{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2023-53513",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2023-53513"
  ],
  "published": "2025-10-01T11:50:00Z",
  "summary": "nbd: fix incomplete validation of ioctl arg",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnbd: fix incomplete validation of ioctl arg\n\nWe tested and found an alarm caused by nbd_ioctl arg without verification.\nThe UBSAN warning calltrace like below:\n\nUBSAN: Undefined behaviour in fs/buffer.c:1709:35\nsigned integer overflow:\n-9223372036854775808 - 1 cannot be represented in type 'long long int'\nCPU: 3 PID: 2523 Comm: syz-executor.0 Not tainted 4.19.90 #1\nHardware name: linux,dummy-virt (DT)\nCall trace:\n dump_backtrace+0x0/0x3f0 arch/arm64/kernel/time.c:78\n show_stack+0x28/0x38 arch/arm64/kernel/traps.c:158\n __dump_stack lib/dump_stack.c:77 [inline]\n dump_stack+0x170/0x1dc lib/dump_stack.c:118\n ubsan_epilogue+0x18/0xb4 lib/ubsan.c:161\n handle_overflow+0x188/0x1dc lib/ubsan.c:192\n __ubsan_handle_sub_overflow+0x34/0x44 lib/ubsan.c:206\n __block_write_full_page+0x94c/0xa20 fs/buffer.c:1709\n block_write_full_page+0x1f0/0x280 fs/buffer.c:2934\n blkdev_writepage+0x34/0x40 fs/block_dev.c:607\n __writepage+0x68/0xe8 mm/page-writeback.c:2305\n write_cache_pages+0x44c/0xc70 mm/page-writeback.c:2240\n generic_writepages+0xdc/0x148 mm/page-writeback.c:2329\n blkdev_writepages+0x2c/0x38 fs/block_dev.c:2114\n do_writepages+0xd4/0x250 mm/page-writeback.c:2344\n\nThe reason for triggering this warning is __block_write_full_page()\n-> i_size_read(inode) - 1 overflow.\ninode->i_size is assigned in __nbd_ioctl() -> nbd_set_size() -> bytesize.\nWe think it is necessary to limit the size of arg to prevent errors.\n\nMoreover, __nbd_ioctl() -> nbd_add_socket(), arg will be cast to int.\nAssuming the value of arg is 0x80000000000000001) (on a 64-bit machine),\nit will become 1 after the coercion, which will return unexpected results.\n\nFix it by adding checks to prevent passing in too large numbers.",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.21-1+rpt1"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v6",
            "binary_version": "1:6.1.21-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v7",
            "binary_version": "1:6.1.21-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v7l",
            "binary_version": "1:6.1.21-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v8",
            "binary_version": "1:6.1.21-1+rpt1"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.21-1+rpt1": {
            "linux_commit": "0afb5e98488aed7017b9bf321b575d0177feb7ed",
            "upstream_version": "6.1.21",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.30"
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2023-53513"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/52851d0c3354b397c11d31dfeb8b2a2fc85a0002"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/fab766c8a1aff715bce7075aab40e780266f8e1a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ffb75ffaa68723276365d0f9d00b03362b750657"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/55793ea54d77719a071b1ccc05a05056e3b5e009"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-05-12T04:54:46Z"
  }
}