net: ena: fix shift-out-of-bounds in exponential backoff

{
  "id": "f09b375ec1e6ce64e8baefedd8a3efd33a9378ea50e4f241267e80a69f9292f4",
  "url": "https://osv.dev/vulnerability/CVE-2023-53272",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "net: ena: fix shift-out-of-bounds in exponential backoff",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: net: ena: fix shift-out-of-bounds in exponential backoff The ENA adapters on our instances occasionally reset. Once recently logged a UBSAN failure to console in the process: UBSAN: shift-out-of-bounds in build/linux/drivers/net/ethernet/amazon/ena/ena_com.c:540:13 shift exponent 32 is too large for 32-bit type 'unsigned int' CPU: 28 PID: 70012 Comm: kworker/u72:2 Kdump: loaded not tainted 5.15.117 Hardware name: Amazon EC2 c5d.9xlarge/, BIOS 1.0 10/16/2017 Workqueue: ena ena_fw_reset_device [ena] Call Trace: dump_stack_lvl+0x4a/0x63 dump_stack+0x10/0x16 ubsan_epilogue+0x9/0x36 __ubsan_handle_shift_out_of_bounds.cold+0x61/0x10e ? __const_udelay+0x43/0x50 ena_delay_exponential_backoff_us.cold+0x16/0x1e [ena] wait_for_reset_state+0x54/0xa0 [ena] ena_com_dev_reset+0xc8/0x110 [ena] ena_down+0x3fe/0x480 [ena] ena_destroy_device+0xeb/0xf0 [ena] ena_fw_reset_device+0x30/0x50 [ena] process_one_work+0x22b/0x3d0 worker_thread+0x4d/0x3f0 ? process_one_work+0x3d0/0x3d0 kthread+0x12a/0x150 ? set_kthread_struct+0x50/0x50 ret_from_fork+0x22/0x30 Apparently, the reset delays are getting so large they can trigger a UBSAN panic. Looking at the code, the current timeout is capped at 5000us. Using a base value of 100us, the current code will overflow after (1<<29). Even at values before 32, this function wraps around, perhaps unintentionally. Cap the value of the exponent used for this backoff at (1<<16) which is larger than cur",
    "evidence": "osv:CVE-2023-53272",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
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            "value": "5.10.188",
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            "value": "5.15.121",
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        "affected_versions": []
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    "severity": "high",
    "structured": {
      "id": "CVE-2023-53272",
      "aliases": [
        "CVE-2023-53272"
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      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H"
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              "type": "ECOSYSTEM",
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                  "introduced": "5.8.0"
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          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
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      ],
      "modified": "2026-10-28T02:30:48.593853535Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/0939c264729d4a081ff88efce2ffdf85dc5331e0",
        "https://git.kernel.org/stable/c/1e760b2d18bf129b3da052c2946c02758e97d15e",
        "https://git.kernel.org/stable/c/1e9cb763e9bacf0c932aa948f50dcfca6f519a26",
        "https://git.kernel.org/stable/c/3e36cc94d6e60a27f27498adf1c71eeba769ab33",
        "https://git.kernel.org/stable/c/90947ebf8794e3c229fb2e16e37f1bfea6877f14",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/53xxx/CVE-2023-53272.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2023-53272",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/53xxx/CVE-2023-53272.json"
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        "value": "CVE-2023-53272",
        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
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  "source_id": "core-osv",
  "document_id": 516781,
  "published_at": "2025-09-16T08:07:01.589+00:00"
}