CVE-2025-68264 (GCVE-0-2025-68264)
Vulnerability from cvelistv5
Published
2025-12-16 14:45
Modified
2025-12-16 14:45
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: ext4: refresh inline data size before write operations The cached ei->i_inline_size can become stale between the initial size check and when ext4_update_inline_data()/ext4_create_inline_data() use it. Although ext4_get_max_inline_size() reads the correct value at the time of the check, concurrent xattr operations can modify i_inline_size before ext4_write_lock_xattr() is acquired. This causes ext4_update_inline_data() and ext4_create_inline_data() to work with stale capacity values, leading to a BUG_ON() crash in ext4_write_inline_data(): kernel BUG at fs/ext4/inline.c:1331! BUG_ON(pos + len > EXT4_I(inode)->i_inline_size); The race window: 1. ext4_get_max_inline_size() reads i_inline_size = 60 (correct) 2. Size check passes for 50-byte write 3. [Another thread adds xattr, i_inline_size changes to 40] 4. ext4_write_lock_xattr() acquires lock 5. ext4_update_inline_data() uses stale i_inline_size = 60 6. Attempts to write 50 bytes but only 40 bytes actually available 7. BUG_ON() triggers Fix this by recalculating i_inline_size via ext4_find_inline_data_nolock() immediately after acquiring xattr_sem. This ensures ext4_update_inline_data() and ext4_create_inline_data() work with current values that are protected from concurrent modifications. This is similar to commit a54c4613dac1 ("ext4: fix race writing to an inline_data file while its xattrs are changing") which fixed i_inline_off staleness. This patch addresses the related i_inline_size staleness issue.
References
Impacted products
Vendor Product Version
Linux Linux Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
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{
  "containers": {
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/ext4/inline.c"
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              "versionType": "original_commit_for_fix"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: refresh inline data size before write operations\n\nThe cached ei-\u003ei_inline_size can become stale between the initial size\ncheck and when ext4_update_inline_data()/ext4_create_inline_data() use\nit. Although ext4_get_max_inline_size() reads the correct value at the\ntime of the check, concurrent xattr operations can modify i_inline_size\nbefore ext4_write_lock_xattr() is acquired.\n\nThis causes ext4_update_inline_data() and ext4_create_inline_data() to\nwork with stale capacity values, leading to a BUG_ON() crash in\next4_write_inline_data():\n\n  kernel BUG at fs/ext4/inline.c:1331!\n  BUG_ON(pos + len \u003e EXT4_I(inode)-\u003ei_inline_size);\n\nThe race window:\n1. ext4_get_max_inline_size() reads i_inline_size = 60 (correct)\n2. Size check passes for 50-byte write\n3. [Another thread adds xattr, i_inline_size changes to 40]\n4. ext4_write_lock_xattr() acquires lock\n5. ext4_update_inline_data() uses stale i_inline_size = 60\n6. Attempts to write 50 bytes but only 40 bytes actually available\n7. BUG_ON() triggers\n\nFix this by recalculating i_inline_size via ext4_find_inline_data_nolock()\nimmediately after acquiring xattr_sem. This ensures ext4_update_inline_data()\nand ext4_create_inline_data() work with current values that are protected\nfrom concurrent modifications.\n\nThis is similar to commit a54c4613dac1 (\"ext4: fix race writing to an\ninline_data file while its xattrs are changing\") which fixed i_inline_off\nstaleness. This patch addresses the related i_inline_size staleness issue."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-12-16T14:45:06.268Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/210ac60a86a3ad2c76ae60e0dc71c34af6e7ea0b"
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          "url": "https://git.kernel.org/stable/c/ca43ea29b4c4d2764aec8a26cffcfb677a871e6e"
        },
        {
          "url": "https://git.kernel.org/stable/c/58df743faf21ceb1880f930aa5dd428e2a5e415d"
        },
        {
          "url": "https://git.kernel.org/stable/c/892e1cf17555735e9d021ab036c36bc7b58b0e3b"
        }
      ],
      "title": "ext4: refresh inline data size before write operations",
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-68264",
    "datePublished": "2025-12-16T14:45:06.268Z",
    "dateReserved": "2025-12-16T13:41:40.267Z",
    "dateUpdated": "2025-12-16T14:45:06.268Z",
    "state": "PUBLISHED"
  },
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    "nvd": "{\"cve\":{\"id\":\"CVE-2025-68264\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-12-16T15:15:55.920\",\"lastModified\":\"2025-12-18T15:08:06.237\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\next4: refresh inline data size before write operations\\n\\nThe cached ei-\u003ei_inline_size can become stale between the initial size\\ncheck and when ext4_update_inline_data()/ext4_create_inline_data() use\\nit. Although ext4_get_max_inline_size() reads the correct value at the\\ntime of the check, concurrent xattr operations can modify i_inline_size\\nbefore ext4_write_lock_xattr() is acquired.\\n\\nThis causes ext4_update_inline_data() and ext4_create_inline_data() to\\nwork with stale capacity values, leading to a BUG_ON() crash in\\next4_write_inline_data():\\n\\n  kernel BUG at fs/ext4/inline.c:1331!\\n  BUG_ON(pos + len \u003e EXT4_I(inode)-\u003ei_inline_size);\\n\\nThe race window:\\n1. ext4_get_max_inline_size() reads i_inline_size = 60 (correct)\\n2. Size check passes for 50-byte write\\n3. [Another thread adds xattr, i_inline_size changes to 40]\\n4. ext4_write_lock_xattr() acquires lock\\n5. ext4_update_inline_data() uses stale i_inline_size = 60\\n6. Attempts to write 50 bytes but only 40 bytes actually available\\n7. BUG_ON() triggers\\n\\nFix this by recalculating i_inline_size via ext4_find_inline_data_nolock()\\nimmediately after acquiring xattr_sem. This ensures ext4_update_inline_data()\\nand ext4_create_inline_data() work with current values that are protected\\nfrom concurrent modifications.\\n\\nThis is similar to commit a54c4613dac1 (\\\"ext4: fix race writing to an\\ninline_data file while its xattrs are changing\\\") which fixed i_inline_off\\nstaleness. This patch addresses the related i_inline_size staleness issue.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/210ac60a86a3ad2c76ae60e0dc71c34af6e7ea0b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/58df743faf21ceb1880f930aa5dd428e2a5e415d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/892e1cf17555735e9d021ab036c36bc7b58b0e3b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ca43ea29b4c4d2764aec8a26cffcfb677a871e6e\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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