GHSA-54QC-M2PH-JW4R

Vulnerability from github – Published: 2024-12-28 12:30 – Updated: 2025-09-26 21:30
VLAI?
Details

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

ASoC: mediatek: Check num_codecs is not zero to avoid panic during probe

Following commit 13f58267cda3 ("ASoC: soc.h: don't create dummy Component via COMP_DUMMY()"), COMP_DUMMY() became an array with zero length, and only gets populated with the dummy struct after the card is registered. Since the sound card driver's probe happens before the card registration, accessing any of the members of a dummy component during probe will result in undefined behavior.

This can be observed in the mt8188 and mt8195 machine sound drivers. By omitting a dai link subnode in the sound card's node in the Devicetree, the default uninitialized dummy codec is used, and when its dai_name pointer gets passed to strcmp() it results in a null pointer dereference and a kernel panic.

In addition to that, set_card_codec_info() in the generic helpers file, mtk-soundcard-driver.c, will populate a dai link with a dummy codec when a dai link node is present in DT but with no codec property.

The result is that at probe time, a dummy codec can either be uninitialized with num_codecs = 0, or be an initialized dummy codec, with num_codecs = 1 and dai_name = "snd-soc-dummy-dai". In order to accommodate for both situations, check that num_codecs is not zero before accessing the codecs' fields but still check for the codec's dai name against "snd-soc-dummy-dai" as needed.

While at it, also drop the check that dai_name is not null in the mt8192 driver, introduced in commit 4d4e1b6319e5 ("ASoC: mediatek: mt8192: Check existence of dai_name before dereferencing"), as it is actually redundant given the preceding num_codecs != 0 check.

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-2024-56685"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-908"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-12-28T10:15:11Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nASoC: mediatek: Check num_codecs is not zero to avoid panic during probe\n\nFollowing commit 13f58267cda3 (\"ASoC: soc.h: don\u0027t create dummy\nComponent via COMP_DUMMY()\"), COMP_DUMMY() became an array with zero\nlength, and only gets populated with the dummy struct after the card is\nregistered. Since the sound card driver\u0027s probe happens before the card\nregistration, accessing any of the members of a dummy component during\nprobe will result in undefined behavior.\n\nThis can be observed in the mt8188 and mt8195 machine sound drivers. By\nomitting a dai link subnode in the sound card\u0027s node in the Devicetree,\nthe default uninitialized dummy codec is used, and when its dai_name\npointer gets passed to strcmp() it results in a null pointer dereference\nand a kernel panic.\n\nIn addition to that, set_card_codec_info() in the generic helpers file,\nmtk-soundcard-driver.c, will populate a dai link with a dummy codec when\na dai link node is present in DT but with no codec property.\n\nThe result is that at probe time, a dummy codec can either be\nuninitialized with num_codecs = 0, or be an initialized dummy codec,\nwith num_codecs = 1 and dai_name = \"snd-soc-dummy-dai\". In order to\naccommodate for both situations, check that num_codecs is not zero\nbefore accessing the codecs\u0027 fields but still check for the codec\u0027s dai\nname against \"snd-soc-dummy-dai\" as needed.\n\nWhile at it, also drop the check that dai_name is not null in the mt8192\ndriver, introduced in commit 4d4e1b6319e5 (\"ASoC: mediatek: mt8192:\nCheck existence of dai_name before dereferencing\"), as it is actually\nredundant given the preceding num_codecs != 0 check.",
  "id": "GHSA-54qc-m2ph-jw4r",
  "modified": "2025-09-26T21:30:26Z",
  "published": "2024-12-28T12:30:47Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-56685"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2f2020327cc8561d7c520d2f2d9acea84fa7b3a3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/376f4800f34a28def026ff5c5d4fc5e54e1744ff"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/550279449ff54c5aa28cfca5c567308cbfb145f0"
    }
  ],
  "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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