Description

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.

Metrics

 

CVSS Version 4.0 CVSS Version 3.x CVSS Version 2.0

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.

CVSS 4.0 Severity and Vector Strings:

NIST: NVD

N/A

NVD assessment not yet provided.

CVSS 3.x Severity and Vector Strings:

NIST: NVD

Base Score:  N/A

NVD assessment not yet provided.

ADP:  CISA-ADP

Base Score:  8.8 HIGH

Vector:  CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS 2.0 Severity and Vector Strings:

NIST: NVD

Base Score: N/A

NVD assessment not yet provided.

CISA-ADP AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CISA-ADP CWE-476

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

kernel.org https://git.kernel.org/stable/c/39381fe7394e5eafac76e7e9367e7351138a29c1 [No types assigned]

kernel.org https://git.kernel.org/stable/c/6b8374ee2cabcf034faa34e69a855dc496a9ec12 [No types assigned]

kernel.org https://git.kernel.org/stable/c/c935e72139e6d523defd60fe875c01eb1f9ea5c5 [No types assigned]

kernel.org https://git.kernel.org/stable/c/d7ff29a429b56f04783152ad7bbd7233b740e434 [No types assigned]

kernel.org https://git.kernel.org/stable/c/e007476725730c1a68387b54b7629486d8a8301e [No types assigned]

kernel.org https://git.kernel.org/stable/c/e644036a3e2b2c9b3eee3c61b5d31c2ca8b5ba92 [No types assigned]

kernel.org https://git.kernel.org/stable/c/e7e0ca200772bdb2fdc6d43d32d341e87a36f811 [No types assigned]