16384 : 537223168.. 537239552 | 16384 ... Here, extent 0/1 are physically overlapped although it's entirely _impossible_ for normal filesystem images generated by mkfs. First, managed folios containing compressed data will be marked as up-to-date and then unlocked immediately (unlike in-place folios) when compressed I/Os are complete. If physical blocks are not submitted in the incremental order, there should be separate BIOs to avoid dependency issues. However, the current code mis-arranges z_erofs_fill_bio_vec() and BIO submission which causes unexpected BIO waits. Second, managed folios will be connected to their own pclusters for efficient inter-queries. However, this is somewhat hard to implement easily if overlapped big pclusters exist. Again, these only appear in fuzzed images so let's simply fall back to temporary short-lived pages for correctness. Additionally, it justifies that referenced managed folios canno

Announced Source revision 1
Original source ↗

CVE-2024-47736

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2024-47736

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
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Prerequisites
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Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "8e6c8fa9f2e95c88a642521a5da19a8e31748846",
        "lessThan": "c1172e65aad4b115392ea4c6e61e56e5b9b69df4",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "8e6c8fa9f2e95c88a642521a5da19a8e31748846",
        "lessThan": "1bf7e414cac303c9aec1be67872e19be8b64980c",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "8e6c8fa9f2e95c88a642521a5da19a8e31748846",
        "lessThan": "b9b30af0e86ffb485301ecd83b9129c9dfb7ebf8",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "8e6c8fa9f2e95c88a642521a5da19a8e31748846",
        "lessThan": "9cfa199bcbbbba31cbf97b2786f44f4464f3f29a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "8e6c8fa9f2e95c88a642521a5da19a8e31748846",
        "lessThan": "9e2f9d34dd12e6e5b244ec488bcebd0c2d566c50",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "fs/erofs/zdata.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.13"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.13",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.1.168",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.72",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.10.13",
        "versionType": "semver",
        "lessThanOrEqual": "6.10.*"
      },
      {
        "status": "unaffected",
        "version": "6.11.2",
        "versionType": "semver",
        "lessThanOrEqual": "6.11.*"
      },
      {
        "status": "unaffected",
        "version": "6.12",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "fs/erofs/zdata.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2024-47736

Source reference: /cveMetadata/cveId

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No explicit severity was provided.

Event
#26740 · Revision 1
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