GHSA-9PG7-C56M-XQJX

Vulnerability from github – Published: 2024-12-27 15:31 – Updated: 2025-11-03 21:31
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

wifi: brcmfmac: Fix oops due to NULL pointer dereference in brcmf_sdiod_sglist_rw()

This patch fixes a NULL pointer dereference bug in brcmfmac that occurs when a high 'sd_sgentry_align' value applies (e.g. 512) and a lot of queued SKBs are sent from the pkt queue.

The problem is the number of entries in the pre-allocated sgtable, it is nents = max(rxglom_size, txglom_size) + max(rxglom_size, txglom_size) >> 4 + 1. Given the default [rt]xglom_size=32 it's actually 35 which is too small. Worst case, the pkt queue can end up with 64 SKBs. This occurs when a new SKB is added for each original SKB if tailroom isn't enough to hold tail_pad. At least one sg entry is needed for each SKB. So, eventually the "skb_queue_walk loop" in brcmf_sdiod_sglist_rw may run out of sg entries. This makes sg_next return NULL and this causes the oops.

The patch sets nents to max(rxglom_size, txglom_size) * 2 to be able handle the worst-case. Btw. this requires only 64-35=29 * 16 (or 20 if CONFIG_NEED_SG_DMA_LENGTH) = 464 additional bytes of memory.

Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2024-56593"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-476"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-12-27T15:15:18Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: brcmfmac: Fix oops due to NULL pointer dereference in brcmf_sdiod_sglist_rw()\n\nThis patch fixes a NULL pointer dereference bug in brcmfmac that occurs\nwhen a high \u0027sd_sgentry_align\u0027 value applies (e.g. 512) and a lot of queued SKBs\nare sent from the pkt queue.\n\nThe problem is the number of entries in the pre-allocated sgtable, it is\nnents = max(rxglom_size, txglom_size) + max(rxglom_size, txglom_size) \u003e\u003e 4 + 1.\nGiven the default [rt]xglom_size=32 it\u0027s actually 35 which is too small.\nWorst case, the pkt queue can end up with 64 SKBs. This occurs when a new SKB\nis added for each original SKB if tailroom isn\u0027t enough to hold tail_pad.\nAt least one sg entry is needed for each SKB. So, eventually the \"skb_queue_walk loop\"\nin brcmf_sdiod_sglist_rw may run out of sg entries. This makes sg_next return\nNULL and this causes the oops.\n\nThe patch sets nents to max(rxglom_size, txglom_size) * 2 to be able handle\nthe worst-case.\nBtw. this requires only 64-35=29 * 16 (or 20 if CONFIG_NEED_SG_DMA_LENGTH) = 464\nadditional bytes of memory.",
  "id": "GHSA-9pg7-c56m-xqjx",
  "modified": "2025-11-03T21:31:53Z",
  "published": "2024-12-27T15:31:54Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-56593"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/07c020c6d14d29e5a3ea4e4576b8ecf956a80834"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/342f87d263462c2670b77ea9a32074cab2ac6fa1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/34941321b516bd7c6103bd01287d71a1804d19d3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/67a25ea28f8ec1da8894f2f115d01d3becf67dc7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7522d7d745d13fbeff3350fe6aa56c8dae263571"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/857282b819cbaa0675aaab1e7542e2c0579f52d7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dfb3f9d3f602602de208da7bdcc0f6d5ee74af68"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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