ghsa-c4mh-cv6m-6477
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
ALSA: core: Fix NULL module pointer assignment at card init
The commit 81033c6b584b ("ALSA: core: Warn on empty module") introduced a WARN_ON() for a NULL module pointer passed at snd_card object creation, and it also wraps the code around it with '#ifdef MODULE'. This works in most cases, but the devils are always in details. "MODULE" is defined when the target code (i.e. the sound core) is built as a module; but this doesn't mean that the caller is also built-in or not. Namely, when only the sound core is built-in (CONFIG_SND=y) while the driver is a module (CONFIG_SND_USB_AUDIO=m), the passed module pointer is ignored even if it's non-NULL, and card->module remains as NULL. This would result in the missing module reference up/down at the device open/close, leading to a race with the code execution after the module removal.
For addressing the bug, move the assignment of card->module again out of ifdef. The WARN_ON() is still wrapped with ifdef because the module can be really NULL when all sound drivers are built-in.
Note that we keep 'ifdef MODULE' for WARN_ON(), otherwise it would lead to a false-positive NULL module check. Admittedly it won't catch perfectly, i.e. no check is performed when CONFIG_SND=y. But, it's no real problem as it's only for debugging, and the condition is pretty rare.
{
"affected": [],
"aliases": [
"CVE-2024-38605"
],
"database_specific": {
"cwe_ids": [
"CWE-476"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-06-19T14:15:20Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: core: Fix NULL module pointer assignment at card init\n\nThe commit 81033c6b584b (\"ALSA: core: Warn on empty module\")\nintroduced a WARN_ON() for a NULL module pointer passed at snd_card\nobject creation, and it also wraps the code around it with \u0027#ifdef\nMODULE\u0027. This works in most cases, but the devils are always in\ndetails. \"MODULE\" is defined when the target code (i.e. the sound\ncore) is built as a module; but this doesn\u0027t mean that the caller is\nalso built-in or not. Namely, when only the sound core is built-in\n(CONFIG_SND=y) while the driver is a module (CONFIG_SND_USB_AUDIO=m),\nthe passed module pointer is ignored even if it\u0027s non-NULL, and\ncard-\u003emodule remains as NULL. This would result in the missing module\nreference up/down at the device open/close, leading to a race with the\ncode execution after the module removal.\n\nFor addressing the bug, move the assignment of card-\u003emodule again out\nof ifdef. The WARN_ON() is still wrapped with ifdef because the\nmodule can be really NULL when all sound drivers are built-in.\n\nNote that we keep \u0027ifdef MODULE\u0027 for WARN_ON(), otherwise it would\nlead to a false-positive NULL module check. Admittedly it won\u0027t catch\nperfectly, i.e. no check is performed when CONFIG_SND=y. But, it\u0027s no\nreal problem as it\u0027s only for debugging, and the condition is pretty\nrare.",
"id": "GHSA-c4mh-cv6m-6477",
"modified": "2024-07-03T18:45:57Z",
"published": "2024-06-19T15:30:54Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-38605"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/39381fe7394e5eafac76e7e9367e7351138a29c1"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6b8374ee2cabcf034faa34e69a855dc496a9ec12"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c935e72139e6d523defd60fe875c01eb1f9ea5c5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d7ff29a429b56f04783152ad7bbd7233b740e434"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e007476725730c1a68387b54b7629486d8a8301e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e644036a3e2b2c9b3eee3c61b5d31c2ca8b5ba92"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e7e0ca200772bdb2fdc6d43d32d341e87a36f811"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}